Hello all!

I have a large 10 x 54 vertical milling machine, Grizzly Model # G9905 that I would like to convert over to CNC. I bought it new last year, and installed a Newall C80 3-axis (X, Y and knee for Z) DRO. My goals:

Convert X and Y axis lead screws to precision rolled ball screws.

Install servos on X, Y, knee & quill. I want to be able to use the knee as the Z axis for contour milling and increased travel capability (vs. quill), and also use the quill for things like peck drilling, threading, etc.

Use a small rotary table as a fourth (A?) axis.

Use a Gecko G320 / breakout board combo ( or Gecko G100 ?????) to interface the PC to the mill.

Use a 19" touch screen lcd, mounted on an arm off of the mill, for control.

Use Mach 3/Quantum to control mill.

Use a VFD to interface Mach 3 with the motor for spindle speed control.

Interface things like flood coolant, mist, air etc. with Mach 3.

Install a tooling indexer, to be able to quickly set the Z depth of mills, drills, taps, etc.

Use a high speed air motor installed in R8 collet to use as a CNC jig grinder.

Use a spindle mounted electric router motor for routing / carving wood.

I am a Tooling Engineer by trade, with a tool & die maker background.
I work for a large metal stamping company, specializing in proggressive and transfer tooling for the automotive industry. I am also an expert Unigraphics and AutoCAD user.

I know that I'll need plenty of help with the electronics portion of this project from some of the CNCzone members. I have a good understanding of basic electronics and computers(see www.ultramame.com (http://www.ultramame.com/)) but alot of this (electrical control) stuff is very foreign to me.

If all goes well, I also have a Grizzly 16 x 40 lathe (Model #G0509) I would also like to convert to CNC. Then ultimately I would like to build a 4' x 8' plasma cutter / router cutter table with 5-axis capability.

Have a great day! :banana:

My first dilema with the conversion seems to be locating a precision ball screw assembly for the X and Y axis.

I have seen that companies like Hiwin and Rockford Ball Screw have retrofit kits for Bridgeport type Series I and II mills. None of them seem to have a standard ball screw assembly that will fit my 10 x 54 table / travel size.

I have contacted Nook and Thompson, with little hope. They both told me that they do not have a standard assembly that I can use. They could make a custom assembly to my liking, but I fear that this would be very cost prohibative. Neither of them would give me a "ballpark" as to what the cost would be.

Can anyone direct me to a source for the ball screws that would fit this mill. I also need to know if I need to replace or convert anything else, such as ball / thrust bearings. Will I need to replace the yoke, or the
"cross-piece" that the ball nuts will be mounted to? I see that Hiwin has a yoke as part of their (smaller) retrofit kits.

I would like to make this machine as highly accurate and repeatable as possible. Would I need to get a precision ground ball screw assembly (+/- .0005" per foot)?

Could I instead go with the rolled (+/- .003 per foot) or precision rolled (+/-.001 per foot) ball screw assembly, and use the backlash compensation feature in Mach 3 to negate any unwanted tolerance stack up? Would this have a negative impact on climb milling performance / finish or limit table speed / feed drastically?

Thanks for your feedback.

Here are some (before) pics of the mill:

Back lash mode is not to be used for ANYTHING other then drilling operations in mach far as I've been told. Basicly the mode makes sure when coming to a location that it aproches it from both sides. (ie when told to move to x4 y4)

try to imagin the moves it would be trying to make while aproching a point while cutting a line or series of small moves. The servo motors can express their unhappyness.

So what I'm saying is mach backlash isn't to cure backlash if you are milling out a piece. only for accurate drilling. Least that is the only time I turn it on. In those cases it's usefull.

Far as the ball screws. You can order rolled from mcmaster car how ever you mention accuracy. In any event those are the least expencive ones I know of but you will have to mill your own ends, buy pullies, angled contact bearings ect to go with everything..

Frankly I can't see it being done for cheep in any event. Bearings get expencive and I don't think you can count on re-use of any of the thrust bearings used on the acme screws currently on the mill but I could be wrong.

After picking up my s1 bridgeport CNC and seeing it works so well I have a hard time with cost justification of conversions now seeing I only paid 1000.00 and the machine came with all those parts you are looking to make this CNC..

that mill looks nice though. even have a dro on the table height.. nice..

Thanks for the feedback, wcarrothers1.

I thought that you could minimize any backlash in a ball screw assembly using software, because I have seen a couple of companies with a guide to programming backlash compensation based on length of the ball screw and it's manufacturing tolerances.

I do realize that it won't be cheap to replace the lead screws on this mill.
I would like to do it with as little cost and pain involved though. I have most of the components, or know where to get them, for the rest of the conversion.

I just can't seem to find someone / somplace that can get me a ball screw assembly that I can use. I can't believe that I am the only person around that has ever attempted to retrofit a 10 x 54 mill with a ball screw.

I also do not know exactly how to go about the disassembly / reassembly process. What else will I need to replace / modify? What do I remove first? What do I stay away from? How does it come apart? What do I need to tweak or check after reassembly to verify that all is stright / square, etc....

Unfortunately the owner's manual that I received with the mill is a copy, of a copy, of a copy, of a copy, if you know what I mean. It has a few pages with exploded views of the main assemblies, but you really can't make anything out.

I wish I could find some sort of repair or service manual that would be able to guide me through the process. Does anyone know if there are any out there?

I think you are confusing backlash comp. with the screw mapping capabilities of mach 3 (and others).
The screw mapping compensates for the lead deviation found in rolled ball screws. With a ball screw no backlash compensation is required, unless of course your screw is completely shot.

For your conversion you may need to purchase screw stock, that is a ballscrew with no machining on the ends, and turn it to match your bearings, pulleys and possibly thread it for your bearing preload. But ballscrews are pretty hard and a 54" one may be difficult to fit in your lathe.

But!!!! don't be put off, many hundreds/thousands? have done this conversion before, the results will be worth it.

The problem with backlash comp is that it doesn't solve the main problem caused by backlash. All backlash comp really does is tell the stepper (or servo) to add some extra steps when it reverses direction, on the theory that the table isn't going to start moving until the screw has turned that far, which may, or may not, be the case. It works reasonably well if all you use the mill for is to drive around between drilling locations. The problem comes in when you try to mill something. Much CNC milling is done climb cutting, as that yields a better finish, provided there is no backlash. If there is backlash, there is nothing to keep the table (and work) from continually jerking forward into the tool, which is bad for the machine, tool, and finish on the work. In manual machining on a mill with worn lead screws, one works around this by planning the work to never climb cut, but this isn't an option when doing CNC.

Dwayne Elrod should be able to supply ballscrews for you. See http://www.elrodmachine.com/CNC%20XY%20Ball%20Screws.htm.

He also has yokes, motor mounts, and other hardware you way want.

Thanks for the input klxrcr and Dennis Storzek.

Hey klxrcr, yea it's looking more and more like I'm going to have to fabricate my own ball screw assembly. I just need to figure out what type of screw I need to get (ie rolled, precision rolled, or precision ground).
I also don't know whether I need to be looking at a single preloaded ballnut, or a double preloaded ballnut. Any ideas or pointers?

Dennis Storzek, yea I know all about the perils of trying, either intentionally or accidentally, to climb mill on a manual mill without ball screws. That's why I want to make this mill as "tight" as possible, but without wasting time / money where it's not needed. I want it to be able to climb mill and contour mill and be able to get a nice finish with no chatter marks or blemishes.

That the main reason that I am having a hard time deciding on which way to go with the ball screws, in respect to a rolled vs. precision rolled vs. precision ground assembly.

It sounds like, if I am understanding correctly, that I do not need to waste my money on a more expensive ball screw assembly. I can get the same accuracy with a rolled ball screw vs. ground ball scew assembly, as long as I map the screw correctly in the software.

Though I am sure that the ground ball screw would be more efficient, relatively speaking, and allow for higher ipm speeds. Is this correect, or am I totally missing something?

MarcL, Thank You!!!!!!!!!!!!!!!!!!!!!

I sent an RFQ to Elrodmachine. Hopefully they can accomodate this mill.

Thanks for the input klxrcr and Dennis Storzek.

Hey klxrcr, yea it's looking more and more like I'm going to have to fabricate my own ball screw assembly. I just need to figure out what type of screw I need to get (ie rolled, precision rolled, or precision ground).
I also don't know whether I need to be looking at a single preloaded ballnut, or a double preloaded ballnut. Any ideas or pointers?

Though I am sure that the ground ball screw would be more efficient, relatively speaking, and allow for higher ipm speeds. Is this correct, or am I totally missing something?

A rolled ball screw should be plenty accurate for your machine, a rolled/precision rolled will not have as accurate of a lead as a ground, but can be mapped to nearly equal precision. A single or double preload nut will work, a single preloaded nut has 2 seperate "races" in it that preload against each other, where as a double would be 2 unpreloaded nuts back to back that preload against each other.

Ground screws are slightly more efficient but a rolled screw still has a 90% efficient force transmission which is a ton better than an acme. A rolled screw will not limit the feed rate of your mill, unless you plan on 1000ipm rapids. Which I hope your not. also a rolled screw will have a bit more noise than a ground screw, just the sound of the balls spinning around inside the nut.

One last bit I priced a set of screws from elrod, precision ground for a 9x42 bridgport, $1750...... I'm looking for a cheaper set now (rolled) And I hear that Rockford has sets starting around $700.

Well I finally got a hold of somebody at Rockford Ball Screw that could help me out, I hope. I talked to Ryan T., and he told me that they could make me some custom rolled ball screws.

I would need to send him my original lead screws so that they can duplicate them, or send him a drawing. I think that I need disassemble my table to see if I can take some measurements. Then I'll e-mail it to Ryan to see what they can do.

He gave me a ball park figure of about $800 for a complete assembly including the yoke.

This is a lot cheaper than Elrod Machine's $1525 for a X&Y axis kit, though I do realize that Elrod's kit has .0005 per foot precision ball screws. I am not sure if Elrod's kit includes a yoke though. I e-mailed them some questions, but never got a reply.

It seems that alot of these companies want nothing to do with hobbyists, or "one-offers". Too bad, I bet that they lose a lot of potential revenue that way.

Anywho, I priced some raw (unmachined) rolled ball screw stock and single pre-loaded ball nuts and flanges through Nook Inustries, and recieved a quote for $520. That does not include a yoke, and would require me to machine the ends.

Now all I need to do is to figure out how to take this thing apart! Anybody got any suggestions?

On another, completely unrelated note, I just finished installing my new 8-inch 6-jaw "set tru" chuck on my lathe.

I wanted to upgrade the plain 3-jaw chuck that came on the lathe standard, especially since it did not have reversible jaws.

I thought that this would come in handy if I had to machine the ends of the ball screws. If not, I'm sure it'll be put to good use on other projects!:)

Here are some before and after pics:

I received my 19" Touch Screen LCD on Thursday. It is an industrial open frame type with a 3M touch screen and serial interface. I pruchased it on eBay, item # 230156459157. This thing is awesome!:)

I unpacked it, connected it to my PC (future machine controller), downloaded and installed the software driver from the 3M site, and it all worked as planned. It took all of about 5 minutes.

Now all I need to do is fabricate a mount for the LCD, and an arm to hang it off of the side of the mill.

The only have two issues with the LCD.

Issue # 1, I can't seem to get the Mach 3 screen to "scale up" to a 1280 x 1024 resolution (see attached pic). Is this a limitation of the trial software (haven't purchased a license yet), or do I need to get / create a custom screen layout for Mach 3? I works fine at 1024 x 768, but the LCD looks much better and "crisper" at 1280 x 1024 since that is it's native resolution.

Issue # 2, I would like to be able to use the LCD in a portrait orientation. This way I can use the upper (approximately) 2/3 of the screen for Mach 3, and the lower 1/3 for an integral keyboard.

Can anyone tell me if there is a "generic" software driver out there that will allow me to rotate the sceen on any LCD?. I have "Pivot Pro" software that I got with my Samsung 23.1 LCD to perform this function, but it seems to be LCD model specific.

I would also need to make a custom 1024 x 1280 screen layout for use in the portrait orientation. It would have the standard Mach 3 control functions in the top of the layout and an integral keyboard layout in the bottom of the screen. Is it possible to create a custom screen layout for Mach 3 to accomodate all this?

I think that this would be the ultimate interface for a conversion like this, and it would really give it that "just like the real thing" flavor. :cool:

I have also received my Combo Breakout board from Bob Campbell Designs(see attached pic):

http://www.campbelldesigns.com/Combo-board.php

This is a big board! I like the fact that it is seems to have anything that you would ever need integrated already.

Finally, I got my contact probe from IMService (see attached pic):

http://www.cadcamcadcam.com/index.asp?PageAction=VIEWPROD&ProdID=10

This will work great for digitizing surfaces and generating point clouds for surface models, as well as making measurements like a CMM, or as a quick tool indexer when changing from one to another.

It's been a busy week. Got a lot more pieces and parts delivered. I think the UPS guy's been here every day!

I got four G320's from Gecko Drive:

http://www.geckodrive.com/product.cfm?pid=13

I got three Keling KL34-180-90 1125 oz-in. peak servo motors, along with UD Digital 500 CPR encoders (see attached pic):

http://www.kelinginc.net/KL34-180-90.pdf

Could anyone tell me how to figure out the proper limit, damping, and gain settings on the G320's when using these servo motors?

I got my 80 VDC, 20 amp power prep module from PMDX (see attached pic):

http://www.pmdx.com/PMDX-135/index.html

I purchased my transformer on eBay, item # 270152210432. It is a 56+56V 1KVA Toroidal type (see attached pic). Thanks again Al_The_Man for the assistance. Wow, this is a big sucker.

Now I can start laying things out to see how big of a steel enclosure that I'll need to fit all this stuff into.

I also received one of the two air cylinders that I plan on using for the Z (knee) axis air assist, or counterbalance system. This has got to be one of the biggest air cylinders that I have ever seen (see attached pic)! It has a 80mm (3.149" bore and 500mm (19.685") stroke. I purchased them on eBay, item # 330155200698.

They (both of them combined) should be able to give me about 1240 lb. of lift or "air assist" with 80 psi of air. I plan on cutting them down somewhat, as they are longer than I need them to be. I am going to beusing them in a "closed" type of system with an accumulator or surge tank. I need to find an air tank with about 4000 cubic inches of volume to minimize pressure rise as the cylinders are stroked. Hopefully I can find a 30 gallon air compressor tank somewhere, as this should fit the bill nicely.

Today I made my first baby step in the conversion. I made a mount for the four Gecko G320's, with four integral aluminum heat sinks and fans.

The heat sinks and fans were some old P4 CPU coolers that I had laying around, so I decide to put them to good use. They were a perfect size for the G320's, 2.875 x 2.960 x 1.375 tall, almost as if they were made for them.

I took the CPU coolers apart and used a 3-1/2" inserted face mill to flatten the back of the heat sink and get rid of a .075" boss that was sticking up, being careful not to fold the heatsink in half in the vise jaw.

I then drilled and tapped four #6-32 threads on the finished face in a 1.750 x 2.375 rectangular array to mount the G320's. I also drilled and tapped two #8-32 threads on one side of the heat sinks that I'll use to mount them to a riser bar.

I then removed the terminal blocks from the G320's, fastening them using BHCS's. I then re-assembled the fan and replaced the terminal strips, finally installing the four assemblies onto the riser bar. The riser bar will be installed into the enclosure using four aluminum spacers or stand offs using 1/4-20 SHCS's.

Step one done, with about one thousand more to go.:)

Went to go pick up my 2000 lb. capacity elevating lift table from Yellow Trucking on Monday (see attached pic). Purchased table from Northern Tool. This will give me the adjustable height and weight capacity that I will need to remove my mill's table when changing the lead screw.

Got my ball screws from Elrod Machine today (see attached pics). Boy they sure look nice. They are Hiwin precision ground ball screws. Funny, but when I spoke to someone at Hiwin directly, they told me that they did not think that they had a ball screw that would fit my mill. I just hope that these do fit.

These sure are some BIG screws! The X axis is 64" long, the Y axis is 30.5" long.

I bought them from Elrod because Dwayne seemed to be the only person that I've talked to in the last couple of months that seemed to know what he was talking about, and what I wanted. They were VERY expen$ive, but I think in the long run they'll be worth the investment.

If all goes well and according to plan, I'll try to do the actual retrofit this (long) weekend.

Started the ball screw conversion yesterday. Everything with the disassembly went smoothly. The problems started when I got the lead screws and yoke out and compared them to the ones that I purchased from Elrod Mechine.

The ball screws are smaller in diameter than my originals, and the machined ends are slightly different. I'm pretty sure that I'll be able to use these with some slight alterations to my support plates. I think I'll also have to make a spacer on the right side of the X axis, as it seems that the bearing journal's shoulders do not line up exactly.

The distance between the X & Y axis bore is about 3/8"-1/2" greater on my original yoke, the bores in my original are .090 larger in diameter, and the mounting holes' center to center distance is about .300 greater on my original. My original also has two 6mm dowel holes.

Looks like I'll need to return Elrod's yoke. I will either modify my original by chroming or sleeving the bores, then drilling and tapping for the ball nut flange screws, or I'll have to make a new one using pre-toughened 4140.
I'm leaning towards making a new one, as I think that will be much easier, and make for a stronger unit in the end.

My goal today is to take readings and precisely measure the original, so that I can create a detail print for a new yoke.

Wow... you sure are using the cream of the crop for parts. This will be a rockin' mill when you get it finished. Thanks for the idea using the P4 fans to cool the Geckos. I found them for $.99 at surpluscomputers.com so this was a good day for me. I am looking forward to your progress and love all the pictures.

Did you get answer on scaling Mach 3 up to 1280 x 1024? I am looking at that monitor also if you got that problem solved. Keep it going, it is looking great.

Thanks for the kind words txcowdog!

Haven't found anything more on using Mach 3 at 1280 x 1024, but if I do, you can be sure that I'll post my findings here. I will be focusing on that later on in the conversion.

Right now, I need to figure out how to make a new yoke that'll fit my mill.:rolleyes:

After about 4 hours of making measurements and readings with a digital height gage, I think that I finally came up with a yoke design that'll work in my mill, using the Hiwin precision ball screws.

I used the top of the milling machine's table as a surface plate for making the measurements. Of course, just to make it more exciting, there wasn't a single square corner on the casting that I could work off of with any confidence.

I wound up using Elrod's design concept, while making alteration as needed for use in my machine.

I modeled and detailed the part in Unigraphics NX4. I plan on making the new yoke out of pre-toughened 4140, as opposed to the original's cast iron. Now I just need to send out the drawings to get manufactured, and hopefully it'll be done within a couple of weeks.

I received my NEMA 12, 16" x 20" x 6", steel enclosure box from www.automationdirect.com (http://www.automationdirect.com) yesterday. I will be making my own sub-panel for it, to suit.

I also got the shielded encoder cables from www.usdigital.com (http://www.usdigital.com). I finally got around to installing the encoders on the servo motors.

My main focus in the last few days has been gathering all of the little pieces and parts like wire, fuses, fuse holders, terminal strips, switches, etc.

I also got around to installing a 2 HP 3-phase motor, and a Hitachi L200 VFD on my 17" vertical wood cutting band saw. Now I have the ability to
cut either wood or metal, adjusting the speed as needed.

The conversion / install was a lot easier than I thought it would be. I should have done it a long time ago, as I have needed a metal cutting band saw many a time in the past. The hardest part was boring out the hole in the "V" pulley from .625 to .875, to accomodate the larger shaft on the new Baldor motor. I also had to transfer, drill and tap four M8 threads into the front of the motor housing to suit the pivoting motor mount plate from the stock motor.

I purchas both the VFD and motor from www.driveswarehouse.com (http://www.driveswarehouse.com). They seemed to have just about the best prices that I could find.

Very informative conversion. Is that a grizzly bandsaw?
Just ordered p4 fans and a PMDX module. Based upon the PMDX manual is a 56 volt toroid going to be too much DC voltage for the Gecko's?
1.10X1.08X56vX1.414-1.5v = 92.57 VDC?

Thanks bemfarmer. Yes that is a Grizzly Model G0513 17" 2 HP Bandsaw.

Now about the power supply, I have read a lot of different posts on power supplies and Gecko drives. There seems to be a lot of different opinions on how much (maximum) voltage you can actually feed into a G320. Some users are supposedly feeding them a lot more than 80 VDC.

I also read the user's manual for the PMDX-135-8020 power prep module, which states a maximum input of 56 VAC, and the formula that you stated. My understanding is this, right or wrong:

The G320's are rated at 18 to 80 VDC input. The 80 VDC rating does not include the "worst case scenario factors" that the PMDX formula states.
The formula that I used is simply 56 VAC x 1.414 = 79.184 VDC.

Besides, since 56 VAC is the maximum input rating for the "80 VDC @ 20 amp" power prep module, I felt that this was a safe way to go.

I asked the question myself, and was told that that this toroidal transformer would be a good match for the motors that I was using.

I wanted to provide as much voltage and current to my servo motors as possible, to attain the most torque and rpm that I could. I did not want to limit the motors' potential by not providing them with enough power.

I guess that this is what I am going to try to do, based on my research, questions and conclusions. This has been one of the more difficult things for me to get a grasp of, because the whole power / electronics portion of this project is definately not my strong point.

I suggest that you look through some of the Power Supply and Geckodrive forums' postings, and see for yourself. Maybe that'll help to clear some things up for you.

Personally I found that the more that I read into it, the more confused I was getting. I think it's called "information overload".:confused:

Sounds good, robhrzic. I recently bought 72 volt servos and 48VAC toroid from homeshopcnc, for router or G0519 (R45 type milldrill), (someday).
What blades do you use on bandsaw? Speeds?
What type and source of bearings for your ballscrews?

bemfarmer,

I have used a 6 TPI "Hook" style blade on aluminum up to 4" thick with great success so far. It is a Grizzly # H4804 (1/4" wide) or # H4807 (1/2" wide) in a 131-1/2" length for the G0513 band saw.

I have my "V" drive belt on the 1700 FPM pulley groove. I have my VFD set at about 10 Hz. So, if 60 Hz equals 1700 FPM then I am assuming that 10 Hz is equivalent to about 283 FPM.

I can turn it down to about 3-4 Hz before it actually stops turning. It seems to cut 4" thick aluminum at 10 Hz very well, and tninner 1/2" thick aluminum at 20 Hz (about 566 FPM), using the same blade. By the way, I have been cutting 6061-T6 aluminum at these speeds.

I am currently looking for 7204 series angular contact bearings from a few different suppliers. I'll post my findings when I have found out more info. This company seems to have anything that you'd ever need:

http://www.bearing-service.com/

Nice online bearing site with ballscrew bearing info., Alpinebearing.com, precision angular contact bearings. (Found some inch sizes too.)
Maybe M20BS47, or NSK 20TAC47A?
The rockfordballscrew manual sure looks good.
Found locknuts at Whittet-Higgins.com.
What kind of mounting plate for the six jaw chuck, vs camlock mounts? I am totally ignorant about lathes, just got the smaller G0509G. Is it worth it to get the six-jaw chuck?

bemfarmer, I ordered (4) FAG 7204B. TVP. UA angular contact bearings from Bearing Service Company today. They were $27.06 each, plus shipping. I got that bearing part number from the Rockford ball screw online service manual. Hopefully they'll fit my Hiwin ballscrews.

I asked the sales rep to send me some technical data on shaft / bore tolerances, sizes and any instructions that might give me a clue about how to install them and preload them properly.

Unfortunately, all I got was a fax of a very bad copy of some pages from an old FAG catalog he had laying around. I can barely read most of the verbage and numbers, let alone decipher any of it. Looks like I'll have to look elsewhere to try to find out how to install them correctly.

I got the 6-jaw set-tru chuck for several reasons. Mainly because it has hardened reversable jaws, and it is a "set-tru" style.

The lathe came with a plain, non-adjustable, 3-jaw scroll chuck. This is a perfectly adequate chuck for day to day turning. It did not have a few features that I needed, and had some drawbacks that I did not care for.

The first being that if you needed to change your "grip" from the I.D. to the O.D., you had to "unscrew" the 3 jaws completely out of the chuck, and replace them with the other 3 jaws that came with the chuck. You have to be careful to be sure that the correct jaw goes into the proper receiver, and "screw" them all the way back in. If you do not have the correct jaw in the correct receiver, or are one "tooth" off, you need to take it all apart, and start all over.

Hint:You must identify the jaws and their corresponding receiver, with a pencil grinder or something else that will be permanent, to ensure that you are placing the jaw in the correct receiver every time. The jaws do not come identified from the factory. When I had to do this the first time, it took me about 10 minutes to figure out which jaw goes in which receiver, so that they all come to the center accordingly! (chair)

This can be a major PITA if you need to do this frequently.

The 6-jaw chuck that I chose has hardened "reversable" jaws. In order to change the "grip", you simply take out the two cap screws from each jaw, rotate the jaw 180 degrees, place it back into the locating key slot, and replace the screws. With a small 3/8" drive impact wrench, it takes me less than a minute to reverse all 6 jaws.

You also have the advantage of purchasing or making spare replacement jaws or "soft jaws" if needed for different materials.

The other main reason is the "set-tru" feature. I feel that his is really only necessary or needed if you need to do high precision turning, or grinding using a tool post grinder, on a finished piece that needs to be altered or modified. This type of chuck has four set screws in the body of the chuck that are used to "fine tune" the concentricity of your work piece. Using a .0001" dial indicator, you can indicate a workpiece to within .0005" by alternately loosening and /or tightening opposing set screws to move the centerline of your chuck / work piece.

With a standard, plain chuck your work piece concentricity with only be as good as the wear on your scroll / jaws, and lathe will allow. I have worked with lathes where you'll be lucky to be within .005"+.010" with a plain chuck.

Again, in my opinion, this feature is only needed if you have a finished part that needs to be indicated "dead nuts" so that you can perform a machining operation that will be true to the work piece.

As for why 6-jaws? Well, I knew that I was going to buy a new chuck, so for the minimal (higher) price difference between a 3-jaw and 6-jaw reversable set-tru chuck, I opted for the 6-jaw. 6 jaws will distribute the holding force more evenly around the perimeter of your work piece. It will have less of a tendancy to mar the surface on softer materials like wood, plastic, aluminum, etc...

The only disadvantage that I can see so far, is that the smallest diameter workpiece that can be held is .450" (checked with a gage pin). So if you needed to hold anything smaller in diameter than 1/2", you would need to use a collet of some sort. I have used R-8 collets in the past for "standard" sizes, but if you had an oddball size, you would have to come up with something.

As for mounting, this "set tru" style of chuck needs a special mounting / adapter plate to be used. You need to purchase a mounting plate separately, as one does not come with the chuck, to suit your lathe's chuck mounting type. The G0509/G lathe has a D1-6 camlock spindle nose.

I purchased my chuck and mounting plate from:

https://www.travers.com/Default.asp

The Grizzly catalog also lathe chucks available. I called about their 6-jaw chuck. The description in their catalog says "requires a mounting plate":

http://www.grizzly.com/catalog/2007/Main/593

When I called and talked to a sales rep there, she had no idea what a mounting plate was, what type I needed, or where I can find one.

Needless to say, I was kind of put off, so I looked elsewhere. I did some looking around, and Travers Tool seemed to have the best selection and prices. I got their TTC brand, catalog # 63-323-358 chuck, and matching D1-6 mounting plate, catalog # 63-323-049. I have attached the catalog page.

The TTC chuck was more expensive than Grizzly's, but at least I new that I had a mounting plate that I would be able to use.

When it comes to installing, you need to mount the plate into the lathe's spindle, then fasten the chuck onto the mounting plate. The mounting plate comes with a set of cam posts and hold down screws. You can see the (dull finish) mounting plate sandwiched in between the "shiny" lathe spindle and chuck in the attached pic.

The chuck gets fastened to the mounting plate using six 3/8-16 UNC (I think they were either 3" or 3-1/4" long) socket head cap screws (not provided of course!). The cap screws must not be too tight, or else the four adjusting set screws will not be able to "move" the chuck around on the plate. I just snugged them firmly by hand, and then indicated a work piece to assure that I can make adjustments with the set screws.

Note: all four adjusting set screws must be tight, to insure that the chuck / workpiece does not move while you are turning.

As I stated earlier, I only got a 6-jaw chuck because I felt that the 3-jaw chuck that came with the lathe was not suitable for the tasks that I had in mind.

I hope this answers some of your questions.

Thank You

I went ahead and bought the touchscreen you discussed and WOW... it looks great. Concerning the resolution, I looked at the MACH forum and found a thread from May 2006 discussing the autosize problems but Art fixed it and the screen should autosize up from 1024 x 768 to 1280 x 1024 automatically. The guy who had the problem said the new update looked very crisp at the higher resolution.

txcowdog, I saw the same post (Mach Blue screen set) and I already have downloaded it. I tried loading the screen set in Mach 3 Version 2.3, but it is only a 1024 X 768 screen set. It does not "scale" to 1280 x 1024.

I also went ahead and purchased a license for Mach 3 and the wizards from newfangledsolutions, with the same results. I can not get any screen sets to scale to 1280 x 1024. I had previously thought that the trial version of Mach 3 might have had a 1024 x 768 resolution limit.

Are you using Mach 3? Have you had any success with any screens or settings at 1280 x 1024? If so, how?

Re: Screensize. Loaded Mach3 Version R2.41, licensed copy.
Select Config, General, CheckBox Hi-Res Screen, CheckBox Autoscreen enlarge, (lower middle of config screen). Reload screen, (a 1024 version).
Close Mach3. Re-open Mach3. Now the fullscreen box of windows, upper right corner, makes Mach3 fullscreen, On Windows Vista, 1600 X 1200 screen resolution. I guess the resolution is still 1024?, but it is fullscreen.

Hey bemfarmer,
That sounds like a fix I will definitely try when I get home. Thanks for the input.

-cowdog

Thanks a bunch bemfarmer! That did it. I wasn't even aware that this setting was available in the Config section. :rolleyes:

I came across this rotation software from Portrait Displays that is supposed to allow you to rotate any display as the user sees fit:

http://www.portrait.com/us/products/pp_overview.html

Only problem is that it doesn't seem to work with my touchscreen display. I am using an older 1.6 Ghz P4 with an Nvidia TNT2 32 MB video card for the controller. I'm going to try to get a hold of someone for some technical support to see if I can resolve this issue.

Meanwhile, I received my angular contact bearings from Bearing Service:

http://www.bearing-service.com/

I got the VFD for my machine spindle from www.driveswarehouse.com (http://www.driveswarehouse.com) and a larger steel enclosure from www.automationdirect.com (http://www.automationdirect.com). This enclosure measures 20" H x 16" W x 6" Deep. The previous one that I ordered was 16" H x 14" W x 6" Deep, and though I was able to fit all of the components, there wasn't too much room available for anything else. This larger enclosure should be much easier to work with. I am contemplating on putting a lexan window in the door, so the various LED's will be easy to see.

I machined some standoffs for my G320 drive "rack" and the various PCB's for the control box. Now all I am waiting for is the various little pieces and parts from www.alliedelec.com (http://www.alliedelec.com) to get here, then I can start assembling the control box.

I received my 3/8" drive butterfly impact wrench and two (2) 10 gallon air tanks from www.harborfreight.com (http://www.harborfreight.com). I found a set of plans for making a power drawbar using this impact wrench from this site:

http://home.insightbb.com/~joevicar3/cheap_drawbar.htm

The two 10 gallon air tanks are going to be used for the surge tanks that I will need to use for the air cylinder counterbalance. I was hoping to find some larger (15 gallon) tanks, but I think that these will work without too much pressure rise.

I got started on a new yoke for my machine. Thanks John & Larry! Hopefully it'll be finished in a couple of weeks. I can't wait to get it, so that I can start putting things back together on the mill, and see how the new ball screws work.

Very nice progress. I see the drawbar on the BobWarfield site www.cnccookbook.com/CCMillDrawbar.html. What about limit switches? Estop? Do you have to re-wire the mill?

I also have one of those vfd's but it is branded as Kimatek, had it for 3 years around a lot of dirt, dust, still running strong!

Are you going to power the knee instead of the quill to use for the Z axis?

In Digital Machinist magazine, Volume No.1 spring 2007, and Vol2 No.2 summer 2007, there is a lengthy article on converting a bridgeport clone with rockford ballscrews. Reprints (800) 773-7798. There are copper oil lines.

bemfarmer, the limit / home switches will be coming this week (hopefully) in the order I made from www.alliedelec.com (http://www.alliedelec.com). I have a large mushroom style E-stop switch somewhere, I just need to find it. As for the wiring, there is nothing for me to re-wire. This is a manual mill to begin with. I'll have to do all of the wiring myself.

DennisCNC, do you have your VFD "out in the open"? If so where do you have it mounted? I have been contemplating on whether or not to install it in an enclosure. I would prefer not to, if I don't have to, but the instructions state that it is very sensitive to dust, debris and of course moisture.

txcowdog, right now my main goal is to power the knee for the Z axis. In my opinion the knee is much more rigid and obviously has a far greater range of movement than the quill. I will eventually also power the quill for making rapid moves for such things as peck drilling. I think that this combination will give me the best of both worlds.

Thanks bemfarmer, I'll have to look that article up to see what I can gain.

Finally received my connectors, wire and various other wiring components from www.alliedelec.com (http://www.alliedelec.com).

Since I am still waiting for the yoke to be finished, I guess that I'll start working on some of the electronic component mounting and wiring.

I mounted the steel enclosure box on the side of the mill using rubber isolators to minimize any vibration, and to allow for some space between the mill and enclosure.

I made my owm sub-panel for the enclosure from a piece of 3/16" thick aluminum that I had laying around. I cut it to size using my variable speed band saw.:) I wanted to use a thicker panel than the enclosures usually come with, so that I can easily place #6-32 to #10-32 tapped holes where I need them to mount the various pieces.

WOW! That panel is beautiful. Man you do some nice work. If imitation is the sincerest form of flattery then you should be flattered indeed. First I bought that touch screen monitor you got and now I am in the midst of making that power drawbar you pointed out. You have a great build going here and it has spurred me to action in my own shop. Thanks for the great ideas.

Any progress in a mount and articulating arm for supporting the monitor?

Thanks for the kind words, txcowdog. I haven't got around to coming up with a way to make a mount for the LCD monitor yet.

I have been focusing on gettting the last few little pieces and parts for the control enclosure, and trying to get a new yoke made.

The yoke, as of last hight, has been "rough machined", and the large holes have been bored. Hopefully it will be completed by the end of the week, and I'll be able to really get going on the conversion process.

I'm still waiting on a couple of things that are on back order from www.alliedelec.com (http://www.alliedelec.com), also.

The Yoke is finally finished! Hopefully it'll be here by the end of the day.

Thanks again John, Larry, Chuck, Mark & Rob!

Today I got around to putting all of the holes into the steel enclosure box. I also test fitted all of the bulkhead connectors for the various inputs and outputs.

The "front" of the box has four large 3-pin connectors for the four servo motors and smaller 6-pin connectors (5 pins of which will be used) for the four servo motor encoders. All of the connectors have built in caps to protect the unused connections from dust and moisture.

The "back" of the box has a power switch, eight 3-pin connectors for four limit switches and four outputs, as well as a 2-pin connector for an e-stop
mushroom, and a 2-pin connector for the VFD. There is also a PC case style AC male plug for power.

The "top" and "bottom" of the box will each have two 92mm double ball bearing fans with filters. The bottom two will draw air in, and the top two will draw air out.

I am using Bob Campbell's Combo break out board, and I wanted to make sure that I had everything covered. I hope I'm not missing anything. I will not be using all of these connections now, but I am trying to "future proof" the enclosure as much as possible.

The only thing I seem to be missing is a contact probe input. Does anyone know how to physically interface a touch probe to Mach 3? In other words, where do I connect the touch probe so that Mach 3 can use it?

The contact probe itself has a small malle mini stereo type plug found on headphones. If I install a matching female mini stereo jack, where do I connect that on Bob Campbell's combo break out board?

Finally got the finished yoke!:banana: :banana: :banana:

Now I'll finally be able to put the mill back together, and hopefully start making some serious progress on the conversion.

Here are some pics of the new next to the old.

The new yoke is finally installed, and the table is back on the milling machine. Everything so far seemed to go back together smoothly. The X axis ball screw was easy to put in, because everything was out in the open.

The Y axis ball screw, on the other hand, was a major PITA, though. It was really difficult trying to line up the two 1/4-20 UNC threaded holes with the slots in the ball nut flange, while trying to line up the ball nut body with the yoke's bore. The jig ground bores were only about .0002-.0003 larger than the ball nut body, for a nice snug "slip" fit. I wound up screwing in a couple of long threaded rod pieces to use as guides.

I made sure to pump the lube handle a few times before I put the table back on, to make sure that way lube was getting to the ball nuts, through the new rubber hoses.

Hello all,

I am in the States, and I have been mailing parts to Australia for a while now, (I'll gladly ship your items also)to different CNC machine builders and one is in the process of converting a knee mill, his first project. He is thinking computer for processor. I sent him a power supply, and a couple controllers. I'm sending him this Forum link so he can get info straight from the experts.

Can anyone provide a list of recommended items and other instructional material to help him get started on the right foot?

From what I have seen, there is a wealth of information and sources for someone taking on a conversion project such as a manual to CNC mill.

Thanks Gents.

Woody Beauchamp
http://goodthings.ecrater.com

Hi robhrzic,

You have a good start on your project. Kudos. I have a friend in NSW who is just into the planning stages of converting his knee mill to CNC. Do you have any advice for us(he wants me to help find the items for the project and draw the prints as well as create the code to make a line of personal signature tooling fixtures.

I posted a general reply to the rest of the thread, but you have photos to "show me the money" of your progress.

Any advice, recommendations for mech. or elect. items/brands to get our project off the drawing board.

Thanks for "showing your stuff"
Woody

Hi, Hows the project going? I wondered what dia the ballscrews are? Also the wiring plugs on your enclosure- do they come as a set with both halfs and pins and stuff? Do you have the part number or name of the style plugs so I can narrow them down on the website and order. Thanks very much, Dave

How y'all doing on the mill conversion? Like what I see so far.

John

I finally have a functional manual mill, again. The conversion to ball screws has been a major PITA! I had to make all of the pieces to put the handles back on from scratch, since the original grizzly components were different sizes than on the Hiwin ball screws.

I purchases a couple of safety hand wheels with folding handles, which I had to bore and ream to .6245 to fit on the screws.

I also had to make some custom "dial" adapters so that I could put the manual vernier dials back on the screws. I made them from some 304L stainless bar stock that I had laying around.

In order to thread the dial carrier and lock nut, I made a custom tap and die holder to fit my 1" Jacobs BB chuck in my lathe's tailstock. I made the die holder with a triangulated shank to fit into the chuck, so that the torque from threading the 1-1/4"-20 UNF thread does not turn the holder, and damage the chuck's jaws. The die size is 2-1/2" in diameter. I also made a special modular 1.020 I.D. tap holder to place into the die holder. I plan on eventually making different size tap holders to fit other sizes of taps and dies.

Yes, I know that I could have used the lathe for both the internal and external threading of these pieces. But, since I have never done and manual thread turning before, I didn't want to start experimenting right now. I'll have to find some time in the future to try that out on some other project.

I am very pleased with the fit and finish of the new stainless dial carriers and nuts. I was surprised it took about 30 minutes to machine the heavy course knurl into that tough stainless.

I also had to make some custom spacers to adapt the new hand wheels to the screws. The Y-axis has to have a really long spacer, since the Y-axis screw had a much longer journal than the original one. I didn't put a hand wheel on the left side of the table, since it will not be needed once the mill is under CNC control.

Since the mill is operational again, now I can finally start making the components for the CNC conversion. I've been busy finalizing the design of the components for the X-Axis drive. I've ordered some of the raw material, and started making chips! :)

I purchased the timing pulleys and drive belts from Stock Drive Products:

http://www.sdp-si.com/

I plan on using a 3:1 drive ratio initially. I am fabricating all of the mounts and brackets with enough room to allow for a 4:1 drive if necessary, by changing the motor pulley from a 24-tooth to a 18-tooth pulley. I think that my motors will have plenty of power, but I wanted to incorporate some adjustability in case I need to make some changes or upgrades in the future.

Got a few new toys recently. I bought a Phase II 10" Precision Horizontal / Vertical Rotary Table, an SPI 3D Indicator, a 12-Ton Hydraulic Tubing Bender, and a 12-Ton Shop Press.

I bought the shop press so that I can do the broaching that I need to do for all of the pulleys and such. I'm sure it'll come in handy for much more. I eventually plan on building a 75-100 Ton model myself for some decent forming and punching capability.

I got the tubing bender, in part, for bending the 2" EMT for the Monitor Support Arm. I guess I had to find out the hard way that you can't bend EMT in a hydraulic tubing bender. I need to go to plan "B". I ordered a 90 degree elbow and a couple of EMT couplings from McMaster Carr.

I plan on mounting the monitor on an arm that can be moved out of the way easily for setups, cleaning, etc...

I am using 2" EMT for the support arm because the I.D. is large enough to run the various power, VGA, serial amd USB cables that I am going to need to route to the control PC.

The monior will be "framed" with 3" x 3" x 3/16" wall aluminum angle, and will be mounted at eye level. It will be fully adjustable to allow tilting and pivoting as necessary. The back will be open to provide for access to the cabling, and allow some air circulation for cooling.

I am still contemplating mounting a hinged protective cover to the front frame for protecting the delicate glass touch screen surface from flying chips and debris.

I was looking at this item on ebay http://cgi.ebay.com/LCD-TV-Universal-Arm-Wall-Mount-15-17-19-20-23-26-a6_W0QQitemZ230217180204QQihZ013QQcategoryZ48656QQssPageNameZWDVWQQrdZ1QQcmdZViewItem to use as a mount or to put on the end of a longer swing away mount. This piece adds swivel and tilt to the lcd and it is only $10

txcowdog, I was originally looking at something similar to this, but I would still have to find a way to attach it to the LCD. Since my LCD is an "open back" industrial model, it does not have any standard VESA hole pattern or mounting capability. That's why I've decided to make my own "frame" and swivel / pivot mount. I also like the added protection that a tube provides to the various cabling.

I bought a 24" digital caliper on ebay for $80. I can't believe what a great price for such a large, all stainless steel digital caliper.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=350012948183

I have finished some of the pieces for the monitor support arm, as well as most of the X-axis drive assembly. I found a 2" EMT 90 degree elbow, and a couple of 2" steel couplings on the McMaster Carr website, for the monitor support arm.

http://www.mcmaster.com

Finally got to use my rotary table to machine the X-axis motor mount plate. Next, I need to set-up the 4-jaw chuck in the lathe to drill and bore the 2.200" hole in the lower monitor support arm base. Then the monitor support arm will be ready to mount to the machine.

Got the base of the monitor support arm finished. Used the 4-jaw chuck and a 1" inserted boring bar for the large 2.200" hole in the mount blocks.

Monitor support arm is finally all finished and installed on the mill. I ordered an extra long (15' long) shielded VGA cable, power cable and DB9 serial cable for the touch screen from http://www.cablestogo.com

I took off about .007-.010 from one face of a 3/16" wall a 3" x 3" aluminum angle to square it up with a flycutter, so that I could make a precise square frame for the LCD. I then milled the radius off of both sides of the aluminum angle edge, to get a square edge/corner. This made the aluminum angle a finished size of 2-3/4" x 2-3/4". Had to clamp and support the long pieces with a series of 1-2-3 blocks to cut down the vibration.

I them milled the 45 degree corners using a 7/8" diameter x 3-1/2" long 2-flute HSS endmill on the rotary table. This made a for a really nice and super square frame for the LCD.

This was my first attempt at TIG welding aluminum with my Hobart Tigmate welder. The welds don't look as good as I'd like, as I need some practice, but I think it'll hold together.

http://www.hobartwelders.com/products/tig/tigmate/

I used 1/4" diameter aluminum rivets to fasten the aluminum LCD frame to the mount plates. This will allow for easier removal and remounting if I decide to rotate the LCD on the mount in the future. I had wanted to mount the LCD in a "portrait" orientation, originally, but I can't seem to get this LCD to rotate the display 90 degrees.

I hooked up the PC temporarily to see what it'll look like when it's all done. So far so good!
:banana:

I haven't decided on whether or not to paint the frame and arm assembly. I kind of like the raw aluminum look of the wire brushed finish.

As nice of a monitor arm as that is, that was a considerable effort to get there. One hell of a nice job.

txcowdog, yes it was a VERY considerable effort on my part to make this monitor support arm. I know I could have purchased a suitable counterpart readily and for relatively little $$.

I wanted to fabricate it, so I could justify all of the tools and equipment that I have been accumilating over the past couple of years. Besides, it feels good to actually "turn handles" again after being stuck in an engineering desk job for the last 9 years.

At least the raw material did not cost me anything, except for the EMT elbow and couplings, as I had it laying around.

Anyhow, to me, that's the major motivation for doing a project like this. To be able to say that "I did that", instead of "I bought that".

I've been trying to get ready to mount the X-axis drive, and see if it'll work. I've just made the final pieces, the covers, and am finally ready to install the drive assembly.

I also completed "Phase I" of the controller wiring. Turned the power on, and I was happy to see a bunch of green LED's turn on. More important than that, there was no "expensive" smoke.:)

I am getting 55 VAC from the transformer. and 81 VDC from the power supply, according to my multimeter. So far, so good. Now all I need to do is install the sub panel into the enclosure, and finish wiring all of the inputs and outputs. Then I can connect it to the PC, and try it (X-axis) out.

Are those Gecko Vipers I see there? Very nice attention to detail. This is a beautiful build.

txcowdog, I am using (4) Gecko G320's. Got them last fall. They are identified with an "H7" marking (August 2007?).

Hi:
What's the game plan for the Z axis, are you going to use a ballscrew on the knee?
We have a First CV 250 CNC mill at work with the Z axis on the Knee, and it's a really nice feature.


regards

Quick note:

Putting CPU fans and heat sinks on your Geckos is ingenious. I'm stealing that idea.

I just bought four of the HSF from http://www.surpluscomputers.com/store/main.aspx?p=ItemDetail&item=ACC10812 for only $5 ea. They are a good large size that seem perfect for the Geckos.

Dude! Looks excellent. Very nice.

John

cam1, I plan on driving the knee for the Z-axis when I need a precise milling depth and/or lots of travel. I am also planning on driving the quill for higher speed operations like peck drilling and boring, where Z depth is not necessarily that important. This would provide less wear and tear on the (knee) Z-axis servo motor, trying to move all that mass at a rapid rate.

I do not have any plans, yet, to change to a ball screw on the knee. I do not think that a ball screw may be needed, as the weigth of the table, and gravity, should be able to eliminate any backlash in the lead screw.

I will be using a double air cylinder counterbalance to lighten the load on the Z-axis servo motor for the knee.

Thanks robhriz:
Using the knee for boring operations could be more desirable than the quill, as in order for the quill to move, it must be unlocked, the clearance (.0003-.0005) in this interface can sometimes be a hassle for boring.

regards

cam1, I plan on driving the knee for the Z-axis when I need a precise milling depth and/or lots of travel. I am also planning on driving the quill for higher speed operations like peck drilling and boring, where Z depth is not necessarily that important. This would provide less wear and tear on the (knee) Z-axis servo motor, trying to move all that mass at a rapid rate.

I do not have any plans, yet, to change to a ball screw on the knee. I do not think that a ball screw may be needed, as the weigth of the table, and gravity, should be able to eliminate any backlash in the lead screw.

I will be using a double air cylinder counterbalance to lighten the load on the Z-axis servo motor for the knee.



You might want to consider a ballscrew for the driven knee. It will help with travel speeds and allow you to use a servo with less power. I woouldn't worry about wear too much as long as you use a proper oiler.

The convesion I accomplished some time ago can drive the knee up to a software limited 135ipm. I find this plenty fast for drilling operations. Soon I will be making upgrades to this mill that will allow travel speeds of 500ipm:).

Can anyone out there tell me if i could possibly use a PC Based Oscilliscope to tune a servo motor for use with a G320, such as this on that I found on eBay:

http://cgi.ebay.com/5-Channel-USB-Oscilloscope-Portable-PC-Based-Software_W0QQitemZ350036573868QQihZ022QQcategoryZ105806QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

Are there any (explicit) instructions anywhere as to how to go about doing this (tuning with a scope). Where do you connect the leads / probes? How do you setup the scope for the measurement?

I know that one can "tune by hand", but I would really like to use a scope to tune the servos. That way I may be able to have a bit more confidence that the servos are critically damped as they should be.

Since the servo tuning / electronics portion of this project is, by far, the most enigmatic and misunderstood for me (I'm have a mechanical backgound), I'd like to be able to confirm my tuning by hand or "guesstimate" with something that is a little more concrete (in ny eyes).

If I can't use this type of PC Based Oscilliscope, what type of scope would I need to do the job?

I'm interested in this question too. Maybe post in electronic forum or gecko forum? I see an oscilloscope trace over at homeshopcnc, with current probe.

bemfarmer, I've posted this question in the Gecko Drives forum, also. Hope I don't get flamed for double posting. :o

robhrzic, apparently tuning is done in mach3. There are instructions on the artsoft forum. Also there is a yahoo Geckodrive group, but I cannot understand the postings. lol

bemfarmer, yes, I am aware that the Mach 3 user's guide has a a "Tuning motors" (Section 5.5) chapter, where it shows you how you calculate steps per unit, steps per revolution, acceleration and deceleration curves, etc.... That's not what I am talking about.

I want to know how to go about critical damping / tuning the servo motors to the Gecko G320 drives, using an oscilloscope, as shown on pages 2-3 in the G320 manual:

http://www.geckodrive.com/product.cfm?pid=13

I have never used an oscilloscope before, and would like some sort of guidance / direction as to how to procede in doing this correctly, and most of all safely, without making any expensive "smoke". :eek:

I know exactly what you mean about not understanding!
:withstupi

I finished installing the sub-panel into the enclosure. I found a "hammer finish" green Rustoleum spray paint that seems to come close to the green on the mill, so I painted the enclosure. Now I am finally ready for Phase II of the wiring, and hooking up all of the connectors for the inputs and outputs.

I also got a chance to finish up the drive design for the Y-axis. I should have all of the stock already, so all I need to do is start making some chips. :)

I finished wiring up the machine control enclosure today. I took the covers off of the G320's and soldered a lead to the test point and ground point, which I'll connect to a common terminal strip for easy access for tuning the drives / motors with an oscilliscope. I wish that the G320's would come with an externally accessible test and ground point, as I REALLY, REALLY, REALLY, did not like soldering anything to the PCB inside the G320 enclosure. I hope I didn't fry anything internally doing this. The "test" access hole is totally useless in my opinion, and I do not see how you are supposed to access the test and ground point through this little opening, that doesn't seem to be anywhere near where it should be.

The connectors and sockets were a lot easier to (solder) use than I thought they would be, and they give the appearance of a really nice looking professional install. The only (male) socket that I've done so far is for the E-stop mushroom. I still need to install the sockets on all of the other input/output wiring.

I am a little concerned, as when I powered it up (not connected to a PC) for the first time, only two of the green LED's lit up on the status board connected to the combo break out board. I also noticed that as I turn the power on and off, I would get some of the other LED'd to light up, but could never get to see all four come on. Why this is, I do not know. On my previous power on test (with only the power and step, dir, and common connected to the G320's) all 4 green LED's lit up.:confused:

I hooked up a motor and respective encoder to a one of the connections to see what, if anything happens. To my bewilderment, the motor seems to turn and accelerate, then stall (fault light comes on the G320), repeatedly over and over. I guess the good thing is that it does do something, but i need to figure out why it's operating as it is, and how to adlust whatever needs to be adjusted.

There is a lot of wire and connections here!! I triple and quadruple checked all the connections before I powered it up. I hope that all of the connections are right, and all I need to do now is tweaking and tuning. I hope that I did not damage anything when wiring it up. At least I haven't seen any expensive smoke, yet.:)

I am really confused about the ERR/RES connection. It seems that if it is not connected to the ENC+ terminal, the G320 remains in a fault state. That's the way that I left it for now(ERR/RES jumpered to ENC+), though I am not sure if this is the right way to connect it, or if I need to do anything else.:confused::confused::confused::confused::confused::confused:

I am getting 77 VDC at the power terminals on the G320's, which I believe is right where it should be. Though, I am getting about 7.4 VDC across the ENC-/ENC+ terminals. I thought that this was sUpposed to read 5 VDC. I am not sure why I am getting a higher voltage.

I have yet to receive my proximity sensors, which are backordered. Once I get them, I'll try to see if I can hook up the X axis, and see if I can make anything move under power.

I haven'y connected any of the output relays yet, as I am not sure if I'll be using any, yet. I also made a couple of extra access holes that I installed a couple of large grommets and plugs in, for and future additional connections that may be needed.

I did have to leave one fan out, as I did not leave enough room for it. It interfered with the AC input wiring from the transormer to the power supply prep module. I hope that the 7 fans that are in there will be able to keep everything cool!:cool:

I hooked up a motor and respective encoder to a one of the connections to see what, if anything happens. To my bewilderment, the motor seems to turn and accelerate, then stall (fault light comes on the G320), repeatedly over and over.


I switched the "A" phase and "B" phase wires on the G320's, and that solved the accelerating / stalling problem.

I set the gain and damp settings to the default 10 o'clock position, and the limit all the way CW. The servo seemed to be "singing" like it should. So, I figured that it was finally time to install the X-axis drive. I took the left side bearing retainer apart, and placed a .014" shim between the outer races of the angular contact bearings to get rid of the "sponginess" or "springy" feel that I have had in the X-axis since I put the table back together. To my surprise, I noticed that I had installed the AC bearings backwards.:rolleyes:

Once I had everything put back together (with the .014" shim), I was pleased that I had no more "springy" feel in the handle. I have yet to actually physically measure the backlash, but I am pretty confident that, at least according to feel, that there is very little, if any.

Once I had everything tightened up, I fired up the controller, PC, and Mach 3 to see if I could make some motion. I tried to jog the X-axis, and I had a brief very slow and jerky movement, and then the G320 would fault. I was a bit disappointed, as I really wanted to see some smooth servo CNC motion. Oh well................

I e-mailed some questions to the support group at Geckodrive, and Marcus very quickly replied, and suggested that I separate the step and direction wires going from the combo board to the G320's, and to use shielded cabling to make this connection. Thanks again Marcus for the quick reply. I see why people say that Geckodrive provides top notch support

I have placed an order for some shielded cabling from McMaster Carr. Once it gets here, I'll re-wire the step / direction wiring and hopefully make some motion.

:banana::banana::banana:

Finally!!!!!!!!!!!

I re-wired the step and direction wires using (2) separate shielded 22 gauge cables. I am currently able to move the X-axis (using G0 manual input) at about 71-72 ipm. I still have to play with the pulse frequency and accel / velocity settings to get it up to 150-200 ipm rapids, which is my goal.

The only thing that concerns me is that the motor is still a bit "noisy" as it moves the table in the -X direction. When moving in the +X direction it is relatively quiet and smooth. It makes some noise though, and the handles on the table vibrate a little when going in the -X direction. It also seems to get a lot worse at lower feed rates.

When turning the handles manually (with everything turned off, of course) it is very smooth in both directions, no matter how fast or slowly that I try to turn them.

Anybody out there have any ideas as to what may be causing this?

So the shielded cable did the trick. Nice to see it move, but, for the life of me I don't know why you only get problems in one direction. I wouldn't think it is mechanical since you can not reproduce the problem manually so I have to think electronics and something in the resonance of the driver is causing your problem... but this is really just a guess.

hi

robhrzic excellent work and nice thread write up

cheers