PDA

View Full Version : Belt drive in the works !



Cruiser
04-13-2007, 10:56 PM
I have only seen one belt drive pic and it was external and would have eliminated the posibility of doing the air tool changer mod. So I have been looking at sprockets and belts and doing my home work and finally tore my gear box apart after ordering sprockets and belts from the local ! I am at the same time going to change out the spindle bearings i just put in with some new ones, I looked at the angular's and decided on precision ball with shields or one side seal with oil for the bottom bearing, I was also surprised to find in my tool box 4 super precision bearings that are same size as the top bearings, so i'll have plenty of those. My gear ratio will be 1.583 so soon i'll be worried about what i can do with the low speeds without gears to change, I have no idea what to expect there. After gutting my box and taking a good look and then taking a few other pieces out not needed and a couple that will be used I think i have a good solution to having my drive in the box with no oil or excess baggage. I found out that there is a trick to taking apart the bearing carrier assy for the spindle driver and I plan on using it to carry my driven sprocket. It looks like i'll cut the gear off but if i can keep it i'll maybe use it for speed senser if i can. Enough for now i spose, I'll be taking some pics as i go and have a few i'll try to wedge in here now.

wildcat
04-14-2007, 07:55 AM
Very cool idea! How do you plan to tighten the belt? Best of luck.

Cruiser
04-14-2007, 08:39 AM
I'm hoping i did my homework correctly and the belt just fits ! If i need to tighten it then i'll have to use an idler.

ozzie34231
04-14-2007, 12:51 PM
I'll be interested in this thread, hope you take it to the end.
A few months before Aaron gave up the ship, he sold me a headless machine. I really didn't want all those gears and the movable spindle, etc., and he just happened to have a machine, less head.
I picked up a spindle with a Kwick switch end from a Huco machine on Ebay for little money; big sturdy spindle.
So now I'm mentally engineering the rest of the head.

If I might add my two cents to what you already have planned, I might suggest that a single belt cog ratio probably will not satisfy you even with a variable speed motor, unless you intend to use a very limited range of spindle speeds or you have a huge motor, (5 HP). A large surfacing cutter needs slow speed and good torque and if you're talking 2 HP and want to get up to 4000 rpm for aluminum you can't do both with a single belt ratio.
Hope this helps, not hinders.

Ozzie

Cruiser
04-14-2007, 06:23 PM
Well Ozzie I have thought of it a lot and figure i'll just avoid the large cutters altogether. My concern would be with say a 1/2" em in steel. If i need more horse i'll go 3 or have to do a whole new engeneering scheme. 5 horse all come lower rpm's and i'd need a new ratio and not enough room for it without making a new box to put it all in and if that was the case i'd then pick on a 7 because i'd need new vfd as well no matter which way i turn so .... did ya hear me screem, i was defening. ! all i want is to get rid of the box noise and have a usable system again !

BobWarfield
04-15-2007, 07:23 AM
This should be quite interesting. Bully for you, Cruiser!

I've been agitating a bit over the pulley ratio question myself. I think a vari-speed (variable pitch) pulley has been the best idea I've seen so far. You can pick them up off eBay sometimes pretty cheaply. Once I got one in my hand it doesn't look that hard to make one either.

Ozzie, be sure to post your adaptation of the new head, as that will also be quite interesting.


Best,

BW

ozzie34231
04-15-2007, 08:06 AM
Hi Bob,
Please post a pic of your variable speed pulley and some idea of its size. I picked up 3 a few years back and haven't used them. I've looked for belts that might be suitable and can't really find something perfect.

I had a restaurant mixer that used two of them on a common shaft as idlers and that gave a very large range of speed. Looks to me like one of mine would give a range of ratios of 1 to about 3 or maybe a bit less.

I'm thinking I want my new head to have a range of 40 to 4000 RPM with good torque at the lower end. Electrically I can get 10 to 1 but not with much torque at the low end. So that probably means about three steps on timing pulleys. I think my DC motor turns 2550 top so I need 1 to 1 1/2 on the high end and assuming I don't want to go lower than 400 RPM electrically, I'd need 10 to 1 there.
That's too big so I should shoot for 80 or 100 RPM on the low end.
Ozzie

ozzie34231
04-15-2007, 08:31 AM
I just spent a few minutes with my machinists calculator and even cutting 4130 steel with a big surfacing tool or a HSS mill, 200 RPM should be low enough. Don't remember where I got the idea that I wanted to go down to 40.

Ozzie

Cruiser
04-15-2007, 11:11 AM
I have spent some time looking into the vary pitch & looked for the dynamic drive systems. I won't buy something like that off e-bay nor will i gamble with size's. Also with a dynamic drive you will need some way of sync'ing with mach for some applications, such as tapping. For the time being i'll put this into application when the parts come in next week, then do a discovery of what my torque will be in the low speeds. I must admit that a dynamic drive would be nice with an encoder > or < but I couldn't even find anything at all searching the net for sourcing info or units and i used all of my limited vocabulary. its like they don't exist.

ozzie34231
04-15-2007, 12:02 PM
Cruiser,
After stripping the gears and stuff you don't need, can you estimate the weight of what you have left, (without the motor).
I'd like to know what general amount of mass is there.

Thanks,
Ozzie

ozzie34231
04-15-2007, 12:07 PM
Another question Cruiser,
What belt size have you decided on, width, teeth per inch?

Ozzie

BobWarfield
04-15-2007, 12:22 PM
Fellas, my notes on my own belt drive conversion and the vari-speed pulleys are on my web page here:

http://www.thewarfields.com/cnccookbook/CCMillBeltDrive.html

I plan to use the vari-speed pulley to implement a simple Hi-Lo gear. In low gear, the spindle speed will range from 0 -2600 rpm, which will be fine for steel. Hi gear will be 2600 rpm - 8000 rpm, which should be great for aluminum and other soft materials. Within those ranges, Mach will vary the speed electronically. Since Mach already has provision to let a microswitch tell it what gear its in, it should be straightforward to keep it up to date on what's happening. I'm envisioning a 3:1 ratio on the vari-speed, which ought to be enough to keep the torque up reasonably well. We will see. I may fiddle with these ranges after thinking it over for a bit.

Frankly, I am most concerned at this stage about getting my bearings to live at 8K rpm. My project will be a long time in planning as I intend to get my mill CNC converted before attempting it.

For those interested in vari-speed pulleys, I would research the Go Kart torque converter angle carefully. That looks like the cheapest source. You'll want to ditch the centrifigul mode and go manual, but that should be an easy modification to one of those units.

Best,

BW

ozzie34231
04-15-2007, 02:14 PM
Fantastic site Bob,
I can see myself spending a lot of time reviewing all the great info you've gathered.
About the variable pulleys; I'm thinking that 3:1 just isn't quite enough, but if one were to use two of them as in the mixer I mentioned, you'ld get a 9:1 ratio and that is enough, for sure.

Two vari-pulleys are mounted on a common shaft between the motor and spindle, which each carry a solid pulley. An arrangement is made to enable the idler to be moved toward the motor or spindle, and consequently away from the other. A relatively small amount of movement will give a big change in ratios. Total idler movement maybe 2 inches will give equivalent of 9:1 change.
Ozzie

QSIMDO
04-15-2007, 03:16 PM
This is from a site that's full of engineering calculators you folks might find valuable.
http://www.engineersedge.com/motors/speed_reduction_motion_torque_force_equation.htm

Ok, what now?
I'm having trouble opening the link from here.

Ahh..just slow to connect.
Here's the main site too; http://www.engineersedge.com/Calulators_Online.shtml

Cruiser
04-16-2007, 08:57 AM
I talked to the guys at the bearing shop and learned that with aungular contact bearings you don't have seal or shield and lubrication will be a problem. With the presision bearings you can go shield with grease or sealed pull the inside and run some permanant oil in spindle. If i recall correctly one seal and oil had top speed allowance of 11,000 rpm. I am going most likely with shield and grease. I think he said it was good to 9,000 and i'm only going to 5,400. I suppose we could device a seal on the spindle itself, there's plenty of room, but the added expense of agular and seal would be high versus the chance of failing.

BobWarfield
04-18-2007, 01:34 AM
Ozzie, you're probably right about the 3:1 not being enough. I was just reading about a Hurco mill that has an 8:1 ratio for its hi/lo gearing. Will just have to see when I get ready to engineer the thing what can be done!

Cruiser, if it was me, I would definitely plan on some sort of spindle seal. A little compressed air or jet of coolant in the wrong place could result in some expensive damage. I don't think it would be that hard to fabricate a simple labyrinth seal at the bottom of the spindle that would do a great job shield things. If you run a power drawbar you could tap a little air and put positive pressure on the spindle chamber as well. This would help keep the dust out and would even cool things a bit. I plan to experiment with air-oil mist cooling for my spindle project.

Best,

BW

Cruiser
04-19-2007, 07:07 AM
There have been some gliches in the ordering parts process but i think all these have been resolved and i hear that they will be shipped today. The belt i got is rated at 20 hp with the speeds i'll be running. After it is all finallized and parts are delivered i'll give out part numbers and full specs. If all goes right I'll gloat a little and if it goes awry then i'll cry a lot ! I just hope it goes better than the rotors i ordered for the front of my f250, I still haven't identified what they sent me ! Add in that i crushed an expensive part in my machine at work, i'm not a happy camper lately !

RICHARD ZASTROW
04-19-2007, 12:42 PM
Cruiser, Sealed angular contact bearings, precision & otherwise, are available. Sealed are usually factory filled with grease (in the correct amount). I use these often, especially in vertical spindle applications. But I still put a seal between the bearing and the atmosphere and fill the gap with grease to prevent inward migration of ????. If the grease expands the pressure will squeeze it out the seal. I always am concerned with lack of oil to the top open bearing in a vertical application when there is not some sort of lube circulation/injection system.

You can use open angular contact bearings at the bottom (with outside seal) and a sealed radial bearing at the top I suppose. I think I might want to have a sight glass or dipstick or ??? so I would be confident there was adequate lube in the spindle.

Cruiser
04-19-2007, 07:30 PM
Dzaster, I like that ! well, as it is I don't feel that angular contact is money well spent so I'm going with the precision shielded with grease on the bottom, and i will be using angular contacts open and grease at top. OH I can hear it allready WHAT ? well, its like this I have found that I have or had four of them sitting in my tool box for over 15yrs and they are exactly sized for the top of the spindle and I already used one to help support the motor driven shaft that held a gear before but will soon hold my large pulley. Since it fits, and makes the shaft more rigid even without any load then i'll use one there since after all free is a good price as they were taken out of a t-stock using four of those for the load and three of another brng for the radial and i might as well use them up. The way the spindle is set up i can always fit a seal to the end without even bothering to take it out. I have been considering even cutting a leather wiper to put under the screw in protective cap in liew of seal which will seal enough without the added friction. Now if my parts would just get into my grubby hands so i can get something done, I'd be set.

RICHARD ZASTROW
04-19-2007, 08:21 PM
cruiser, WHAT? OK, that takes care of that! I'm confused!!! Are you saying you intend to use one (1) angular contact bearing at the top by itself? (unacceptable) Are you saying there was a gear drive where you intend to put a belt drive? If so, the radial load will be extremely increased and your single angular contact bearing (at any price including "0") will be demolished damn near instantly. Pray that NC cams ears start ringing and his wrath be put on you!!! Seriously, If you really won't/can't spend the money for high quality A/C bearings, how about lesser grade bearings that are more appropriate to the application?
Shields do not stop loss of lube. As the grease warms up and melts, it runs out the bottom of the shield in a vertical app. Shields slow down ingress of SOME larger particles. A VERTICAL SPINDLE REQUIRES SEALS.
I love doing it as inexpensively as possible, typical DIY. But being CHEAP on bearings/seals is false economy!!!!!!!!!! When you finally get done replacing parts after your machines shortened useful life it will have cost you more and your machine will have "dropped dead" sooner than it should have. Then, you will hear in your mind " nananananana' I told you so" from that old fart

Cruiser
04-20-2007, 08:34 AM
The top bearing of the spindle only supports the top of the spindle, the load of the drive is carried by the driver which has a gear on it and an ID spline drive for spindle. the top bearing takes no load and only spins. The other place i'm using one is very similar, no load to speak of just a little added support for the shaft that the motor plugs into, which carried a gear and will next have a pully. So what i'm saying is "Don't worry about it dude" this 40deg bearing will do the job like being on vacation !

RICHARD ZASTROW
04-20-2007, 01:51 PM
Cruiser, I thought you were converting this to a belt drive (which exerts a radial load from the motor/tool and belt tension). A gear is a bunch of levers extending out from the center. Unless the gear in question is an idler, it also has radial load exerted on it. A 40 deg. angular contact bearing is designed for mostly axial load (in one direction which is why they are normally used in opposed pairs) and partial radial load. I don't worry about anything, including your spindle, but maybe you should start. Anyway, I hope for the best, good luck dude.

Cruiser
04-20-2007, 02:28 PM
Dzastr, Well, its simple really it is, the belt drive tension will be taken by other bearings than these angulars ! For a little clarity go back and see pic of gear box lid with two shafts one of which is splined (pic 2) and maybe you will see what will take the load. also another pic (pic 1)you will see the lid with some bearings and the shafts sitting atop, one of the bearings for support duty is in the lid and the bearingd end of longer shaft will enter it adding just a little security and actually could be left out altogether. I do know a little something of bearings and everything is fine. Now the spindle will take one of those angulars in the top position, with more radial than thrust with the precision at bottom taking the thrust and radial load of cutting and shock. what did I miss now ?

RICHARD ZASTROW
04-20-2007, 03:22 PM
Cruiser, You just pulled an Ace from your sleeve with that bearing in the cover! That is part of my "bag of tricks". If everything is lined up properly, what is really your middle angular contact bearing will probably last as you have said. As long as the spindle shaft stays straight and the middle bearing is lubricated, it is actually redundant. Only thing left now will be the small amount of end play coming from the clearance in the front "precision" bearing. What is that bearing anyway? I,m making one of those assumptions that we never should that it is a deep groove ball bearing.

Cruiser
04-20-2007, 03:36 PM
Dzastr, I think the stock bearings are deep groove ball as they have a wiggle and says spin me. there are two on the driver which the spindle slides into and is pretty firm with both bearings. the stock bearing on the driven shaft which connects to motor is same and with the little spinner on the end which rides in bottom of box i'd be prone to switch my angular with the stock so the shaft will hold angular into play and the stocker can do support. but the way it all fits together i don't really it will matter or make any differance. what really counts is getting the parts and putting it all into play. with the call a little while ago i find that everything is available except the smaller pully which will mount on the spindle driver. The other concern is that i ordered the correct belt, with a 6.102" or 155 mm center distance my belt selected will fit "net". But ! will everything nest together as planned ? The way things have been going lately ! I'm worried and i'll be several weeks for the little guy to arrive off back order to find out. So I sit and wait and ammuse myself here wondering, what did I miss ? what did I forget !

Cruiser
04-21-2007, 10:46 AM
Just a short update, I did switch the two bearings per above puting the AC on shaft side and the stock on support side and it made all kinds of differance. It is now maybe 300% more rigid as the AC now has axial load (minimal) the shaft when assembled will hold the AC solid. Most of my parts will be in next week with the small driven pully being out 3 weeks !

RICHARD ZASTROW
04-21-2007, 02:13 PM
Cruiser, I have to start over.(my fault, I didn't realize the spindle was a quill type. Now driver etc. makes sense) IN AN IDEAL WORLD, the gear or "soon to be belt" driver would be supported on both sides with a bearing. Since the driver really sees mostly radial force. It sees only the axial force from whatever friction is involved with the splines on the spindle shaft moving thru the driver.
The spindle shaft (again, in AN IDEAL WORLD) would have at least two bearings or sets of bearings supporting radially and axially. The axial support is needed to counter the push and pull of cutting tools and maintain position axially.
The clearance built into typical nonA/C bearings will have some degree of end play. How much your application will tolerate is up to you and your wallet. Personally, I,d go with A/C's but I don't pay for them, my client's do.

Guess what I found in my desk drawer? An SKF double row cylindrical roller bearing with a 20mm ID, 42mm OD and 16mm Width. The cage is brass or bronze and hold the rollers in alternating positions so they are not next to each other. The inner race also is shouldered on both ends to retain the rollers. The outer race is plain, it can slide right off the ends. My desk is kindalike your tool box.
Well, gotta go, Good Luck

RICHARD ZASTROW
04-21-2007, 03:26 PM
Cruiser, That bearing I found turned out to be an SKF high precision NN3004K 1:12 taper bore spindle bearing. This is supposed to be part of an extremely stiff spindle bearing setup SKF calls "The NN Solution" in a brochure I had laying around in my archives dated 1989. I am getting old.

Cruiser
04-27-2007, 06:38 PM
Well, after ordering parts for this adventure twice now and cancelling twice ! Today I worked with the salesman (who really earned his oats) till we had a working system of parts that are available and ordered ! they will be in late next week. As for the spindle bearing, we did some crunching there too and i bought the AC and a seal for the bottom, and i already have a store of AC's for the top. So today I pulled the gearbox (empty!) off the machine and started to do the conversions in play. I still have one conversion that i haven't mention'd but i did give it a name "Can't E Lever" ! can ya figure it out ? My gear ratio has changed with todays engeneering to give me a top rpm of just over 5800. So I should have aluminum speeds covered and maybe still be able to work steel with small endmills. Hopefully i'll have the heavy work done this weekend and have it ready to just install and try out. I am seriously hoping that getting rid of the gear noise will elliminate the problems of noise interferance with the electronics. That box really got noisy after the spindle bearings going out and changing the oil. We shall see !

Cruiser
04-28-2007, 03:28 PM
"A thousand Words" !
I am progressing quite better than expected with my rendition of "can't e lever" ! read (can't even lever)

davo727
04-28-2007, 04:55 PM
Cool! Looking forward to seeing more. Why the milling on the side of the column? Dave

davo727
04-28-2007, 05:35 PM
Oh, maybe you are mounting the rail and bearing blocks on the side of the column and connecting the Z slide and bearing blocks with a plate, thus transferring the cantalevering force to the bearing blocks instead of the Z slide dovetails?

BobWarfield
04-28-2007, 08:05 PM
Ah, very good. I've been writing about putting linear slides on an Asian lathe for some time and now someone's going to do it. Should be interesting!

The router jig is presumably making a nice true spot for the rails to be bolted down on. Does everything clear the existing dovetails?

If I were going this far, I'd be tempted to move the ballscrew out of the column and fill that column with epoxy/granite ala Davo's base.

Best,

BW

kimoyo
04-29-2007, 04:52 PM
Cruiser, very cool thread!

Are you changing tapers also?

Why do you feel the cantilever mod is necessary for your mill? Do you think you will see a big improvement?

Cruiser
04-29-2007, 06:20 PM
the tapers if spindle is what your refering to NO i'm using same spindle but new bearings. The cantelevering is only a problem when pressure is applied that can lift the head and with the added pressure needed in the gib to make the differance then it starts spreading the dove and making it difficult for the drive, this will take the pressure needed to lift and hold the weight of the box and allow me to back off the gib to near neutral and hopefully relieve the friction tremendously. I've been thinking of doing this since i got the machine and first tried setting the gib and noticed what was happening and did some measuring. Now if it just works as planned. I am drilling now, i made a custom tap drill bushing and i've been clamping measuring and and and etc ! Warning don't use the high carbon taps, only high speed ! The surface milled with the router turned out satisfactory, its not perfect by any means, but is is trued to the axis now close enough that it'll work. the most important measure at this time is the trueness to the slide along the axis and i'm setting it to the nut ! (so far) only 20 more holes to go. the brackets to hold the bearings on the rails will have to wait till i have the mill running again. OH I washed the slides off after the milling to get rid of the cast dust and found that it didn't want to drive anymore, that means the molylube i put on the slides really does do wonders against stickion. I will put some more on after my final cleanup ! As for moving the ball screw and filling the collumn, I'd say Just a waste of time ! The collumn is plenty stout now, just needs this and the set screw helpers for aligning, and it'll do fine. and when the belt drive comes in I'm hoping it all works out too .....

Cruiser
04-29-2007, 10:53 PM
This is an update, i got the rails mounted and looking good. then i cleaned up a bit more and smeared molylube on the slide & run it in some and found out the bad news ! I went just a bit too low and heard the triplets go tink tink katink in the chip pan. they were easy to find but seems i have created more work necessary that i don't want to do ! This is enough for now i guess, i'm tired. Probably should have kept this part quiet & to myself huh ?

Cruiser
05-03-2007, 10:43 AM
Here are a couple of pics showing the bearings i refered to above, and another of the first mod to case for the input of driver pulley. This is going to be a one way trip for this gear box. I even buffed off the paint and bondo from the machined sides of box as well the rest of it too then painted it black (all i had for color). I mentioned above about loosing a few balls from my "z" ball nut, now for what i learned. Never use grease on the ball screws unless there is no way whatsoever of chips getting to it ! I took my screw out and cleaned nut finding lots of aluminum fine within. Then i counted all the balls and found that I was short more than three balls. I hustled to the McGuires bearings and got a bag of balls, sized close enough and reloaded the nut. This time i elected to treat the screw with a dry lube coating which won't hold chips or anything else (i hope). I really want to take out the "x" & "y" too but won't at this time. I will plan on replacing them at a later date with "preloaded" nuts. These double circuit nuts are fine for now, but deffinately looser than i'd like. I wish now i'd asked more about them before ordering but had other stuff on my mind. I'll flush the "x" & "y" more with spray brake clean (read dry cleaning fluid) and hope i get them clean enough to last a while. My parts should be here today to assemble the belt drive system, they use the taper lock bushings, one is 1.375 (driven) and the other .9375 if i remember correctly for the driver (motor). I'll spec out the parts list if your interested later. Now I'm bored till I get my phone call of parts ready to pic up !

wildcat
05-03-2007, 11:57 AM
Cruiser,

I am having problems coming up with words to show how impressed I am with your work. Needless to say, I am really looking forward reading your next posts.

BobWarfield
05-03-2007, 12:21 PM
Cruiser,

I am having problems coming up with words to show how impressed I am with your work. Needless to say, I am really looking forward reading your next posts.

Ditto!

I'm watching with rapt attention on this. A belt drive has been on my mind every time I have to cut aluminum. I honestly haven't had the stones to just rip into the mill and "Git er done" like Cruiser!

:cheers:

It's gonna be so nice to have those extra rpms we'll all be jealous!

Best,

BW

davo727
05-03-2007, 12:31 PM
Yes it will be very cool. Will be a major improvment. Thats why were here, to improve our mills and make them better than they were supposed to be, not just leaving them cause they (is what they is). Thanks for sharing your project with us cruser. Wish some more guys had some stuff going on. Dave

davo727
05-03-2007, 12:54 PM
Bob, After you get your lathe project up and running you will have time to start on one of your mills. Having a spare you can make parts for the one your working on plus not have to stress too much about doing a point of no return modification or if you mess up and kill a component not the end of the world. Well, Im gonna get back in the garage and back to work on mine, Dave

Cruiser
05-03-2007, 01:54 PM
Thanks guys, I feel's better now ! My parts just came in so i'm off to McGuire now to pic them up ! Stones ! I thought they were Bumble bee's in my Gut but they could be Stones i guess ! ha ha ha be back later with the goodies !

Cruiser
05-03-2007, 08:10 PM
I got most of my parts, so far had a typo error with the ac bearing, replacement tomarrow. and the belt even with all of our calculations is too small, numbers seem good but still too small, larger belt tomarrow. As you can see with the pics i just took, Its looking like it'll all work ! I'm hoping that adding almost an inch to circumferance of belt that it'll allow another .270"ish to centerline so belt will fit. I'll take the case top with me tomarrow and try it there. So, I think that I deserve pizza tonight ! Its so close now that I can taste it. Its been a bit of a PITA ! but will it be worth it ? One way trip !

kimoyo
05-03-2007, 08:22 PM
Awesome!


I got most of my parts, so far had a typo error with the ac bearing, replacement tomarrow. and the belt even with all of our calculations is too small, numbers seem good but still too small, larger belt tomarrow. As you can see with the pics i just took, Its looking like it'll all work ! I'm hoping that adding almost an inch to circumferance of belt that it'll allow another .270"ish to centerline so belt will fit. I'll take the case top with me tomarrow and try it there. So, I think that I deserve pizza tonight ! Its so close now that I can taste it. Its been a bit of a PITA ! but will it be worth it ? One way trip !

BobWarfield
05-04-2007, 01:22 AM
Cruiser, that's looking good!

That belt is aggressive, I like it!

Best,

BW

Cruiser
05-04-2007, 10:50 AM
I think its time to give out some of the gravy ! I'll start with the parts list.
1 tcm 35x72x10tc oil seal (spindle bottom) $5
1 bls 1610 1 3/8" taperlock bushing (spindle) $13.
1 ban p48L100 timing Pulley (driver) $47.40
1 bls tl28L100 Pulley w/hub 1610*c (driven) $32.09
1 msk sdsx15/16 qdbushing (driver) $15.71
1 Belt = ? L100 (3/8" pitch) size didn't work yet ! $12.19
1 koy 7207b gc3fy Bearing angular contact
(spindle bottom) $37.01

If you've read up on this you caught on to the bearings switching @ the driver shaft, this is a functional change.
The driver shaft (motor side) is turned down to 15/16" or .9375" for the gear bushing, being carful to cut up to the swedge shoulder holding the two piece shaft together, cut too far and you loose the shaft although you could seperate it and remachine for larger motor shaft then put it back together with welding and then machine to 15/16"

Watch out for the C-clips holding some of the bearings in place ! especially the driven stub, there is the cover on top of gear box lid which is a light press fit, just wedge it off carefully with chisle and screw driver. Then knock out stub with bearings staying in lid. The gear on stub will be cut off and size is going to be 1.375" and it is almost that now, but continue size into area of gear and about half of shoulder, most of this is for alignment of sprockets and getting them close to bearings !

I used a tube (alum) with a slight turn on end to fit into bearing socket at bottom of case slipping a thin disk over tube for marking and checking of the 6" clearance required in case at motor or driver end. I trimmed out obstructions with router carefully using carbide end mill 4 flute coated and long 4"? I used up four of them. I also used a sawzall to cut crude notch and broke out piece before milling with router, took two blades.

The gear box is going to be dry now and since i'm using the little stock bearing to help stabilize driver shaft i'll grease it at assembly time.

There is a spacer with seal inside gear box in conjuntion with top of quill. this is removed, If I can ! I'll machine off some of it to clear the pulley and re-install what is left of it. Not sure of clearance yet, didn't measure out this aspect, one way or another it'll be the pulley in there !

I have the angular contact bearings already for top of spindle and use on the driver (motor) shaft already size 30mm x 62mm and I'm not getting the expensive ones, I don't think the high presision ones will give me any advantage here ! These bearings are rated at 11,000 rpm plus with grease and a very high life expectancy as well !

Well, I think that about covers it till i get the belt this morning and try it out, i'm taking the cover and pulleys with so i can trial fit there, and they can see how the error applies to the belt size, I crunched the same numbers they did and came up with same belt but it won't fit ! I recalc'd with differance and came up with a theoretical center distance of 6.356" when actual is 6.102" or 155mm it don't figure yet. but we'll prevail one way or another .... it has to work ..... there is no option .... resistance is futile ! Later guys !

Cruiser
05-04-2007, 11:09 AM
Kimoyo, post your pic here ! It is right on and will help.

RICHARD ZASTROW
05-04-2007, 11:13 AM
Cruiser, It loks like there's room for a tensioning idler if you need one. It appears you could install a bar between the sprockets and place an eccentric like a cam roller to adjust tension on the belt. In a dry environment it works. (BTDT).

Cruiser
05-04-2007, 11:19 AM
I've considered it and it will happen if the belt warrants it ! probably will mount it to the box with a pusher bolt of sorts, must be careful tho of not giving too much load or the radial or side load may effect bearing life, which may be questionable as it is at the driven end or quill end of this setup, that is why i'm setting the pulley as close to the bearings as I can, so leverage is minimal against bearings.

Cruiser
05-04-2007, 12:19 PM
Here are two pics, one is to clarify clearancing of gear box, which may look scary ! As I said more than once this is a one way trip !
The other pic is of the mod i made to the router and of the end mills used for milling of the cast iron, there may be a better end mill available but you will need a long one to reach! Four end mills did the cutting of the gear box and the side machining of the collumn for the mounting of the rails.
of the 34 holes for both rails, I used 31, loosing two to the voids on left side low and one at top right side, borken carbon tap, don't bother using a cabon tap, high speed only ! One very old bottom tap i've had over 30 yrs did the whole project, after new carbon tap broke !
These two projects were the primary of my thoughts every since i got the mill a yr ago. and soon they will both come to fruition !
I do need the mill to make the tie in mounts for the three little linear bearings which ride the rails, each side, with some adjustment so i can take the weight of the now much lighter gear box onto the rails and off of the gib's, then the gib can be backed off to a more neutral setting. I've had to buff off some gauling from gib tension at the top of collumn, at the time when the tab of gib which holds screw head adjuster broke off ! I had to flip gib and recut a better fitting notch, and smooth notch so no sharp corners (used file here) lest a fracture starts again and breaks off last chance notch for this gib.
This has been and i'm sure it will continue to be a chalanging learning experience for sure, I've really been challenging my own mechanical abilities here, some enjoyably, and some with anger !
It better start paying off soon as i told the tax man this was / is a busyness to make money ! To date gross earnings $0,000,000.00 $ gross expenditure getting close to $30,000 !
Ok, nuff of that .... hopefully in an hour or so, i'll find out if the next size belt fits, if not the next bigger size will have to come from further away than ptlnd or. means time waiting ! Not much more till this thing is a done deal ! HOPE HOPE HOPE !

kimoyo
05-04-2007, 07:24 PM
Cruiser, thanks for the help. Here's the pic of the driver shaft (motor shaft) before being modded. Someone else posted this in another thread, I just circled what I thought Cruiser was explaining he turned down to 15/16". Hope its right.

http://i19.photobucket.com/albums/b170/kimoyo_/sprocketmod.jpg


Kimoyo, post your pic here ! It is right on and will help.

Cruiser
05-04-2007, 11:17 PM
here you can see that i have belt on, its loose and needs a tensioner. I made one from scratch and used a bearing which should last forever. the gear box is back on the machine now with lid in place. tomarrow i'll see about getting this thing to run again. The pins in lid are tapered and can easily be knocked out after lid is off, then fit a metric bolt for it, leave them off as for assembly it is necessary to set lid on crooked so belt will not snag tensioner, then rotate into position and drop in pins and bolt her down. We'll see what we see tomarrow !

Cruiser
05-05-2007, 10:57 PM
The belt system is running, the belt i got has a slight irregularity in its thickness which is heard when spindle is running, but it appears to be settling down some. The idler bearing is a bit stiff too and needs some run in. all in all it is one big bunch quieter and i did for a brief moment run it up to the top speed 5900, scary, i'll get a bit more time on it at slower speeds tho before taking it up for any time. I am concerned tho that at 3,000 rpm i can stop spindle with 3 fingers. I don't know if that would run an end mill or not. tomarrow we play with it some more.

Runner4404spd
05-05-2007, 11:20 PM
how large of a motor do you have running it? also are you using the original 1725 RPM motor? you realize that without going to a larger motor, you are decreasing your available torque and trading it for speed?

Cruiser
05-06-2007, 12:55 AM
I got the 3470 2hp motor when i first got the mill, I was close to getting the 3 hp motor .... shoulda woulda couda ! I understand the loss of torque but didn't think it would be so pronounced. Tomarrow i will do some fine tune and test cut and see what i can get away with !

BobWarfield
05-06-2007, 09:52 AM
I got the 3470 2hp motor when i first got the mill, I was close to getting the 3 hp motor .... shoulda woulda couda ! I understand the loss of torque but didn't think it would be so pronounced. Tomarrow i will do some fine tune and test cut and see what i can get away with !

Cruiser, congratulations. Looking forward to hearing how it goes with the trial cuts. With this new belt drive, if you choose to look at new motors, you might even want a 5HP to make sure there's plenty on tap at lower rpms.

You no longer have to worry about whether the gearbox can take it or not!

Best,

BW

Cruiser
05-09-2007, 07:24 AM
Well, I haven't got to make any chips yet, i have a couple of needs to accomplish in that order soon tho. I have got a little time on the spindle and it is sounding really good now at top speed but i don't let it hold there for long yet ! I find that the setting on the pusher is critical, and only requires to be close to belt, re: No real tension, lest it causes any imperfection in belt to reverberate through the whole machine structure. I think i have it about right now and it is very quiet ! compared to all the gear clashing from before, My computed top speed is close to 5900, but don't know the actual yet. I think i'll mount a prop to it and use my optical tach from model airplanes stuff to see what it says. I have my vfd control back onto the combo board and it is so far fairly stable, I did get a few limit/estop faults but with an increase of index debounce it seems to be subsided now, HOPEFULLY ! I think that the first thing i need to make is a box spanner wrench for the spindle splines so i can work the drawbar. It has no resistance now ! Seems someone already made a nice one, (Wildcat ?) Later, day job time now.

davo727
05-09-2007, 08:09 AM
Hi cruiser, Have you shopped for a bigger motor at all? Curious what can be made to fit. I have one of Wildcats spindle wrenches and its very nice. Also got a nice step bushing from him for the drawbar to top of spindle shaft. Dave

Cruiser
05-09-2007, 07:19 PM
Davo, Yes, i been shopping and its down right depressing to say the least ! I can find a 3 hp motor for same money i spent on this 2 hp and same rpm. mostly tho the motors in the 5 to 7.5 hp range drop in rpm by half. I did find a source for 5 & 7.5 @ 3450 but they were over $1000 and no specs to say if they were vfd compatible, then i'd need the vfd too and I don't have two nickles right now to call in a squirl for dinner ! I figure tho that when i'm rich i'll go for 5 if i can to insure some usable low end torque, it will entail making a new shaft It will mate to so i don't have to turn down motor and making some sort of mounting adapter but that is all do-able. humpf, just went to get the name of the place i was finding the best motors and its not there ! I'm sure i put it somewhere !

davo727
05-09-2007, 10:12 PM
Maybe you can find one surplus or used for a deal. I wouldnt mind a used one if it saved $800.00. Might take a lot of scrounging though. Dave

BobWarfield
05-12-2007, 01:16 AM
Cruiser, they are more money, but vector drives and motors carry more torque down into the lower rpms. Maybe you can find a deal on one. It's at least worth doing a little Internet research to learn more about them.

Best,

BW

Cruiser
05-12-2007, 08:50 AM
I did some whittlin on steel yesterday with more success than i figured. Butt I was still getting hammered by noise. So, I dis'd the vfd from combo board and still got hammered. This morning i'm going to take the last connections off the board and connect the gecko's direct and the board comes off the machine permanant ! I think it would work better somewhere else than on my machine. I also have a couple of cnc4pc boards too. Humm, maybe i better try just the vfd on the board before i off it ! AS for the cutting, i was taking lite cuts at under 3000 somewhere and the spindle just cruised right along till the fault trips things up.

BobWarfield
05-12-2007, 10:52 AM
Cruiser, I see your problem with the lower speeds and loss of power. It's something I've fretted about for my own belt drive design. I did some rough back of the envelope calculations on different configurations and came up with this spreadsheet:

http://www.thewarfields.com/cnccookbook/img/MillStuff/BeltDrive/SpindleRatios.jpg

The model just assumes the power drops off after you get below 1/2 the motor's rated speed. That's not quite right, but it's close enough to figures I've seen for various VFD's.

My conclusions from playing with that model:

- Bumping from 2HP to 5HP is not even quite a 2:1 gear ratio change, surprisingly. It doesn't really buy you that much wider range of decent power.

- A 2:1 back gear seems like the minimum needed to still work with the fairly low rpms.

- Either 2:1 with a 5HP or 3:1 with a 2HP seems like a pretty nice setup.

There's a lot of ways to rig a back gear, but I personally favor variable pitch pulleys. Hey, if its good enough for Bridgeport, its good enough for me!

A 2:1 set will fit the mill housing just fine. But you have to be able to shift them in and out. 3.5 or 4:1 is needed if the pulley set runs all the time and you're using the variable pitch as the hi/lo shifter.

Another alternative would be a "tumbler" gear arrangement like the lathe guys use. I wonder if there is a way to reuse some of the IH gears in low speed mode. Or you could use the planetary set from an automatic transmission. They're compact.

Just some ideas for your next evolution.

Best,

BW

Cruiser
05-12-2007, 12:38 PM
Bob, your chart looks close enough to me ! as for cutting steel, i have it running right now @ .06x.05 w/22.9f and 1.4" 4flt tian cbide end mill. it is doing ok for the light pass and backed off feed from chart of 32f which i tried but the radial depth feed seems hard on endmill. OOPs i think it just quit ! nope ! shop door just closed ! whew ! I disconnected the gecko's from my combo board this morning and wired them up direct and now only have spindle and coolant hooked up to board. If this holds and runs without faulting then i'm going to look for a good board to run them and get rid of the combo ! I also have the spindle board and power supply from cnc4pc but couldn't get them to work well or tuned to any degree, so i'm not going that route ! anybody wantem ? make an offer. I like the system holman has for spindle and coolant but the rest of it just won't stabilize on my system. don't know what the hell ! anyway right now it is running much longer than i had before and we will see if it stays running. Well, so much for that ! it lost position in "x" and broke end mill ! Maybe have "x" gib too tight ? lets see .............

Cruiser
05-13-2007, 09:56 PM
Well, i'm down for a while, seems my "y" servo went south for count. I checked what i could and it all comes back to the motor ! Later guys

davo727
05-14-2007, 02:08 AM
What about using a big servomotor and appropriate controller to drive the spindle belt drive? Dont they make huge power right away at low rpm? And at 4000rpm you would be over 6000 on the spindle right? Dave

Cruiser
05-14-2007, 11:25 PM
spindle servomotor ! controller ! need huge powersupply ! need huge pocket book ! oh wait are you offering me a signed blank check ! I'll be happy if'n when I get things back up and running. turnes out i burned out a servo and it is not only difficult to do, I didn't know i'd done it ! SO ! as far as the belt drive system I'd have to say I'm glad i did it ! The drive had a slight warm spot neer top of spindle where the bearings are and i'd say it got slightly pee warm almost. That was while running about 3900 for close to 1.7 hrs with end mill in steel taking light cuts. I may be a week or two till i get things back and running so ! Does that conclude this thread ?> or will i be required to continue when i get back to cutting the brackets for the "z" can'tevenlever project ! Later guys

Cruiser
05-28-2007, 01:52 AM
Well, I'm back up and running after some turmoil. I replaced the servo and retried things, I decided to tune in and run mach 2 and i'm happy with it. I haven't had any gliches or faults since. I will have my brackets done so i can hang the z to the slide rails tomarrow i hope. The only thing i am wondering about is the spindle torque. I set it light and when it warms up it gets loose, so i pulled it one more notch on the lock ring but it still loosed up, i could grab tool and get some wiggle, I don't know how tight i should take it without burning up bearings. I did burn up the bearing i had for belt idler, so i took some trailer brngs and made up a hub and spindle for it and it is in the box now, i ran it all day and it is quieter yet. So far i'm pleased with the belt drive. I don't percieve any problems doing steel with 1/4" endmills. coated doin 3,500 to 4,500 rpm's. the looseness's allow endmill to breakdown so i gotta get things tighter now. Any advise on tightening the spindle bearings for preload ? With that and the blocks in place, it should be quite solid !

5/29/7 update ! Smoked the idler again, this time i went to McGuire and got some ball bearings for speed and rebuilt my idler again with two of them. they are smaller and are rated for high speed and shielded to hold their greese. If my calc is correct the belt moves at more than 63,000 ipm ! that really spins the little idler bearings and will smoke them ! If this don't hold up i'll do one more repair and start building a new lid for my box that can be adjusted so there will be no idler at all ....... I'm not ancious to do that right now. I did apply more preload to the spindle bearings and so far it looks like what was needed, no measurement tho, just pretty dern tight.

BobWarfield
05-28-2007, 10:53 AM
One way to adjust the spindle bearing preload is by temperature. The trick will be gaining access to them to do it. Maybe you can contrive a way to use a thermocouple or IR thermometer.

If you can, you want to shoot for no more than about 140 degrees F while running with a load. If it is running at say, 100 degrees, you can tighten slightly.

If you can't measure via temperature, I think you have to consider fabricating precision spacers so you can lock the nuts down tight and the preload is controlled by the spacer.

Best,

BW

Cruiser
05-30-2007, 04:18 PM
Well, what with the idler bearing failure i'm a bit behind schedule, but here is a pic of the "z" can'tevenlever ! I'll give no tech on this one. Its simple and self explanitory. I am enjoying the belt drive but think i'm going to need to re-engeneer the lid to eliminate the idler sooner or later.

You just can't see the bearing blocks, they are in behind and roll nicely on the backside of the rail. The brackets are merely to tie everything together and make it work. I been inside the machine the last two days and this is the only pic i took. I'll add that the large set you see in the front of the bracket is to apply the tension and draw the box up against the slide. before i tightened it i could stick a .oo6 feeler in top of slide. Now I can't even catch it with a .002 and I detect no ill effects while driving slide up and down. Yesterday was drilling and fitting and today was retramming the collumn and box back to spec. Now it is ready to go and the only week link i know of is the darned Idler bearing assy, but this one sounds much better than either of the priors so we or I will see.

davo727
05-30-2007, 06:21 PM
Hey Cruiser, The roller setup is not obvious enough to me.. ( I dont get it! Too dum )Need a close up pic or explanation of what you did on those brackets on the slide that hold rollers? I was expecting to see typical linear bearing blocks. Did you custom make those? Are there rollers on the front too or just the backside? Anyway thanks. Dave

Cruiser
06-01-2007, 02:34 PM
Here is a closeup of the brg and bracket, I did look at the other brg's but they weren't what i wanted or needed. I only need the bearing on one side of the rail, i'll admit the bracket i made is odd but it works pretty good as does the whole assemby. I'll have you know Davo, I had just got myself all cleaned up and went out and climbed into the machine just so you could have this pic. Was it worth it ?

Ron111
06-01-2007, 06:38 PM
Dave,
Don't feel bad, I trying to figure out why Cruiser's machine is sticking it's head into the attic. I knew these machines were large, but....
Ron

Cruiser
06-02-2007, 12:49 AM
Ron I got a good laugh out of that comment, I loved it ! actually the wood is the top cover to keep the coolant spray inside the enclosure and off the wall behind machine, and the machine is underneath a storage area in shop. Head in the attic ! just love that one !

Ron111
06-02-2007, 08:34 AM
Thanks for the clarification, I was about the scratch the IH off the list, my wife would like the hole in the attic, nor would my father allow me to encroach on the storage space of his shop.

Ron

ozzie34231
06-02-2007, 11:55 AM
Sure looks like its head is in the attic!

davo727
06-02-2007, 05:39 PM
Hey Cruiser, Yes thank you, and I would do the same for you if you asked :) So you sawed the bearing blocks in half. Later, Dave

Cruiser
06-03-2007, 12:23 AM
No Davo, Sawing was not necessary, used them as they came to me !HL4500M222001 Series 1 Linear Bearings Set $49.00 3 $147.00 http://www.techno-isel.com/LMC/Products/Bearings1.htm

davo727
06-03-2007, 09:07 AM
Ohhhhhhhhhhhhhhhh, Now I see. I was not familiar with those little individual one side carriages. Those are very nice and compact. I may consider something like this on my mill. Thanks for the link on the bearings and showing me how you did it . Have a good one, Dave

Shepard
06-03-2007, 10:08 AM
Are the column and head ways still in contact? It looks like it would be much smoother than my stock setup but I don't understand how it works. Is the head suspended by 3 brackets on each side without touching the ways? is there a away to adjust them to get the spindle perpendicular to the table? Sorry for the newbie questions, Shepard

Cruiser
06-03-2007, 10:40 AM
Shepard, The bearing brackets have a set screw in the front, you can see it in pic, these PULL the head and collumn together to contact the slideways ! Before applying tension i could slip a feeler gauge into the gap at top of slideways, the gib could not hold it in contact without so much tension as to fault out the drive and gaul the friction area's. With the tension applied, and only just enough tension (no torque specs) there is full contact at top and the gib can be relaxed some ! You will still have to jump through the hoops aligning the head and collumn as unual, i redid my alignment and things did in fact change, re-align was necessary.
just a few notes to consider while looking at pics !
note only one small bolt holding bracket to the mount ! more is not "NOT" better ! the bracket must be allowed to find it's perpindicularity to the axis ( is that the right word?) also the set screw i used were 5/8" and i machined flats to ends so that they "WOULD NOT" bite when setting tension, this is also to allow the bracket to align itself correctly. then just a bit more tension is applied to the small bolt holding the bracket to mount, but not allthat much, at this point it does not do all that much nor does it bare a load. you will notice one bearing full top, full bottom, & above center ! the bottom has the advantage of the box weight, the top pulls a lot of load, so the middle one is above center to assist the top bearing ! This does in fact make a very big differance when taking a heavy cut, especially if you run the cutter on both sides of the work, as when cutter is on outside of work from collumn it can lift the box and shake while taking monster cuts, damaging cutters. In general use with moderate "by the book" cuts there is probably no benifit with my mod here, other than having a more consistant "Z" resistance to motion. What i saw early on was that the "STICTION" was a factor of the gib not the slideway, so my mysterious mind came up with this concoction !
Clear as Bloody Mudd ?
All in all I'd have to say that i'm happy with the results of this venture with the exception of the belt idler bearings, i had to make three differant assembies with the latest one looking the most promising, its all in the bearing selection, first was more of a high pressure low speed bearing and it literally smoked ! the second was with some used small cup&cone bearing i had and they smoked but it was a long weekend and nobody was open. the third set uses high speed ball races, two of them on a spindle i turned to fit and hold them in place and the od's of bearings ride the belt, i kept dia. small to keep speed down as much as possible as the belt surface speed is in the 60,000 IPM range @ 3450 motor speed. The only cure is to make a new lid with an adjustable motor slider so belt can be tensioned.
I think this is all I have !
Just one warning !
This project has the potential of "painting oneself in corner with non drying paint" !

llino
06-03-2007, 10:57 AM
...the third set uses high speed ball races, two of them on a spindle i turned to fit and hold them in place and the od's of bearings ride the belt, i kept dia. small to keep speed down as much as possible as the belt surface speed is in the 60,000 IPM range @ 3450 motor speed...


Maybe I'm misunderstanding, but wouldn't a larger idler decrease the "idler rotation speed" for a given belt speed.

Actually, the best way would be to have a large bearing OD, with the races at a much smaller diameter.

That is, ideally you'd want the OD of the idler large to minimize it's rotational speed, and then you'd want the bearing race diameter to be as small as practically possible to minimize the linear velocity of the balls/races.

Or am I all mixed up?:confused:

ciao

lino

Shepard
06-03-2007, 11:01 AM
Thank you for breaking it down for me. I'll be staring at your setup for a long time before trying it, or a version of it, myself.
Also, congratulations on the belt drive! I expect that if you wanted you could sell quite a few of them.

Cruiser
06-03-2007, 11:01 AM
LLINO, of course you are correct, but it is a double edged sword ! Space is limited ! The smaller bearings work !

Cruiser
06-03-2007, 11:07 AM
Sheppard, This has crossed my mind, but, It could end up being a can of dead worms ! To market such a thing it would have to be nearly a complete kit with all the componants, and a new top for the gearbox eliminating the idler bearing too ! This would make for one exspensive upgrade to make it profitable and I'd be leary of having stock on hand to sell to the few which could afford it and use it. The time involved to just make a few would be somewhat high ! The added stumble would be to provide a variety of ratio's to keep everyone happy. And those who wanted dual ratio's ? I'd like that myself but .............. !

RICHARD ZASTROW
06-03-2007, 11:33 AM
And then there's product liability etc. Been there. Keep going Cruiser

Cruiser
06-22-2007, 09:52 AM
Just a short update of the whats ! I figure this thread has been defused so lets call this closure unless someone has differant opinion. The Idler that i last put together is holding on quite well, no noise, no heat, no complaining, & most of the time the spindle is on at 6 grand (per tach surprise on me!). I did do an upgrade on the pc and found that it was needed. I like amd and the 1200 was lacking. I found a sourse (new to me) "new egg" which has new stuff, yr or so out of date, greatly reduced prices ! I restuffed my pc for $238. whereas before with last pc i updated was over $1300. with less componants. I very quickly noticed that Mach was running smoother and with a fresh tune-up of motors and such, the machine could be sped up too max in X & Y and almost max in Z. I also put a troublesome piece of code back and re-run it to find it was no trouble anymore ! This new pc can well better handle the high degree of math per pulse than did the prior could. Now i need to go out and do an interpolation around a broken drill bit that i forgot about and broke another bit trying to finish the hole "AAAGGGG" good thing it is just a center hole pilot for a larger hole later on! have fun guys and gals. Keep the sunny side covered while the moons out !