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  1. #21
    Registered jakemestre's Avatar
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    Quote Originally Posted by Fastest1 View Post
    Nice build and modeling.

    In post #7 you mention replacing the bolts with stainless to gain strength and or rigidity. Stainless though great for corrosive environments is not very strong, how about grade 8 bolts?

    Also with the new design you have presented and the new spindle, a little more Z would be nice. Seems like a lot of effort to be limited by a 10" piece.

    You are doing great.
    Thank you very much for the suggestion. I'll try the highest grade bolts I can get a hold of and report back. I have some 4130 to machine this week so that will put it to the test.

    Quote Originally Posted by BobWarfield View Post
    Jake, I think you'll find a little experimentation will help with the preload as well. By all means, start with the calculated values and try to figure the spacing needed for that. I believe I have the spacing info in the article you referenced.

    Then you'll want to assemble the spindle and test it while keeping a careful eye on bearing temperatures. You'll want to be sure that's possible and that the bearings aren't buried too well in the headstock to access them. Make sure you're using good quality grease, like the Kluber I reference. Follow the run in procedures you find in the various bearing manuals, again monitoring temps. Once you've run in a bit and temps are stable, you can see whether you've got the bearings too tight or too loose based on the temperatures you're getting. See my spindle article for details.

    Best,

    BW
    Thank you Bob,
    I'll be sure to add a hole in the spindle cartridge to measure temp. I'll probably just use an arduino lying around, they're so easy to program to display multiple temps.
    I think I've landed on the final design for the cartridge: two angular contact bearings in the front with two deep groove ball bearings in the back. I'll have to precision grind the spindle to 55mm for the ID of a 7211 bearing. It'll all be an assembly that bolts together and can be serviced outside of the machine if necessary. The headstock will be based around a granite epoxy mix. Thanks for all your help so far, your blog has been invaluable.

    Quote Originally Posted by Runner4404spd View Post
    for this spindle build i would use tapered roller bearings. i have them in my 13x40 geared head lathe using the same spindle. there is a massive thread here on cnczone on spindle construction, bearing preload is the least of your worries. the housing itself will need to be ground and the seats need to be straight and perpendicular to the bearing and concentric and paralle with each other. also you don't have to grind the bearings themselves you can use hardened spacers between the bearings that are ground to create the clearance you need. it will be easier to grind these than to try and keep the bearings clean. abec 3 bearings will be just fine for your build and you won't notice any decrease in performance.
    i think your going to find that constructing the housing for the spindle will be a fairly difficult task and i do wish you all the luck and will offer any advice during your construction.
    Thank you for the suggestions Runner. Could you by chance post a link to that thread? I'm having trouble finding it. I think tapered roller bearings will be difficult to control preload as the temperature of the spindle changes. I'm really shooting for a repeatability of this machine to be between 1-3 tenths so I'll have to be very careful about how I design the spindle. I like the idea of having two preloaded angular contact bearings in the front with support bearings in the back.

    So I got most of the linear motion in the other day. Precision ground ball screw for x by Issoku, and linear guides by THK. I still need to order the Z screw, I have a rolled ball screw for the moment but ground is a must to meet the precision. Now I just need to verify all the designs for the motion system before I can start drilling some holes in my plate. I also got a duplex AC bearing set but they're ABEC 1. I want to figure out how to make the spindle cartridge before I spend $300 on a set of nice bearings. Thanks everyone for the help, keep it coming. If you see something I'm doing incorrectly please feel free to post and/or email me directly at jakemestre@yahoo.com. Until next time.



  2. #22
    Registered jakemestre's Avatar
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    Default Spindle speed

    Is it unrealistic to shoot for 5K rpm? The 3505 5" Bison chuck I've got is rated to 5500 rpm, and the bearings will be way above that. A 1.35:1 for a 3700rpm 3hp motor will still be 2.2 ponies. I'll have a couple pulleys 1:3 for lower speed applications in Titaniums or Inconel. Any thoughts? Thanks



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    I think I'm going to use Leadshine easy servo motors. They're an interesting mix between servos and steppers. Apparently they run smoothly up to 3000RPM, eliminating the mid-band resonance we hate with steppers. They have the advantage of steppers with high holding torque, but the positional accuracy of a servo. They're a bit expensive, though less than a good servo system. I realize that normal steppers would be fine with the correct calculation of load, but based on this initial video it sounds like they're a really interesting option. I love to test new technology so I'll order a couple of them here in the next few days. I like the idea of not having to put sensors on the turret to monitor position. We'll see how it works.




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    I ordered a 2Nm stepper servo from leadshine yesterday. I'm really excited to see how it works. Because I'm an engineer every project needs a tiny bit of math, so I started in on some accuracy and speed calculations to ball park this build. Please correct me if you see a mistake, but based on a 5mm ground ballscrew, linear guides, and a leadshine stepper/servo, I'm calculating ~400"/min rapids with .0000656"/mstep.
    (.1969"/rev)(1rev/360deg)(1.2deg/1step)(1step/10mstep)= .0000656"/mstep Assuming there's some error I'll throw in +-1 mstep of target which puts me right at .00013" which is inside my 2tenths goal.
    Based on the conservative 2000RPM (3000 max speed), (2000rev/1min)(.1969"/1rev)=393"/min
    At 600RPM the torque curve shows 1.5Nm torque which I think is a good reserve of torque for cutting. If I do a 2:1 pulley I'll get 4Nm holding torque max and 3Nm at 60"/min. That'll bring the rapids down to 200"/min while increasing the accuracy +-mstep to .0000656 again. Well within my accuracy goals. And that's still pretty fast on a prototyping lathe, especially on one that's only got 13" in the Z. I may not even need to have so much torque anyway we'll see once the motor gets here.
    I've made lots of progress on the design. I've got a headstock and am doing analysis to the structure to see how minor changes will affect rigidity. Having bolts in the front and back made a huge difference. Saved about .002" of deflection under the 3000lb of resultant load.


    I still have to design the spindle cartridge, figure out what ballscrew I want on Z, design the way covers, and cable/coolant routing. I'm also thinking about updating to a C axis spindle.
    How useful is live tooling on a lathe? I could attach motor to the front of the turret to drive a live tool. It seams like most of the stuff I'm machining on my current lathe requires a simple second op on my mill. Anybody have any experience with live tooling and a C axis in Mach?



  5. #25
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    That closed loop stepper system is interesting. I am not sure if I understand its advantages as much as its marketing. They only seem to offer it in 1 size, like 290oz. It would be nice if they offered it in many sizes.



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    Who's using what motion control boards, and what do you like about them most?



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    Member Fastest1's Avatar
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    I am using a SS USB. I would use the Ethernet/ESS version now. The USB version is alright (most likely a set up issue on my part) though I have had a few issues. Mostly watchdog time outs and Mach locking up. I never have those problems with PP driven units. I have problems, just not communication related ;-)



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    I use the Smoothstepper USB too. Same as Fastest1, it works well for me but if I use the PC for anything meaningful while it is running the watchdog often times out. So I just don't do that. As a result it is very reliable and the main benefit - I get very smooth and fast step rates that just weren't possible on the parallel. This is essential on my 5 axis machine which demands a pulse rate far above what the parallel can output, when moving all axes simultaneously.

    LongRat
    www.fulloption.co.uk


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    jakemestre - Do you have any other info pertaining to your 9x20 cnc conversion? Hopefully a build thread?



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    Quote Originally Posted by Fastest1 View Post
    I am using a SS USB. I would use the Ethernet/ESS version now. The USB version is alright (most likely a set up issue on my part) though I have had a few issues. Mostly watchdog time outs and Mach locking up. I never have those problems with PP driven units. I have problems, just not communication related ;-)
    I've had similar problems with the USB SS. I think if I put a good faraday cage around the computer and SS it should really help. Plus some filters on the power to the computer as well as a 5V supply for the SS.

    Quote Originally Posted by LongRat View Post
    I use the Smoothstepper USB too. Same as Fastest1, it works well for me but if I use the PC for anything meaningful while it is running the watchdog often times out. So I just don't do that. As a result it is very reliable and the main benefit - I get very smooth and fast step rates that just weren't possible on the parallel. This is essential on my 5 axis machine which demands a pulse rate far above what the parallel can output, when moving all axes simultaneously.
    Cool, Do you have a thread on your 5 axis?
    Quote Originally Posted by Dirty Engineer View Post
    jakemestre - Do you have any other info pertaining to your 9x20 cnc conversion? Hopefully a build thread?
    No build log of the 9x20. It took like 4 years of fiddling and meddling to get it to "sort of work". If you're thinking of converting just start from scratch. It's cheeper, more precise, and faster to build in the long run. You put stuff where you want and design in rigidity where you need it. It's much better than trying to get things to work and fit the constraints of a flimsy poorly cast machine. The 9x20 lathe is way too flimsy to do any meaningful work. Just my 2 cents.



  11. #31
    Member Fastest1's Avatar
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    Btw after I wrote about the SS problems I went thru and changed some settings. I changed the USB power characteristics and have had a lot less problems if any. Still not sure if I fixed it but it appears so.



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    Quote Originally Posted by jakemestre View Post
    Cool, Do you have a thread on your 5 axis?
    Sorry I don't, as I built it for work. I can't show too much detail online about what it is used for. Needless to say it was a manual Wabeco F1410LF High Speed, with a DC servo conversion and the TN4 trunnion table from MDA Precision. I used Gecko G320X drives. It is a very, very nice machine.

    LongRat
    www.fulloption.co.uk


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    Quote Originally Posted by Fastest1 View Post
    Btw after I wrote about the SS problems I went thru and changed some settings. I changed the USB power characteristics and have had a lot less problems if any. Still not sure if I fixed it but it appears so.
    What was it you changed exactly? I've had plenty of time out errors, and spindle indexing issues in the past. I was trying to use the USB before I even really knew what noise was so maybe that was it. All the same I'd love to see what you did, maybe it's another piece of the puzzle. I'd love to not have to buy another $200 board if possible.
    Quote Originally Posted by LongRat View Post
    Sorry I don't, as I built it for work. I can't show too much detail online about what it is used for. Needless to say it was a manual Wabeco F1410LF High Speed, with a DC servo conversion and the TN4 trunnion table from MDA Precision. I used Gecko G320X drives. It is a very, very nice machine.
    That's a really nice table. A similar table is on my project list for after the lathe. One project at a time though. lol



  14. #34
    Member Fastest1's Avatar
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    I went thru the tips Soigenris (Jeff Birt) provides. I run XP. So I opened the device manager and went thru each item in "Universal Serial Bus Controllers", I opened each item, right clicked "properties", if it had power management, I made sure the "allow the computer to turn off this device to save power" was UNCHECKED.

    I haven't had the FTDI error since.

    Btw, I make sure my controller is powered up prior to opening Mach 3.

    A lazy man does it twice.


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    Very nice lathe build... I'm envious!



  16. #36
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    Quote Originally Posted by Fastest1 View Post
    I went thru the tips Soigenris (Jeff Birt) provides. I run XP. So I opened the device manager and went thru each item in "Universal Serial Bus Controllers", I opened each item, right clicked "properties", if it had power management, I made sure the "allow the computer to turn off this device to save power" was UNCHECKED.

    I haven't had the FTDI error since.

    Btw, I make sure my controller is powered up prior to opening Mach 3.
    Thanks for pointing Jeff's site out. I'll be sure to give it a try when this thing is running.

    Quote Originally Posted by mikesims View Post
    Very nice lathe build... I'm envious!
    Thank you very much. I think I'm going to keep the current lathe as is but swap the 3hp motor for a 1hp. I'll just put a QCTP on it and use it as a dedicated super lite duty machine.



  17. #37
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    Default Update 3

    Lots to talk about today.

    First is the design for this new machine is coming along nicely. I've been tweaking parts, plates, and bolt holes to get everything the way I like. This way when I start cutting all the alignments will have been considered beforehand.

    I got a nice C1 ballscrew for the z-axis. Inadvertently in my excitement to get this project going I ordered a C5 ground screw for the x. Not a horrible mistake, but it may be remedied yet. I'll use the C1 Z screw to quantify the error of the C5 X screw. I'll just hook up the two leadshine servos with the screws mounted parallel. Then I'll command each screw to move a desired amount and measure where the x is relative to the super precise Z. If the screw is not acceptable I'll find myself another C1 for the x. Now that I have all the parts in hand the model is progressing very quickly.
    In the last month I've run about 500 steel parts on my current lathe. I think I need to integrate a chip conveyor into the new design. It just takes too long to vacuum up all the chips after 50 parts are finished. A majority of the parts I've been making are 1.5"dia stock with over 80% material removal. The chips are about two inches thick in the whole bottom of the pan and slows the coolant return. This leads me towards an entirely new machine that has it's own stand and enclosure. I've learned a lot about doors and seals with the current machine, so the next time around should be a breeze. If anyone has some cool links to a good conveyor I'm all ears. The whole point of designing a new machine was to stop constraining the design with existing parts(aside from guides, ballscrews, etc.) So a new stand it is. I think I might shop around for a smokin deal on a lista cabinet to put into the stand. I'll finish the machine design then I'll move onto the stand.
    Here's the basic layout of pieces and parts I've accumulated.

    When the time comes I'll pull the 3hp motor from the current machine and replace that with a 1hp I've got laying around.
    Oh, and I was able to get this guy up to 12"dia x 12"length. Not quite as big as most machining centers but I haven't made a part larger than 6" yet. I know the second I build this machine I'll get a job for something 11". That's just the way murphy's law works, and If I don't set a diameter I can't build the headstock or turret.
    I've been printing the parts of the turret to see if everything jives before I write toolpaths.


    The beauty is that I can check to see fits and function without spending a ton of time machining. I just printed these at night when my printer wasn't working on anything important. There's only a few dollars in plastic and very little cost in running the printer.
    That's all I've got for the moment. Now that I've got all the key components I should be able to get cookin with this build. If anyone has any suggestions as to how to make the machine run more smoothly or sees a problem please let me know! Thanks guys.



  18. #38
    Member DICKEYBIRD's Avatar
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    Very impressive project Jake! I envy your CAD skills. I do all my stuff in 2D TurboCAD and have done a little bit of 3D with an old version TurboCAD Pro but sadly I'll never be able to use it as a very useful tool as you do. Is that SolidWorks you're using?

    What type of printer are you using...homebuilt?



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    Quote Originally Posted by DICKEYBIRD View Post
    Very impressive project Jake! I envy your CAD skills. I do all my stuff in 2D TurboCAD and have done a little bit of 3D with an old version TurboCAD Pro but sadly I'll never be able to use it as a very useful tool as you do. Is that SolidWorks you're using?

    What type of printer are you using...homebuilt?
    Thanks Dickeybird,
    I use Solidworks for design and analysis. It gets me in the ballpark for analysis but I find it to be very intuitive for 3D design work. If I design everything it 3D first I can move things, edit parts, and play with clearances so easily before I cut any metal. Then when it's time I've got a detailed drawing to go off of so I know things are in the right spot. I've got a little Makerbot Replicator 2 that I've hotrodded. It'll go all the way down to .002" layers with careful calibration. I'm also building a new printer for Nylon now. Something that will go a lot faster with a smaller nozzle.



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    Good Morning Forum,
    Important design question for all of you: Minifridge for beer or Lista cabinet built into the stand?I've got a full size fridge upstairs in my apartment but it would be nice to have a place purely stocked with beer.



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10"x12" Scratch built lathe

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