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Type: Posts; User: Eldon_Joh

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  1. Replies
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    3,309

    Thats what the bolt hole through the center is...

    Thats what the bolt hole through the center is for, to keep the composite under compression, and so you can compare two or more tubes with the same cutting tool.
  2. Replies
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    3,309

    In my opinion the best way to test a new material...

    In my opinion the best way to test a new material for a rigidity multiplied by dampening coefficient divided by density experiment is to make a boring bar and test against other boring bars under...
  3. Wont recommend folks build machines from polyester counter top remnants anymore.

    I have about 1 inch of creep across 5 feet on a 3/4" thick bar, under its own weight, most of that creep is in the last couple months when it would have been over 100F for 8 hours a day.
    Also have...
  4. Most motors have a breakdown torque at least...

    Most motors have a breakdown torque at least twice rated hp at nominal rpm. And they run about 20 percent saturated.

    As such, if you drive a 240vac motor at twice its nominal frequency, but at the...
  5. Replies
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    3,893

    Re: Granite base router

    granite is more like 2/3rds as stiff as aluminum if its good quality and laminated with epoxy. figure 50Gpa. aluminum is 70 gpa, steel is 200. aluminum and granite are both about the same density,...
  6. Re: 2.2 Kw Spindle/Huanyang VFD spins in one direction only/over current in reverse

    try disconnecting the motor and connect 3, 120v lightbulbs connected in wye and see if you get medium brightness at start up and full brightness at 400hz (220volts will push 140volts across each bulb...
  7. Replies
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    4,331

    Re: The Haas desktop mill.

    buy the toy machine just for the control?
  8. Re: coefficient thermal expansion on disimilar materials (epoxy resin, steel, aggregg

    if your epoxy is 1cm thick then the thermal expansion of 10C would be 4.5 microns.

    my guess is tramming epoxies are filled with various fillers to prevent creep. not restrain thermal expansion....
  9. Re: New Machine Build - Massive CNC router for timber components

    you can't run them through a bandsaw first then cut them on the router?

    i'm assuming you're talking about using a 7 inch long endmill to cut the profile of the 6" deep gluelam. so you are shaving...
  10. Replies
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    515

    Re: DIY ballscrew wiper seals

    I think this is a really great idea but i would save anyone the labor of shrinking the heatshrink and then trying to thread it off and cut it and put it back on.

    rather i would put between the...
  11. Re: Lot of experiments with genuine Huanyang VFDs

    but seeing as you spend half your time defending Chinese spindles, why bother defending western codes?

    which you normally can't be bothered to specify the code anyways?

    and most everyone on...
  12. Re: How to remove travel stop post on Taig mill

    the screw was probably pressing on the gib or it was distorting the aluminum and pushing on the gib
  13. Re: 16/3 @ 18 AMP per conductor - for VFC Cable ?

    2.2kw at 110vac 3 phase is only 11.5 amps. 16 gauge is fine.

    a vfd delivering 2.2kw from 120vac single phase (with a dumb rectifier and capacitor input filter) will draw as high as 30 amps rms...
  14. Re: Getting single phase 220v and 110v from 3 phase 220v

    why not just run your neutral through the phase perfect and wire up a
    L21-20R plug.

    if you're too lazy to add another 3 phase contactor in your machine so you can power off the spindle and servo...
  15. Re: Getting single phase 220v and 110v from 3 phase 220v

    you likely do not need 120vac for your computer. many are 100-260vac, they take the incoming ac and convert it to 400 volts dc.

    the older computer power supplies have a switch you need to set for...
  16. Thread: Concrete VMC

    by Eldon_Joh
    Replies
    304
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    84,078

    Re: Concrete VMC

    i believe that. but my comment regards my own experience of bolting a 20mm rail to about 1/8" or 3mm of system 3 mirror coat.

    under a 20mm rails there are only two, about 5 or 6 mm wide contact...
  17. Thread: Concrete VMC

    by Eldon_Joh
    Replies
    304
    Views
    84,078

    Re: Concrete VMC

    i recommend just lapping the top of the X axis rails flat. epoxy a strip of steel just as wide as the rails so you don't need to remove any more metal than necessary.

    to get the twist out of it,...
  18. Re: Increasing torque with high power 380V spindle on a low power 220V VFD ?

    you can do that, but i would buy the 4.5KW spindle if you need to get 1.8nm of torque continuously.

    you will need to program the vfd correctly so as to get the most torque for the least amount of...
  19. Re: Repair and upgrade of high voltage power supply

    i'm not sure its worth your time or money to attempt to drive a 100w tube from a 50 watt power supply.
  20. Re: Repair and upgrade of high voltage power supply

    did you burn out the 50 watt transformer?


    if you can verify the 100 watt flyback has the same turns ratio, you may be able to change the air gap of the core so that they both have the same...
  21. Replies
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    Re: Ballscrew and nut mismatch

    there is a chance you can fit oversize bearings into it but the oversize bearings are going to contact the nut in only the outer portions of the helix, so its going to wear out quickly, literally...
  22. Replies
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    2,432

    Re: DIY Power drawbar what are the options...

    the wide flange is revealed if i'm not mistaken and needs to contact the face of the spindle nose, not the collet.

    what you saw on the ebay link.. you could add a flange to that but i find it...
  23. Replies
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    1,839

    Re: China Spindle Cooling

    you have a dc brushed motor, so yes pulling air through the air gap between the rotor and the magnets is going to be 10 times more effective than simply cooling the outer casing of the motor.
  24. Re: im upgrading my taig spindle motor to a clearpath AC motor... will it work?

    with a counter weight you can use as large a motor as you want.

    as for the taig being stiff enough, forget it.


    replace the 2.5" square steel L frame with 100 pound box beam made from 6" or...
  25. Replies
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    1,839

    Re: China Spindle Cooling

    or use the 24v fan but epoxy a finned heat-sink onto the side of the motor.


    or drill larger holes in the motor case to get more airflow through the motor, or 3-d print a better shroud to suck...
  26. Replies
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    1,839

    Re: China Spindle Cooling

    i'm not op but i'd try to balance the existing blade or replace it with an aux fan before waiting 3 weeks for a new fanblade.
  27. Replies
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    1,839

    Re: China Spindle Cooling

    doesn't make a damn bit of difference.

    i had a friend of mine 3d print a fan blade for a vacuum cleaner motor, 6" diameter, probably ran at 12,000 rpm.
  28. Replies
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    1,839

    Re: China Spindle Cooling

    he reminds me of digger doug on practical machinist, always defending thermite, who got banned.


    anyhow while it would be a challenge to ballance a 3d printed fan blade for maybe 3" diamter at...
  29. Replies
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    934

    Re: V-Rail vs Linear Guide Rail

    are the v rails and their roller bearings arranged properly or are they subject to slop in the bearings.

    and even if they are subject to slop in the bearings are the bearings doubled up and...
  30. Re: 8,000# Machine Delivery on Asphalt Driveway

    Just build a skid and drag it into the garage, have the rigger drop the machine on the skid. use your car to pull it, just need some folks to pickup the broom handles and lay them out in front of the...
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