speelwerk | 20/06/2020 14:54:16 |
377 forum posts 1 photos | If you check the Myford motor drive pulley then the larger diameter of it has a shake of around 0.015 mm on a close fitting turned arbor in the lathe. It also has a good fit on the motor arbor itself but if you tighten the grubscrew that secures it on its arbor, that shake increases to around 0.25 mm which of course gives unwanted vibration. Because there is very little room the grubscrew is placed off-centre. Has anyone come-up with an idea to improve the securing of that motor pulley on its arbor? Niko. |
Michael Gilligan | 20/06/2020 16:30:27 |
![]() 17063 forum posts 759 photos | Well-spotted, Niko Mine [currently dismantled] is quite badly worn ‘bell-mouthed’ as a result of this. Although the motor shaft has a keyway, the pulley was retained by just a single grubscrew [which must have come slightly loose] Both motor-shaft and pulley now need attention ... but I will probably fit a 3-phase motor and then ‘bore & bush‘ to suit MichaelG. |
Hopper | 21/06/2020 22:51:12 |
![]() 5084 forum posts 114 photos | Running the belt looser reduces the vibration. Rebushing the pulley in steel would be a longer term solution. |
Paul Lousick | 22/06/2020 00:45:18 |
1655 forum posts 614 photos | Use a pulley that has a taper-lock bush if you want more accuracy with axial alignment. |
DMB | 22/06/2020 07:25:51 |
1054 forum posts | Niko, My S7 supplied new with an Ali pulley which eventually worked loose and Nottingham replaced it foc with a CI one. Apparently, they were CI then Myfords tried a change to Ali probably to cut costs. They went back to CI and appeared to know all about the problem so there must have been a lot of other complainants. John |
DiogenesII | 22/06/2020 07:35:36 |
174 forum posts 78 photos | ..with that kind of gap you may be able to insert slips of shimstock either opposite to (or maybe better), 120 degrees either side of the screw? ..a bit expedient, I know..
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Lee Rogers | 22/06/2020 07:57:53 |
![]() 92 forum posts | Posted by Paul Lousick on 22/06/2020 00:45:18:
Use a pulley that has a taper-lock bush if you want more accuracy with axial alignment. Cast iron wheels and taperlock bushes from Bearingboys. I don't think I'd use any other method having tried it once. Bearingboys a good UK company. Satisfied customer , no connection. |
roy entwistle | 22/06/2020 13:52:44 |
1303 forum posts | The motor shaft has a keyway, usually the pulley has a keyway, and yet manufacturers insist on just using a grub screw. Why not a key with a grub screw onto that ? In fact a properly fitted key should be sufficient. Obviously cost must be a factor |
speelwerk | 22/06/2020 14:52:52 |
377 forum posts 1 photos | Over the weekend I made an attempt to improve the pulley fitting by making a conical plug pushed in by a M6 screw in the motor shaft. It gave not the improvement I hoped for but a wobble of around 0.10 mm is good enough for me. Niko. |
Hopper | 23/06/2020 00:07:07 |
![]() 5084 forum posts 114 photos | Very ingeious. Your own version of taper lock. Neat. |
speelwerk | 23/06/2020 16:49:26 |
377 forum posts 1 photos | Posted by Hopper on 23/06/2020 00:07:07:
Very ingeious. Your own version of taper lock. Neat. Thanks! I should have made the taper a little less steep, 2 instead of 3deg. Niko. |
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