Author Topic: Myford Super7 rattle  (Read 1437 times)

Offline Allen Smithee

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Myford Super7 rattle
« on: August 03, 2020, 11:17:07 AM »
I've been getting a bit of a rattle on my Myford Super7B at high speeds, and it appears to be due to play between the backgear/bullwheel and the main v-cone pulley assembly. I'm assuming that this means wear in either the backgear key, the bore for the key in the bullwheel or the corresponding rebate in the v-cone pulley. Is this a common wear mode?

To investigate I will obviously have to remove the spindle, which looks simple enough to do if the exploded diagram is accurate - it looks like I just unclamp and then remove the end adjusting collar, push the spindle through towards the bed end with a piece of wooden dowel (to catch all the pulleys/spacers etc) and then curse and shout a lot while I search through the accumulated swarf for the two woodruff keys I forgot to keep an eye out for.

I note the angular contact bearings are pre-loaded, but as far as I can see I don't need to unclamp those just to take the spindle out - is this correct? If so does that mean for reassembly I re-insert the spindle and just wind the clamped adjuster finger-tight to remove any play and then clamp it?

Finally - if the wear is in the backgear key or the bullwheel it looks like I can get replacements (although the bulwheel is a bit pricey), but there don't seem to be any new V-cone pulley assemblies around. If the wear is in that I guess I'm looking at some sort of bushing or remetalling job. Has anyone ever done this?

AS
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Offline Charles Lamont

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Re: Myford Super7 rattle
« Reply #1 on: August 03, 2020, 02:43:13 PM »
A Super-7 rattle at high speed is quite common. I was lucky in that it was many years before it developed on my machine. The usual solution, which worked for me, is a link belt (eg T-link) on the primary drive. I think the source of the noise is unlikely to be where you suggest.

The screwed and clamped adjusting collar on the end of the spindle is what does the preload, and I was told by Myford (Beeston Rd) to screw that collar up as tight as you can get it by hand. The castle-nutted collars do not preload the ball bearings, but move the whole assembly to provide the right clearance for the cone at the front end.

Offline Charles Lamont

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Re: Myford Super7 rattle
« Reply #2 on: August 04, 2020, 09:05:11 AM »
I forgot - check the end float on the spindle cone pulley, and adjust by moving the bullwheel.

Offline Allen Smithee

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Re: Myford Super7 rattle
« Reply #3 on: August 04, 2020, 11:26:08 AM »
Yes, I had spotted that one a couple of years ago and regularly check it. This play is definitely angular play in the backgear key rather than axial float in the bullwheel.

AS
Quidquid latine dictum sit altum sonatur

 

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