Myford BackGear Lever

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Myford BackGear Lever

This topic has 8 replies, 5 voices, and was last updated 29 July 2013 at 11:40 by Martin Kyte.

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25 July 2013 at 12:17 #125390
Martin Kyte
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@martinkyte99762
Hi Chaps

I have an annoying issue with my Myford Super7. When running at high speed the cetrifugal force on the lever of the BackGear key causes it to rotate and foul on the headstock casting. Has anyone done a modification to solve this.? The only hing I can come up with so far is a spring detent which would be quite involved, probably why Myfords never bothered in the first place.

Thanks in anticipation.

Martin
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25 July 2013 at 12:17 #12157
Martin Kyte
Participant
@martinkyte99762
25 July 2013 at 12:32 #125391
Roderick Jenkins
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@roderickjenkins93242
I didn't come across this problem until I was running at 3000 rpm with my VFD and the lever broke off. I don't have a solution though. I don't intend to run at that speed again!

Rod
25 July 2013 at 14:39 #125401
KWIL
Participant
@kwil
As I recall there is a small spring and ball in that back gear key assembly to allow a detent action. Never had this problem at high speed.

Just looked at the Parts Breakdown in the Manual and it shows the above items.

Edited By KWIL on 25/07/2013 14:41:27
26 July 2013 at 14:15 #125473
Robbo
Participant
@robbo
Martin,

As Kwil says, there is a detent in the form of a spring and ball inside the key assembly.

I know because I took one off a damaged bullwheel and of course the spring shot the ball across the room! Had to buy a pack of 10 to get a replacement, so if you need a ball?? message me.

Phil
26 July 2013 at 16:01 #125478
Bazyle
Participant
@bazyle
Seems possible that
a) the spring deteriorates with age,
b) the dimple the ball sets into needs deepening,
c) the mechanism gets gunged up with old oil & dirt so doesn't work so well.
29 July 2013 at 09:11 #125635
Martin Kyte
Participant
@martinkyte99762
Hi Chaps

Had a quick look at my spare bull wheel and you are correct of course re the assembly. I am not entirely sure the spring and ball detent is fitted on my lathe. Could be that when I bought a new bull wheel and lever Myfords didn't supply the spring and balls so I didn't fit them. When I get time I will strip the mandrel and find out.

Thanks for the responses.

regards Martin
29 July 2013 at 09:23 #125636
Robbo
Participant
@robbo
Martin,

A word to the wise. When you dismantle the key assy., don't try and twist the handle out, it breaks easily. It's on a slight taper, so needs to be driven out from the reverse side. Guess how I know this!!

If you eventually need a ball and spring, get in touch.

Phil
29 July 2013 at 11:40 #125644
Martin Kyte
Participant
@martinkyte99762
Thanks for all the offers, I'm OK for parts but I'm impressed with the level of support.

regards Martin
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