MEW253 Dual action feed for a lathe tailstock

[tadpoleParticipant @tadpole]

I am a bit behind with my reading, having just got to MEW 253, and I would like to thank Geoff Walker for his interesting article. I was "building" the dual lever/screw feed tailstock in my mind, and have one question. How is positive drive communicated, in both directions, from the barrel extension to the barrel, when the one fits over the other with "a neat sliding fit"? This sliding fit is mentioned twice, and Geoff even mentions that he didn't need a clamp as he thought he might. If I'd bought this at a club sale, made as descibed, I'd be thinking of fitting a dog-end screw through the wall of the extension piece to engage the thread on the barrel. Something must be missing, either from my brain cell (again!) or from the printed article.

Kevin

[tadpoleParticipant @tadpole]

[geoff walker 1Participant @geoffwalker1]

Hi Kevin,

First post, welcome to the forum.

Yes you are right, the barrel extension "should really have" a clamp of some kind to secure it soundly on the barrel.

I have not had problem with it being pulled off except when I inadvertently leave the latch engaged but yes it would improve the design to fit a clamp. I would suggest that you slit the end of the extension like a collet and make a small clamp from 1/2" M.S. plate bored out to fit the extension. This clamp would also be split and have a set screw fitted to close it on the extension. This clamp would squeeze the extension on the barrel and secure it in place. You could just use a jubilee clip as clamp but to be fair it wouldn't look good?

I would not use a single set screw as you describe as that may damage the thread on the barrel.

If you need any more help P.M. me Regards geoff

[tadpoleParticipant @tadpole]

"I would not use a single set screw as you describe as that may damage the thread on the barrel."

Hi Geoff, thanks for clarifying things a bit. Your "nice sliding fit" must be what I would call a push fit or a press fit, I think. I wasn't thinking of a set screw when I mentioned a dog-end screw, I was thinking of a screw that has had the end turned down to a cylindrical or other shape to match the thread flank, which would just enter the valley of the screw thread. No damage caused. Maybe other people use a different name. Still, thanks for the article, something else to add to the list!

Kevin

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