Machining question…

[tmac1956]

This question is for the machinists amoung us…

I just bought another face plate for my Levin 8mm lathe made by the American Watch Tool Company and the collet part (shaft) is marked “Whitcomb”. The threads are correct but the keyway on the collet parts is a little too short for the key in the head stock, so the cross bar won’t engage. The standard collet keyway length is about 0.5″ long but this one measures about 0.40″ long.

My question is… can the collet part be unscrewed and replaced, or must I get the slot in the shaft milled to the correct length? If the latter, what would be involved in milling that slot to the right length?

Thanks!
Tom

[david pierce]

Tom,
The slot was origionally cut with a horizontal milling machine cutter. This could have been done either on a horizontal mill or a vertical mill at the factory. The good news for you is the slot is a low precision aspect of the part and you can be cut by hand. If the cutter is a steel horizontal cutter it must turn slowly with a machine such as a Foredom Flex Shaft machine. It can also be cut with a die grinder or Dremel tool but due to the speed of the grinder an abrasive tool must be used.
david

[tmac1956]

David:

I have a new dremel with lots of attachements, so I’ll give it a try tomorrow. Is there any particular grit you would recommend?

Thanks!
Tom

[david pierce]

Tom,
I would start by trying to wack it out with the cutoff wheel. You can try one of the steel horizontal milling wheel cutters but you run the risk of burning the cutting tool due to the high speed of the Dremel.
david

[tmac1956]

David:

I found a cutting wheel in my Dremel assortment the just fits inside the keyway. I’ll post another pic when I’m done (for good or ill).

Thanks again!
Tom

[tmac1956]

David:

I extended the keyway, but I had a defective (cracked) disk of which I was unaware. By the time I figured it out, the thing has wallowed out the keyway. ANyway, I was able to put on another one and clean it up enough to make it work. It fits nicely into my head stock now.

I don’t think I want to post an “after” picture of this near disaster.

Thanks!
Tom

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