wheels17
Stainless
- Joined
- May 10, 2012
- Location
- Pittsford, NY
I recently bought a faceplate(TPP-100N) for my 10K, literally out of a trunk in a parking lot. Today I finally got around to seeing how it fit on my lathe. I pulled my 3-jaw off, and it looked like the register(I know, I know) area was longer on the faceplate than on the 3-jaw. This made me concerned about the number of threads engaged with the spindle.
I bought the lathe with the SB 5" 3 jaw, a Skinner for South Bend 4 jaw, a dog plate, and a Bison Set-tru 5C collet chuck. So I pulled them all out and started taking rough measurements (Mitytoyo caliper). The results were somewhat disturbing:
The 3 jaw, the new face plate, and the dog plate all seemed in the same ballpark with over 4 threads of engagement. The 4 jaw only has 3.15 threads engaged, and the heavy. overhung 5C collet chuck only has 2.9 threads of engagement.
I've used the 4 jaw extensively, and it appears by the invoice to have come with the machine, so apparently 3.1 threads engaged is OK.
I can't say for sure whether the Bison has ever been used on the lathe. The 5C collets that came with the lathe were all still in plastic. It seems to me that the right answer is to take this chuck assembly (which lists for 2/3 of what I paid for the lathe and tooling) apart and face at least .0625 off the boss. I'd probably go for .125-.1875 as long as I had everything set up. It makes me nervous though, as I am not the most skilled machinist in the shop.
Where should the line be drawn for an acceptable number of engaged threads?
I bought the lathe with the SB 5" 3 jaw, a Skinner for South Bend 4 jaw, a dog plate, and a Bison Set-tru 5C collet chuck. So I pulled them all out and started taking rough measurements (Mitytoyo caliper). The results were somewhat disturbing:
The 3 jaw, the new face plate, and the dog plate all seemed in the same ballpark with over 4 threads of engagement. The 4 jaw only has 3.15 threads engaged, and the heavy. overhung 5C collet chuck only has 2.9 threads of engagement.
I've used the 4 jaw extensively, and it appears by the invoice to have come with the machine, so apparently 3.1 threads engaged is OK.
I can't say for sure whether the Bison has ever been used on the lathe. The 5C collets that came with the lathe were all still in plastic. It seems to me that the right answer is to take this chuck assembly (which lists for 2/3 of what I paid for the lathe and tooling) apart and face at least .0625 off the boss. I'd probably go for .125-.1875 as long as I had everything set up. It makes me nervous though, as I am not the most skilled machinist in the shop.
Where should the line be drawn for an acceptable number of engaged threads?
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