Central Machinery Tailstock Question

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Fine Engineer

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Joined
Nov 17, 2021
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302
Location
Carson City, NV
I have a Central Machinery T34706 12" x 36" lathe that I bought second hand. The previous owner had never even taken it out of the box, so it is brand new, but is a 2022 machine. Anyway, I get it all assembled, only to find that the tailstock is about 0.060" off center laterally. It looks to be right on vertically. There doesn't appear to be any adjustment I can make, so my question is how can I get this properly aligned with the centerline of the machine? It looks like this will require machining and shimming the bottom of the tailstock where it aligns with the lathe bed. I'm hoping there's an easier way to fix this. Any ideas?




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Sometimes you just need to get away from the problem to have the solution jump out at you. I'd forgotten that the drive head pivots for turning larger items, and so has a spring loaded detent to index the head at different positions. It turns out that the detent is a bit sloppy, so there's about 2° of slop in the mechanism. So all I did was loosen the clamp slightly, push the head to the edge of the stop, and the alignment is close enough to be useful now. Not metalworking precision, but close enough for woodworking. Problem solved.
 
You can use two pen mandrels to check the alignment. Install one in the head stock, (no tail stock). Spin the lathe by hand or on slowest speed. make sure it spins true, (no wobble). If not, tap it gently unto it does. Remove carefully so you don't bend the mandrel. Repeat for the second mandrel. Now put a 7mm brass tube on one mandrel and put both mandrels on the lathe. Bring them together until ALMOST touching. If you can slide the brass tube from one mandrel to the other, alignment is good. This is very sensitive to runout as the mandrels length multiplies any run out error.
 
I've used this: Headstock/Tailstock centering tool. You will still need to loosed, then tighten the tailstock mountings.
I've got an older Nova DVR-XP and this tool is an essential one since this lathe, like the one being spoken about, allows the headstock to be swung out for large turnings. I find that no matter how tight I make things, the assembly fairly regularly goes out of whack and the centering tool is the best thing I have found yet to get things right again. I might suggest when using it, extend the tailstock quill out pretty far when doing the setup, as it magnifies any alignment issues. Then when turning, move the quill as close as you can to the tailstock body, essentially reducing the errors and increasing the level of alignment.

Kevin
 
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