Re: Spindle register issue


I machined a piece of steel.

On my 10K, it repeats within less than half a thou.

Same chuck transferred on 9A with intact spindle, it repeats within 3 thou.

On the 9A with altered spindle, it is off centered by 7 thou.

3 thou is acceptable, 7 is not.


---------- Original Message ----------
From: "Jim_B" <@Jim_B>
Subject: Re: [SouthBendLathe] Spindle register issue
Date: Thu, 21 Jun 2018 21:44:12 -0400

I have many times removed a chuck with a face plate in it, while threading the face plate, to test the fit on the spindle threads.
When the chuck and face plate were screwed back on registration was perfect.

I am not sure if all my chucks were tight fits on the “registration step” or they used the threads and the spindle stop.

The 9” Workshop and the 10k have a very small stop behind the register.
If the faceplate has any radius on the threaded bore you may or may not properly register on the stop.
The Heavy 10 and larger lathes have a good stop.

Sent from my iPhone-8
Jim B,

On Jun 21, 2018, at 8:28 PM, Davis Johnson <davis@...> wrote:

HTRL agrees with you (heresy around here, tho).

I'd be interested in an experiment.

Chuck up a short piece of scrap, turn the outside for a bit.

The part you just turned will be exactly concentric. Check it with an indicator.

Unmount/remount the chuck several times without removing the piece of scrap. Each time check it with an indicator.

I really would be interested in the results, and would do the experiment myself except that I don't have a chuck with a loose register.

Jim B

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