[How do I?] Oops ... Now It's Too Small

First part of the solution ... I ordered another back plate from Grizzly.

Second part of the solution ... pay MUCH MORE ATTENTION when I turn this one down.

I'll let you know how it turns out.
 
Shifting the compound to 60 degrees makes the feed 1/2 marked.

Take it more by shifting compound past 70 maybe 80 so it feeds very very tiny amount.

Remember if it is warm it will he larger.



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tq60 said:
Shifting the compound to 60 degrees makes the feed 1/2 marked.

Take it more by shifting compound past 70 maybe 80 so it feeds very very tiny amount.

Remember if it is warm it will he larger.
Click to expand...

Thanks for the good ideas and advice. Finally a use for those trig functions I learned so very long ago.
 
And unless you have a DRO, use a mag base and a indicator to tell you exactly how far the tool moves (if you don't want to rely on the trig and compound method) Around here, that's a standard operation for an old, worn machine. Just remember it's going to read on the radius, not the diameter. Even if you do use the angle of the compound to get better control of the -X- axis position, it won't hurt to hang an indicator somewhere on it to let you know if something gets moved or bumped along the way. It's a good practice for manual machines without DRO's. It will also turn up errors in the crossfeed screw or dial. I have run machines where that is just about the only way to get any kind of precision out of them.
 
I guess I don't fully understand the problem. In any event you could use this back plate for a 4 jaw.
Robert
 
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nothing wrong with the suggestion of mounting the chuck loose enough that it can be adjusted by hitting with a MALLET(NOT a hard hammer!). Then,tighten the screws down. It won't come loose,don't worry.
 
I have one "non-adjustable" 3-jaw chuck in the shop I use on my 9" SBL. All my other 3-jaw chucks are either Adjuster-True or Set-True chucks. On the non-adjustable chuck as I call it, I purposely turned the boss about .005-.007" smaller than the register on the chuck. Doing this allows me to "bump it" around as George mentioned above to get the work piece running true. One thing to remember, as the chuck gets used, you will notice some runout in a couple of thousandths on different diameters as you use it. So what do you do? On mine, I loosen the screws so they are snugged, then start bumping the chuck around until it is running true, then tighten down the screws. They don't need to be hammer tight, tight enough with a long allen wrench. With a chuck tight against the back plate register, you don't have that option of adjustment. Ken
 
You could, as has been suggested, tighten the screws until just snug then beat it around until it's to your satisfaction then nip the screws up tight check it's still true, then remove from lathe and drill and ream for a couple of dowel pins from the rear. Do this with chuck set at most comon dia, it will probably still vary across the size range. 3 jaws are generally not known for being perfectly true. When I was an apprentice I had a 5" 3 jaw that I would mount in the 14" 4 jaw set it up true with a shaft of the size I was going to machine It would then be true within about 0.001 for the multiple pieces I had to machine.
 
Why'd you heat it in the oven. I would assume that it would shrink when cold, and that's why you're off in size.
I would have cut it while cold, then wait for it to cool, then do a final.
When it expands from heat, it would be nicely locked on.
 
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