Learning to dial in a 4-jaw

ttabbal said:
Let me know if you want a printed QCTP indicator holder. I don't mind letting the printer run a bit for you. I might set it up with hot pink filament, depends on the mood at the time... :)
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Gosh, that would be fantastic!


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DavidR8 said:
I got the 4-jaw mounted up on the new backplate today and so tried my hand at chucking up some round stock.

It was a bit frustrating as I struggled to start from a place where the shock was even reasonably centered so my indicator was spinning round like a top.

I was using the rings scribed on the face of the chuck and eventually got it dialed in to about thou of runout but it took me probably 10 minutes of fussing.

Part of the problem is the my mag stand is a piece of rubbish so I was struggling to get the thing to stay put.

Any tips on the dialing in part?


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I made this little tool for the 4 jaw. It has all the common sizes I normally use (1/4, 3/8, 1/2 and 3/4”). I chuck it into the tailstock and run it up into the 4 Jaw. You can then close the jaws down on the size needed, loosen the jaws slightly, remove the tool and install the actual part. Gets you real close.

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It sounds like you're spending too much time while the part is a mile off. I stick ANY tool is the tool holder and run it up to the part. Spin the part in the chuck (BY HAND) until you touch a high spot. Rotate to the opposite jaw and eyeball to cut the space in half. When the space is roughly even with jaws 1 & 3 do the same with jaws 2 & 4. Now when you grab the DI it will be within one rotation (.100") of the dial and will be easy to figure out using what every one has said in this thread. It's also a good idea to have 2 short opposing chuck keys. I made mine by just welding some appropriately sized keystock into a "T". Others on the board have made works of art. Whatever floats your boat.
(edit; added BY HAND in line #2)
 
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When I was doing my apprenticeship we were only allowed to use a three jaw for production jobs
and if you didn't hit close to the bosses bid time you got an a$$ chewin, so dialin in a four jaw quickly
was priority one ................
 
Someone may have mentioned this, but I didn't see it so here goes.
Right after I bought my first lathe, I turned some concentric grooves in the face of the 4 jaw chuck. I put them about every 3/8 inch but you can space them as you see fit. You can use a corner or edge of the jaws and the lines to get the work piece very close to true, saves a lot of guess work.


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David, get a piece of 1/2" key stock. Drill the 3/8" hole back about 9/16-5/8". Flip 90 degrees and drill #21 tap hole for 10/32 screw about 1/4" from end. Tap it. Hacksaw a cut across the 3/8" hole so it closes with screw. Drill one side of tapped hole with #10 or 11 drill to remove threads. Install indicator and mount in AXA holder. No mill needed, just 3 drill bits, a hacksaw and some kind of drill.

Mine is approximately what i said except that both ends are done and I use two indicators. By switching positions I can dial the face also.
 
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