Tightening a 3-Jaw Chuck

[EdK]

Good discussion. I knew I had read about a master jaw somewhere.

Ed

[Mayhem]

I also read about a master jaw and tried on my friends 3 jaw and found that one of the jaws did result is less run out than the others. I can't recall the amount but less is less, which can only be good

I marked the jaw and will have to see if it is #1

[PixMan]

I have a Pratt-Burnerd Super Precision 3-jaw scroll chuck on my dad's lathe. I got it for $200 from a Harrison lathe distributor who had dropped it and damaged one of the top jaws.

It runs out less than .0005" no matter which of the 3 holes I use.

[Mayhem]

Well I have zero run out on my 3 jaw, as I currently have to hold it in my 4 jaw!

[EdK]

(01-24-2013, 06:39 PM)Mayhem Wrote: Well I have zero run out on my 3 jaw, as I currently have to hold it in my 4 jaw!

Good one!

[Tony Wells]

One of my 3 jaws has a socket marked with a "O" and it is considered the primary socket. it does seem to yield a better ruout than the other two. Not all chucks are so marked, but it might be worth going through and seeing if there is a consistently better result using one over the others and marking it as primary.

[Sunset Machine]

Heavy cuts, I tighten all three.

[Highpower]

(01-24-2013, 07:50 PM)Tony Wells Wrote: One of my 3 jaws has a socket marked with a "O" and it is considered the primary socket. it does seem to yield a better ruout than the other two. Not all chucks are so marked, but it might be worth going through and seeing if there is a consistently better result using one over the others and marking it as primary.

Well, I'll be......

I just went and looked at my chuck. So THAT'S what that means?
All these years and I never knew.

   

[PixMan]

Willie,

That poor chuck (and it's holder, the lathe) appear to have never done any serious machining. Get to it man!

Just kidding!

[Highpower]

The guys that pick up my trash might argue that point Ken.



Besides, you can't see the "zero" mark on the chuck from down here.