Where To Buy Cast Iron

[roadie33]

Well, I got the back plate and turned down the register to a snug fit. Transferred the hole pattern to plate and drilled and counter bored for M8 socket screws. Screwed the plate to chuck and took to the lathe to check run out. I used a 12mm shaft out of a printer stuck out 2" to test.
No matter where I checked in those 2" or how much I tightened the screws or threaded it on, it always showed around .002 to .004 run out. The only thing I didn't try was drilling the holes the next size bigger for a little more wiggle room, then lightly tighten the screws and check for run out and adjust accordingly.
I just wasn't sure if that was a good idea or if the chuck would loosen up and I'd be back to square one again.
Any ideas on how to get it trued up?

 

[atlas ten]

Is it possible the run out is from the chuck and not the backing plate? You could grind jaws to correct it.
Jack

Sent from my SGH-I337M using Tapatalk

 

[roadie33]

I forgot to mention I also checked run out from the chuck itself where it connect to the back plate and it was the same there too.
.002-4 run out so I need to figure out how to make the chuck do something like an adjust-tru chuck and get it centered better.
I have no way to grind the jaws even if I wanted too.

 

[george wilson]

I bought some 6" cast iron blank back plates from Wholesale Tool years ago for $15.00 each. I have used some to make backplates for my tapered nose Hardinge HLVH. Had no problems with machining these back plates.

Wholesale tool may have backplates still. Might want to Google them and see what they now have.

 

[Smithdoor]

I use a weight set from Target lots of blanks
Also if need long piece try use weights off of weight machines

Dave

 

[4GSR]

...........I tightened the screws or threaded it on, it always showed around .002 to .004 run out. ...........

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I have a 6" 3-jaw chuck, brand new out of the box, just like yours mounted on a back plate that I made several years ago. I too, had the same runout problem. I took and turned down the register on the back plate that is for locating the chuck, down about .005". re-mounted the 3-jaw chuck and left the three M8 screws snugged, not tight. Chucked up a H & G dowel pin about a 3/4" diameter. Where it was high on the pin, took a chunk of brass and bumped the chuck on the OD until I got it running true, less than a .0005" TIR. Once I did that, tighten the M8 screws. Been running like that for nearly 15 years, only had to re-adjust the runout a couple of time since.

Ken

 

[roadie33]

I have a 6" 3-jaw chuck, brand new out of the box, just like yours mounted on a back plate that I made several years ago. I too, had the same runout problem. I took and turned down the register on the back plate that is for locating the chuck, down about .005". re-mounted the 3-jaw chuck and left the three M8 screws snugged, not tight. Chucked up a H & G dowel pin about a 3/4" diameter. Where it was high on the pin, took a chunk of brass and bumped the chuck on the OD until I got it running true, less than a .0005" TIR. Once I did that, tighten the M8 screws. Been running like that for nearly 15 years, only had to re-adjust the runout a couple of time since.

Ken

I turned down the boss another .002 like you did Ken. Then re-mounted the chuck and got it set to .0003 runout. I tightened down the 3 screws as tight as I could, so I hope they don't slip.
That new chuck sure is nice and smooth now compared to the old original Craftsman 6" chuck.
I may end up using it on the wood lathe after I make an adapter to the 1-1/2 x 8 tpi.

 

[4GSR]

I turned down the boss another .002 like you did Ken. Then re-mounted the chuck and got it set to .0003 runout. I tightened down the 3 screws as tight as I could, so I hope they don't slip.........

It won't slip. I've even hung up and broken off a couple of cut off blades and didn't move!