Lathe chuck advise

Lathe chuck advise

Joined: September 28th, 2005, 5:18 am

March 30th, 2007, 4:26 am #1

I am looking to buy a 3-jaw chuck for my new-to-me craftsman/Atlas 12x36 lathe. It came with a 4-jaw independent chuck which is in very nice shape, a milling attachment, steady rest, 2 dead centers, drill chuck and a good assortment of tooling but no 3-jaw scroll chuck. Is a Bison chuck worth the money? I am new to machining and this is my first metal lathe. What other tooling/accessories would be handy to have? I will post pics this weekend when I get her in place in the garage. Thanks

Rob
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Joined: March 9th, 2007, 3:30 pm

March 30th, 2007, 6:07 am #2

I've bought several and never had one yet that wouldn't beat the published specs on a carefully machined backplate.
Keep in mind that a 4 jaw self centering chuck has 25% more holding power with the same amount of tension as a 3 jaw. It doesn't take much force to distort a guide or thin wallled part.

A quick change toolpost is one of the first things I would buy.
You can shell out big bucks for an Aloris but the PhaseII is plenty good enough for most applications.
I would pop for the wedge type as it's more repeatable than a piston type and not much more money but the piston type is fine for the home machine shop.

I would also get a good live center. This is a must have.
A long nose type is better for turning small parts. Don't skimp on the live center. A good one will run true for many years.
You can buy a cheap one for 30 or 40 bucks but a good one will set you back 100 bucks or so.



Try here.
http://www.use-enco.com

Flying chuck keys will make you st,st,st,st,studder!!
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Joined: July 11th, 2001, 7:44 pm

March 30th, 2007, 2:46 pm #3

<P>materials do y'all "real machinists" use for making a backplate? I made one for a 5" chuck out of T6 aluminium but the runout was about .003 after mounting it on the lathe. Perhaps this was an issue for the cheap 3 kaw chuck I bought but I ended up recutting it for my 5" 4 independent jaw chuck. The reason I made it so thick is because I could give it a 1 1/8" diameter bore which allowed me to directly machine my custom R9 pistons without live centers.</P>
<P><IMG height=362 src="http://img.photobucket.com/albums/v734/ ... dapter.jpg" width=483></P>
<P></P>
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Joined: May 5th, 2005, 12:41 pm

March 30th, 2007, 6:59 pm #4

I am looking to buy a 3-jaw chuck for my new-to-me craftsman/Atlas 12x36 lathe. It came with a 4-jaw independent chuck which is in very nice shape, a milling attachment, steady rest, 2 dead centers, drill chuck and a good assortment of tooling but no 3-jaw scroll chuck. Is a Bison chuck worth the money? I am new to machining and this is my first metal lathe. What other tooling/accessories would be handy to have? I will post pics this weekend when I get her in place in the garage. Thanks

Rob
I would go for a Bison Set Tru 6 jaw.

Love mine, can hold delicate parts, good grip, and you can dial it in to nothing for runout.

JT
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Joined: March 9th, 2007, 3:30 pm

March 31st, 2007, 11:25 am #5

<P>materials do y'all "real machinists" use for making a backplate? I made one for a 5" chuck out of T6 aluminium but the runout was about .003 after mounting it on the lathe. Perhaps this was an issue for the cheap 3 kaw chuck I bought but I ended up recutting it for my 5" 4 independent jaw chuck. The reason I made it so thick is because I could give it a 1 1/8" diameter bore which allowed me to directly machine my custom R9 pistons without live centers.</P>
<P><IMG height=362 src="http://img.photobucket.com/albums/v734/ ... dapter.jpg" width=483></P>
<P></P>
Aluminum is too temperature sensitive for a back plate.

Machine the back plate to fit your spindle but leave the OD and face .025 large and then mount it to the spindle.
Finish machine the face of the back plate on YOUR lathe to fit YOUR chuck and it should be dead nut.
If there's any runout, it's in the chuck then.

I agree about the six jaw. If you can afford it, that's the way to go. You can hold very soft parts with very little tension with a six jaw.





Flying chuck keys will make you st,st,st,st,studder!!
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Joined: July 11th, 2001, 7:44 pm

April 1st, 2007, 2:30 am #6

for making my adapters. I did notice that when I first cut my aluminum adapter it was a snug fit to the spindle and chuck but when I removed it the fit wasn't as snug anymore. I does seem that the c-bore in the thing "wore" just by using it even though the adapter and chuck weren't removed. Real strange to me!
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Joined: October 14th, 2003, 4:56 am

April 1st, 2007, 10:03 am #7

It will expand and contract uniformly about the diameter and along the length (And by less than .001" in such a small piece anyway) and not cause any measurable concentricity variations due to normal temperature changes encountered on the machine.

The problems you have seen with your adapter are due to other factors (Unless it was too hot to touch while you were fitting it to your spindle/chuck).
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Joined: August 22nd, 2001, 3:27 pm

April 3rd, 2007, 11:28 am #8

I would go for a Bison Set Tru 6 jaw.

Love mine, can hold delicate parts, good grip, and you can dial it in to nothing for runout.

JT
6 jaw, 4 jaw, 3 jaw, and 2 jaw, syncronius chuck, many holding options! james
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