Chuck selection

All discussion about lathes including but not limited to: South Bend, Hardinge, Logan, Monarch, Clausing and other HSM lathes, including imports

Moderators: GlennW, Harold_V

Tpro
Posts: 40
Joined: Thu Oct 18, 2012 6:25 pm
Location: Selah Washington

Chuck selection

Post by Tpro »

I have a 3 jaw chuck which is not very accurate, but does ok for most stuff. Think I will add soft jaws to it and use like that. I have a 4 jaw, but dialing it in seems to be taking longer than I want/like. That said, should I consider a 6 jaw chuck. I would like it to be my "go to" chuck for 90% of what I do. For example, chambering rifle barrels, accurizing actions, threading barrels etc. Seems to me the 6 jaw would be quick and dirty if dialed in once and would be a real time saver. Or should I invest in something different. What do you think??

Thanks
Tim
Chuck K
Posts: 188
Joined: Sat May 28, 2011 8:14 pm
Location: Northern Illinois

Re: Chuck selection

Post by Chuck K »

It's pretty hard to beat a good 4 jaw once you get used to dialing it in. Having said that, I've never wanted to pony up the cash for a good six jaw. I'm assuming it's a set-tru chuck you're considering. I would still have to check it each time I was doing something that had to be right. Maybe they're more precise than I think they are.

Chuck
User avatar
rudd
Posts: 754
Joined: Wed Dec 12, 2007 11:21 pm
Location: savannah ga.

Re: Chuck selection

Post by rudd »

Any three jaw is going to have accuracy problems when you get down to it. A six jaw self centering chuck probably won't be any better.

I'll share a tip I was given on the 4 jaws. Here it is:

get a second chuck key.

With TWO keys, chuck up your part eyeball centered, jaws just snug, not tight. Set up your indicator. Mark your jaws 1-2-3-4. Zero out with jaw 1 aligned with indicator. Turn 180 to jaw 3. Look at your reading. Simultaneously adjust the screws on jaw 1 and jaw 3 to halve your reading. Keep the part snug in the jaws as you turn your keys. Tighten up a bit on both at the same time, keeping your reading.
Repeat for jaws 2-4.
After two rounds of this, you should be within a couple thou. At this point, you can just horse the high jaw down a bit both locking the work in place, and nailing your zero.

Takes longer to type than to do.
dly31
Posts: 1052
Joined: Sun Jun 27, 2004 11:29 pm
Location: Northeast Alabama

Re: Chuck selection

Post by dly31 »

Six jaws don't inherently give you any more accuracy than three, although a six jaw chuck may be better made and more expensive and thus more accurate. The only advantage I can see in six jaws is less tendency to deform thin walled work. I personally like a three jaw for things within its capability and a four jaw for everything else. A set of soft jaws on a three jaw can give you the best of both.
Don Young
User avatar
SteveHGraham
Posts: 7788
Joined: Sat Jan 17, 2009 7:55 pm
Location: Florida

Re: Chuck selection

Post by SteveHGraham »

I can see how a 4-jaw would be a pain in the butt if you were opening and closing it all day, but if you're not, it shouldn't be unpleasant to use. On my first lathe (may its name never be mentioned), I got to where I never bothered switching to the 3-jaw.

Have you considered some type of adjustable 3-jaw? The Gator I bought seems very nice.
Every hard-fried egg began life sunny-side up.
stevec
Posts: 1949
Joined: Thu Oct 21, 2010 12:40 pm
Location: N.S. Canada

Re: Chuck selection

Post by stevec »

Sometin' bothers me about a Floridian using a "gator". (hi steve :oops:)
Richard_W
Posts: 2031
Joined: Fri Jan 10, 2003 1:00 am
Location: Molalla, Oregon

Re: Chuck selection

Post by Richard_W »

An upgrade to a set true 3 jaw is sometimes a good idea. But if you don't use your lathe much, several sets of soft jaws may be money better spent. That is assuming the chuck you have isn't worn out. You ask a difficult question because the answer may be different for each person and what they do. I don't see myself ever buying a set true 3 jaw, since a 4 jaw or soft jaws will work just fine for me. But then I have 40 years of machine work behind me and generally only do one off items. How ever I would like a 5C collet setup of some sort.

Richard W.
stevec
Posts: 1949
Joined: Thu Oct 21, 2010 12:40 pm
Location: N.S. Canada

Re: Chuck selection

Post by stevec »

I'm wworking toward a 5C set up too. I'll share what I come up with (don't wait up!).
Steve
User avatar
SteveHGraham
Posts: 7788
Joined: Sat Jan 17, 2009 7:55 pm
Location: Florida

Re: Chuck selection

Post by SteveHGraham »

stevec wrote:Sometin' bothers me about a Floridian using a "gator".
It didn't even come with tartar sauce.
Every hard-fried egg began life sunny-side up.
Ron of Va
Posts: 16
Joined: Fri Sep 25, 2009 2:01 pm
Location: Tidewater, Va

Re: Chuck selection

Post by Ron of Va »

A couple of things about a 6 jaw.

You would think that a 6 jaw would have twice the holding power of a 3 jaw. It doesn’t. It seems to me that in goes the other way having only half the holding power of a 3 jaw.

A 6 jaw set true chuck wouldn’t necessarily have an advantage when dialing in a gun barrel. It would only dial in the outside of the barrel, not the bore, which is what you want. The bore is never perfectly centered in the barrel.

Watch this video on Youtube and it will make centering the 4 jaw easier.
http://www.youtube.com/watch?v=2KMhx4DbyDg

If you get a new scroll chuck, make sure it is the Set True type. I have a 6 jaw Bison set true and like it a lot, but I know its limitations.
User avatar
rodw
Posts: 20
Joined: Fri Nov 30, 2012 6:29 am

Re: Chuck selection

Post by rodw »

I'm only a noob but have just fitted a 4 jaw chuck and I find it quicker to dial in one job I do all the time facing plastic rod ranging from 60 to 75 mm in diameter. I had to use the dial indicator to get it straight in the 3 jaw anyway as I needed to reverse the jaws so I was only gripping the piece by 5 mm and the plastic is not dimensionally accurate like metal is.

Using the 2 key technique, with the part now fully seated in the 4 jaw, on average, I am 30 seconds faster per operation with greater precision. Does not sound like much but when you have a few hundred to do it makes a big difference as it works out at about 25% time saving. However, on the second face, I revert to the 3 jaw because I have a square face that seats nicely in the chuck so the result is accurate enough for this part and it is quicker.
RodW
Brisbane, Australia
http://www.vehiclemods.net.au
User avatar
Harold_V
Posts: 20231
Joined: Fri Dec 20, 2002 11:02 pm
Location: Onalaska, WA USA

Re: Chuck selection

Post by Harold_V »

rodw wrote:I'm only a noob but have just fitted a 4 jaw chuck and I find it quicker to dial in one job I do all the time facing plastic rod ranging from 60 to 75 mm in diameter. I had to use the dial indicator to get it straight in the 3 jaw anyway as I needed to reverse the jaws so I was only gripping the piece by 5 mm and the plastic is not dimensionally accurate like metal is.

Using the 2 key technique, with the part now fully seated in the 4 jaw, on average, I am 30 seconds faster per operation with greater precision. Does not sound like much but when you have a few hundred to do it makes a big difference as it works out at about 25% time saving. However, on the second face, I revert to the 3 jaw because I have a square face that seats nicely in the chuck so the result is accurate enough for this part and it is quicker.
What you have described would be faster using a three jaw with soft jaws, assuming you have the capability.

Harold
Wise people talk because they have something to say. Fools talk because they have to say something.
Post Reply