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I bought a grizzly 4 jaw self centering chuck and removed the jaw bowl turning attachments per usual so as to install 2 machined rectangular tower jaws. I've bought quite a bit of stuff from grizzly over the years and it was usually quite serviceable. I machined the tower jaws, installed them and chucked up a block, or lyrics find that the jaws at the nose end (where the gouge is pointing in the pic) spring open when tightening the chuck, causing a slanted grip face. It's not the adapter towers that are springing, it's the chuck base jaws moving in their guide channels, where there's a lot of slop. My question is do the oneway or others also do this? Is the grizzly a crap chuck? It certainly isn't usable this way since the grip is reduced to essentially an edge grip on the slant, so it's not tight. I'm wondering if I'm out the money for the grizzly and have to buy a oneway or similar, or do some rube Goldberging. You can see in the pic the slop angle. The front of the jaws move about .070 inch. Terrible.


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I'm not sure about the chuck, and I'm not a machinist, but the briar chucks I've seen have jaws with little teeth cut on them for a better grip. Perhaps you're applying too much force to clamp these on and teeth would decrease the clamping force required?

IAWJ - I'm new to the lathe, but my jaws have both pretty aggressive teeth as well as center screws.

I didn't put center pins or serrations on it until I checked it's functionality. No amount of serrations will help the tilt the jaws take on due to slop in the chuck body jaw carriers.

Could you adjust the jaws to take into account the angle?

If you're sure the slop is on the carriers, it could well be the chuck. I do know my oneway chuck worked great with briar jaws when I had them. Unfortunately, I wouldn't have the slightest clue how to correct the slop since I'm not a machinist.

Your post says you machined the jaws. Could you amplify or clarify that statement?
DocAitch

DocAitch wrote:Your post says you machined the jaws. Could you amplify or clarify that statement?
DocAitch

Yep. I milled and drilled them with my vertical mill, and took great care in the dimensions to ensure concentricity.. I can see that the cant the jaws take on as soon as I tighten it against a block is from slop in the jaw carriers in the chuck body.

None of the chucks I have have any play in the carriers. I have Nova, Oneway, and no name chucks that came with my metal lathe as well as the chuck that Trent Rudat uses. I'm curious if the tower jaws you machined sit flush on the face of the chuck. I know all of my jaws fit very flush against the face of the chuck so, even if there was play in the carriers, they couldn't tilt. Yours appears to have a gap.

So shim them inward a bit, and they'll sit straight when you tighten...

Sasquatch wrote:So shim them inward a bit, and they'll sit straight when you tighten...

Sas, That's what I figured I'd have to do, or making a ring clamp, or both as a jerry- rigged work around. But it is crude. I was wondering if the oneway or Nova chucks had the same problem, to determine if I should plan on eventually buying one of those and belly aching to grizzly. Thanks for the inputs. It confirms that part of my thinking.

wdteipen wrote:None of the chucks I have have any play in the carriers. I have Nova, Oneway, and no name chucks that came with my metal lathe as well as the chuck that Trent Rudat uses. I'm curious if the tower jaws you machined sit flush on the face of the chuck. I know all of my jaws fit very flush against the face of the chuck so, even if there was play in the carriers, they couldn't tilt. Yours appears to have a gap.

Wayne thanks for the inputs on the other chucks. You're right, I do have a gap, because I machined them to ride flat on the carrier, not thinking they might have such slop. The carriers are a bit proud of the chuck face. I guess another solution is to machine a channel in the bottom of my tower jaws so they just drag on the surface. Now, to see if I have an end mill just that size to make it easy. Back to the mill and micrometers. Thanks again all.

Slop in chucks should not produce an angle. How are the tower jaws mounted to the chuck jaws?

Both my Oneway Chucks have slop, in fact one is 10 thousands off center and the other is 20, and stopped using it because of it.
There made for wood turners and not for precision work needed when drilling a mortise or turning tenons and that's why there only $199.

RDPowell wrote:Both my Oneway Chucks have slop, in fact one is 10 thousands off center and the other is 20, and stopped using it because of it.
There made for wood turners and not for precision work needed when drilling a mortise or turning tenons and that's why there only $199.

$199 strikes me as very expensive for a non-precision chuck. It's more than I paid for my 4 jaw precision metal working chuck that formed the basis of my main pipe making chuck. No slop or anything in that at all.

PremalChheda wrote:Slop in chucks should not produce an angle. How are the tower jaws mounted to the chuck jaws?

The original jaws unscrewed, and the tower jaws screwed in their place.. excessive slop in the lathe axial direction would cause lift on the jaw, resulting in an an angle. If it were purely backlash, no. It's slop in all directions in the jaw carriers unfortunately.

Caskwith, I'm spoiled too. My metal working chucks have no slop at all. I didn't expect it to be this bad. I was tempted, but reluctant to modify one of my 4 jaw independent chucks.. I thought about welding towers on a small one, but I'm not sure I can find another set of jaws so I can still use it on metal work.

caskwith wrote:

RDPowell wrote:Both my Oneway Chucks have slop, in fact one is 10 thousands off center and the other is 20, and stopped using it because of it.
There made for wood turners and not for precision work needed when drilling a mortise or turning tenons and that's why there only $199.

$199 strikes me as very expensive for a non-precision chuck. It's more than I paid for my 4 jaw precision metal working chuck that formed the basis of my main pipe making chuck. No slop or anything in that at all.

In comparison to chuck's I've seen $199 is cheap for a good metal lathe chuck (which it isn't) but, I haven't seen them all either.

And maybe I should have said "that would fit my LATHE" I have an antique just about and it's not the best lathe out there.
A 1948 Craftsman/ Dunlap 6" lathe, like what Scottie has for turning stems but, I make pipes on mine. LOL!

With a suitable back plate you can put any chuck on any lathe (within reason).
I use a 100mm 4jaw self centre chuck as the basis for my pipemaking chuck, they cost about £125 with backplate. You could modify the existing jaws or buy extras which I did. Trent Rudat made the custom jaws for me as it was easier than doing it myself and the quality is superb.

RDPowell wrote:

caskwith wrote:

RDPowell wrote:Both my Oneway Chucks have slop, in fact one is 10 thousands off center and the other is 20, and stopped using it because of it.
There made for wood turners and not for precision work needed when drilling a mortise or turning tenons and that's why there only $199.

$199 strikes me as very expensive for a non-precision chuck. It's more than I paid for my 4 jaw precision metal working chuck that formed the basis of my main pipe making chuck. No slop or anything in that at all.

In comparison to chuck's I've seen $199 is cheap for a good metal lathe chuck (which it isn't) but, I haven't seen them all either.

And maybe I should have said "that would fit my LATHE" I have an antique just about and it's not the best lathe out there.
A 1948 Craftsman/ Dunlap 6" lathe, like what Scottie has for turning stems but, I make pipes on mine. LOL!

I held off buying a 3 jaw for my old Logan until I found what I wanted. I kept my eye on eBay and found a really nice 6", used Polish made Bison for a couple of hundred bucks. New ones are over $600. Then there's Buck (read second mortgage). Usually anything under $500 is going to be Chi-Com.

We're doing pipe making here, we don't need super fancy chucks. Chinese or Indian made are perfectly good enough for the work we do. I have some really nice chucks, proper British made stuff, they are not much more accurate than the new Chinese made stuff. A 3 jaw isn't a precision tool no matter who makes it, that's why I use collets, and Chinese made ones, they have repeatable runout of 0.02mm or less.