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6-jaw chuck?

Odie

Odie

Panning for Montana gold, with Betsy, the mule!
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I was not aware there was such a thing as a six jaw wood lathe chuck until I ran across it searching for something else. My question: Why would a turner want one?......what advantage is there over a standard four jaw chuck?

The information suggests it's a more secure mount, but is it really? Unless the jaws are fully closed, the grip would be at 12 points, instead of 8 with a four jaw chuck.
s-l1600.jpg

-----odie-----
 
Well, 12 is 50% more than 8. I've seen 3 jaw wood lathe chucks, too, but I don't think there's much of a market for them. Don't know if the 50% increase translates into a 50% improvement. Maybe somone is testing the market waters.

Who is the maker, by the way.
 
Dave DeJong said:
I'm in the market for a new chuck but I'm also not to fond of changing 4 jaws much less 6 so I think I'll pass on this one. Who makes it?
Click to expand...
Mark Jundanian said:
Well, 12 is 50% more than 8. I've seen 3 jaw wood lathe chucks, too, but I don't think there's much of a market for them. Don't know if the 50% increase translates into a 50% improvement. Maybe somone is testing the market waters.

Who is the maker, by the way.
Click to expand...

Barracuda

If you search for it on eBay, you'll find it......but, I guess forum rules do not allow me to supply a link.

Use these words in the search: 6-Jaw x 4" Self-Centering

-----odie-----
 
Also......I see each jaw is numbered. Why is that, since they are screwed to the chuck slides? The slides should be numbered, but the jaws?

-o-
 
A 6 jaw chuck with dovetails would grip a round tenon better than a 4 jaw chuck with dovetails.
A 6 jaw chuck is not going grip a square spindle blank at all.
With two jaws removed to hold a board end the 4 jaw will out perform the 6 jaw with 4 jaws removed.

A ONEWAY profile jaw is likely to outperform both on holding ability.
That said it is rare object that won’t be held well enough with 4 dovetails.

A ONEWAY profile provides the best grip on square stock for finials etc.
A vickmarc dovetail will hold it just fine.

Sort of like jacking up a 2,000 pound trailer with a 3 ton jack or a 5 ton jack.
More holding power is good but adequate holding power is all we need.
 
Holding a piece of wood with (2) fingers and it can easily be pried from your hand, the larger number of fingers compressing the wood billet at concentric angles around the circumference of the wood billet should provide a secure hold. When you tighten a (4) jaw chuck onto a hard piece of wood you usually end up with (8) marks around the circumference of the billet, This indicates (8) points of contact with the billet, (6) jaws should provide (12) points of contact with the wood billet depending on the diameter of the billet and the diameter of the jaws when tightened onto the billet. More points of contact should provide a better hold of the item in the chuck.
 
Mike Johnson said:
Holding a piece of wood with (2) fingers and it can easily be pried from your hand, the larger number of fingers compressing the wood billet at concentric angles around the circumference of the wood billet should provide a secure hold.
Click to expand...
Mike,
Good anology but you have consider what you are doing to the wood
:)
A finger and a thumb hold a pencil quite well for writing.
A full fist grip,employed by preschoolers is a stronger grip.

Both work. one is a stronger hold but the two finger is most likely not more effective.
:)
I also had a baseball coach who told us if he could not walk up behind us and pull the bat from our hands we were holding too tightly.

If stronger hold were paramount we would all use faceplates and screws on face work.
For bowls I use the lesser holding power four jaw chuck for its speed and convenience
For hollow forms I use a faceplate for the stronger less vibrating hold.
 
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REVISED

Odie, you are correct in stating that it is against the rules to start a thread that is intended to promote a product, but including a link is irrelevant.

The reviews on the Penn State site didn't impress me. It uses tommy bars and the grip can loosen according to a reviewer. There is only one size set of jaws which all the reviews complained about (which also says there is no need to number the jaws or have screws since there is no reason to ever remove them). Six jaws are a non-starter when it comes to gripping square stock.

Apparently it isn't a great selling item ... the price has been reduced from $170 to $99. I normally only use dovetail jaws at the perfect circle diameter so six jaws have no advantage over four jaws (the perfect circle diameter is when the gap between the jaws is about ⅛"). It's interesting that the jaw size is referred to as #2 despite the fact that there isn't a #1 set of jaws (nor #3, etc). The specs say that the chuck is threaded for a 1⅓ X 8 spindle. :D The gripping range for tenons and mortises are crossed with each other. They neglected to mention that the chuck uses tommy bars instead of ring and pinion gears. Perhaps Penn State could do a better job proofreading the specs and description.
 
odie said:
Also......I see each jaw is numbered. Why is that, since they are screwed to the chuck slides? The slides should be numbered, but the jaws?

-o-
Click to expand...
Probably the slides are numbered as well. My Nova chucks and jaws are similarly numbered.

As I understand it chucks used to be balanced with a particular jaw on a particular slide. I don't think this is an important factor these days. In any case I have two identical chucks and two sets of 50mm jaws. At this point I have no idea which #2 jaw goes to which #2 slide.
 
Mark Jundanian said:
Probably the slides are numbered as well. My Nova chucks and jaws are similarly numbered.

As I understand it chucks used to be balanced with a particular jaw on a particular slide. I don't think this is an important factor these days. In any case I have two identical chucks and two sets of 50mm jaws. At this point I have no idea which #2 jaw goes to which #2 slide.
Click to expand...

Odie As Mark said Nova jaws are numbered and I think it has to do with making sure the balance is the best possible with the jaws balances in that position. I have a Baracuda and yes mine too will loosen. I have no problem with the grip in a 4 jaw chuck so not looking for the "next best thing"
 
odie said:
I was not aware there was such a thing as a six jaw wood lathe chuck until I ran across it searching for something else. My question: Why would a turner want one?......what advantage is there over a standard four jaw chuck?

The information suggests it's a more secure mount, but is it really? Unless the jaws are fully closed, the grip would be at 12 points, instead of 8 with a four jaw chuck.
s-l1600.jpg

-----odie-----
Click to expand...
My jaw dropped when I saw your posting! LOL. Joking aside, I see no advantages of having the extra jaws.
 
For engineering (metal) lathes 6 jaw chucks are used for two reasons:

Normally higher precision than 3 jaw versions so will hold variety of diameter pieces with reduced run-out.
Grip force is spread across 6 jaws rather than three so ideal for holding thin wall tube or finish turned items without marking the surface or deforming the tube.

Neither of these is really helpful in a wood turning context so but of a oddity I think.

Simon
 
Looks like something Lee Valley would come up with for one of their April Fools tools, cept it would be a 12 jawed chuck...
It's new, it's amazing, its amazing and new... Be the first to own the new Dodecagon 150, not only does it have 12 jaws and 12 slides, it weighs 12 pounds... But wait, if you order before midnight...

Odie, I think it's the Chuck de Jour and would end up in the drawer of useless tools.
 
john lucas said:
Why not go with 8 jaws :) 8 jaws would hold a square piece, although only 4 jaws would grab it.
Click to expand...

One obvious reason is that there would be an interference of the base jaws and possibly also the inner screw heads. I think that a collet chuck set might be a better solution for situations where a scroll chuck doesn't grip smoothly enough around the whole circumference.
 
I'll continue using my vicmarc vm100 4 jaw --- often I'm chucking up a square piece --- like Lucas said why not 8 --- 6 is odd in lathe terms.
 
odie said:
Also......I see each jaw is numbered. Why is that, since they are screwed to the chuck slides? The slides should be numbered, but the jaws?

-o-
Click to expand...
My first 4 jaw scroll chuck was a Nova and that had numbered jaws and I think it had something to do with accuracy.
 
The early chucks all had numbers. Probably a throw back from metal lathe chucks that required the jaws to go on in a certain order. Of course the inner jaws still do. I was told by the Vicmarc rep that the outer jaws are all identical due to CNC machining and that the only reason they were numbered was to please customers who thought they should be.
 
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