Stronghold chuck jaws, whats wrong with this picture.

What's the beef? You have a set of go/no-go gages at hand to help size the tenons. Plywood will do.

If it won't fit, don't make it that size.

Hi Neill!

I do believe Oneway listens to their fans. If you pop over to th Oneway forums, they have a poll going on now about whether or not ther are enough accessories for their jaws. Make your voice heard!

-- wrz0170

Not really much of a problem at all. I use a go-nogo gauge and if you do get it wrong just cut the tenon down to fit the smaller jaw. A set of #4 jaws is about $65Cdn or ~$50.US not $270 and if you don't like them don't buy them. Personally, I like to keep the jaws operating near their minimum size so there is less metal flying around the bottom of the workpiece. Billh

I agree that it is usually possible to work around the limitations of a chuck. However, there may be times when it is not practical to change the size of the object you want to hold. A "rational" system ought to provide slight overlaps in the size ranges, not big overlaps, and certainly not gaps. My vote goes with Neil

Is there an optimum size for each jaw set, Leo?

Most agree there is.

So are you advocating less than optimum, or an infinite number of jaws?

"George" wrote: Is there an optimum size for each jaw set, Leo? Most agree there is. So are you advocating less than optimum, or an infinite number of jaws? ^^^^^^^^^^^^^^^ The only "optimum" I know is that for jaws with a quarter-circle shape, they should ideally grip a spigot that they fit, ie, same radius. One-way overcomes that restriction by creating a wavy shaped jaw, so that at all radii, there are two contacts for each jaw, for a total of eight around the circle. This, combined with their ribbed design results in excellent holding power, regardless of how much the jaws have to be opened or closed to fit the spigot.

With the sophistication of that design, it is surprising to me that they have sets of jaws with gaps in the coverage.

George, if you can explain to me what you mean by an "optimum" size, I will be grateful.

I'm with Neill. Are we are the only two turners who have ever had to put a blank back on centers to adjust a tenon? Or, as Leo said, needed to seat a fixed tenon in the jaw gap?

Tenons are usually easily adjusted for jaw gaps, dents on soft iron tool rests are easily smoothed and spindle movements are easily measured on ungraduated tailstock rams, but we shouldn't have to. I think " keeping costs down" is a weak excuse. At the price of turning equipment today, we shouldn't need to buy corrective add ons or take corrective actions?

Turn to Safety, Arch Fortiter

The max size number is sort of irrelevant as the farther you get from the minimum size number you get the less and less wood is in contact with the jaw. When you grip on such a small area the wood is crushed under the jaws also the wood is unlikely to compress evenly and is not going to running true.

Walt

Optimum size is that which puts the greatest amount of metal against wood without distorting the latter. The quarter-circle types have an optimum size of circularity plus or minus perhaps 5%. I call this the optimum situation, because any deformation makes realignment after a dismount more difficult. The status quo ante just no longer exists. The weakness of the Oneway design is that it has to "grip" by distorting or destroying the integrity of the portion gripped.

Thus my preference for non-destructive mounting using dovetails to shoulder either in recess or against an external shoulder. It makes circularity a cinch, because the wedge centers as it draws the piece back into the chuck, where the shoulder or recess now resists angular forces. Optimum size is slightly less critical here, because it is easier to ensure registry against its shoulders or interior recess. It does not have to grip nor distort that which it holds.

If you really want to improve a ridged external hold, you would do well to consider asymmetrical ridges, with the flat toward the piece, and the wedge toward the chuck. That way they would automatically push against the fibers engaged, snugging the chuck against a shoulder as mini wedges or dovetails. You still would want to have minimum disturbance in the fiber structure, therefore an optimum size would exist, but at least you would not have a situation where symmetrical ridges are as likely to push away from shouldering as toward.

On Fri, 29 Apr 2005 3:28:10 -0700, George wrote (in message ):

yea yea... ...i know i know, go/no-go gages, hrumpff! wouldn't it be better if the chucking system where designed without any no-go gaps to worry about?

well yea... obviously. but wouldn't it be better if i *could* make it that size if i wanted to?

On Fri, 29 Apr 2005 6:27:16 -0700, billh wrote (in message ):

in fact i don't like them and i am not going to buy them. as i said earlier why would i for only 1/2" larger capacity than my #3 jaws? shame too because there have been times when i wanted a larger tenon. the $207 i mentioned is about what i would have to spend for a stronghold chuck-body only, insert, and jaws. doesn't everyone have a dedicated chuck for each jaw set? changing chuck jaws is so tortuous. i know im supposed to suffer for my art but lets not be ridiculous.

to each his own. im not at all squeamish about opening the jaws up as far as they will go if that is what i feel that particular size workpiece calls for.

On Fri, 29 Apr 2005 9:25:48 -0700, Leo Lichtman wrote (in message ):

very well put Leo. concise and to the point.

thanks for the heads up on that poll. i took your advice and posted my beef over there as well.

On Fri, 29 Apr 2005 11:02:46 -0700, George wrote (in message ):

i don't concern myself with the optimum size for the jaws. i try to find the optimum size for the workpiece. do you only use your jaws at the optimum size? that would be very limiting indeed!

On Fri, 29 Apr 2005 11:34:27 -0700, Arch wrote (in message ):

here here!

On Fri, 29 Apr 2005 11:58:24 -0700, Walt & Jenne Ahlgrim wrote (in message ):

for me the max size number is not at all irrelevant. i understand what you are saying and in thoery it is true... well at least it is a true part of the story. personally, for the way i work, the whole story is more complicated than that. i turn many different sizes and shapes. mostly bowls and hollow forms. i use every bit of my chuck's capacity. i figure scroll chucks open and close as far as they do for a reason. when i am turning a large bowl i feel better making the tenon as large as my chuck will hold.

On Fri, 29 Apr 2005 14:23:51 -0700, George wrote (in message ):

i have not found the ribbed oneway jaws to be as distructive as you make them sound. a screw may distort or "destroy" more wood fibers than a nail does but the screw still holds better. im not saying the way you do things is wrong. if dovetail jaws work better for the work you do and the way you do it than thats what you should use.

On Fri, 29 Apr 2005 14:23:51 -0700, George wrote (in message ):

actually thats a really good idea. does anyone make such an animal?

Well, perhaps they should have a set called "2 1/2".....