Chuck Jaw Terminology Question

[mksj]

The jaws appear to be ground incorrectly and do not match the stock photo. You do not want to hold a piece with a single point contact, which would occur with the jaws you show. I have not seen single piece solid jaws that are reversible, as the scroll is directional, I am only aware that two piece jaws are reversible. I would return the chuck and be done with it, there is no reason you should have to regrind/modify a stock chuck of this type. I would go for the Pratt-Burnerd or a Bison, a couple of us have the PB which are well machined and a pleasure to use.

Uploaded a better description

 

[markba633csi]

I wish John H was right, but I can slip a feeler gauge in under the front tooth after chucking a piece of stock. Also checked with a square. That's what makes it such a pisser- how did they screw it up so bad unless they are using girls with hand grinders and some sort of crude fixture to do the finishing who are poorly trained? Bob S. is correct, it happens with USA stuff too. (when you can find such)
Mark S.
Oh yes, back to the original question: what are the "standard" jaws called? Combination jaws? They clamp externally on the tips and internally on the steps so I was thinking combination or "inside/outside" jaws. I'm having no problem whatsoever with those- and the chuck itself is satisfactory (if a bit long and heavy for a MK2)

 

[mksj]

Standard Jaws are usually the steel (hard) serrated kind, either solid one piece and scroll chucks usually require two sets of jaws, an internal and external set. A two piece jaw with a removable top jaw that can be reversed with some jaws or interchanged with different types of top jaws. There are many variations. Take a look at the Bison Jaw Catalog which might help on the descriptions and types.
http://www.bison-bial.com/public/data/resource/upload/00244/243372/bison-2014-7-de-en.pdf

Per the Bison catalog Inside/Outside is the way they clamp, inside clamping type the steps face in:

Outside clamping, the steps face out:


It is a bit confusing, seems to be some variation on type and clamping.

 

[John Hasler]

I wish John H was right, but I can slip a feeler gauge in under the front tooth after chucking a piece of stock.

That's what I would expect unless the radius of the stock is smaller than the radius to which those teeth were ground. But in any case you clearly did not get what you ordered.

 

[joshua43214]

...
Oh yes, back to the original question: what are the "standard" jaws called? Combination jaws? They clamp externally on the tips and internally on the steps so I was thinking combination or "inside/outside" jaws. I'm having no problem whatsoever with those- and the chuck itself is satisfactory (if a bit long and heavy for a MK2)

I don't know that there is such a thing as a "standard" jaw. There are internal, external, and reversible. Reversible jaws are bolted on to the moving part typically.

 

[planeflyer21]

It is disconcerting at how many items purchased in recent years have to be reworked before use. And its not just Chinese products. I have had similar experiences with Made in USA products.

Bob

Boy that's the understatement of the century Bob! Across the entire spectrum of consumer products, from household to industrial and everything in between.

 

[markba633csi]

It seems MKSJ is correct- and I have to conceed Shars is correct in the terminology they use: If the INSIDE of the jaw touches the work, it's an INSIDE jaw. And vice-versa. Counter intuitive I know. The "outside" jaws are dual purpose however cause the tips touch the work, hence they could be called "inside/outside" or "combination" jaws. Anyhow, Shars has kindly offered to send me yet another set after I sent them a very polite email so this story may have a happy ending. It took me a while but I have found being polite often gets good results. And yes MKSJ, that is the exact Pratt chuck (9580-01005) my throbbing wallet was telling me to buy. I should listen to the throb more often. According to Myford, they are still made in the UK, and are excellent quality. I have no doubt.
Mark S.