Double-six chucks?

I envisage a double-six-jaw self-centering chuck. It has six internal jaws, and six external jaws. The internal and external jaws are operated by two different scrolls*.

A double-three/four/more-jaw chuck would probably work too.

It is for very thin wall tube/pipe. The internal jaws hold the inside of the pipe and the external jaws hold the outside. The ext and int jaws would meet each other if the pipe wall was not in between, so any overall force exerted by the chuck on the pipe merely squeezes the wall itself and does not act to distort the pipe.

Does anyone make anything like this?

You may be interested in thi

have been trying to contact them as to wether they will expor outside the USA, no answer as yet. :( If you did want an internal gri I dont think it would be to hard to have them ground in

-- olmo

----------------------------------------------------------------------- olmod's Profile:

this thread:

So how do you get 12 jaws around a circle and still have room for the chuck ?

Assuming that the ratio to inside and outside is always the same..

-- Regards,

John Stevenson Nottingham, England.

Visit the new Model Engineering adverts page at:-

I have been trying to contact them as to wether they will export

If all you want is a small six-jaw self-centering chuck, J&L sell them. Part No PCC-64000H for a 4 inch one. Described as good for holding thin tube.

They also do 6-jaw chucks up to 6 inch diameter - described as "for drills"

For the reasons given by other people, I doubt it but would it be possible to use a 6-jaw chuck with some kind of spindle fitting akin to a backstop but with a solid cylindrical central portion whose OD was same as the pipe ID so giving the chuck jaws something to bite against ? You could make up a new centre part for each pipe diameter.

This idea would have the disadvantage of preventing you from using the spindle bore to hold the pipe while you're turning the end though, if the length won't fit in the chuck body you'd be stuck.

Hth,

Another point to bear in mind is that the only self centering chuck that grips evenly [ not always centrally - different animal ] is a 3 jaw. Other self centering chuck with more that 3 jaws are at the mercy of the material. A 4Jaw SC chuck on brand new cold rolled bar isn't guaranteed to hold firm, think of a milking stool and a 4 legged stool on uneven ground.

Just adding jaws doesn't mean that you increase grip.

Industry always works out the best and most cost effective way and these aren't seen that much in industry.

What are seen are collets in the smaller sizes and soft jaws in others or specials.

Once you have used soft jaws you wonder why you never made the move ages ago.

Out of interest has anyone every seen a 6 jaw with two sets of jaws, internal and external ? I haven't but it doesn't mean to say they don't exist but they are not advertised with the current batch of new chucks.

-- Regards,

John Stevenson Nottingham, England.

Visit the new Model Engineering adverts page at:-

> I have been trying to contact them as to wether they will export

I have no idea who J&L are or even where the are

-- olmo

----------------------------------------------------------------------- olmod's Profile:

this thread:

Only 6 jaw chucks I've seen a lot of are those fitted to Brierley drill point grinders. They dont have to grip tight anyway.

You point about softjaws is all too valid. I also use a lot of 5c soft collets, epsecially for those fiddly short jobs. Their only drawback is that they drawback lol....

Another thing I do a lot is use a straight shank ER16 collet holder to hold tiny parts. Some of these are tapped in the shank and can have a backstop fitted.

Wayne....

six at a time :)

But six jaws will do, three internal and three external.

The face of the chuck has three slots as in a normal 3-jaw, and each slot has two jaw pieces in it, one internal and one external.

The internal jaws are operated by a scroll facing backwards, with the jaws coming through the centre of the chuck, and the external jaws are operated by a normal scroll.

Alternatively, the inside jaws are operated by a scroll as normal but a bit smaller, and the outside jaws are operated by a scroll that has the scroll for the inside jaws at it's center. Or the scrolls can be staggered, and so on.

Enjoy... Best give wallet to SHMBO before you visit :-)

Regards Jonathan

Yep.I`ve got a 10" six jaw with both internal and external jaws.Very handy.From the Pratt Burnerd catalogue they seem to do six jaw chucks upto 12" . Mark.

I have been trying to contact them as to wether they will expor

Just recieved a 1 word email back "NO" :eek: mmm migh have to find a buddy who can help :) as to J&L phew ill keep my har won $s :

-- olmo

----------------------------------------------------------------------- olmod's Profile:

this thread: