4-Jaw Self-Centering chucks

[sicero]

I noticed on Fleabay some 4 jaw self centering chucks. I have a Rohm 4 jaw scroll chucks that I like a lot but it has the capability for each jaw to move independent also. I find almost without fail the need to tighten one or more jaws independent when I chuck a shaft. This is no problem for me as I always use an indicator anyway. In my opinion a four jaw scroll with out independent jaw capability would be nearly useless. If your experience is different, lets hear it. There are other Home Shop guys here and maybe this will help someone. I have not seen or used a plain self centering 4 jaw chuck. But never the less I have formed an opinion with very little information. Kenny

 

[aametalmaster]

They would be good for production where the op is chucking up sq bar to do a few cuts on lots of parts...Bob

 

[sicero]

Bob, I find square bar doesn't work any better than round with mine. There is still the likelyhood one jaw will have consideratly less pressur than another. Kenny

 

[Ox]

What does "home shop" have to doo with this?

The lathe that I had for many yrs before I bought the one from you had a Cucshman 4 jaw self centering on it. The chuck was worn out. Or - at least the scroll was loose. I got to the point that I started only using one pinion in particularly so that I stayed on C/L.

I would have expected much worse results - as you doo, but quite honestly - I hardly ever had an issue that I can think of.

If a guy has just such a chuck and he finds that 1 jaw is taller than the rest - that jaw can be pulled aside and dusted off a tad in the surfaces grinder to git everyone on the team to be even players.


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Think Snow Eh!
Ox

 

[rockfish]

As aametalmaster said, these chucks are for production, most likely parts that concentricity isn't a big issue. I have a universal four jaw lying around here somewhere.
I've never used it, and may never use it .......... but hang onto it just in case.







Frank

 

[Toolmaker51]

As aametalmaster said, these chucks are for production, most likely parts that concentricity isn't a big issue. I have a universal four jaw lying around here somewhere.
I've never used it, and may never use it .......... but hang onto it just in case.
Frank

A job shop, is somewhat an oversized homeshop; constantly changing projects, some border right on edge of a machines work envelope. If reasonable tooling crosses your path, it's worth considering.
If it's logical, but goes unused, that's small risk, and potentially salable.
Found a full set of Hardinge #215 collets, not a popular pattern, sort of giant 2J, great condition very low price. Sat on them forever hunting a spindle nose, almost started on a shop-made chuck. They are too long to modify from any like a 2J.
The calculator is ~6.1" x 3.8" (155mm x 85mm). Big damn collet, taped note records thread Ø as 1.985

Anyway, diligence paid off with a D1-6 & D1-3, no back plates. Big deal, 3 mounting holes, face a recess, bore for a stop plug. Compared to a Rubber Flex, neither is better, just different
Whatever work a machine is capable of, small OR large; a good portion lies in fixturing.

 

[Ox]

You could have made a closer for that years ago for the price of a chunk of 4140 prehard.

Make the spindle interface end, bolt it up, and finish the other side.
Perfect run-out...

Closers for pull-back collets are not rocket science....
I know that they charge real $ for them to buy them, but they are about the simplest thing to make in-house.


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Think Snow Eh!
Ox

 

[BDRetz]

I have a Bison 5” four jaw scroll chuck that I pick up for relatively short money at an auction. I have used it a couple times in my hobby shop and find it holds better than my three jaw with less run out on larger tubing. I also got less distortion on the same stock than my independent four jaw but I know that is user error.

It has the two piece jaws and I plan to make soft jaws for it eventually as I think those might be useful for some operations.

I wouldn’t say it’s a must have item but it has been handy a couple times. The price was right for my purchase but would not be willing to pay new retail for it unless I had a well paying job that required it’s use.

Your mileage may vary.

Ben