Help on getting a new 4 jaw chuck

[projectnut]

I forgot to comment about the chuck in your original post. Taking a look at it I would prefer a different style. The one you have chosen requires 2 sets of jaws. One for holding on the outside of a work piece, and a second for holding on the inside of a work piece. I have no problem with the way it functions (I do have several of this style), however my preference is to have a chuck with replaceable top jaws. This style only requires one set of jaws. They are unbolted from the base jaw and turned around for inside holding.

Here's a link to the style I'm referring to:
http://www.ebay.com/itm/6-4-JAW-SEL...300499?hash=item4841a9ec93:g:Aa4AAOSwTapV46Z1

The major advantage is that there is only one set of jaws. There's nothing to store in that "special place" until needed. In time you'll forget where that 'special place" is and spend more time looking for the jaws than changing them out. Also if in time you acquire more chucks you'll have to sort and identify which jaws fit which chucks. In addition I believe there are at least 500 or more different design of this style jaws. Finding a replacement could be a nightmare. As a side note I "lost" a set of inside jaws for several months. Finally deciding I must have inadvertently thrown them out I broke down and purchased a new chuck. I didn't have the new chuck 3 weeks when I stumbled across the "special place" where I'd stored the jaws.

The replaceable top jaws on the linked chuck are known as American Standard design. There are dozens of vendors that make replacement hard jaws and also soft jaws. While hard jaws are expensive at least they can be replaced. Soft jaws on the other hand are inexpensive. Some are as low as $50.00 a set. In addition I don't know of anyone that even makes soft jaws for the style chuck in your picture. I do have one set of soft jaws for an older chuck of that style. This is an older Union brand chuck that was ordered new with a second set of hardened outside jaws. They were then cut ground, and fitted with bolt on soft top jaws. I'm not aware of any manufacturers today that offer additional replacement jaws when ordering a chuck.

 

[benmychree]

I do not have experience with the chuck you show. I have experience with Shars chucks and have been happy. They have 6in 4 jaw chuck onsale for $90 with $54 backing plate, so $144 plus shipping.

Whatever chuck you purchase, make sure you check if the jaws are reversible or whether you get internal and external jaws. Also ensure you get a chuck key. Sometimes included, sometimes extra.

http://www.shars.com/products/toolholding-workholding/lathe-chucks/6-4-jaw-independent-chuck-1http://www.shars.com/products/toolholding-workholding/lathe-chucks/6-4-jaw-independent-chuck-1

I have never, in my nearly 60 years of machine tool consciousness seen a 4 jaw chuck, that does not have reversible jaws, not counting combination chucks. With used chucks, if MUCH used, the jaws will fit loosely in the body, making the OD end of the jaws bell mouthed, which will effect their accuracy in (attempting) to hold longer rounds or squares accurately.

 

[4GSR]

I have never, in my nearly 60 years of machine tool consciousness seen a 4 jaw chuck, that does not have reversible jaws, not counting combination chucks. With used chucks, if MUCH used, the jaws will fit loosely in the body, making the OD end of the jaws bell mouthed, which will effect their accuracy in (attempting) to hold longer rounds or squares accurately.

It's like a 6-jaw but missing 2-jaws.

 

[benmychree]

It's like a 6-jaw but missing 2-jaws.

I realize the definition that you offer is correct, but still, I have never seen suchlike, and doubt that a US manufacturer has made one since the first world war; I have many old catalogs for machinery, all one sees is 3 jaw scroll chucks, and 4 jaw independent chucks and occasionally a 3 jaw combination chuck with screws rather than a scroll; we do not see 6 jaw scroll chucks until more recently. I cannot see why a 4 jaw scroll chuck would be of much use due to all four jaws coming together perfectly enough to avoid having at least one opposite jaw not close without a bit of clearance, especially on less than perfectly sized or imperfect squareness.

 

[4GSR]

I recall seeing them somewhere in a catalog a few years ago. Cushman used to make the 4-jaw combination jaw chuck, which I've only see one in my life. My dad pulled it from a dumpster dive and later gave it away because he didn't want it, but kept the 4-jaw Cushman independent chuck. I think the Chinese are the first ones to come out with one. I personally don't care for it either. I'm happy with the 3-jaw chucks I have along with the 4-jaw independent chucks too.

 

[benmychree]

I recall seeing them somewhere in a catalog a few years ago. Cushman used to make the 4-jaw combination jaw chuck, which I've only see one in my life. My dad pulled it from a dumpster dive and later gave it away because he didn't want it, but kept the 4-jaw Cushman independent chuck. I think the Chinese are the first ones to come out with one. I personally don't care for it either. I'm happy with the 3-jaw chucks I have along with the 4-jaw independent chuck too.

Amen!

 

[Wreck™Wreck]

I recall seeing them somewhere in a catalog a few years ago. Cushman used to make the 4-jaw combination jaw chuck, which I've only see one in my life. My dad pulled it from a dumpster dive and later gave it away because he didn't want it, but kept the 4-jaw Cushman independent chuck. I think the Chinese are the first ones to come out with one. I personally don't care for it either. I'm happy with the 3-jaw chucks I have along with the 4-jaw independent chucks too.

Do you mean a 4 Jaw scroll chuck?

 

[4GSR]

Do you mean a 4 Jaw scroll chuck?

Referring to the Chinese chuck? yes.

 

[mksj]

Bison and few other manufactures still make 4 jaw combination chucks, if I just needed one chuck for everything it would be a combo. A few of the hobbyist use them. Below is the Bison 8", the scroll will repeat to ~0.002" and it takes about 30 seconds to dial it to nil with the independent jaws. The jaws are much slimmer then standard 4J independents, so you can grab stock down to 0.2". If you want to hold a large rectangular plate, a 4J independent with wider jaws would work better. I probably use my 5C the most, then the combo, and I have a Set-Tru 6" that I only use if I need to do a lot of repeat clamping for multiple pieces. The Set-Tru will repeat to better than 0.0004" so I set it once and leave it. The only time I will recheck it is when I reverse the two piece jaws, there is a slight variation on how they mount. Different people have different preference, so it varies based on what you do.

 

[Splat]

IMO you don't have to spend a lot to get a decent enough 4-jaw independent. Unless the jaws are really shoddily made or worn you'll be dialing in the work anyway. I don't know anyone with a Shars chuck so I can't speak to their quality but for myself, I would go with something from Gator or Fuerda. I don't like taking a gamble on a used chuck I cannot inspect in person so used for me is pretty much not gonna happen.