6 jaw chuck jaws

I picked-up a nice BTC 8" 6 Jaw Set True chuck at HGR a while ago. Has 2 piece jaws with soft jaws mounted, no hard top jaws. Soft jaws were hardly used and I had a job I wanted to try a 6 jaw chuck on and wanted the soft jaws. I just milled 30° angles on the soft jaws to chuck small diameter (9/16").
I'm sure some day I might want the hard top jaws, anyone know if the Bison top jaws for 8" 6 jaw chuck will fit?

Frank

I have several Bisons which all have the American Standard tongue and groove jaws. Check out Ajax or other to check the measurements. Should fit.

I bought a used 6 jaw a while back. 3 of the top jaws were damaged by a crash. I bought a full set of top jaws from Wholesale Tool. The price was not outrageous. I believe they were Gator brand. The 3 old good jaws went to a member that needed top jaws for a 3 jaw.

Froneck said:

I picked-up a nice BTC 8" 6 Jaw Set True chuck at HGR a while ago. Has 2 piece jaws with soft jaws mounted, no hard top jaws. Soft jaws were hardly used and I had a job I wanted to try a 6 jaw chuck on and wanted the soft jaws. I just milled 30° angles on the soft jaws to chuck small diameter (9/16").
I'm sure some day I might want the hard top jaws, anyone know if the Bison top jaws for 8" 6 jaw chuck will fit?

Frank

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BTC sells exact copies of the original Buck Ajust-Tru chucks. Buck two-piece jaws are not standard American tongue and groove design, but a unique Buck design. Kalamazoo Chuck also makes copies of the Buck chuck. So standard T&G jaws, as used by Pratt Burnerd, Bison and many other companies will not fit a BTC chuck. You need BTC, Buck or Kalamazoo jaws. I have read on PM that Kalamazoo has decent prices. I expect Buck is expensive and don't know where to get BTC jaws.

Kalamazoo Chuck

I have a couple sets of new hard top jaws for Buck/BTC 6" 3-jaw chucks, but none for a 6-jaw. You could put a set of three hard jaws on a 6-jaw chuck.

I think I have an extra set of used hard one-piece jaws for a Buck 6" 6-jaw that would probably fit a BTC chuck.

The chuck factories usually grind the jaw faces after chuck assembly, so accuracy would be questionable when using new jaws without the grinding operation.

Larry

Thanks Larry; I guess the Bison Brand will not fit, ebay has a guy in Poland selling Bison top jaws for $250ish + $20 shipping.
I do expect to have to grind them.
My chuck is 8" so your 6" will not fit.
This chuck has only one pinion/key hole, I have a Chushman 6" the same. Any reason for one key hole not the typical 3?
Don't remember where but I did see a set of top jaws for a BTC 8" for over $1000! I'll make my own for that price!

Froneck said:

Thanks Larry; I guess the Bison Brand will not fit, ebay has a guy in Poland selling Bison top jaws for $250ish + $20 shipping.
I do expect to have to grind them.
My chuck is 8" so your 6" will not fit.
This chuck has only one pinion/key hole, I have a Chushman 6" the same. Any reason for one key hole not the typical 3?
Don't remember where but I did see a set of top jaws for a BTC 8" for over $1000! I'll make my own for that price!

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Go and download the ladner.fr catalog as a .pdf.

They have a huge selection of top jaws listed. AFAIK, they don't stock them, they just load-code and make a batch if/as/when when they have actual orders.

Not that you want to order from France, anyway.

But they have the illustrations, specs, nomenclature, and which of SEVERAL chuck-makers each of the many top-jaw styles FIT.

That's useful info to have.

Once certain what your one is common with, you might find jaws more easily and at less painful cost. LOTS of third-party folks make them, much as they do vise jaws. Hardened and ground cost more. Plain-jane for you to machine on your own? Not so much.

It's only a "top". How hard does it need to be?

The guidance, anchors, and positioning goods that take the REAL wear are already built into the body. THOSE must be precise, hardened, and ground.

Thanks thermite! I will do that! Would be nice to get the standard type top jaws just to have in case I need them. Like I mentioned I just milled 30° on soft jaws to chuck 9/16" but they look dangerous so when doing some hand finishing work I loosen the jaws and extend the work well away from the jaws and work left handed. The set true feature and soft jaws worked great for what I'm doing, I have another operation I'm going to try the 6 jaw with soft jaws and that is reducing larger than 1/2" drills to have 1/2" shank.
I agree the jaws don't have to be rock hard, I was thinking of making a set of jaws from AR500 or AR550 but can't find it cheap. McCaster has 1" thick but it's not cheap and will take quite a bit of time to make jaws from but I might go that route if I have some time to spare, as it is now I don't have time to think!

I've tried a few times to get information from Ladner.fr. Get a few pages but all in French nor can I find their catalog.
Any information on how to get it in Elglish??

Try US Shop tools, they are in the US and have a huge inventory of top jaws, good prices and service in my experience.

Thanks Colt45 I'll check them out. Am a bit confused, it was mentioned that Bison Jaws will not fit but when in a site that sells jaws (expensive) they listed Bison, Buck, BTW and quite a few others that took the same jaws. They had dimensions and my jaws were the same, does anyone know what the difference is. The 8" Jaw large cross key as .500" and the long key parallel with the jaw as .3125". Bolt holes c/c 1.750", measured my jaws and it was the same.

Location of the tenon is one factor- some jaws have it in the center, others have it offset.
Then there can be different screw sizes (clearance holes in the top jaw) for the same size jaw depending on the chuck maker.
Additionally, there are 2 styles that look similar, but the tenon is on the master jaw vs on the top jaw.

I bought a used Cushman 8" direct mount 3 jaw, really common light duty chuck. The jaws are worn, the previous owner bought replacement jaws, they fit except for they are about 1/8" shorter.
For the replacement jaws to work, the master jaws have to be ground. I have run into this before with a Skinner 12" chuck, I went ahead and ground the master jaws on that one, then had to grind the replacements true "not an adjust true chuck", to make it work.

I have no problem grinding the jaws. Well clean-up is a pain! I have a few 8" 3 jaw chucks. One is made in Japan (really nice accurate chuck, Bison, Buck, Chinese brand and who know what else. I measure the 6 Jaw BTC and compare. I'm not that fond of 6 jaw chucks but they do have their specific use. Being Set-True and with soft jaws bored to size needed (9/16") it worked well!

Yes, I find them useful also. I was looking at the aftermarket jaws that came with the 8" chuck I just got, there is no marking at all on them.
Not everyone is comfortable with grinding chuck jaws, the Cushman 8", all it needed was the original jaws to be loaded and reground, the replacement jaws are out even further, and the owner gave up on it, sold it on ebay for cheap.

It was late (11PM) yesterday when I left my shop, just before leaving I took a scale and compared the jaws on 2 different 3 jaw chucks a Bison and Chinese made. All had the same dimensions as my 8" 6 jaw, best as I could get them without removing the jaws. Today time permitting I'll remove the jaws and get better dimensions, maybe try interchanging them.
If anyone is interested there was a set of 6 top jaws for I think $67 on ebay, it ended but I asked for dimensions. Not very good job of showing the dimensions but the cross key looks to be 5/8" or 16mm, hard to tell what the parallel key measures but seems to be 12mm or 1/2". Not sure if it was relisted but I do have the guy in ebay messaging.

up date

I removed jaws from Bison 8" 3 jaw chuck and it fit perfectly on my BTC 6 jaw chuck. BUT!! Bison jaw is 3" long and BTC is 3-1/2" long, Checked Chinese 3 jaw and it fits too and is 3-1/2". Bison Jaw is 1/4" short on both sides and of course the other jaws are 3 jaw not 6 jaw style.

I found the same with the 8" Cushman chuck, the aftermarket hard jaws are short, and narrow compared to the original hard top jaws.
The standard appears to be in the bolt holes only. Soft jaws seem to be longer in comparison.
I just dont need soft jaws for the work I do, I buy used chucks because they are easy to rebuild. There are a lot of scroll chucks for sale missing the original hard top jaws, with the Skinner chuck I had, the master jaws had to be modified, for the after marker jaws to work.
Something to keep in mind, when buying used scroll chucks.

Froneck said:

I removed jaws from Bison 8" 3 jaw chuck and it fit perfectly on my BTC 6 jaw chuck. BUT!! Bison jaw is 3" long and BTC is 3-1/2" long, Checked Chinese 3 jaw and it fits too and is 3-1/2". Bison Jaw is 1/4" short on both sides and of course the other jaws are 3 jaw not 6 jaw style.

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It's extra work, but.. now and then it is well worth it to have fabbed and put by a set of "overshoes" that pad the tips of chuck jaws with Aluminium, Bronze, Copper, or even just a softer steel.

They only need a springish grip to not fumble about. No need to drill and pin. Once in-place, the clamping pressure holds them.

TWO made with a Vee, and a 4-Jaw grips relatively common HEX stock rather nicely.

These one SHOULD have. Part of the reason I have never needed an "apprentice chuck" with only three jaws.

Scrolls, even when not worn or damaged, only have about HALF the grip of jackscrews anyway.. or they soon BECOME "damaged".

If your work really NEEDs a 3-Jaw? Go ahead and scout a decent power closer. You already HAVE shop air.

Then you can use a NON-scroll 3-Jaw. Same as the full-gallop CNC spindles rely on to not waste time AKA "money".

The catalog is new goods, only:

Samchully Power Chucks

Small tools have been my source for SEVERAL European made high-grade chucks, Swedish, for example. They sell their used-but-good and "NOS" and "orphans" on their ebay pages. Not "free, but savings can be VERY substantial for quality goods. They do not deal in junk or not-even-looked-at roadkill for the desperate-poor gamblers as HGR do.

I have a large collection of chucks, have 4 lathes with D1-6 spindles. I have every size 3 jaw chuck from 5" to 12" even a Japanese chuck that's 9.5", all with 2 piece jaws. Plus quite a few with no back plates with one piece jaws. Also the same with 4 jaw chucks 16" to 6" with D1-6. I have them because I do maintenance work and jaw size from time to time is important. I also have a few scroll/independent combination both in 3 and 4 jaw. Yes Thermite your correct the scroll is weak, when using the combination chucks and tighten the independent jaws it's very hard to open the chuck with the scroll sometimes I can't and have to loosen the screw jaws. They do come in handy from time to time but are Heavy! My plan for the 6 jaw since it was in new condition and came with soft jaws and set-true was to use it to hold drills to reduce 5/8" shank to 1/2" on a lot of drills! Collets don't work and 4 jaw to slow. It's working great, have .0005: or less run out drill to drill with only using the scroll. But having the hard jaws might come in handy sometime so I'm thinking why not get hard top jaws. For what I have no idea but at least it will be a typical 6 jaw chuck!
The Bison chuck was new when I got it, both master and top jaws are 3", Master on the 6 jaw is 3-1/2" though the Bison is not set-true type. However a set-true Chinese 8"chuck does have 3-1/2" jaws that fit.
Other than for this drill cutting job I have no use for a 6 jaw chuck but at least it has 2 piece jaws, I do have a 6" Chushman set-true 6 jaw chuck with 1 piece jaws but in addition to the 2 sets of jaws there is a third with hard scroll yet semi hard top that I use quite a bit for another job where I chuck Al Bronze bored to 1.375 X 17/32" long. OD 1.800". I have never put the other jaws on.

Froneck said:

was to use it to hold drills to reduce 5/8" shank to 1/2" on a lot of drills! Collets don't work and 4 jaw to slow.

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IF I had the drill modification work to do collets ARE the way to go.
HOWEVER...

. NOT my 5C. NOT my 2J

FIRST choice would be the Burnerd-Multisize with front-lever closer. FAST as well as true and able to grip a drill quite well even on the flutes.

SECOND choice would be my Rubberflex 9XX. Much the same grip. Just not as fast to cycle.

THIRD choice you can do .. and on the cheap.

"Plate mount" ER-40 and an El Cheapo collet set.

- Put the plate in a 4-J, center it ONCE and leave it there.

- Spanner-wrench to tighten and loosen ER is slower than the Burnerd Multisize, but not all that much slower than the Rubberflex.

Each ER collet has a full 1 mm collapse range, so you might not need to swap-out for every drill size.

And the TIR is damned good, even with Taiwanese or PRC CNC machines making them by the brazilians

I have a similar rig for TG-100, but mostly those are on 40-taper tails for use on the mill.

ER is much cheaper. Seriously. Just price a set.

"Plate mount" has a through HOLE!

Straight tail, MT tail, 40-taper are here, too, and USEFUL. But would not do for drills. No place for the drill to "be".

If you are worried about damage? Might be a "throwaway"? See CDCO for cheap... better-yet .. HH Industrial for affordable but generally nicer goods by a skosh.

Otherwise "MariTool". Frank's goods are fine jewelry by contrast to the lesser stuff. That's what you need to JFDI. Reliability.

IF/AS/WHEN you NEED to do an eccentric? Just offset the plate in the 4-J and now it holds that same eccentric part after part after part, no jaw movement required.

I have a 5C key-cranker with no backplate for the same duty.

And I only own the one set of ER-40 collets for the entire tribe of mounts.
Same again, ER-20.

Get any more collet systems under-roof, I shall have to annex Maryland.