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Buying first 8" chuck questions

FlyinChip

Aluminum
Joined
Dec 20, 2017
From reading everything I found here and watching a few youtube videos, it seems like the most versatile chuck for my heavy 10 will be an 8" independent 4-jaw with reversible jaws.

Starting at the bottom, there are some (likely chinese) on ebay for around $175 shipped. No back plate. They have four bolts. Presumably, I need to get (cant make) a back plate that has the 2-1/4 8tpi threads and a snout which fits into the chuck recess with tight tolerance.

One video I saw was a review of a shars china chuck and actually the only real issues (for hobby machining) was that it needed total disassembly and cleaning as there was a lot of debris left everywhere inside.

Maybe I am not looking in enough places, but where would I find a back plate for this chuck (link below)? I cant seem to find one with the right thread and dimensions.

8" 4-JAW LATHE CHUCK with independent jaws #0804F0- NEW | eBay

UPDATE: found this set, maybe the ticket if nothing comes up on here to avoid:

SHARS 8" 4 JAW INDEPENDENT LATHE CHUCK TIR CERTIFICATE + 2-1/4"-8 BACK PLATE NEW | eBay


thanks to any advice (especially where to find a back plate)

PS I am also looking for something used, nothing good yet but may turn up. Herd to tell if there isnt a defect in a used unit though.
 
Presumably, I need to get (cant make) a back plate that has the 2-1/4 8tpi threads and a snout which fits into the chuck recess with tight tolerance.



Maybe I am not looking in enough places, but where would I find a back plate for this chuck (link below)? I cant seem to find one with the right thread and dimensions.


thanks to any advice (especially where to find a back plate)

PS I am also looking for something used, nothing good yet but may turn up. Herd to tell if there isnt a defect in a used unit though.

Lost Creek Machine currently has two 8" 2-1/4x8 backplate for sale.

Look under used chucks and steadys, then scroll down to faceplates and backplates.

Lostcreekmachine.com
 
Bruce is top notch. Thanks for the post by the way, it led me to a buck adjust tru he had!
 
thats a 6" chuck I just found out. looking for 8" thanks for the tip though!

So-called "heavy" ten or not, a 6" 4-J is "generally" way to hell and gone more practical than an 8". South Bent even shipped most of them that way.

Extended jaws have to "be" somewhere, and chewing up yer compound isn't one of the preferred places, even if they clear the bed or front-edge of the saddle & cross.

Mind, "both" is better-yet.

My stable goes clear down to 80 mm, but the EXPENSIVE ones are all 6-inchers, bought new or NOS.

Several.

Some are light, some are medium, one has stout screws, heavy body, and jaws like Godzilla's Momma could only wish she had.

If your work NEEDS 8", or if it has to be your ONLY 4-J for a while, go for it.

Otherwise a 6" first, add larger and smaller when you spot a good deal.

It is the type of work that should drive your choice. Not the tape-measure as to max you can shoehorn into the space.

Big chucks don't like high RPM, most especially on JR HS training-wheel mass lathes as can shake like a hound dog s**ting shattered chicken bone when you have to mount an assymetrical workpiece. Or it volunteers to BECOME such.

If you had missed that small detail, now you have a picture without need of the actual experience of it? No fear. Cats are wise enough not to eat the bones in the first place. Different dentition.

Chik'n nuggets are rightous enough.

So is a 6" chuck.

;)
 
Actually with that reply (thank you) I should say that the part I was unable to chuck is 5" diameter because my larger 6" chuck jaws dont reverse. Then I discovered the smaller spindle issue and thanks to PM was swapped (although I have another thread where can I get shims). But now I will have the common 2-1/4 8tpi spindle, and there's a lot more chuck options for that thread.

I figured 8" since it is a 10" lathe why not have some head room. The jaws could stick out up to almost 1" and accommodate up to about an 8" part. That was my reasoning.

U got me thinking on a 6" reversible jaw option.

Yes right now there is only budget for one chuck for now.
 
the linked 6" one IS reversible.
as is the one in the message.

your call on 6" or 8"....i personally prefer the 6"...but some guys like the 8s, use caution as mentioned above.

shims are available on ebay...just search "south bend shims" - 50 bucks a set
 
Actually with that reply (thank you) I should say that the part I was unable to chuck is 5" diameter because my larger 6" chuck jaws dont reverse.
Old Fart or not, I have not actually seen EVERYTHING, but one thing I have not yet seen is a 4-J *independent* chuck whose jaws were NOT reversible.

Simple sort of "half nuts" bearing against a modified Acme screw, it doesn't give a damn which end goes in first, annnnnd

"Oh.. BTW." amongst the reason some OF's have never seen the need of owning even ONE of the weak-ass-grip THREE jaw chuck tribe, is that not ALL jaws on a 4-J have to "be there", nor even point the SAME direction if they are there.

Seriously. A 4-J can hold some insanely complex shapes. So can a fixtured-up faceplate.

I can only wish my 6-Jaw was "independent" instead of scroll-operated!

:)

I figured 8" since it is a 10" lathe why not have some head room. The jaws could stick out up to almost 1" and accommodate up to about an 8" part. That was my reasoning.

U got me thinking on a 6" reversible jaw option.
Yah well. about that one-inch..

The OEM 3-J (2 pc jaws) French-made "Handy" of the metric equivalent of 8" on the Cazeneuve hit the damn sliding cover at not a lot more than that, threatened the nice dovetail at the front edge of the cross, and that, dear hearts is not on a 10" lathe. An HBX-360 is a nominal 14" with an actual just the metrfuckated skosh under SIXTEEN inch swing.

It has been gifted a pair of 7 1/4" 4-J. Comes out even when metrifuckated, but I don't recall at what. HBX is kinda bisexual, so I leave the damn conversions to the machinery. I have less than zero use for a 3-J scroll-operated "self OFF centering" anyway.

"nuther thing...

Don't confuse "reversible" on a scroll chuck, which USUALLy wants separate jaws because double cutting to fit the scroll (yah, some fools DO that..) makes them as weak as kittens.

With .....screw-operated, where jaws are inherently reversible, as above.

OR with TWO piece or master/top jaws which make most sense on 2-Jaw - because they are nearly ALWAYS going to be custom-machined to hold a specific item, bi-laterally symmetrical only maybe, round very damned seldom....

OR 6-jaw where 12 fasteners are a pain in the arse, but cranking 6 jaws out and swapping them for the other SET. if not yet lost. strayed, stolen, is a BIGGER pain.

3-jaw is worth 2-piece for soft-jaw/pie jaw, similar custom tooling to a 2-J, just different about release for 3-segment "parting line" than a two-segment 2-J.

Otherwise, two 3-J, one set each way and left that way are cheaper as well as faster.

That's part of why I have more 6" 4-J that the average Bear, BTW.

Pop one off the D1-3 that has it jaws one direction and LEFT that way, pop one on the D1-3 as has its jaws the other direction and LEFT that way....

...and I don't have to spend the time cranking 4-jaws out turning them around, then cranking them back in.

I did that once. A long time ago. About fifty years I think it was?

WTF new lore am I going to learn from doing it a second time when a second chuck will easily serve fifty years if not abused?

MY curse? Simple enough. I was NEVER a "hobbyist" until I got older than dirt and was handed 20/15 bionic vision. Wuddnya know it? No longer blind, I could SEE pretty wimmin' but too damned late - couldn't remember why I was supposed to care!

:(

"Old Iron" on the other hand? Now THAT I could still play with - if only 'coz it couldn't run fast enough to escape my greedy hands!

:)

Mentally, I buy tooling as if still running the manufacturing operation where I was going to have to PAY an operator Union Scale - or even more-yet when NOT Union - and I don't want him wasting that fully-burdened TIME. No shop I ever ran had to beg for tooling - it was always there before my team even knew they needed it. Manager's JOB to see to that ahead of time. That's a major part of why I was always profitable.

It isn't as expensive a bad habit for a hobbyist, either. Yah only get but the one life. Why waste the hours of it ...and still be short of money, anyway?

Yes right now there is only budget for one chuck for now.

Buy a brand-new Chinese "San Ou" or Taiwanese "Vertex" then. The ones with THEIR OWN brand-name (and max RPM) right on them. No no-names. Ever. Too damned many of the no-names are factory QC rejects, They weren't going to just shove them up their ass and keep on doing that, were they? Sold-off to "remaindermen", rather - same as last month's funny-papers or condoms used but the one time.

Shars backplates are OK, but that's as far as it goes. Dice-roll after that, some good some not-so-much.

Brand-new chuck at least won't be wore out, have been in a fire, have internal cracks 'coz it was dropped four stories, etc.

Those two brands ain't actually ain't half bad. San Ou has even been striving to be seen as GOOD, yet is still cheap.

Vertex Taiwan may of may not be - they built a daughter factory on the mainland several years back, supposedy kept only the higher-profit CNC goods in the Taiwan plant, but at least the experience and QC should be the same.

Your goal is to get up and running with the promise to yerself any "El Cheapo" will become a secondary-use tooling in the fullness of time.

The one with the jaws always bass-ackwards, for example.

What's a GOOD 4-J?

Well.. My medium-width-jaw forged steel Swedish SCA's are stronger than my elegant but slender high-RPM forged-steel Polish NOS "old Bison", but my OLDER Skewl yet NOS forged-steel Yuasa is the Godzilla jawed heavy-cruncher when I really, really need a trusted GRIP. The 5" and under - down to the - $90 was it? San Ou 80 mm are Semi-Steel or Grey iron.

Nearly all the "Grand Old" chuck makers simply QUIT making manual chucks of any kind under ten inch or larger sizes a long time ago and/or sold-on their brand-name. Even Bison ain't always Bison. See Toolmex.

All the MONEY is in chucks that get wore out faster and are worth serious coin for a factory rebuild.

Read: BIG ones, "oilfield", even. Or POWER operated chucks on a brazillion hard-working 24 hr, X 5, 6, or 7 days a week CNC spindles or some combination thereof. Go price a 20" chuck, a Kitegawa, Samchully, SMT, or Schunk. You'll "get it". They all followed the money.

AND NOT a "manual" operated chuck that won't need a replacement for another 70 - 90 years on some hobbyist's personal lathe.

There's yer problem. Motor car and tires yah can sell and keep selling.

Drager tire guage I bought in 1968 still works as-new, will surely outlive ME.

Wasn't for SCUBA divers drowning their ass now and then, body not recovered, Drager wouldn't have a market. Some stuff just lasts too long for the maker to earn a crust.
 
"Big chucks don't like high RPM, most especially on JR HS training-wheel mass lathe..."

SB heavy ten will use a 9" six-jaw chuck just fine. 8 inch even easier.
Don't put it on much but some jobs just work better on that Buck six-jaw.
 
I wonder how much I am limited at the small end with 8" ??? I have a 5" 3 jaw and a 6" 4 jaw. I think it was the 3 jaw I made a very small special screw in it maybe 7/16" knurled head diameter, and I think #10 screw size (used a die to thread it). Would the 8" just not do something like that? The bigger 7/16" diameter was where I would have held it (been a while)
 
I wonder how much I am limited at the small end with 8" ??? I have a 5" 3 jaw and a 6" 4 jaw. I think it was the 3 jaw I made a very small special screw in it maybe 7/16" knurled head diameter, and I think #10 screw size (used a die to thread it). Would the 8" just not do something like that? The bigger 7/16" diameter was where I would have held it (been a while)

Some 8" struggle to grip even half-inch round without add-on "overshoes".
A 3" on 5C tail or straight-shank might do yah?

But a "jaw" chuck isn't ordinarily even relevant for that. Straight-tail or plate-mount ER-whatsit is cheaper.

The number, as-in ER 40 isn't diameter, BTW. Oddly it is how LONG the collets are in the millimetrifuckated language dialect of confused archaic European.

Jacobs chuck is the more common poor-boy substitute for odds and sods of small s**t you didn't have any better plan for.

What "real" collet system do you have [1]?

Tooling a lathe is like sex.

If you have to ask the price, you are money ahead buying a used Learjet and a few DVD's on how best to pound sand up yer own patootie.... or hand scrape.

[1]
(says the OCD tool whore with..lessee.. 5C, 5C step/pot, 2J, Rubberflex 9XX, Burnerd Multisize, ER 20, ER 40, TG-100. all sorts of drill chucks, micro to 3/4" and a coupla weird or antique goods even their own maker might not want to take the blame for.... Got a magnetic chuck yet? Walker..for Hardinge label.. oh.. and several grades of sand. Of course.)
 
Old Fart or not, I have not actually seen EVERYTHING, but one thing I have not yet seen is a 4-J *independent* chuck whose jaws were NOT reversible.


thermite you were absolutely spot on here. upon further examination my 6" jaws DO reverse I just didnt try hard enough.

however, now that I've upgraded to the more common large spindle size, no real regrets even if for now, I will have spent hundreds to get back where I started. in fact, I will have one 6" or 8" 4 jaw and a new used large spindle, instead of a 5" 3 jaw scroll chuck, and a 6" 4 jaw independent, so it's a step back initially LOL

BUT thanks to you guys here, I learned a lot about working on my machine and about chucks in general. :)
 
I've upgraded to the more common large spindle size, no real regrets even if for now, I will have spent hundreds to get back where I started. in fact, I will have one 6" or 8" 4 jaw and a new used large spindle, instead of a 5" 3 jaw scroll chuck, and a 6" 4 jaw independent, so it's a step back initially LOL

Do you still have the 5" 3 jaw and the 6" 4 jaw chucks? Change the back plates if so?
 
Unfortunately thats not an option. The 4 jaw 6" is a Skinner and the 3 jaw is a Cushman, old school, one piece chucks...
 
I ended up with a 6" Skinner / South Bend 4006-46 four jaw paid $150 shipped. Should get me going for now...

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Once you get another chuck or faceplate that fits your new spindle, use it to hold your old chucks and modify them to accept backplates.

allan

THAT is why I appreciate this site so much. :) Didnt think of that. Al;so, wonder about just enlarging the opening and rethreading inside it if enough material there. Is that 2-1/4 8tpi thread standard or special in some way such as tapered I wonder?
 








 
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