What's new
What's new

Replacement 3 jaw chuck jaws

taiwanluthiers

Cast Iron
Joined
Dec 6, 2016
Location
Xinjhuan District, New Taipei City
I bought a Vertex 6" Rotary Table that came with a 5" 3 jaw chuck.

Unfortunately it didn't come with any reverse jaws which is a bummer because I need to grab bigger stuff (for making bolt hole circles for example) and the regular jaws means I can't grab anything bigger than about 2.5 inches.

I tried local shops and they said that lathe jaw chucks are made specifically for that chuck and replacements aren't available. Are they full of it or is that true?

Am I SOL or do replacement jaws exist?

Maybe this is an excuse for me to put a 8" 4 jaw chuck on it (if I can find a way to adapt it)
 
Am I SOL or do replacement jaws exist?

Maybe this is an excuse for me to put a 8" 4 jaw chuck on it (if I can find a way to adapt it)

It's only a DH, not a lathe. Cheap enough to put about a $90 USD San Ou sub 5-inch 4-Jaw on it. ISTR the threaded nose is a not terribly uncommon size?

May be "good enough" to use the taper (#2 MT, or is it #3 MT?) with a small chuck sold already so mounted.

The #9 B&S on my Ellis DH is far handier that way than with its thread-mount nose carrying a threaded backplate+chuck that weights more than the DH!
 
Sorry but I forgot what a DH is... is that slang for a rotary table?

I found a set of reverse jaws on Aliexpress for around 25 dollars. The dimensions appear to be consistent.

How does soft jaws work? Is this something I make to fit my chuck?
 
Sorry but I forgot what a DH is... is that slang for a rotary table?
Vertex (and others..) make both, also supply divider plates, crank & and quadrant to make the rotab function as a DH. Ratios are usually different, but that can be a "good thing" as a key few DH plates now cover an extended range, the maths are easy, and the tables are already published as well if one digs for them.

Both rotab and DH ordinarily have a useful and common taper at the center.

Mounting a(ny) "plain back" chuck to a rotab is easy enough - backplate optional.

Generally all one needs are a "front bolted" type of chuck, a few tee-slot nuts, bolts to fit or cut to fit, and.... the patience to center the fool thing.

That last part is why I suggested one with a MT (or in my case #9 B&S) tail. Way faster reconfiguration.

Unless your rotab is assigned to "dedicated use" anyway. My Yuasa must have been such in a prior life. It came in the door with a Jacobs drill chuck on #2 MT tail locktited into the taper!

PS: 3-jaw scroll chucks with two-piece jaws exist, PRC-made and other.

They cost more than one-piece or even one-piece with both inside and outside jaw sets, BUT... that's what you need if you expect to use "soft" top jaws, pins, plates, or any other sort of shop-adaptable top fixturing.
 
One minor gotcha with using soft jaws on a chuck fitted to a rotary table or dividing head is the need to use a lathe to easily cut them to the shape you want. So either the mounting systems need to be compatible or you have to indulge in chucks mounted in chucks or similar horrors. Not thinking about changing backplates just to do jaws. The whole point of soft jaws being that you can easily cut them to shape for that difficult job so need to make life easy.

Memo to me really must get round to making a D1-4 adapter for my 10" rotary table and a D1-5 adapter for the 12". Lord knows what I shall eventually do for my Edgewick, Cincinnati copy, dividing head. Yet to use it in 30 years so probably no rush on. But I have the extended range plate set so good for bragging rights if nowt else.

The Vertex plates to convert a rotary table to a proper dividing head work OK but fitting is a bit of a faff. Table interference issues with my 8" one didn't help. Tall block underneath or hang over the edge.

As Bill says. Get an economy range front bolted chuck and be done with it. But verify that the bolt spacing and table slots line up or you are in for an intermediate backplate. MT centre in a rotab is, generally a pain. Screw in chuck sitting up on an MT adapter looks silly and isn't overly strong. My bigger ones have a good size parallel bore and a 1/4" register plate held on by screws so a special can be made if need be.

Clive
 
One minor gotcha with using soft jaws on a chuck fitted to a rotary table or dividing head is the need to use a lathe to easily cut them to the shape you want.

Uhh... nooo.. Only "maybe".

It is, after all, a "rotab" we are working with, here.

One can mill and/or drill the shape of bespoke jaws/fixturing. Most especially if it isn't "just" round, is only partially defined by "round features", has supplemental "layers", stops, clamps... etc..

As is not really a rare situation.

Otherwise, we might use (only) the lathe - 4-J or a fixtured faceplate - and not necessarily need the rotab at all... as is also common.

And.. some of those fixtured faceplates ... for USE on a lathe.. are amenable to crafting on a rotab ... with a mill... before going back onto the lathe for production use, too.

So yeah.... "minor" as gotcha's go.. as much solution / opportunity as it is a potential problem.

:)
 








 
Back
Top