Chuck & Jaws Selection Reccomendations

[jephw]

Hello everyone.
We currently run a 15" chuck in our Mori Sieki NL3000 lathe. We have a job coming that will require us to hold the parts on the ID, which is a 2.50" diameter. Cutting soft jaws that size for the 15" chuck seems unreasonable.
We are thinking of getting a smaller chuck to fit on the machine so we can cut soft jaws to grab the ID. What size chuck would you guys recommend for this?
Any help is appreciated.

 

[Orange Vise]

What quantities are we talking about here?

I'd look into something like this: Royal I.D. Workholding Systems – Royal Products

 

[michiganbuck]

Any chance you might make a stub mandril sticking out of the chuck
How close to one size might the ID run?

A 2 1/4 collet can be od ground to fit a taper mandrel to hold a 2.5 ID part.

I used to simply wrap a collet on a tapered mandrel with rubber bands and grind one side (left) and move the rubber bands to run the other side.(right) Yes, there is enough springiness in a collet to make the ID conform to the taper mandrel as the OD is being ground straight to the desired OD.

Use an automotive hose clamp to rough grind it to +.005, and then just hold with rubber bands to skim the .005...Grind/travel feed diredtion towards the up-side (bigger) of the mandrel taper.

I have a set of expanding mandrels but don't know if they go that big (2 1/2).

On a flange type part you make the part tight enough, then tap the gauge side in with an indicator at the gauge side,

The tapered mandrel and collet can even be drawn into a bore to make tight when brought up to a flange or faceplate. This way the part is held at the center line, and at the same place at true right angle out of the headstock...with using the tail...or just as a stub going into a headstock bore, so with not using the tailstock.

Yes, this is much like a Royal.

 

[jephw]

What quantities are we talking about here?

I'd look into something like this: Royal I.D. Workholding Systems – Royal Products

This is an ongoing job for us. I will look into this product, never seen this before. Thank you.

 

[jephw]

Any chance you might make a stub mandril sticking out of the chuck
How close to one size might the ID run?

A 2 1/4 collet can be od ground to fit a taper mandrel to hold a 2.5 ID part.

I used to simply wrap a collet on a tapered mandrel with rubber bands and grind one side (left) and move the rubber bands to run the other side.(right) Yes, there is enough springiness in a collet to make the ID conform to the taper mandrel as the OD is being ground straight to the desired OD.

I have a set of expanding mandrels but don't know if they go that big (2 1/2).

On a flange type part you make the part tight enough, then tap the gauge side in with an indicator at the gauge side,

The tapered mandrel and collet can even be drawn into a bore to make tight when brought up to a flange or faceplate. This way the part is held at the center line, and at the same place at true right angle out of the headstock...with using the tail...or just as a stub going into a headstock bore, so with not using the tailstock.

Yes, this is much like a Royal.

There are a few different ID's that we need to hold, and needs to be quite repeatable as well.

 

[michiganbuck]

QT Op: needs to be quite repeatable as well. what spec?
likely a Royal or my suggestion would run within a few tenths.

 

[michiganbuck]

What? Is nobody interested? or doesn't understand the concept of the Buck's precision ID holder?

Guess I will just put it back in the box (file)

 

[jephw]

What? Is nobody interested? or doesn't understand the concept of the Buck's precision ID holder?

Guess I will just put it back in the box (file)

I don't really understand what you're saying. I'm a more visual learner if you will. But definitely thanks for contributing.