Thread: How do you hold small diameters in big CNC chuck?

The new CNC we bought has a 12'' hydrualic chuck,the soft jaws are hudge compaired to the 10'' chuck on the other CNC plus these jaws run about $75 a set.As large as they are it is a PITA to chuck on anything less than 1'' in diameter.It is doable of course with the pointed jaws but there has to be a better way.I thought about buying a 4'' manual 3 jaw I could chuck on with the CNC chuck but was warned by a tool rep that sudden RPM changes could cause the scroll to spin and chunk the part and it's jaws right out...not to fond of testing just how impact resistant that glass is in the door.

Do any of you have a setup that mounts to your chuck that would allow you to use 5C collets for small diameters?
Do you have any other methods for holding small parts in a large CNC chuck?
Even if it cost a grand it would pay for itself in time saved from boring jaws and replacing with new ones at 75 bucks a set.

Only other option I can think of is dedicate several sets to cover from .250 up to 1.00'' in .062'' increments.


Any help with pictures or links would be a great help.
Thanks


David

i persoanlly think your sell rep is a little scare of something that dont have alot of chance to happen. if you put enought pressure on your piece the chuck wont slip out. we use a 10" manual chukc on ours cnc lathe and using css we can get from 80 to 2500 within second and get down to 80 in a second too and nothing bad happen.

Kalamazoo makes a 5c collet block in a form intended for this use.
1CC, 5C Collet Fixture for Chucks | Kalamazoo Industries

I have one, but have never used it in this particular way.

Also, you could get a set of Warner&Swassey style "collet pads" or "jaws for collet pads" (might have to make the jaws) and then set of collets. See the usshoptools catalog.

Take your old jaws, beat and worn, well used. Machine them down relatively thin, toss them on the mill and put a 90 degree included point on them.

Slap them puppies back on your chuck, IN THE OPEN POSITION, points smaller than what you want to hold. Stuff an endmill down the center (they make great small boring bars also).

DO NOT close the chuck until you have material in there.

I've held down to 3/32 in a 10 inch chuck this way.

Edit: I've never grabbed a manual 3 jaw in the CNC 3 jaw(your salesman sounds like a puss), but I see no reason you can't. I've grabbed 4 jaws quite a lot.

Why is it difficult to put points on the soft jaws? I do everything with a 12" chuck from .25 to 14.5"

Gripping a small chuck in a big chuck is done all the time. You do, however, need to be careful that you don't accidentally hit the foot pedal out of habit.

Try a Kalamazoo 5C chuck.

1CC, 5C Collet Fixture for Chucks | Kalamazoo Industries

i think in the mazak forum there is a thread about turning a set of soft jaws to take warner swasey collet pads

Originally Posted by bryan_machine

Also, you could get a set of Warner&Swassey style "collet pads" or "jaws for collet pads" (might have to make the jaws) and then set of collets. See the usshoptools catalog.

This. I bought a set of the jaws from US Shop Tools and it's so easy to just change out the collets, of which we already had.

Curtis

+3 On the Kalamazoo 5C collet actuator. Works great for smaller sizes.

What I do is take a set of jaws, mill a flat on them and weld a pad on them thick enough to allow me to get down to the dia I want. I made one set of jaws for our bigger lathe about 4 years ago and we're still using them when we need to get down to smaller dia's.

Yes the warner swasey collet pads work great. I have a 10 inch chuck with the collet pads you can get in square, hex, round. The name on my pads are Superior cincinnati. I have in range from 2 3/8 down to 3/8

Huron Machine: Accessories: Collet Pad Top Jaws & Collet Pads this is where we got our jaws for the warner swasey style pads

Turret Lathe Collet Pads on Positrol Workholding this is where we get some pads from, MSC also can you the pads

Originally Posted by racen857

Yes the warner swasey collet pads work great. I have a 10 inch chuck with the collet pads you can get in square, hex, round. The name on my pads are Superior cincinnati. I have in range from 2 3/8 down to 3/8

Huron Machine: Accessories: Collet Pad Top Jaws & Collet Pads this is where we got our jaws for the warner swasey style pads

Turret Lathe Collet Pads on Positrol Workholding this is where we get some pads from, MSC also can you the pads

Well I'll be, that is a fantastic idea!

So the pads, when clamped, would be solid and you bore them out to size? Or do they come in set sizes?

Thank you all for the ideas.
I like the collet pad set up,looks pretty sweet.
I think I'm gonna go with the Kalamazoo 5c holder.We have 5c collets that were bought at an auction with sizes from .062-1.125''.
If we go with the 5c holder we can make use of the ass load of collets collecting dust we have plus it can be used for work holding else were in the shop.

Originally Posted by Armedsask

Well I'll be, that is a fantastic idea!

So the pads, when clamped, would be solid and you bore them out to size? Or do they come in set sizes?

The Warner Swasey collet pads are hardened and ground like a regular Hardinge 5C collet. They also make soft collet pads (similar to a 5C emergency collet) which you bore to suit your parts.

The Warner Swasey collet pads can also be sourced on ebay for cheap since they are for 'outdated' machinery aka a turret lathe. I just happen to own such a beast. The pads that fit my turret lathe max out at 2.5" in diameter.

http://www.ebay.com/sch/i.html?_nkw=...+pad&_osacat=0

Originally Posted by Armedsask

Well I'll be, that is a fantastic idea!

So the pads, when clamped, would be solid and you bore them out to size? Or do they come in set sizes?

You can get in most any size you want, we evem got in a custom 1.65, now I am working on getting a few sets of the emergency for my custom size materials.