Turning Large Diameters with collet

[CarbideCarGuy]

Hello all!

I've been working with this company for about a year now and the first thing I did when I got here was install a Royal Collet system in the Haas ST25Y. I haven't turned back since and I love it!
Most of what we do are small runs or one off parts, small parts, all bar jobs that fit in the spindle bore. Occasionally we get some jobs too big to fit in the collet or envelope of the machine. Now is one of those times.
My CEO and Supervisor insist on putting the 3 jaw chuck back in to turn large diameters. I really don't want to swap out the collet system to put in a 3 jaw chuck that I haven't had much luck with, especially since it's dialed in really well at less than .0001" run out.


My questions are:
Is there a work around or trick to turning larger diameters in a collet system?
This may be a stupid question but I'll ask anyway, is there a Chuck with a boss on the back to stick into a collet? It sounds like a bad idea but I have to ask.
Am I being a wuss not wanting to swap it out or am I right for not wanting to break down my nice setup?
Please validate my insecurities, I mean please help. Any information or tips are welcome.

 

[L Vanice]

"Royal Collet system" tells me nothing because Royal makes a lot of different collet devices. Provide more information about the type of collet and the actual part sizes you want to hold. Pictures of the lathe spindle nose and current collet will help a lot.

Yes, you can buy small 3- and 4-jaw chucks with 5C collet-shape arbors to fit in any 5C collet chuck. Other collet chucks, maybe.

Look up "step chuck" to help understand how larger than normal parts can be held in collets.

Larry

 

[Mtndew]

Am I being a wuss not wanting to swap it out or am I right for not wanting to break down my nice setup?

Yes.
Being able to quickly swap out a 3 jaw to a collet and vise versa will make that machine much more versatile. And it only takes like 10 minutes once you get the hang of it.
Royal makes good stuff, and should repeat when re-mounted pretty good.

 

[CarbideCarGuy]

"Royal Collet system" tells me nothing because Royal makes a lot of different collet devices. Provide more information about the type of collet and the actual part sizes you want to hold. Pictures of the lathe spindle nose and current collet will help a lot.

Yes, you can buy small 3- and 4-jaw chucks with 5C collet-shape arbors to fit in any 5C collet chuck. Other collet chucks, maybe.

Look up "step chuck" to help understand how larger than normal parts can be held in collets.

Larry

Royal Collet system PN 46165. 80 A2-6.
It has a max size of 3" and I would like to turn something that is 6"

I dont think a step chuck is what i'm looking for unless royal makes a step collet for their proprietary collets.
Im also trying very hard to not make a step-chuck joke. "Help me step-chuck, I'm stuck in a vise." My appologies. It's out of my system now

Yes.
Being able to quickly swap out a 3 jaw to a collet and vise versa will make that machine much more versatile. And it only takes like 10 minutes once you get the hang of it.
Royal makes good stuff, and should repeat when re-mounted pretty good.

Fair enough. It took me a day to get the royal collet chuck in the machine, i guess practice make perfect.

 

[L Vanice]

So does your Royal Quick-Grip Accu-Length CNC collet chuck have the Bolt & Go feature that allows quick chuck changes without adjusting runout?

Royal Quick-Grip™ CNC Collet Chucks – Royal Products

royalproducts.com

Larry

 

[GregSY]

In general, 6" is too large for that setup...but of course, it's not too large if you're taking a few light cuts on aluminum versus lots of heavy cuts on SS.

 

[SeymourDumore]

That Flex collet setup does not let you go larger than the 3", so that's out.
Can you get a manual 3 jaw chuck with a straight "shank" to hold in the collet? Perhaps, likely home grown tho.
Even if you did that, my personal preference would be to use it once or maybe twice in a lifetime.

So, that leaves you with swapping the collet chuck to a 3 jaw chuck...
No brainer as far as I am concerned!
A2-6 nose suggests an 8" machine, so the 3 jaw chuck is a manageable weight, change over should take less than 30 minutes from collet to chuck, and perhaps an hour from chuck to collet.

Alternately, Hainbuch has a system that can swap between external collet, internal grip collet and a 3 jaw chuck using a common interface mounted to the A2-6 nose.
Very handy system if it's needed, but I have not yet muscled up the courage to ask about the price.
Even then, the jaws are proprietary, or at least cannot be sourced from common suppliers.

 

[SeymourDumore]

So does your Royal Quick-Grip Accu-Length CNC collet chuck have the Bolt & Go feature that allows quick chuck changes without adjusting runout?

Royal Quick-Grip™ CNC Collet Chucks – Royal Products

royalproducts.com

Larry

It is a bolt-and go that uses an "interface" between the chuck and the spindle, and Royal's claim to fame is that the interface is ground precisely enough as to eliminate the "dialing-in" of the runout.
I have a Microcentric flex setup, and it also uses the interface plate, but it does have the adjusting screws as shown in your link.

In any case, these Flex collets are typically not going to give you a dead nuts runout anyway, so if you're looking for something less-than .0005 TIR, you will need to bore a soft collet.

 

[Limy Sami]

Soft jaws for a 3 jaw chuck ??????

 

[Ox]

For onesie / twosie work, if it was me, I would just cut your 6" an extra 1.25" long, chuck THAT up in the engine lathe, and turn down 1" of it to 3". Or maybe even 2.75 and use serrated pads.

Now your whole part is out in the open to work on, rather than sunk down in the jaws.
(Can work on the OD)

I have done this many times when I need to git a little bigger than bore.
Works just fine - but doesn't help you if you need to turn the part around for Opp2.

Can your side 2 work be finished in the engine lathe easily?

Now, if you have many parts, then I will change to the 3 jaw, but for a cpl?
Nah...


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Think Snow Eh!
Ox

 

[CarbideCarGuy]

For onesie / twosie work, if it was me, I would just cut your 6" an extra 1.25" long, chuck THAT up in the engine lathe, and turn down 1" of it to 3". Or maybe even 2.75 and use serrated pads.

Now your whole part is out in the open to work on, rather than sunk down in the jaws.
(Can work on the OD)

I have done this many times when I need to git a little bigger than bore.
Works just fine - but doesn't help you if you need to turn the part around for Opp2.

Can your side 2 work be finished in the engine lathe easily?

Now, if you have many parts, then I will change to the 3 jaw, but for a cpl?
Nah...

This would work perfectly and this is kind of what I was expecting to read. BUT we only have this one CNC Lathe. Many of us have been begging for a manual lathe or something else to turn down parts without breaking a cnc setup. One day, we will get one...
Needless to say, I can not turn it down outside Haas lathe we have.

Alternately, Hainbuch has a system that can swap between external collet, internal grip collet and a 3 jaw chuck using a common interface mounted to the A2-6 nose.

I will look into this also, it might be a nice addition to our limited shop. The boss isn't afraid to spend money on quality products that will make change overs and setups faster.


I think after reading everyone's input, im just going to have to put the 3 jaw chuck in. Thanks everyone for the options and input.

 

[Ox]

The boss isn't afraid to spend money on quality products that will make change overs and setups faster.

Well, you can buy an engine lathe for what you will likely spend on a fancy chuck set-up for your CNC.


-------------

Think Snow Eh!
Ox

 

[just Dave]

This would work perfectly and this is kind of what I was expecting to read. BUT we only have this one CNC Lathe. Many of us have been begging for a manual lathe or something else to turn down parts without breaking a cnc setup. One day, we will get one...
Needless to say, I can not turn it down outside Haas lathe we have.


I will look into this also, it might be a nice addition to our limited shop. The boss isn't afraid to spend money on quality products that will make change overs and setups faster.


I think after reading everyone's input, im just going to have to put the 3 jaw chuck in. Thanks everyone for the options and input.

Getting started is the hard part.Become he best chuck changer you can be. All experience counts.

 

[Orange Vise]

As @Ox suggested: machine a boss and grip the boss in the QG-80. You can do this with an engine lathe or a mill.

Depending on the shape of the finished part, you can also machine an ID thread in the blank, machine a spigot, thread the spigot into the blank, and clamp on the spigot. BTDT running 5" diameter blanks in an ST20Y. Worked fine. Just make sure the spigot has sufficient diameter and engagement, and if it's a RH thread, only run the main spindle in M03. M04 will unthread the blank.

 

[BT Fabrication]

you could always turn down the stock end extra left on it and try to chuck 3" dia in the collet, but that is another op in a different machine.
either way, chucking 6" is better in a jaw setup, be it 3 or 4 or 6 jaw chucks, collets are only designed to do smaller parts with that system.
most chuck switching is fast, especially D6 styles, its loosten, pull off, clean mating faces and put the other on it and tighten.

 

[Ox]

either way, chucking 6" is better in a jaw setup, be it 3 or 4 or 6 jaw chucks, collets are only designed to do smaller parts with that system.

IDK how you come to that conclussion?

Bay far - the lions share of our work here is turning, and I would feel much more secure with a [serrated] collet held part than a jaw chuck.

Only time a 3 jaw would be better is if you have out-of-round material, where the collet may only grab on 2 high points, and a "non-pie jaw" 3 jaw chuck would balance that out.


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Think Snow Eh!
Ox

 

[majohnson]

On 5C collets I just started using the sleeve that fits the larger collets that have a 2” face for additional holding. It holds the work piece much better, I was able to turn a 1.75” X 4.5” long without any shifting in the collet.

 

[Bill D]

No expert here but you have the collet chuck dialed in. Mark its orientation before removing it so it goes back clocked the same way. That should help reduce change back time. I am not really sure if that applies to a collet chuck or not?
Hopefully the chuck was marked before it was removed and can be clocked the way it was before. I will assume it was okay runout, more or less. At least they played with it and it was in the best of three possible orientations befor eyou removed it.
BilL D