PDA

View Full Version : collet holder project



dp
11-21-2007, 06:50 PM
I bought one of the 5C collet fixture mounts from Enco so that I can try to make an adapter for my existing collets purchased long ago from Grizzly. Here's the challenge:

http://TheVirtualBarAndGrill.com/machinery/pictures/collet_holder.jpg.

I need to turn and thread the fixture on the right to accept the collet and collet nut shown on the left. 1.5 metric thread and don't recall the diameter. The purpose is to be able to use my existing collets in a 5C spin indexer I just bought. I'll get some 5C collets later, but for now this will do.

Anyone know if it is necessary to anneal that fixture before turning it? I've no idea what the metal is. The catalog just says "steel".

mochinist
11-21-2007, 06:55 PM
I have never used one, but I believe those are made to be custom machined to whatever you need, could be wrong though. Anyways just run a file over it to see if it is hardened, if not cut away.

R W
11-21-2007, 07:20 PM
Congratulations on your photos. I would have a go at machining the fixture
first, you may not have to anneal it.

dp
11-22-2007, 12:48 AM
In looking more at the problem I have several thou to muck with it while I work out the speeds and feeds issues. But if anyone's been there, done that, and knows the ropes I'm all ears. I know that Sir John, Earl of Sudspumpwater, MBE has dealt with these very objects as it was he who put me on to them.

Good Earl, I beseecheth thee, is my fetid Grizzly 3-in-1 up to the task of taming this shrew? Sheweth me the light. And any non-Earls can chime in, too.

Your Old Dog
11-22-2007, 09:35 AM
His Lordship should be along directly. Gert likely has him re-arranging the patio stones at the moment. :D

Ian B
11-22-2007, 11:58 AM
Talking of annealing:

I want to make a ball turning attachment that's part of a Dickson S3 quick change toolholder block. Being too lazy to cut the 2 vee grooves and tee slot, I found a rusty toolholder with a 2 morse taper hole. Ideal; just stick it on the toolpost, bore it parallel and bush it, off we go.

But - it was as hard as the knockers of hell. No problems - I put it in a hot fire for a couple of hours, it was glowing a really nice orange colour. I left it in there to cool slowly, overnight.

Next day I checked it - hard as the knockers of hell...

Where did I go wrong?

Ian

Mark Hockett
11-22-2007, 02:20 PM
Dennis,
The 5C adapter on the right should be easy to machine. They are usually designed to be machined. The only thing I would be worried about is if it will be hard enough to withstand repeated use as a collet chuck.

You are welcome to come over to my shop and use my lathe to machine it. I have a 5C collet nose on the spindle and with the CNC the metric threading and inside taper is a no brainer.

Your Old Dog
11-22-2007, 04:57 PM
I put it in a hot fire for a couple of hours, it was glowing a really nice orange colour. I left it in there to cool slowly, overnight.

Next day I checked it - hard as the knockers of hell...

Where did I go wrong?

Ian

You want to heat it cherry red with a torch before you put it in the hot coals. And, don't subject it to a cold draft of air while it's still cooling down or you'll air quench it again.

rotate
11-22-2007, 05:06 PM
But - it was as hard as the knockers of hell. No problems - I put it in a hot fire for a couple of hours, it was glowing a really nice orange colour. I left it in there to cool slowly, overnight.


I had to anneal a hardened QCTP once for modification and I had to heat it until it was bright orange (check it with a magnet and make sure that it doesn't stick). I'm not all together sure how slowly it has to cool. People say overnight but I think that's an overkill. I had to do it twice before it had annealed evenly enough that I was able to machine it easily.

Ian B
11-23-2007, 05:20 AM
I forgot to use a magnet; good idea, I'll try it again.

I'm pretty sure it didn't get air hardened, it cooled very slowly in the fire.

I now have an oxy propane kit, so if I can find some firebricks, I'll try with that.

Ian

5Bears
11-23-2007, 09:59 AM
Dennis,
The 5C adapter on the right should be easy to machine. They are usually designed to be machined. The only thing I would be worried about is if it will be hard enough to withstand repeated use as a collet chuck.


I believe Mark is entirely correct. It should machine with relative ease, but it will not have the longevity of a hardened collet holder. Even with that, if used with care, it should last a long time in it's soft state and do good work for you.

It might be possible to harden it, but considerations must be given to the type of alloy, surface oxidation, warping, etc. Not a trivial process, and you'll probably spend more time and $$ doing that than simply buying a collet holder outright, if one can be found.

J. R. Williams
11-23-2007, 10:39 AM
Dennis
Have you given any thought how to extract the collet or release the work using the nut clamping sytem for use with the 5C collets? The ER style has a top groove that is used with a tab inside teh nut to extract the collet.

JRW

Spin Doctor
11-23-2007, 11:00 AM
Well the fixture head is soft for easy machining so that won't be a problem. The question is how soft. Soft can be a relative thing. If the threaded body is say 50 to 55 RC then the head might be 30 to 35RC. Which would put it in the machinable range with HSS but will still give it the wear reistance needed for light use. Sir John had a post awhile back about converting one of the 5C Spin Indexers to take 5C and one of the ER(32?) series of collets. Just one of his many attempts to convert the 5C faithful to the heresy of the ER theory of work holding. :D \:D/

The main thing that would concern me is addition of another layer of interface between the work and workholding device. If you have the material laying around these things are something you can make your self. I ran off a bunch at my old job to have around for emergency fixturing for some of the really oddball jobs that they would come up with. Used 4140 TG&P @ 35RC

http://img.photobucket.com/albums/v19/markandannie/collet%20stops/P1010299.jpg

http://img.photobucket.com/albums/v19/markandannie/collet%20stops/P1010298.jpg

Dang the other cute little smiley doesn't work

PS, Could you of used a 5C to #3 MT adaptor?

John Stevenson
11-23-2007, 11:16 AM
Sir John had a post awhile back about converting one of the 5C Spin Indexers to take 5C and one of the ER(32?) series of collets. Just one of his many attempts to convert the 5C faithful to the heresy of the ER theory of work holding. :D \:D/

Dang the other cute little smiley doesn't work
Must have had some sucess as they are now available :rolleyes:

Top of the page and 6th one down.;

http://www.arceurotrade.co.uk/en-gb/dept_136.html#item_1291

Coming to a store near you ?


.

Spin Doctor
11-23-2007, 11:25 AM
What is it about heretics that they can never recongnize a little tounge in cheek humor :D

OK, OK. I'll admit the ER is a far and away superior tool holding system to the 5C (or the 3C, 4C, 3J or any other similiar collet) including the R8. Myself I'm kind of partial to the Kwik Switch Acura system as to its easy of changing tools in the spindle. But for lathe work, especially if one is running a lot of parts why anybody would go through the hassle of the ER type is beyond me

dp
11-23-2007, 11:48 AM
Dennis
Have you given any thought how to extract the collet or release the work using the nut clamping sytem for use with the 5C collets? The ER style has a top groove that is used with a tab inside teh nut to extract the collet.

JRW

The existing nut has an offset washer/extractor inside to pull the collet. I'll notch the 5C adapter to accept a spanner like the nut has for removal. Longevity won't be a problem as I've been waiting for John's 5C to E16 adapter to show up on our shores. The collets I have are not ER16 though they look similar. It's a non-standard size, or at least an uncommon size, and I've not found any other collets for it other that what the kit came with.

The last condemnation is there is no way to put long stock in it as there's no hole in the existing tool and that is the reason I've decided to cob up this lashup. 5C collets are generally much too large for my smallish lathe and mill combo, and the only 5C tool I'll have is a spin indexer I just bought for a particular project that requires it, so rather than buy a 5C collet set this home spun adapter looks to solve the problem and to give me yet another machining experience and a new tool.

And I do believe I'll take Marks offer to do the work on his CNC machine because one thing I'd forgotten in my scheme is that my 4-jaw chuck center hole is too small to accept the shank of the 5C fixture, and doing all that critical machining with the turned end so far from the chuck with no other support is a bad idea.

I was hoping to retire this year and get a bigger shop for bigger machines, but it's been put off a couple more years so I have to get by a while longer with what I've got. Best laid plans, and all that :)

Pete H
11-24-2007, 05:58 PM
Old Blacksmith's trick - get yourself a bag of "garden lime" - the powdered or granular sort, not the grey pellets. Dump it in a metal bucket. Heat the piece to the required temperature, and bury it in the limestone overnight. The limestone doesn't conduct heat worth a hoot, so the piece will cool VERY slowly.

BTW, garden lime also works much better than "kitty-litter" for picking up oil spills... it doesn't turn to mortar when it gets wet.

Pete in NJ