Threaded Mandrel for Unimat SL Chucks

[C-Bag]

Collets, man, I need a emoticon of the guy scared of going down the rabbit hole! I've been lurking here trying to let a little of this soften my noggin enough to get the lay of the land. I dipped my toe in with R8 because that's what my old RF30 mill uses. I decided to go with a big set because it dawned on me I could bypass one of the big drawbacks of the mill. Losing where you are if you have to raise the head because of clearance. So with the complete set of collets and short sets of drill bits I elimated having to install the drill chuck and changing height. So I know intimately good reasons for having a full set, but then why are there so many different collets and is it for a reason or just capriciousness?

But you guys are so far along with collets as to be speaking Greek. I also am wanting a spindex and there is a deal on eBay with a set of 5c collets for like $130. But it took a while to get why they don't use R8. Not being in a shop where you can just ask somebody is tough out here in the peanut gallery. Is there some primer on collets? And where do you find an un hardened morse adapter?

[PJs]

Thanks very much for the link Paul. Amazing shop...Wow! Organized, packed to the rafters, clean and most of all his machines are awesome! 4C throughout...quite a coolection in 64ths! Will watch some more of his vids. Thanks again for a great topic and discussion. ~PJ

[Paul Jones]

Thanks PJs.

C-Bag,
Yes, there are many types of collet systems and many are proprietary. I am proponent of using Wikipedia for my introductions to topics I want to know more about at the 30,000' view before researching the details. For example see the Wikipedia topic on collet systems at https://en.wikipedia.org/wiki/Collet . The 5C collet is threaded on the outside so the collet drawbar can also be hollow to allow long parts to pass all the way through the headstock. This is why 5C works so well with lathes. R8 collets are designed for milling machines with the keyway to prevent rotation and self releasing to allow automated tool changes (but the CAT tooling is better for automation (did you know CAT tooling system was invented by Caterpillar Inc. for standardizing the tooling used in their machinery factories)).

The question of the week is "And where do you find an unhardened morse adapter?" I have been looking for the MT5 to MT3 unhardened adapter and can't find these. I have one that is hardened. All we really need for the making the 5C collet chuck (or other collet chucks to fit a MT5 lathe spindle) is any unhardened MT5 to straight shank adapter. I have seen these listed in catalogs. Depending upon the shank diameter, the MT5 adapter straight shank-end could be externally threaded, bored and tapered for an ER-type collet or the straight shank just cut off, bored and tapered for a 5C collet. I will start looking for the adapter

Paul

[PJs]

Paul, Was thinking about the unhardened and wondered if you could heat a hardened one with a torch to anneal it and let it air cool. I think you can test it with a magnet to see if becomes non magnetic during the heating process...and think that is called Austenitic?<¿>? Not sure but might get you what you need. Is there a plan to re-harden after working them?

30,000' view...LOL! Thanks! ~PJ

[Paul Jones]

PJs,

I finally found the unhardened Morse taper sleeves at Victor Machinery Exchange and KBC Tools. I have bought items from them before and now I remember seeing the term "Soft Drill Sleeves" in their catalogs. The sleeves have a Morse taper with hardened tangs and the soft sleeves can be machined to make the 5C collet chuck. The tang end will be cut off to allow boring straight through so a drawbar

Paul

P.S. I later found the same unhardened Morse taper sleeves at Enco.

[PJs]

Great you found some Paul. Good memory and enjoy the way things pop in like that. I get what you are saying about turning the 5C interface but need to look at the specs to get the full flavor of the possibilities...which may be quite broad, as you say. Thanks much also for that re-realization that 5C can pass stock through itself and the spindle. A bigger bonus.

C-Bag, You are way ahead of me with a mill and an R8 set. Always enjoy your perspective and the way you raise the pertinent questions. Thanks guys, fun thread. ~PJ

[C-Bag]

I'm keeping a close eye on this thread as I'm now committed to this rabbit hole.

I did like you said Paul and went to Wikipedia. Thanks, I don't use the site as much as I should and it never would have dawned on me to look there. Lots to grok. I am very interested to see how this whole thing goes as there is a lot of parameters I'm not sure of. And not having anything that's mt5 keeps me from having any use. I did go through something somewhat similar(I hope) in that I wanted to be able to mount my 3" 3jaw Chuck on my 10" rotary table. I did a mod of an arbor on you tube that a guy used to quick align his rotary table. I found this:

Arbor, Blank 3MT Drawbar 2393 - LittleMachineShop.com

So I had my brother the real machinist make this for me:

He had to weld on the steel ring base because the soft machinable end wasn't big enough. I think it came out great and it works great. Added benefit is I can mount any of my three chucks, 3", 6" or 8" 4jaw on the rotary table. I've been meaning to go back and order a couple more to make the centering pilot like the original you tube. Unfortunately this doesn't help you with your quest Paul. But it's kinda related

[Paul Jones]

C-Bag,

Great photo. My compliments to your brother's skills in fabricating the Morse taper threaded arbor. Thanks for the LMS tip. You should show more photos of your rotary table chuck adapters.

I think I found what I need to make the 5C collet chuck. My lathe has a D1-4 spindle with a 5MT inside the spindle. The largest and smallest diameters either ends of a standard 5MT taper are 1.7480" and 1.4750" over a length of 5.19". Lucky for me this is the smallest size Morse taper with enough material to be made into a 5C chuck (still requires boring a hole large enough to accommodate the collet drawbar diameter and then machining a 10 degree taper that opens up to 1.480" dia. at the front to accommodate closing a 5C collet). Someone with your brother's skill could easily wield a ring to the front of this proposed collet chuck design for easier removal from the lathe.

Thank you for joining in this discussion.

Paul

[PJs]

Thanks for showing your rotary table chuck holder C-Bag. Beautiful Piece and Versatile!! I have a few of the LMS MT tapers from them and are quite good and inexpensive! Enjoyed "Grok" too...Mr. Smith really cut some edges off the paradigm. A sharp tool, Mr. RAH! Actually have one of his mustache cups I picked up down in Sonora on a trip years ago and tracked down most of his hard-bounds! Kind of a huge fan...

Thanks for the Numbers Paul, hadn't had a chance to run through them yet to get a feel for where you are going but now makes better sense. Will you harden it after you get it done? Look forward to what you come up with.

Fun educational thread with great folks! ~PJ

[Paul Jones]

PJs,

Rather than think of the numbers just think of holding the 5MT adapter in your left hand and then with your right hand holding a 5C collet over the 5MT adapter to visually see how much needs to be machined away and still have enough metal left for a strong chuck. I had not planned on hardening it the collet chuck. That level of expertise is best left to toolmakers like Doug Ross and his projects at Rossbotics.

As always , thanks for the feedback,

Paul