When you need that ONE special collet...

[The_Apprentice]

Alright, you're working on a project, you find out your 1/2" collet is just too small to fit that piece of round-bar you ordered which was sized at 1/2" diameter by the seller. Ok, while you COULD put on that 3-jaw chuck, it's more of a hassle and you don't wan't to scuff the bar with the teeth...

You check into your imperial set of collets and the next size up is just a mm or so too big. Now what?

When you're in a situation like this, and want just a single collet to buy, where do you turn to?

I'm currently in Niagara Falls, and am open to local options either on the US side or Can side. Looking at stores like Harbor Freight and Princess Auto don't really give much in the collet thing, unless you wish to buy a WHOLE new set maybe.

I have heard of some stores that simply have a vending machine, you punch in the type of collet and what size, and out it drops. Anything like that local?

I don't even mind driving down to Buffalo if I have to.

 

[ttabbal]

I have seen "emergency" collets that you bore to your needed spec. I have no idea how easy they are to obtain locally though.

 

[Ulma Doctor]

I had the very same issue. i bought single collets from Shars.
i'd buy a 17/32 collet for your situation, i'm assuming you have a 5C system
if you have an ER system a 13mm collet should suffice

 

[chips&more]

In my shop, I use the 3-jaw chuck for 99% of larger lathe work. I do not have a problem with jaw marks. On micro machining, I’m pretty much all collets. I have seen chuck jaws that have pyramid teeth and yes that would be a problem. My jaws are smooth. Sometimes I wrap a thin piece of brass sheet around the material…Dave.

 

[Dan_S]

You can get emergency collets form Shars.
http://www.shars.com/5c-emergency-collet

You can but individual collets from a bunch of places in 1/64" incriments.
http://www.shars.com/products/toolholding-workholding/collets?collet_category=5C+Collets
https://www.maritool.com/Collets-5C-Collets-5C-English-Round/c21_152_153/index.html (my preference)

If you want to go a little crazy, you can by individual collets in 0.001" increments from Hardinge.
https://www.shophardinge.com/productGrid.aspx?catID=6896

 

[RJSakowski]

For an emergency, you can shim a slightly oversized collet. Wrap an appropriate thickness shim around the part and trim to just short of a full circle. The additional runout should be minimal.

 

[The_Apprentice]

It's actually an ER 32... I had wondered about shimming for collets, but thought that may end up being a too unorthodox idea. I may end up trying it down the road though... I've seen very small shimming-sheets being sold at places. I guess I know what other stuff I'll be experimenting with next month now.

Alright, I'm off to check out Shars now...

 

[Uglydog]

For an emergency, you can shim a slightly oversized collet. Wrap an appropriate thickness shim around the part and trim to just short of a full circle. The additional runout should be minimal.

RJ, do you use metal shims? Do you wrap the stock, or insert it in the Z direction?
I've had luck with paper (comes in multiple thicknesses) for my tollerances.
Am very open to new ideas and better options!!

Thank you,
Daryl
MN

 

[Holescreek]

Several options, nothing cheap or easy. Staying with the collet scenario, ER collets are designed to clamp down to the next smallest size so you're covered for every size in between, metric or sae. Or second (my preferred choice) get yourself a Jacobs Rubberflex chuck and you're covered for everything between 1/8" and 1 3/8".

 

[higgite]

Staying with the collet scenario, ER collets are designed to clamp down to the next smallest size so you're covered for every size in between, metric or sae.

Not necessarily so. Depends on if you have a 1/16" set or a 1/32" set.

Apprentice,

It would help to know what size collets you have and the size of the bar that you want to hold. Telling us that a nominal 1/2" bar is too big fit a 1/2" collet and your next size up Imperial collet is a mm too big doesn't tell me much.

Not knowing your exact requirements or limitations, I'd offer this as a possible solution, short of buying a collet to fit the bar. Since the bar is obviously of larger diameter than you need, as you were planning on holding it with a 1/2" collet, then it won't matter if you mar the original surface by mounting it in a 3 jaw chuck and turning it down so it will fit your 1/2" collet.

Another alternative is to get on the web and search for the closest tool supply house and give them a call to check on stock. They usually sell individual collets. Hope you get it worked out.

Tom