Collet suitability.

A friend of mine is an engraver for a sign manufacturer. After I recently asked if he had an er11 collet I could look at (thinking of making a little spindle), gave me some food for thought because after showing me both an er11 and er16, he showed me a box of slightly unusual collets in his cupboard. He asked if they might be of use to me and said that I could have them if I wanted.

Naturally I was pretty chuffed at the prospect but I need to figure out if they're are going to be usefull to me or not. They look like this:

Each one has its own closing ring circlipped to the top. From what I can gather they are porter cable collets for use in wood routers. I can see making a little chuck straightforward enough, I may even be able to use one of those soft morse stubs you can buy. One thing that does interest me is the relief (black bit in middle if relief isn't the right word )in the middle if the collet. It's not a double angle type so I don't see what having the gap does. Any suggestions?

So what do people think could I use these for a small mill drill spindle for my lathe?

cheers

martin

A taper seats more accurately with a relief as shown as it eliminates any possibility of rocking in its seat. Also cheaper to grind. Colin

Hi Martin

Colin has answered the point about the relief on the taper, but if these are router collets you need to be aware that they are likely to be available in a very restricted set of sizes, 1/4 in. 8mm and 1/2in., because that's the shank sizes for router cutters. Also I doubt if they will have very much gripping range as the cutter shanks are all made to size so the collets don't need to close up to accommodate variations.

If you can live with those restrictions then I don't see any reason why you shouldn't use them. Routers routinely run at 25k to 30k rpm and don't let go of the cutters provided that they are tightened up correctly.

My gut feeling would be to go with the original idea of the ER collets as they will be more versatile with having a much wider size range available and the work involved in making the spindle end is pretty much the same for either collet. Cost wise if you need to buy replacements for the Porter Cable in time, you'll almost certainly find that ER collets are available at lower cost as well as in more sizes.

Keith

Apparently they are made in a much wider range of eleven sizes HERE but come in a lot pricier than ER11 collets (at least from that source). They must also be used with the key Porter closing nuts, but you seem to have been offered those.

Key difference is that ER11 will cover a range of sizes.

Neil

Edit: I note that they will do 'specials' for any size - if your pockets are deep, I guess!

Edited By Neil Wyatt on 31/03/2014 18:55:55

Thanks everybody, like most of the model engineering community I'm rather adverse to the idea of spending any money so I'll have a bash with the porter cable ones.

i'd like to get some er collets in a larger size like 32 for some more useful work holding on the lathe but the router collets will still be useful for holding a few small slot drill end mill type stuff in my little spindle.

Thanks again.

martin