Do I need ER collets?

T

tigtorch

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I have been enjoying the various joys of working with metal for a few years but my machining expertise is pretty limited. I do, however enjoy the machining I have done so far which is mostly ornamental (machined, articulated LED lamps) and so far not needing high accuracy. I do think I want to start making small artistic mechanical movements that would require more precise machining, though. My machines are a Burke Millrite mill and a Rockwell 10" lathe (I also have a cnc'd chinese mini-mill that I use for making things like gears). The two mills are R8 collet size and the lathe takes 4C collets internally, which are difficult to find.

I have seen ER collets, I don't actually know where they fit it the scheme of things, and I wonder if they are something I could use on my equipment to advantage. Could anyone here tell me if I should look at those for my lathe, or look at a 5C chuck, or try to find a set of 4C collets, or forget the whole thing and use my 3 and 4 jaw chucks?
 
Collets are definitely a worthwhile accessory on the lathe. Their concentricity is much more consistent than three and four jaw, or even six jaw chucks. The ER collets are nicer than 4C or 5C collets because they have a larger range, although you do need to snap them into the nose piece to use them. On the other hand, they don't require a drawbar.

Tom
 
Need? No. Enjoy? Definitely "yes". Used as you describe, I think they would be one a good choice.

Personally, I have little use for 5C collets. Their limited grip range is very frustrating. The ER's grip range is continuous, the 5C's range is not. A part that is a few thou undersized will have to be turned to the next lower standard dimension in order to be held by a 5C. Not so with ER's.

Bill
 
My ignorance is somewhat larger than your answer. So ER collets "snap" into a receiver that mounts on the lathe spindle? All I have seen and even know about is the fact that ER collets exist... PERIOD! Sorry for my lack of knowledge but although I am a graduate EE, I spent my life programming software, owning a plant nursery and (of all things) being a national orchid judge.

Back to my original question: would an ER collet setup be better for my lathe than a 5C collet chuck or trying to find 4C collets? What are the pluses and minuses of the three?
 
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It is true that 5c collets have a very small range of motion.However 5e collets can be bored to fit any size.They come with a radius in each slot for a .125 pin put it in the spindle clamp it closed and bore to size. They can be used over and over untill there is nothing left to bore. 5c collets also come in square and hex.

frankie:))
 
Back to my original answer: ER collets have a greater range than 4C or 5C collets and ER collets do not require a drawbar. Yes,they snap into a threaded nose piece which in turn screws to a collet chuck mounted on the spindle of your machine.

Tom
 
Thank you, what size of ER collet system would you recommend for a 10" Rockwell (more or less the same size as most 10" lathes)?
 
I would imagine the spindle on your Rockwell would handle the ER 40 collets, which will take up to a 1" diameter part or tool. If not, then the ER 32 would be the best size with a 3/4" capacity. Keep in mind though, they are going to be pricey if you opt for the complete set. Of course you'll need to be sure you can get an ER collet chuck that will fit the spindle of your lathe.

Tom
 
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