5C Collets range
I have heard the range for a 5C collet is +/- .005".
Even if you have the full set down to 64ths, sometimes
you still end up making an emergency collet for that
odd size. I think it would be better if 5C collets had
6 slits instead of the regular 3 slits, You might be able
to get some more clamping in the minus, which would
be great. I have made more slits in one and I like the
result. I know with a single angle collet like a 5C it is
difficult to maintain parallel grip, but I think 6 slots help
in many regards. Does anyone see why 6 slots is not a
Move over to the ER series collets, but they cannot handle short parts.
Full grip collets have six slots, three down from the top and three up from the bottom, the purpose is to offer a better range of fit per collet and a more even tool grip. That would not be possible with the 5C. To me it seems like 3 more slots would not offer much benefit for the 5C, perhaps it may if you were using them outside their normal range of use, but then I guess, that's your point!
I have used them for more than +/-.005" and not had a problem. 1/64" is .0156" and half of that is .007" but I normally use sets with 1/32" increments. I haven't had any trouble going +/-.020". I have seen them used close the the next size up or down. It worked but I don't do it with my 5C's but who knows what happened before I got them.
It's only ink and paper
Its a fundemental diffrence in collets that iv managed to peace togethor:
Single angle collets, are only clamped in at the front, they pertty much relie on the body of the collet to be the correct size to 'align' the part. too much undersized and the part could easily be clamped in tilted.
short parts in a single angle collet hold in easy because the griping parts of the collet are only at the front and are the correct diamiter to prevent the part from tilting (assumeing you stay within the recommended 0.005" diamiter, And honestly for most work thats likey fine)
Adding more slits does not improve the fact the body is still the wrong size. And you can't slit the back of a 5C collet because thats where the threads are.. Maybe im wrong but sliting through threads, and your threads compressing sounds.. bad.
Single angle collets lend themselfs to draw tubes because of the typical rear threading to tighten into the collet body.
For double angle collets, they clamp at the front and back by a swishing the two tapers togethor. Not so great at lending itself to a draw tube
On short parts, the back will collapse greatly while the front just barly grips the part, meaning it won't grip at all! You MUST place a plug the same diamiter near the rear of the collet to hold short parts in a double angle collet or it won't hold securely (Nothing for it to clamp onto) and won't hold parallel to the face of the part either.
It can be slited at both ends because well, its designed to collapse at both ends. Hence the double taper mounting required to compense FOR it collapseing at both ends. (Single angle use the round body of the collet to locate the rear of the collet, if it collapsed the collet might not be straight anymore) and can have a larger collapse range.
Where you get into trouble with R8 and 5C collets is going over the size stamped on the collet. You can go undersize to the next 1/64" and 1/32" under would be pushing it. This is with 1/32" increment collets. I wouldn't go over size at all with a collet. I guess some shops have the 5C collets in 1/64" steps but not where I have worked.
The reason you can't put something in over size is the collet is expanded and deformed but if the work is under size when you draw the collet in the taper it will flex and snug up in the taper and on the work. I don't like to have to go under very much but it does work. I prefer to not use undersize work at all in the collet but sometimes you have to.
It's only ink and paper
Ya know what would be sweet, a Jacobs Rubberflex chuck that is made for ER collets. Rubberflex collets kinda suck, but the closer concept is nice. And ER collets have a wide range and grip parallel.
Bernerd 'Multisize' collet chuck that takes EC collets.
Each collet covers a 1/8" - 3mm range. A set goes from 1/8" to 1.5".
Very cool collet type, I assume those 'blades' are the actual griping part and the collet more or less just holds the custom blades.. Maybe not quite as secure as a regular single/double angle collet.. more like a 6 jaw chuck, but likey more accurate due to no scroll to wear out.
Wow found an awsome set of pictures of them and a chuck for it at http://cgi.ebay.ca/BURNERD-Type-EC-M...110224001r2775
Normaly I would'nt post an ebay url but man he took some wonderfuly detailed pictures of how those collets and chuck are setup!
Ouch at that price. No relation to the auction. Course no idea what those collets and chuck should go for.. the chuck seems simple enough to make, though maybe should be hardened and ground to prevent those blades wearing it out.. Very cool that the collets take hex stock as well!
technicaly being a single angle collet too, id think it would take short stock nicely as well?
Last edited by Black_Moons; 01-20-2010 at 05:44 AM.
That's pretty much the setup I've got, but in L00 mount. I paid £250 (about US$400 at current rates) from the tool dealer when I bought my Harrison L5 from him.
You need to put a piece in the back of the collet to hold thin stuff. You can mount a back stop in the collet.