Advantage of collets?

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2manyhobbies

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Hi,

Just wondering what specific purpose collets are used for on a lathe as opposed to a chuck.
I can see why one would choose to use a 3 jaw vs 4 jaw for different situations but what situation would make you choose collet?

-Steve
 
collets are used for accuracy and repeatability of small parts. in a lathe.
 
To add on to what kd4 said, collets are also less likely to mare a part because they provide even pressure. They are a more expensive option, and you need lots of them to cover the full range. They also won't hold oddly shaped parts, round, square, and hex are the only ones I have seen. They are usually used in industry as part of a system with a bar feeder and a mechanical collet closer. The collet closer can be opened quickly, the bar fed in, and the collet closer re-tightened between each part.

In general, you don't _need_ collets. If you are only making a few parts, or you want the highest accuracy possible, use a 3 jaw or a 4 jaw. 3 Jaws are usually faster, but less accurate; 4 jaws are slower, but as accurate as your method of centering.
 
Collets also don't take up as much room as the chucks do, and can allow you to use the Entire bed of the lathe, without the hassle of centers, faceplate, lathe dogs, etc.

Collets are generally more repeatable, which is important when making multiples of the same part.

Don't forget that the right set of collets can make lots of machining tasks easier. A good 5C collet set, with some fixturing jigs, Can make transferring a part from mill to lathe, or vice versa, a dream. REALLY handy for small parts with multiple operations being done.

-Cody
 
Lot of time collets repeat better and faster then chucks. See thread about a week ago called Advantages of collet chucks over regular chucks. Pic shows a rod end that was bore was machined in a soft collet. I ran thousands of them that way.
jimsehr






P1030618-1.jpg
 
If you need to turn something of smallish diameter that requires a high speed, it is much more pleasant to be cheek to cheek with a simple collet chuck spinning at 1500 rpm instead of the lethal jaws of a big 3 or 4 jaw chuck flying by every revolution...

I recently finished an ER40 spindle mounted chuck for my Rockwell 10 and I really like it a lot. I found a deal ($139) on a precision (runout at or under 0.0002) set of 24 metric ER40 collets which span the entire clamping range so the fact that they are metric instead of inch based is meaningless. I use them for the lathe and also got an R8 chuck for my mill, fits drill bits under 1" and all of my endmills.
 
tigtorch said:
I
I recently finished an ER40 spindle mounted chuck for my Rockwell 10 and I really like it a lot. I found a deal ($139) on a precision (runout at or under 0.0002) set of 24 metric ER40 collets which span the entire clamping range so the fact that they are metric instead of inch based is meaningless. I use them for the lathe and also got an R8 chuck for my mill, fits drill bits under 1" and all of my endmills.
Click to expand...

So it don't matter, you can use them for standard and metric?
ls that better than getting the standard size set?
Where did you get them?
Does he have standard too?
 
Hey Steve

Each collet has enough range that the set covers every size.

What machine are you running? Can you run collets directly in your spindle?


Bernie
 
My lathe came with a full collet set, 1/16" steps from 1/16 - 3/4" with drawtube (so work can pass through the spindle), spindle taper bushing etc, they're much quicker than dialling in a 4-jaw and much more accurate than a 3-jaw, plus since hotrodding to get 2500 rpm (using the VFD at 80-some Hz) I really don't like the idea of a big 4-jaw spinning that fast! Disadvantage is that they only hold round workpieces close to nominal sizes, so I've added an ER collet Chuck on a backplate for intermediate sizes and a 5C chuck for square / hex - slowly building a stock of 5C collets as I need 'em!
For small work / high speeds, there's no substitute, particularly if you can fit a length stop either in the drawtube or the spindle - setting up repeat parts can be done in seconds, not minutes!

EDIT - forgot to mention, they hold milling cutters properly, so with a vertical slide-equivalent I can do some light milling in the lathe, handy as I don't have a mill...
 
I got the ER 40 chuck and a back plate from tools 4 cheap.
What is the best way to fit a chuck to a backplate.
Is there a best write up on the subject. I have never done one.
I have heard of making a shoulder oversize and freezing .
Making a shoulder undersize and bolt holes oversize and tapping into true.
 
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