35 vs 72 piece Collet set?

[davidpbest]

Are there emergency ER collets?

I have not seen any, nor do any show up searching. The ER40 collets are much shorter than the 5C, and since they are designed with staggered slots from both ends and have a 1mm clamping range, every ER collet I have seen is made from some kind of spring steel that's very tough material. An emergency collet needs to be soft enough to machine to the desired bore or profile. Intuitively it seems to me that the springiness of the steel required to function well with the ER taper angles would not be a suitable material for modification. Of course, this is all just my speculation.

That said, I do believe it would be possible to machine an inner insert that fits in a larger standard sized ER collet, has a more narrow clamping range, and made of a material that could be machined to fit production parts including a depth limit stop. Kind of a collet within a collet. Again, pure speculation.

Each collet type has it's own set of advantages and disadvantages, and 5C with a quick-release chuck is probably better for production work. But if your need is variety/randomness of clamping diameters with the least number of collets for prototyping and one-off work, ER40 is probably a better choice IMO. And then there's the tradeoff of how much insertion is required to attain a specific TIR tolerance.

 

[ahazi]

Need a complete collet set and looking at these:

https://www.precisionmatthews.com/shop/72-pc-precision-inch-5-c-collet-set-164-to-1-18/

I know twice as many is twice as good - it's also twice the cost and twice the space in my shop. There's not much info on the site - does anyone know the size tolerance these collets have? Should I get the full set? I'd be really cranky if my first project that needed a collet was an inbetween size and I had to go find one online

I have this 72 piece set set and it is very good so far.

Ariel

 

[T Bredehoft]

Ohio, yes, that's home, visiting an old school friend. Weather here ( Holland, just south of Rotterdam) is better than Ohio at this time of year. We're working in the garden sporatically. Flowers blooming all over the place.

 

[Larry$]

My ER40 chuck, set of imperial collets and an ER to R8 adapter for the mill came yesterday. I put the studs in the chuck mounted it on the lathe and adjusted the 4 setscrews until I had barely any wiggle on the dial test indicator running in the chucks taper. Snapped a 1/2" collet in and put a 1/2" gage pin in. Using my Mitutoyo dial test indicator to check runout and was very disappointed. Too long to explain here. I'll start a new thread.

 

[Ischgl99]

That said, I do believe it would be possible to machine an inner insert that fits in a larger standard sized ER collet, has a more narrow clamping range, and made of a material that could be machined to fit production parts including a depth limit stop. Kind of a collet within a collet. Again, pure speculation.

I did that before I got my 5c collet chuck. It worked ok, but I made the clearance too loose, so it took some effort to clamp properly. If it fit better, I think it would work as an emergency collet.