1/8" and 1/4" shanks in metric collets?

[jaru-eri]

Will it do any damage if I use 3mm and 6mm collets for 1/8 and 1/4 mills?

Any experiences?

[SCzEngrgGroup]

Will it do any damage if I use 3mm and 6mm collets for 1/8 and 1/4 mills?

Any experiences?

That depends on what kind of collets you're talking about. If R8, then absolutely not. If ER, then you should be fine.

Regards,
Ray L.

[ihavenofish]

ive done it with both those sizes in an er25 chuck, it does work in a pinch, but its not practical. you need to put the nut on first or the collet wont fit, which makes the whole thing a bit clumsy because especially on the 6mm you have to pry it open a little to make it fit.

basically, unless your really desparate and cat wait, but a properly fitting collet.

[jaru-eri]

I have ER16 and Kress spindle. The collets on my Kress has been divided in 4 grips and is only split in the front.

The Kress spindle is on my router and I need to use a 3/4 planner bits with 1/4 shank in order to plane wooden surfaces.

[ihavenofish]

I have ER16 and Kress spindle. The collets on my Kress has been divided in 4 grips and is only split in the front.

The Kress spindle is on my router and I need to use a 3/4 planner bits with 1/4 shank in order to plane wooden surfaces.

ahh, thats tricky. im going to say no, it wont work. i wonder if you could source the correct collet - or a metric shank tool.

[Andre' B]

Most brands of ER collets are designed to collapse 1mm from the open size. The 1mm collet is good for 0.5 mm collapse.
So for 0.125 use a 4mm collet and for 1/4 use a 7mm collet.

For best grip and concentricity you do want a collet the same size as the tool but for wood working it should not be a problem.

[chalky]

A 6mm ER collet is usually specified as 6-5mm, meaning, in theory, that you can use it to grip anything between 5 and 6mm diameter. For a quarter inch ( 6.35mm ) shank you should use a 7mm collet ( 7-6mm ). If you force a quarter inch shank into a 6mm collet it will permanently expand it and reduce the gripping power over the proper 6-5mm range thereafter - don't ask how I know this! Same considerations apply to an eighth inch shank in a 3-2mm ER collet. I must admit I never make use of the theoretical gripping range of an ER collet and always use the exact size for the job. I would advise imperial collets for imperial shanks. My tuppenceworth.