Alternative ER collets?

Does any know what these are called?
They are alternatives to ER collets but stiffer, and usually with better
accuracy.
They fit into any suitably-sized standard ER socket, but instead of the
30 degree bit at the top they have flat tops. The nuts are different to
standard ER nuts.
The main disadvantage is they don't fit a range of sizes like ER
collets, instead you need a collet for the exact size of tool in use.
They work because ER collets can twist a bit, and these can't.
ER Collet, smaller size:
. ___ ___
. / || \
. /
|| \
. \ || /
. | || |
. \ || /
. \ | | /
. || ||
twist:
Note that the top part is roughly ball-shaped, and especially when the
tool isn't inserted the full length of the collet, or when the hole in
the collet isn't all full-length, ie it has a wide bit at the bottom as
in the diagram, then the collet can twist sideways a bit.
These collets:
. _____ _____
. \ || /
. | || |
. \ || /
. \ || /
. || ||
and the nut fits flush on the flat top, preventing the collet from
twisting from side to side.
-- Peter Fairbrother
Reply to
Peter Fairbrother
Loading thread data ...
Any web links to pictures Peter ?
AWEM
Reply to
Andrew Mawson

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.