1/2" end mill pulling out of collet

[magicniner]

The way to stop pull out of end mills from collets is to not use collets except for light work.

Alternatively you can look up the correct torque for your collets and apply it
You might find are under-torquing by some margin.
ER32, slotted collet nut, about 100ft/lbs.

https://www.cnccookbook.com/getting-the-best-performance-from-er-collet-chucks/

 

[BaronJ]

Bob, will those holders work in a standard R8 spindle?
Hey, I know it's a dumb question but there it is.

You can buy or make Weldon style cutter holders that fit R8.

I would check that your collets are clean and there are no burrs inside them, also check that the cutter shank is clean and dry without any burrs.
It does take quite a bit of force to tighten them properly. A wipe with an oily finger on the taper helps.

 

[macardoso]

Ugh, that's unfortunate for me. For now I will just have to work with what I've got as all of my tool holders are collet type. I will just have to crank on them really good until I can afford to go with something more suitable. I have not purchased any of those weldon style tool holders for two reasons: the length of the end mills cannot really be adjusted and the end mills need to have flats ground in the sides. So making the switch to that style of tool holder will probably drive the cost of the end mills up.

I have used ER20 collet tool holders for tools up to 1/2" and 3 HP into the tool without slippage. Make sure your tools and collets are clean and dry, make sure you are using the exact right size for the shank (metric 12mm for a 1/2" tool isn't good), and make sure you install them in the ER nut properly.

Edit: I tighten mine with some big wrenches, probably 30 ft/lbs or more for a big tool. Tighter than you would think you'd need.

 

[ddickey]

I was having a problem with my end mills slipping out of the R8 collets. I replaced the draw bar, I bought it from H&W Machine or is it H&H, no H&W. It solved my problem.

Really? Why? Better threads?

 

[rcaffin]

DA180 is OK for small cutters on high speed routers on timber. I would NOT use them on metal. The tapers are wrong.
R8 is tolerable for a while and if done up properly should hold. But they are expensive and come in limited sizes. Antique.
ER collets are far far more reliable and far easier to use. That is why they were invented and are now a bit of a standard. ER32 is quite strong. Do not try jamming an over-size cutter into a small collet: bad move.

Cheers
Roger