r8 collets for solid carbide endmills?

[wooleybooger]

a friend just gave me 60 SC re-sharps he picked up for $8.00 most of the EMs i use have 3/8 or 1/2" shanks and i have EM holders for these but with these SC end mills the shank is the same as the cutter diameter so Ill have to buy something just use them. will the SC spin in a collet?

[KiddZimaHater]

Endmills usually don't spin in collets, unless you don't tighten them very good.
Tighten the willies outta them, and let 'er rip.

[beanbag]

a friend just gave me 60 SC re-sharps he picked up for $8.00 most of the EMs i use have 3/8 or 1/2" shanks and i have EM holders for these but with these SC end mills the shank is the same as the cutter diameter so Ill have to buy something just use them. will the SC spin in a collet?

I've never heard of that. When endmills are resharpened, they leave the shank alone.

[Black_Moons]

They will do fine in collets, Just tighten them a little extra, I have heard carbide is harder to get a good grip on.

[lazlo]

I've never heard of that. When endmills are resharpened, they leave the shank alone.

Agreed -- that sounds odd. The shanks should not be undersized -- there's no way to hold them otherwise.

R8 collets have very little clamping range -- I wouldn't try to clamp an undersized tool!

[Arthur.Marks]

If they truly are undersized & you don't have an r8 to fit... my vote is for holding them in an ER adapter. One reason ER collets are very handy---big clamping range.

[lazlo]

If they truly are undersized & you don't have an r8 to fit... my vote is for holding them in an ER adapter. One reason ER collets are very handy---big clamping range.

That's good advice -- an ER-32 or ER-40 set will clamp any arbitrary diameter, but that's a lot of money to spend to hold a resharpened carbide endmill...

[Mcgyver]

If they truly are undersized & you don't have an r8 to fit... my vote is for holding them in an ER adapter. One reason ER collets are very handy---big clamping range.

+2 ....what are the shank diameters? all over the place....or some different fraction , maybe metric?

I use carbide endmills up to 3/4" in R8 collets all the time with no problem. These are ones with on size shanks, some new some regrind.

I do to, but they can definitely slip when its working very hard. I'm using hardingle collets so that's not the issue....Endmill holders are less convenient, use up some daylight, possibly introduce a source of eccentricity, create more leverage on the spindle bearings....but they do hold more solidly. Each has its merits and i use both.

[Toolguy]

I use the collet holders all the time on the CNC mill where it has to maintain a repeatable tool length changing in and out over and over. I use ER, AF, & DA collets. Have lots of different holders for them.

[Fasttrack]

Oh ... I interperted "same as cutter diameter" to mean that they were the same as the nominal size before being sharpened - as in not a reduced shank.