Running carbide end mills in side-lock end mill holders

[Cory]

I've spent some time searching on here for a definitive answer, but there doesn't seem to be one.

Is there anything wrong with running carbide end mills in sidelock holders without grinding a flat on them?

I found a lot of people saying they'll grind a flat on to them, but none who run them as is off the shelf.

We currently run all ER16/32 collet chucks, and I want to get some end mill holders for better rigidity, and would greatly prefer not having to grind flats onto a whole ton of EM's if it isn't necessary.

My guess is there's probably a point at which you can make the EM slip in the holder without a flat.

Thanks,

-Cory

[Caprirs]

I have never ground flats on end mills and the vast majority of the time, I run them in end mill holders. Rarely do I use a collet for an end mill.

[DareBee]

When using the "fast and light" method of cutting I never grind a flat. When heavy cutting is needed with cutters, say, 1/2" and up I usually grind.
The flat can be quite small, no need to seat the whole face of the screw.

[Geof]

As Darebee says do it with larger sizes taking healthy cuts. Actually I do it on evereything 3/8" and up because I have had 3/8" high helix two flute cutters pull down in the holder. Which unfortunately became apparent by the 3/8." by 1/8" groove across a vise jaw.

[HuFlungDung]

Originally Posted by Geof As Darebee says do it with larger sizes taking healthy cuts. Actually I do it on evereything 3/8" and up because I have had 3/8" high helix two flute cutters pull down in the holder. Which unfortunately became apparent by the 3/8." by 1/8" groove across a vise jaw.

Geof,
Don't you just hate that?

FWIW, if you want additional security without grinding flats on the shank, you can also loctite the tool into the holder. You'll have to unscrew the pullstud to press the tool out of the holder, not that loctite gets all that much of a grip on the smooth bore and smooth tool shank, but it will help the setscrew hold the tool.

[Geof]

Originally Posted by HuFlungDung Geof, Don't you just hate that? FWIW, if you want additional security without grinding flats on the shank, you can also loctite the tool into the holder.

Hate is to strong . You could say I rue it; the biggest disadvantage is that when I pull a trick like this it makes it very difficult to dump all over any of my guys that do the same.

Loctite eh; you mean I do not need the $450 Schunk elastomeric clamping collet holders I ordered late last year? The ones that are supposed to get many, many times the grip of a normal taper collet.

[Andre' B]

I have always found collets to be better with carbide endmills, less high freq. vibration in the endmill. With setscrew endmill holders I have problems with the tool breaking at the setscrew, I believe that comes from the tool bending an vibrating inside the holder.

Do need to use good collets and holders and they work best when they are the same size as the tool, like use a 3/8 collet for a 3/8 tool and not a 9-10mm collet.

[Cory]

Originally Posted by Andre' B I have always found collets to be better with carbide endmills, less high freq. vibration in the endmill. With setscrew endmill holders I have problems with the tool breaking at the setscrew, I believe that comes from the tool bending an vibrating inside the holder. Do need to use good collets and holders and they work best when they are the same size as the tool, like use a 3/8 collet for a 3/8 tool and not a 9-10mm collet.

We have some very high quality collet chucks (RegoFix. Expensive too... like $180 per chuck), and I've been getting vibration and chatter depending on my cutting parameters (well within what the tool should be able to handle). Everything I've heard says that end mill holders dampen vibration compared to collet chucks.

[DareBee]

Or going a step further, get something like "Schunk elastomeric clamping collet holders " or any other brand of shrink fit holders for super accuracy and less vibration.

[Geof]

Originally Posted by DareBee ...."Schunk elastomeric clamping collet holders " .....

I just picked them up. We will have to see if the performance matches the name and price .

[5axisguy]

Some of the new high helix endmills put an incredible ammount of pull on the endmill when cutting aggresive. I have had 3/8 dia. endmills pull out of top quality shrink fit tooling when using the side of the flutes in hard material. For that reason I always a milling chuck, or to answer your question directly, yes I always grind a small flat on the endmill for the setscrew to hold against when using the weldon flat holders. For extremely light cuts, I would get away without.

[snowshovelbmx]

I always grind a small flat on my carbide EM's. Even if only for a light cut, reason being it only takes a second and the next person to use the same EM that is already in the holder might not be taking a light cut.

chris.