JasonPAtkins
Hot Rolled
- Joined
- Sep 30, 2010
- Location
- Guinea-Bissau, West Africa
Hey all, I know it's a big no-no to use an endmill in a drill chuck, and understand the radial forces that a drill chuck isn't designed to handle. However, I have a case today where I need to use a 5/16" endmill to drill a hole and didn't realize it, but don't have any collets or endmill holders in that size. I checked my bin for a 5/16 EM with a 3/8" shank and don't seem to have that either. Other than the fact that a drill chuck doesn't grip like an endmill holder, is there still a reason not to drill with an EM in a drill chuck?
My internal reasoning is that I won't miss the extra grip of an EM holder or collet, because the metal removal is going to be less than a 5/16" drill, since I'm going slow, so since obviously the chuck has the bite to do one, it should still be ok with the other.
The other thought is that since runout in a chuck is more than an EM holder or collet, maybe it'd be hard on the EM since it'd be taking uneven bites. However, I don't know if an EM is a lot frailer than a drill, and drills survive slightly uneven bites on their two sides just fine all the time (when slightly improperly sharpened for example, although in that case they don't drill straight, but it doesn't hurt the drill.)
I'm doing this in a mill, not a DP.
So that's the general question, and I kind of think the answer is "probably no big deal."
However, in this case, the *reason* I need an endmill instead of a drill is that I'm putting a hole off-center in a ball, so a drill would skate out of the cut (I even spotted it first, and a drill still moved.) So given this condition, maybe, even though I'd be EM-drilling straight down, I *do* still have radial forces for that first second where the EM is biting on one side and not touching on the other, until it creates a flat - and then after that no radial force. So maybe even those who say the general case above is ok, would still say this arrangement has the potential to damage the chuck in this specific situation?
My internal reasoning is that I won't miss the extra grip of an EM holder or collet, because the metal removal is going to be less than a 5/16" drill, since I'm going slow, so since obviously the chuck has the bite to do one, it should still be ok with the other.
The other thought is that since runout in a chuck is more than an EM holder or collet, maybe it'd be hard on the EM since it'd be taking uneven bites. However, I don't know if an EM is a lot frailer than a drill, and drills survive slightly uneven bites on their two sides just fine all the time (when slightly improperly sharpened for example, although in that case they don't drill straight, but it doesn't hurt the drill.)
I'm doing this in a mill, not a DP.
So that's the general question, and I kind of think the answer is "probably no big deal."
However, in this case, the *reason* I need an endmill instead of a drill is that I'm putting a hole off-center in a ball, so a drill would skate out of the cut (I even spotted it first, and a drill still moved.) So given this condition, maybe, even though I'd be EM-drilling straight down, I *do* still have radial forces for that first second where the EM is biting on one side and not touching on the other, until it creates a flat - and then after that no radial force. So maybe even those who say the general case above is ok, would still say this arrangement has the potential to damage the chuck in this specific situation?