OK to hold triangular shank tools with ER collets ?

[compact8]

I have an annular cutter with three flats on the shank which is about 10 mm in diameter. The width of the curved part on the shank is about the same as the width of one jaw of the ER25 collet . Will it be OK to hold the tool with the collet chuck if the round parts are aligned with jaws of the collet ?

 

[mmcmdl]

I run S@D drills with flats in collets all the time if that helps you any .

 

[aliva]

I have annular cutters with 1 flat and use a 5/8 collet with no problems.

 

[Christianstark]

"The width of the curved part on the shank is about the same as the width of one jaw of the ER25 collet."

I think you should post a picture of this. If I am reading this correctly, it sounds like the part will only be held on 3 points, and those 3 points are round, and the roundness is a smaller radius than the radius of the ER collet that will be holding it. which means it will REALLY only be held on 3 points, in a collet that I dont imagine can handle torque very well under those circumstances.

I would not do it.

 

[compact8]

"The width of the curved part on the shank is about the same as the width of one jaw of the ER25 collet."

I think you should post a picture of this. If I am reading this correctly, it sounds like the part will only be held on 3 points, and those 3 points are round, and the roundness is a smaller radius than the radius of the ER collet that will be holding it. which means it will REALLY only be held on 3 points, in a collet that I dont imagine can handle torque very well under those circumstances.

I would not do it.

Here it is

 

[pontiac428]

I don't think I'd have any issue with 50% engagement evenly distributed like that. It certainly won't hurt anything inboard of the cutter if it started slipping, and it won't damage the collet as far as I can tell. You never know what someone may come up with around here, apparently it's sacrilege to ever consider pressing a bearing race without first measuring the impact of the Coriolis effect and the relative cyclical distance to the moon first. But I wouldn't think twice about running that setup. Collets hold strong, as long as you are within their work envelope.

 

[Christianstark]

Here it is

I’d clock it so the rounds fall on 2 jaws. That way all 6 jaws are engaged. I think that should be fine. I was picturing something more pointy. If all jaws are engaged, it should collapse into the shank nicely.

 

[RaisedByWolves]

"The width of the curved part on the shank is about the same as the width of one jaw of the ER25 collet."

I think you should post a picture of this. If I am reading this correctly, it sounds like the part will only be held on 3 points, and those 3 points are round, and the roundness is a smaller radius than the radius of the ER collet that will be holding it. which means it will REALLY only be held on 3 points, in a collet that I dont imagine can handle torque very well under those circumstances.

I would not do it.

I’m with this especially with an annular cutter.

You stand to ruin the collet and relieve it of any accuracy.

 

[RaisedByWolves]

I’d clock it so the rounds fall on 2 jaws. That way all 6 jaws are engaged. I think that should be fine. I was picturing something more pointy. If all jaws are engaged, it should collapse into the shank nicely.

Second thought that might work.