Straight shank arbor vs R-8

I had the same question a while back when I got a mill. I decided to go with straight shank as I don't expect accuracy from a drill. TIR is still under half a thou holding a ground rod in the drill chuck. I figure the drill bit is likely less accurate than that anyway and it means I can hold it in R8 or ER40 collets, whatever I'm working with at the time. I usually leave the ER40 chuck in there as I have more collets for that style, but it's nice not to have to switch just to drill.

I've never had one spin, but I'm careful about tightening the collet properly.
 
And when you eject your straight shank 9 times out of ten you're going to change out the collet anyway.
 
Thank you everyone for my continuing education.:eagerness:
I did see a vendor stating made in USA for a Jacobs chuck that had a simple USA , but no Hartford anywhere to be seen.
 
I have both R-8 and straight shank. If I'm going to mill then drill I try to use an end mill with the same shank size as my straight chuck. Never saw a difference in the use of either. Never spun the chuck. That said, when I'm drilling in my BP I'm quite aware of chip load and often sneak up to final size................Bob
 
I meant to mention that I've taken to using Blair rotabroaches for larger holes in steel plate. Much better than a S-D bit in my opinion. Plus, the rotabroach arbor fits in my 1/2" drill chuck.

All sorts of ways to spend money, eh?
 
I have the slugger kit, and other sizes of annular cutters also, I do like them. Whew....:)
 
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