On something like a drill press, how is a straight shank arbor retained and engaged? I don't see a clear way that this is accomplished from photos.

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  • Recess is for set screw?
    – Volfram K
    Commented Oct 30, 2021 at 3:31
  • @VolframKOn Without a flat? (as far as I can tell) Seems unlikely.
    – DKNguyen
    Commented Oct 30, 2021 at 3:36
  • I see references to set screws with straight shanks when I search the subject. Like you I don't see how you would retain these by other means :)
    – Volfram K
    Commented Oct 30, 2021 at 3:42
  • @VolframK Me neither, but I expect a flat if it's supposed to be a piece of high torque precision tooling. I found no references at all which is why I resorted to asking here. The wrong search results kept coming up. Can you link?
    – DKNguyen
    Commented Oct 30, 2021 at 3:46
  • @VolframK Usually a recess like that one is just to reduce the area that needs to be machined. On a lathe spindle, for example, you'd have bearings at each end, but not in the middle, so there's no need to machine the middle.
    – Caleb
    Commented Nov 1, 2021 at 17:41

1 Answer 1


On something like a drill press, how is a straight shank arbor retained and engaged?

I think it's meant to be held in a collet or tool holder for a milling machine. The shank is 1/2", which is a common size for an end mill. Here's a tool holder for a 1/2" end mill:

grizzly nt40 mill holder

Note that the description for the arbor you linked to says "no drawbar." A drawbar is a mechanism for pulling a tool holder into a milling machine's spindle, so they're clearly speaking to a milling machine-using audience.

  • Is that what it is? if that's what it was it would make more sense. However, a Morse taper also has a draw bar. Our drill press has one and we use it without the drawbar (unless I misremember and it's a Jacobs Taper).
    – DKNguyen
    Commented Oct 29, 2021 at 19:02
  • @DKNguyen Another option would be to press bearings onto the machined areas. The spindle in my lathe looks a lot like the straight portion of the arbor you show. But I don't think that arbor is meant to be used that way because there's no obvious way to drive it. That tells me that the straight part is meant to be squeezed in something like a collet or maybe a 3-jaw chuck on a lathe.
    – Caleb
    Commented Nov 1, 2021 at 17:38
  • Perhaps my memory was off about the drill press we have being a morse taper. I'll have to check.
    – DKNguyen
    Commented Nov 1, 2021 at 18:13
  • @DKNguyen If it's a woodworking drill press, it almost certainly has a morse taper. If it's a combination mill/drill kind of thing, it might well have a draw bar. But I wonder if you were thinking of the drift that's used to help unseat the arbor?
    – Caleb
    Commented Nov 1, 2021 at 18:22
  • It's a metal working drill press. If I remember, right the guy who uses it sticks a wedge into a slot that runs in the side and hits it with a mallet and it comes right out. And when he installs it, he just shoves it in with this hand.
    – DKNguyen
    Commented Nov 1, 2021 at 18:25

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