Forstner and Brad Point Drill Bits

[Randy Klein]

I was looking at Lee Valley website (it's a daily thing) and noticed that their HSS Brad Point Drill Bits get real pricey above 1/2", while their HSS Forstner bits are much cheaper in those upper diameters.

Which got me thinking, when would you choose a Forstner over a Brad Point of the same diameter? What are the pros/cons of each? They both seem to drill clean holes, at angles, and leave flat bottoms. What application needs a 1" Brad Point bit over the 1" Forstner (because there is a ~$35 difference)?

[Eddie Darby]

If I had to overlap holes when drilling, then I would go with the forstner bits.

[Phil Mease]

I've found a few differences from my use of the two types:

Performance comparison:
- Forstner bits require more chip clearing than brad-points making the operation a little slower. This is because the bradpoint has a nice chip 'escalator' up it's length. If the chips are not cleared, the surface of your work can easily be chipped on removal.
- The brad-points I've used had less tendency to 'walk' I think this is due to the nature of the scoring cutters and the length of the point. In drill-press Forstners are no issue at all if work is held solidly.
- Forstners seem to require more accurate speed considerations than the bradpoints although this I see as debatable due to several other variables.

Other:
- Forstner bits are cheaper in larger diameters b/c there is much less material required to manufacture them. The same shaft can be used for all forstner bits whereas the bradpoints generally have a large portion of the chip clearing twist all the way up the shaft.

I personally like a nice set of sharp brad points in the < 1/2" range. Anything over that I cant justify the $ difference and just buy forstners as needed. Come to think of it, I don't use 'large' forstners much at all... a router, lather, or mill does a better job on the big cutouts for me.

Phil

[Rich Engelhardt]

Hello,

What application needs a 1" Brad Point bit over the 1" Forstner (because there is a ~$35 difference)?

IMHO, anything where the drill has to go to the work and/or the work can't come to the drill (press).

For giggles I stuck a 1" Forstner bit into my 1/2" hammer drill (not using the hammer function of course) and tried to drill a hole in some scrap.

It was a fairly "exciting" experience :D