Guidance on Forstner bits

[storri]

I have been looking at forstner bits since I need to modify a workbench I build via the Fine Woodworking plans. I need to put 5/8" holes into a double layer MDF (1.5 inch thick) top to allow me to use bench dogs and jigs that I plan on making. I was looking at two classes of bits: regular and carbide-tipped. The regular are all the ones we are use to with the aggressive bit pattern. The carbide-tipped have some of the cutting surface of the original bits modified with a carbide cutting surface. I don't want to buy a porsche when I need a camry. Yet neither do I want to go cheap and regret the purchase.

First question: regular or carbide tipped? Please explain why.

Second question: Brand. I see Bormax has a good rep. How about Freud?

[WoodClips]

I was just drilling some holes through a 1.5" MDF sandwich the other day using a brad point bit and was quite pleased with the results. I was using a 1/2" bit, which is pretty close to your 5/8". It created a clean hole, drilled pretty fast, and stayed on track. This was drilling by hand rather than a drill press.

For kicks, I just tried doing the same thing with a CMT forstner bit. It turns out that the forstner bit doesn't like drilling through MDF at all--it created a bunch of fuzzy dust rather than the chips I am used to getting when using it on hardwood, and it hardly made any progress with moderate to heavy pressure. Forstner bits also work best in the drill press, which may not be practical when drilling holes in a workbench top.

So, my recommendation would be to buy one of these German-made brad point bits from Woodcraft for $8.99 and have at it. You could start by drilling a hole in a hardwood block on the drill press and then clamp that to your workbench top and use it as a guide to keep the hole perpendicular to the top and on location.

Rory

[PaulMarcel]

Hmm, sorry, I moved this thread to the general forum since "Forstner" and "Brace" don't seem to go together (it was in the neanderthal group). If you intended to hit MDF with a Forstner with a brace, mea culpa. But I agree with Rory: MDF just packs inside the Forstner making more of a mess; spades do, too.

[storri]

Thanks for the advice. I will just pick up the bit. I have a smaller set of colt bits and have been very happy with their performance.