Re: Forsner bit with longer shaft?

[Terry King]

> ARe there 1.5" dia Forsner bits with say a 6 or 8" long shaft.......or is

> > there a extension one can buy to achieve a longer drill depth?

Related question: Accurately guiding Forstner bits... The typical V shaped center point doesn't do much. A predrilled pilot hole helps somewhat.

Anyone seen (or modified) a Forstner type bit with a long guide bit or pin?

With hole saws the bit is usually removeable, and a smooth guide shaft can be used in predrilled guide holes for better accuracy. Wish I could do that with Forstner bits.

I need to drill about 100 2" to 2 1/4" holes, 2" deep, in the post&beam barn I'm building. The 'wandering' is a definite problem...

[Mike Marlow]

Hey - aren't you supposed to do that kind of drilling with a bit and brace? We're not cheating here, are we?

[Spenzdad]

[Robert Bonomi]

A Forstner bit is the wrong tool for that application.

The right animal is an 'auger bit'. Either used in a 'brace' (the big, old, U-shaped people-powered hand drill. Or get a Milwaukee "Hole Hawg" ('accept no substitutes' applies). To use large-diameter auger bits in a power drill, you need *lots* of power at _low_ RPMs.

For power drilling with a 2-1/2" dia drill, you want to use less than 1/10 the RPMS you would use with a 1/4" bit. i.e., somewhere in the _one_hundred_ RPM range.

[Mike Marlow]

Bit and Brace are the old manual way of drilling. The bit is typically an auger type wood bit and the brace is the old U shaped hand "drill". Was just teasing you about doing an old school woodworking technique with modern day tools.

[klaatu]

You need a boring machine. Very fast for timber frames. You can find them on Ebay sometimes. A good one is expensive. Miller Falls is the best but hard to find.

[Terry King]

Thanks for the several suggestions...

I haven't seen auger type bits in sizes up over 2". I'll look. They do tend to guide well. I use them for the deep holes (8 inch timber etc) but only in 1/2" and 3/4" .

A boring machine is very cool, but this is the "ShoeString Post and Beam" (tm) job on local lumber. I'd like a chain mortiser, too! But these tools are in the $1000 range.

Pardon the blasphemy, but I've got my old Sears Skilsaw, my newer Bosch Router and Jigsaw, and another $200 in Harbor Freight electric chainsaw and slow 1/2" drill. I've built several jigs and fixtures to guide the chainsaw to make decent cuts in 8x8 to 8x12 timbers. After roughing mortises with the big Forstner bits, skilsaw and chisel, the Router finishes them precisely to size.

I love good tools, but sometimes you gotta do with what you can afford.

[Chipper Wood]

My Milwaukee pipe size bits have a reversible/replaceable self feed screw center held with a setscrew. Sure takes the strain out of overhead side drilling. They also have an extension in the kit. (1/2 to 3 inch pipe clearance sizes.) I have had a Milwaukee right angle drill for over 30 years, still chugging along. ( On the third armature.... ) ( The plumbers' model is geared a little tighter than an electricians' model.) Seen some singles of another brand at a plumbing supply house just yesterday. Same type of center pilot.

[bridger]

there's nothing like a big 'ol chisel and mallet for chopping mortises...