Forstner Bits Vs Sawtooth Bits

[Bryan Milham]

Guy's, I need to access the Hive Mind.

I'm going to need to bore several 2" diameter holes in endgrain oak.

Which wood be a better tool, a Forstner Bit or a Sawtooth Bit. And, is there a difference?

Or - what would be a better tool to use?

[seventhdevil]

makes no difference bryan, just keep it sharp and it won't have any trouble.

[Paul Hannaby]

I think (but I could be totally wrong! ) the difference between the two is the outer cutting "ring". On a forstner bit, there is a single cutting point. On a sawtooth bit, there are multiple teeth, like a saw. The main radial cutting edge is pretty much the same on both types.

[Bryan Milham]

Paul,

I think you are right, but is one better for end grain.

Having only ever owned Forstner bits, I has hoping someone could give a logical reason for one or the other.

[edbanger]

I thought a saw tooth bit drills a hole through a board and your left with a solid bit of wood in the cutter where a forstner bores a hole.

If your going to buy a bit Bryan pay the extra and buy a Colt they are by far the best type of forstner bit.

Ed

[Les Symonds]

I thought a saw tooth bit drills a hole through a board and your left with a solid bit of wood in the cutter where a forstner bores a hole.

Ed....you're thinking of something like a tank-cutter. There's two commonly used patterns for flat-bottomed hole boring. Each pattern has a pair of radial cutters (the chipper bevels), radiating from the centre spur out to the rim, but on one pattern the outer rim is a plain cylinder, whilst the other pattern has the shape of saw-teeth cut into it. The saw-tooth bit is intended primarily for use in pillar drills and can run at a higher speed, having better chip-clearance than a plain rim.
Lee Valley/Veritas have info about this on their web-site http://www.leevalley.com/US/garden/page.aspx?cat=1,180,42240&p=45533
Les

[edbanger]

Thanks Les

In my dealings in these over the years many called tank cutters call them saw tooth bits, but then I was dealing with sparkies 

Then Bryan I can tell you from experience when boring end grain the saw tooth forstners that I've used seem to dull very quickly and I've never been able to get as good a cutting edge when sharpening. The Colt forstner bits have a couple of fine groves in the cutting flats and the shavings fly away. When I sharpen these their as good as when I first use them.

I've found that I can run the Colts faster than anything else I've tried. (I have also tried the Axminster forstner bits)

Ed

[Bryan Milham]

Les,

thank you, you've got the two versions I was thinking of and the difference between them, thanks for the link as well.

Ed,

Yes than you, I had intended to buy a Colt Bit, just needed to be sure which cutter pattern I would be best spending my pennies on.

[seventhdevil]

like i said bryan, for the job you intend it won't make a blind bit of difference what you use as long as it's kept sharp...


just out of curiosity, what you making that needs these holes then?

[Bryan Milham]

Church Ceiling Bosses, where the Bell Ropes drop through from the Belfry. Designed so the ropes don't chaff on the floorboards/ceiling.