3" Spade Drill?

Don't think you'll find a spade bit much over 2"...can't imagine the "whap" that a 3-incher would cause...

For 3" hole your choice is adjustable, Forstner (or toothed Forstner, better) or hole saw (assuming you can get to both sides).

you'll probably end up with something like this:

or:

the horsepower requirements aren't too high with a self-feeding bit. a good strong slow speed 6amp 1/2" drill motor should be fine.

this will make a somewhat rough sided hole, appropriate for fitting plumbing through framing members. if you need a cleaner hole you might look at fly cutters.

There are 3" sawtooth bits available in both high speed steel and high carbon steel at

Hole saw is no good. This is being used on an automatic drilling machine (see my web site if you wish...) and the plug created by the hole saw doesn't eject.

Laminated ply.

Regards, Joe Agro, Jr. (800) 871-5022

Good lead. Thank you.

you're welcome. the self-feed may be problematic on automatic machinery. if so, the threaded center spurr can be removed and replaced with a smooth point or a center drill.

these are made by a number of manufacturers. the name of this general configuration of drill bit is planetor. use that term in a google search and you'll get plenty of hits.

Joe AutoDrill wrote: > Anyone know if there is such a thing? Looking for a way to drill through 6" > of wood with a 3" diameter spade drill... Have the machine to drive it, but > don't have the tooling. >

Milwaukee speed bit.

About $100.

Try Grainger.

Lew

We provide constant thrust, not constant feed. In real simple terms, it's similar to putting 50# of weights on the arm of a drill press. If the bit hits something hard, it simply places pressure on the workpiece via the bit and then feeds at whatever rate it can. We provide anywhere from 50 lbs. to

Looks like a very good solution. I'm a bit worried about the RPM and HP needed, but we can determine that with a simple test on my drill press.

Again, thank you. Very helpful.

Regards, Joe Agro, Jr. (800) 871-5022

I've got a 3" high speed steel drill bit around here somewhere. Unfortunately, the only thing I know it chucks into is a lathe that used to be on an aircraft carrier. It has a tapered shaft.

Almost every "standard" 3" bit has a morse taper drive - not useable for me yet. Give me a year. :)

Forget about a 3" spade bit, there are too many things that could go wrong that could cost people an eye or a digit. You need a bit shaped more or less like a Fostner bit that has a cylindrical front end that uses the hole as a guide with the sides of the hole absorbing any sideways forces. Toothed bits cut less clean, b.t.w. but they are faster.

-P.

How about a 3" holesaw from each side after going right thru with a pilot bit

In addition, provided one has a pilot hole right through, it doesn't matter how short the hole saw is. It's just a matter of breaking off what's been cut with the edge of a screwdriver or something and drilling some more.

No can do. It's an automated process. No end-user input other than a push of a start button. Thus, it either has to automatically eject the plug from inside the hole saw or not create a plug to begin with.

As I answered a few other folks, that would be nice, but can't be done. It's an automated process. Either the plug has to eject automatically from the hole saw or there has to be no plug created. The end user needs to be able to push a start button, watch the process, remove the wood part being drilled, load a new part and press the start button again. I do everything along the line except find tooling normally, so that is where my conflict comes in. I'm simply not finding a tool that does this for wood. We have Hougen for metal that positively ejects hole-saw plugs and Starrett makes one for 76MM or 3" in diameter that incorporates a spring, but for this depth, they don't work. Thus, my search for a spade drill initially as it does not create a plug.

Check out my site below (AutoDrill) to see what type of machine is performing the process if you want.

Regards, Joe Agro, Jr. (800) 871-5022

Check one of the woodworking bit manufacturers such as Forest City or Morris Wood. You'll find spur bits to 3" and larger, steel or carbide, made for production use.

John Martin