The Square Drill Bit

[BloodySinner]

...this is lunacy!

[magnusk750]

Originally Posted by Coach James

I've never seen it before. Neither has my dad. My buddies at work have never seen it. Nor has my father in law. My wife and kids haven't seen it. My mom and sister have not seen it before either. The priest at my church said it's new to him. The guys in the Knights of Columbus said they had not seen it before. The autotech teachers at my school said they were not aware of this item. My secretary laughed when I asked her if she had seen a bit that drilled a square hole. The maintenance chief at the school thought I was joking when I told him about a bit that drilled square holes.

So a collective "Thanks" to Ryan for posting this from all of us that have never seen it before.




Coach

+1 here

[TireTracks]

Originally Posted by Lump

That is just plain cool. I've heard of them before, but never seen one in action. I THINK the unit I heard about was used for wood, however.

I'm curious...I note the "arbor" ocillates heavily...does this require a special machine, or would it work in a large drill press? (Is "ocillate" the right word?)

Very impressive.

The machine I belive your talking about is a Motriser(sp). Uses a drillbit in a square chisle to make square holes.

[country83]

They showed us that video at work about a month or so ago. Pretty cool stuff. Wonder if it'll ever see much use in the real world or if it'll be more of a "specialty" thing.

[40Tudor]

I knew I had seen something like this before (April 1956 Pop Sci). Wonder how the head in the video works.

http://books.google.com/books?id=NC0...page&q&f=false

[flatfourfan]

The slowmo makes me think of the internals of a rotary motor.

[TWX]

A buddy of mine could use one, but at the prices they go for, probably will never end up with one.

[imagine44]

This is called rotary broaching. The center axis of the bit follows an ellipse while simultaneously rotating. In this case the ellipse is a circle with a triangular bit. A "square" is only one on many shapes that can be made this way. If you change the ellipse or the bit, any number of shapes can be cut. Harry Watts created this and patented it 100 years ago.

Made in USA...

[alex71]

Pretty cool. Don't think you'll be making this work in your drill press though. To keep that square hole square both the spindle and the fixture would need to be damn rigid.

[Lump]

Originally Posted by alex71

Pretty cool. Don't think you'll be making this work in your drill press though. To keep that square hole square both the spindle and the fixture would need to be damn rigid.

Yeah, I'm sure you're right about that, Alex.

[evildky]

it's a more sophisticated mortising jig

[Michael Bryce Winnick]

Cool. To me it is new. Great for hot rod dash panels.

[onewaydave]

I thought I'd seen a discussion on rotary broaches on this site a few months ago.

But older n dirt, of course. It's just a matter of putting a square peg in a round hole!

Dave, who couldn't file a round hole into a square hole to save his life.

[carbon]

For super old square/star/etc hole wood-boring tools, check out "A Very Boring Program" by a hero of mine, Roy Underhill in his tv series, The Woodwright's Shop. Go to about 14:25.

[70Chevy]

We had a discussion about this drilling a square hole 20+ years ago back in college. I didn't understand it then, but now that I see it work, it seems simple. The oscillation is from the triangular "flutes" of the drill being offset to the shank of the drill - not the spindle of the machine oscillating.
Glad I finally saw it in action after all of this time - I did think about it every now and then.
Thanks for posting.

[bitbycarbug]

Originally Posted by Stick

If you think that's neat, you need to check out How Round Is Your Circle?

You can check how round your circle is by checking it against the most spherical thing ever made.

The pursuit of the Kilogram:


But thanks for the book. I'll have to look it up.

[rtoms]

I can see myself finding one of these and putting it in a corded drill and swearing alot after it cranks my wrist in half

[Richard D]

A Watts drill is not the same as a rotary broach. I can't explain the difference, but there is one. Quoted from the Woodworkforum;

http://www.woodworkforums.com/archiv.../t-142453.html
By Pete F
"I think rotary broaching is actually a different principle to that shown above. IIRC, with a rotary broach, the broach is held stationary on the work and "wobbled" by an eccentric, hmm, not sure how to describe it, I'll say "cam" but I'm sure somebody will shoot me down for that as it's not really a cam at all. Anyway, an eccentric "plate" behind the broach that wobbles the broach from side to side and drives it through the pre-drilled hole. I intend to make one of these, but just haven't had time ... hence why I'm typing while sitting in Tokyo!

On the other hand the one above is a "Harry Watt" drill bit. As I understand it, that rotates pretty much like a normal drill bit, BUT the drive to the specially shaped drill bit ALSO rotates. It's really tricky to describe, but I think it showed it on the video in the link. Imagine getting your drill press quill, mounting that offset on a plate, and also turning that around in a circular shape. Ok that's a really crap description, sorry you'll just have to look at the videos. Google "Harry Watt", he was a clever dude. Edit: Oh, just watched that video, ok, yes that would be another way to rotate the drive, run it through a fixture with universal joints so the axis of the drive is changed. Very cunning. Anyway the point is rotary/wobble broaching, and Harry Watt drill bits work on quite different principles, so may be confusing when intermixed in posts. Both pretty clever, but as mentioned, I've heard the former is better for a number of reasons."

[Richard D]

I contacted Dijet USA; here's their response:

"Dijet Japan sells the tool only to a special spindle maker in Japan.

The special spindle maker does not sell overseas.

Sorry."

[ewe0006]

Originally Posted by Richard D

A Watts drill is not the same as a rotary broach. I can't explain the difference, but there is one. Quoted from the Woodworkforum;

http://www.woodworkforums.com/archiv.../t-142453.html
By Pete F
"I think rotary broaching is actually a different principle to that shown above. IIRC, with a rotary broach, the broach is held stationary on the work and "wobbled" by an eccentric, hmm, not sure how to describe it, I'll say "cam" but I'm sure somebody will shoot me down for that as it's not really a cam at all. Anyway, an eccentric "plate" behind the broach that wobbles the broach from side to side and drives it through the pre-drilled hole. I intend to make one of these, but just haven't had time ... hence why I'm typing while sitting in Tokyo!

On the other hand the one above is a "Harry Watt" drill bit. As I understand it, that rotates pretty much like a normal drill bit, BUT the drive to the specially shaped drill bit ALSO rotates. It's really tricky to describe, but I think it showed it on the video in the link. Imagine getting your drill press quill, mounting that offset on a plate, and also turning that around in a circular shape. Ok that's a really crap description, sorry you'll just have to look at the videos. Google "Harry Watt", he was a clever dude. Edit: Oh, just watched that video, ok, yes that would be another way to rotate the drive, run it through a fixture with universal joints so the axis of the drive is changed. Very cunning. Anyway the point is rotary/wobble broaching, and Harry Watt drill bits work on quite different principles, so may be confusing when intermixed in posts. Both pretty clever, but as mentioned, I've heard the former is better for a number of reasons."

You're close...

Conventional broaching pushes a form tool straight into/through the workpiece. Rotary broaching, done on a lathe, angles the tool about 1 degree off the centerline of the workpiece. The broach is allowed to spin freely, and is pushed into the workpiece. As the workpiece rotates, it rotates the tools, engaging only one edge of the tool into the cut at anytime.

That's probably the best way I've actually ever explained that process!

Slater Tools makes rotary broaching tools for lathes, and they've got some videos of the process in action on their website. We use these where I work to put hex sockets in some aerospace parts.

If I were to classify that Dijet tool into a generic machining category, I would call it an end mill. A really crazy end mill.