The Square Drill Bit

[Richard D]

Slater wants way too much for their rotay broach, as do the few other companies that make them. Plans are out there to make your own, I plan to do so someday.

 

[ewe0006]

Depends on the circumstances, but basically any high-end cutting tools for CNC machines are not going to be cheap. For us, it was cheaper than a broaching machine, and less headaches than subcontracting the work.

There's really not a lot to the mechanics, just good bearings that can stand up to the thrust force while still spinning freely.

 

[Richard D]

I don't expect "cheap" but why are the holders $800? I just don't see it.

 

[vonpahrkur]

that is awesome!

 

[Sarbatche]

I've used a 5-side version of this (for hexagons) on lathes in the Navy. We had the fixtures for this variation on lathes and rotary broach fixtures for drill presses. I think the ones that we used may have had a collar for the piece to guide the shape of the polygon though...

 

[Richard D]

The Little Machine Shop used to carry a holder for about forty bucks. I called them a few months ago. It is on back order indefinitely.

 

[GRX]

Yep. Remember these Reuleaux triangle bit techniques from machine shop class over 30 years back. Square and hexagonal holes. Thanks for posting the video so others can see it.

 

[TEKCRAFT]

Actually this technology is from the good old USA. I have a catalog that is almost 100 years old offering the drill bits and floating head to produce square holes.

I had seen this video on another site and laughed when I read that this "great innovation" was developed in Asia.

Happy Wrenching!

 

[cosmik binturong]

Yep. Remember these Reuleaux triangle bit techniques from machine shop class over 30 years back. Square and hexagonal holes. Thanks for posting the video so others can see it.

looks like a smarter application of the Reuleaux triangle, see this animation on the wikipedia page on said triangle:

added to some kind of wobbly cutting profile to get sharper corners.
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