drilling square holes

[EE]

A friend just showed me this.
[ame]http://www.youtube.com/watch?v=3n9kFqfmwoU&feature=related[/ame]

[ame]http://www.youtube.com/watch?v=Acq7Vuy5wNc&feature=related[/ame]

 

[EE]

I don't know. He just showed me the youtuble links.

 

[shred]

Looks a bit like a wobble-broach.

The other way I know of to do it is with a Reuleaux triangle-type setup, but those leave more rounded corners.

Update: Said to be a "Watts" type drill (the Reuleaux way)

http://www.homegunsmith.com/cgi-bin/ib3/iB_html/uploads/post-8-51813-DrillaSquareHole.pdf

http://www.maa.org/mathtourist/mathtourist_08_31_09.html

 

[Tin Falcon]

the first link if from the book The recycling, use , and repair of tools. by Alexander G Weygers this is also also included in the book the Complete Modern blacksmith.
Tin

 

[Simon0362]

Guys,
There was a wobble broach construction described in Model Engineer (or was it Model Engineer Workshop) during the last year or so.
Simon

 

[Majorstrain]

There was a wobble broach construction described in Model Engineer (or was it Model Engineer Workshop) during the last year or so.

Check out Docsmachine.com for a description of making a rotary broach holder. http://www.docsmachine.com/projects/rotarybroach/rb01.html
He uses a process described by Frank Ford to make the tool bits them selves. http://www.frets.com/HomeShopTech/Tooling/BroachMaking/broachmaking.html

Cheers,
Phil