It won't be quite square but how about drilling small (1mm?) holes in the
corners, milling out the centre and cleaning up with a small endmill? It will
be at least as good as a typical 3/8-inch socket.
> -----Original Message-----
> From: John Kasunich [mailto:jmkasun...@fastmail.fm]
> Sent: Monday, March 20, 2017 10:21 AM
> To: emc-users@lists.sourceforge.net
> Subject: Re: [Emc-users] Thing with a square hole.
>
> You could mill a 10mm wide x 5mm deep slot in two rectangular bars, then
> silver-braze them together.
> Might not be strong enough, depends on if the OD is big enough to leave a
> reasonable joint area.
> Welding would probably leave a hardened zone and be miserable to machine
> afterwards.
>
> John
>
>
> On Mon, Mar 20, 2017, at 09:58 AM, andy pugh wrote:
> > I want to make some D1-4 cams for a 4th-axis project.
> > These need a 10mm square hole (but 3/8 would be fine too).
> > I don't think I can polygon-bore a square, it needs too much
> > tool-relief. (I guess I should try, though).
> >
> > If I could find something like a 3/8" drive socket with no hole in it
> > that would be a good starting point. Any ideas?
> >
> > I have thought of having a hex hole and starting from an M24 grub
> > screw (setscrew). But those cost about the same as an actual cam.
> > (though the only source of cams I have found in the UK have no stock,
> > or I would have bought them).
> > http://spares.xyzmachinetools.com/XYZ-TRAINER-1330-1340/products/29/
> > lists zero stock at £7.77
> >
> >
> > --
> > atp
> > "A motorcycle is a bicycle with a pandemonium attachment and is
> > designed for the especial use of mechanical geniuses, daredevils and
> > lunatics."
> > - George Fitch, Atlanta Constitution Newspaper, 1916
> >
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>
> --
> John Kasunich
> jmkasun...@fastmail.fm
>
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