I seem to remember being taught in school that metric countersunk Allen
srews had a 90 degree countersink angle, and Unified had an 82 degree
angle. Is that right, and does it matter if I just use a 90 degree
countersinking bit for both, as here in the UK no one seems to stock 82
degree bits for ferrous material? Thanks.

On Tue, 10 Nov 2009 13:06:53 +0000, Chris Wilson
wrote:

I seem to remember being taught in school that metric countersunk Allen
srews had a 90 degree countersink angle, and Unified had an 82 degree
angle. Is that right, and does it matter if I just use a 90 degree
countersinking bit for both, as here in the UK no one seems to stock 82
degree bits for ferrous material? Thanks.

Correct.

I guess in non critical applications you could get away with an 90 D
c'sink on a unified flat head.

Thank You,
Randy

Remove 333 from email address to reply.

Chris Wilson wrote:
I seem to remember being taught in school that metric countersunk Allen
srews had a 90 degree countersink angle, and Unified had an 82 degree
angle. Is that right, and does it matter if I just use a 90 degree
countersinking bit for both, as here in the UK no one seems to stock 82
degree bits for ferrous material? Thanks.

J&L have them
http://www.mscjlindustrial.co.uk/CES...D/product.html
and maybe others if you search.

Chronos have a set, http://www.chronos.ltd.uk item XC310 .

Didn't take much to find them after going to their sites and searching
for 82 degree.

On Tue, 10 Nov 2009 13:06:53 +0000, Chris Wilson wrote:

I seem to remember being taught in school that metric countersunk Allen
srews had a 90 degree countersink angle, and Unified had an 82 degree
angle. Is that right, and does it matter if I just use a 90 degree
countersinking bit for both, as here in the UK no one seems to stock 82
degree bits for ferrous material? Thanks.

You can't resharpen the drill bit to any angle you want?

Isn't that what bench grinders, hands, eyes and brains are for?

--
www.wescottdesign.com

On Tue, 10 Nov 2009 16:51:32 +0000, David Billington wrote:

Chris Wilson wrote:
I seem to remember being taught in school that metric countersunk Allen
srews had a 90 degree countersink angle, and Unified had an 82 degree
angle. Is that right, and does it matter if I just use a 90 degree
countersinking bit for both, as here in the UK no one seems to stock 82
degree bits for ferrous material? Thanks.

J&L have them
http://www.mscjlindustrial.co.uk/CES...D/product.html
and maybe others if you search.

Chronos have a set, http://www.chronos.ltd.uk item XC310 .

Didn't take much to find them after going to their sites and searching
for 82 degree.

Thanks for finding me those, I have ordered the set off Chronos. My Google
search within the UK didn't find anything, I did try, but was too generic!


Appreciate your time David, thanks again.

On Tue, 10 Nov 2009 08:48:33 -0500, Randy wrote:

On Tue, 10 Nov 2009 13:06:53 +0000, Chris Wilson
wrote:

I seem to remember being taught in school that metric countersunk Allen
srews had a 90 degree countersink angle, and Unified had an 82 degree
angle. Is that right, and does it matter if I just use a 90 degree
countersinking bit for both, as here in the UK no one seems to stock 82
degree bits for ferrous material? Thanks.

Correct.

I guess in non critical applications you could get away with an 90 D
c'sink on a unified flat head.

Thank You,
Randy

Remove 333 from email address to reply.

Thanks Randy, they are holding a crank position trigger wheel on to a crank
damper on a fairly high RPM race engine, so I have found, thanks to David,
a source of the correct angle bits, and will do them at the correct (not
right ) angles. Appreciate the reply.

On Tue, 10 Nov 2009 11:56:37 -0600, Tim Wescott wrote:

On Tue, 10 Nov 2009 13:06:53 +0000, Chris Wilson wrote:

I seem to remember being taught in school that metric countersunk Allen
srews had a 90 degree countersink angle, and Unified had an 82 degree
angle. Is that right, and does it matter if I just use a 90 degree
countersinking bit for both, as here in the UK no one seems to stock 82
degree bits for ferrous material? Thanks.

You can't resharpen the drill bit to any angle you want?

Isn't that what bench grinders, hands, eyes and brains are for?

I don't have the necessary skill for that, but thank you for the
suggestion. I do pride myself on polite and generally sarcasm free replies
to strangers though