"Ed Huntress" wrote in message
...
On Mon, 2 Apr 2012 13:15:57 -0700, "Bob La Londe"
wrote:



"Karl Townsend" wrote in message
. ..
I've got an egg shaped hole in the lock frame on my 1919 BMG...

This part is hardened 4140 and its hard to get into the deep hole
anyway so welding it shut and remachining don't look like a good
option.

So is there a good way to bond a bushing with a 0.187" OD by 0.150"
high into a bore? What would you use? FWIW, if I tried a press fit, it
would just break the part.

Karl

How about a light press fit and lock it in place with LocTite sleeve and
bushing locker. Loc-Tite green if I recall correctly.

For reference, shear strength of Loctite Green (cured for 24 hours):
3,600 psi. Epoxy, 3,500 - 5,000 psi, depending on type. Soft solder
(60/40 tin/lead): 6,000 psi. silver-bearing soft solder: 10,000 -
14,000 psi.

Silver braze is very hard to nail down because of some issues with
thickness of joint, wetting, etc. It can range as high as 125,000 psi
-- much more than its bulk strength. (Don't ask me how that works;
I've never gotten a good answer.) Typical shear strength in practice
is 25,000 psi.

--
Ed Huntress

It sounds like high shear strength is not an issue during use, although it
may be during assembly if the idea is to hammer a press-fit pin into this
bushing. Even then, I have tried to disassemble parts bonded with loctite
603 by pressing and hammering (almost up to the point of damaging the metal)
with no luck whatsoever. The only thing that works is high temperatures.