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

On Mon, 02 Apr 2012 06:46:18 -0500, Karl Townsend
wrote:

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

I think I'd try silver braze.

Pete Keillor

Den 02-04-2012 13:46, Karl Townsend skrev:
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.

Loctite 638?




--
Uffe Bærentsen

On 4/2/2012 7:46 AM, Karl Townsend wrote:
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

Can you post a picture or a diagram?

On Mon, 02 Apr 2012 12:17:52 -0400, Tom Gardner mars@tacks wrote:

On 4/2/2012 7:46 AM, Karl Townsend wrote:
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

Can you post a picture or a diagram?

http://www.gunbroker.com/Auction/Vie...Item=279377814

in the botton pic, you can see a large diameter hole that soes to
small diameter down in there. its egg shaped on mine. lets the trigger
sit crooked.

karl

"Karl Townsend" wrote in message
...
On Mon, 02 Apr 2012 12:17:52 -0400, Tom Gardner mars@tacks wrote:

On 4/2/2012 7:46 AM, Karl Townsend wrote:
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

Can you post a picture or a diagram?

http://www.gunbroker.com/Auction/Vie...Item=279377814

in the botton pic, you can see a large diameter hole that soes to
small diameter down in there. its egg shaped on mine. lets the trigger
sit crooked.

karl

Can you bore it out and make a bigger pin?

Can you bore it out and make a bigger pin?

nope

On Mon, 02 Apr 2012 14:53:28 -0500, Karl Townsend
wrote:


Can you bore it out and make a bigger pin?

nope

If it has to be really hard, your options are limited. 4140 tempers
over a wide range -- 400 deg. F to 1200 deg. F, with the lower
temperatures producing the hardest result, of course. So silver
brazing isn't an option unless you can tolerate lower hardness.

Epoxies will give you strength, say, "X". Soft solder, then, is around
2X. Silver braze will be 4X - 12X.

Consider a silver-containing soft solder (maybe 3X or possibly 4X).
Some will melt nearer the low tempering range for 4140.

--
Ed Huntress

"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.

"Uffe Bærentsen" wrote in message
. ..
Den 02-04-2012 13:46, Karl Townsend skrev:
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.

Loctite 638?




--
Uffe Bærentsen

I second that. This would be the stuff to use for loose fitting cylindrical
parts with gaps up to .010". For gaps up to 0.015" use loctite 680.

http://www.henkelna.com/industrial/p...UID=0000000I04

http://www.henkelna.com/industrial/p...UID=0000000HWK

McMaster has both.

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

"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.

Karl Townsend wrote:
Can you bore it out and make a bigger pin?

nope

How about reaming it out so it is round. Then press in a hardened piece
of steel then bore that to the correct diameter? To ensure the insert
cannot come out some loctite bearing retainer would do the trick.

--
Steve W.

On Monday, April 2, 2012 4:46:18 AM UTC-7, Karl Townsend wrote:
I've got an egg shaped hole in the lock frame on my 1919 BMG...

No one else recommended this: rivet the hole closed, with
soft iron, or bronze or silver. Then drill your hole in that.
I'm not sure how much sidewall you'll get, of course.

On 4/2/2012 3:53 PM, Karl Townsend wrote:

Can you bore it out and make a bigger pin?

nope

Call "Red Jacket" and ask them. Maybe they will ask you on the show!
http://www.redjacketfirearms.com/

On Apr 2, 5:46*am, Karl Townsend
wrote:
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

Buy a new one, they WERE fairly cheap. Ohio Ordnance was one source.
And what you have depends on the vintage. Some were cast,
some(prewar) were machined from forgings and a bunch were made from
welded-up stampings. This is a key part of the gun, don't cheap out.
It directly controls the timing. If you want to mess with it after
you get another, go to it. My experience with them has been that they
were harder than hell and I didn't want to have to do anything more
with them than I had to to get a legal semi-auto out of the parts
kit. I don't think mine were through-hardened, I think they were case-
hardened or nitrided. Mess with that sort of thing via welding or
silver-brazing and you might get other problems later.

OK, see: http://www.ohioordnanceworks.com/Par...lAutoParts.cat

Stan

"Karl Townsend" wrote in message
...
On Mon, 02 Apr 2012 12:17:52 -0400, Tom Gardner mars@tacks wrote:

On 4/2/2012 7:46 AM, Karl Townsend wrote:
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

Can you post a picture or a diagram?

http://www.gunbroker.com/Auction/Vie...Item=279377814

in the botton pic, you can see a large diameter hole that soes to
small diameter down in there. its egg shaped on mine. lets the trigger
sit crooked.


Drill and tap most of the way through then drive a screw into the tapped
hole until it jams, cut off it's head and file flush.....finally, machine a
hole down the center of it to suit your pin.

On Tue, 3 Apr 2012 23:24:52 -0700, "PrecisionmachinisT"
wrote:


"Karl Townsend" wrote in message
.. .
On Mon, 02 Apr 2012 12:17:52 -0400, Tom Gardner mars@tacks wrote:

On 4/2/2012 7:46 AM, Karl Townsend wrote:
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

Can you post a picture or a diagram?

http://www.gunbroker.com/Auction/Vie...Item=279377814

in the botton pic, you can see a large diameter hole that soes to
small diameter down in there. its egg shaped on mine. lets the trigger
sit crooked.


Drill and tap most of the way through then drive a screw into the tapped
hole until it jams, cut off it's head and file flush.....finally, machine a
hole down the center of it to suit your pin.


Damn, that's a good idea. I'll do it that way.

Karl