Soldering a Steel Bolster On To a Brass Liner

[Jeffinn]

I’m working on a Boker electrician knife and during disassembly one of the bolsters popped off. It looks like it had a very small spot weld holding it in place. I soldered it back on and it seems to be attached well but I’m wondering if this is the right approach.
I could drill it and install a small steel pin but that may end up being visible on the top when finished.
Anyone here have any experience with this?
Thanks.
Jeff

[orvet]

I am working on a Boker right now that popped one of the bolsters. My bolsters were nickel silver and soldered easily.
I glued the stag and hafted it to the bolsters and to the liner but when I picked it up to do a test fitting a a front bolster fell off of one half and a rear bolster fell off the other. I didn't want to pop the stag loose, solder on two bolsters and hope I had everything in the right place. Instead I chose to pin the bolsters. I did that from the inside making sure I did not drill all the way through the bolster.

Let me get some pictures and I will bring it back and post them and show you what it looks like, because I haven't got it put back together yet.

I also decided I'm not going to work on anymore German knives because of the way they barely attach the bolsters.

[Jeffinn]

Thanks Dale, I appreciate it!
Jeff

[Meridian_Mike]

If the bolsters are steel then a piece of a coat hanger or a small nail should work as a pin. If the bolsters are steel, they are probably mind steel so the properties should match (I would think).


Dang, it sure is bad to hear about your German knife experiences Dale.... makes me paranoid.

[Bill DeShivs]

Soldering the bolster is as good an approach as any.

[mrwatch]

when you say soldered them, you do not say how? soft radio solder and flux won't last. Plumbing solder with acid paste may hold okay. The low heat silver solder with liquid flux may hold quite well. But you will need a small torch flame or Prest-O-Lite torch tip. using care to not remove the temper and with out the scales on it. I would wrap the blade with a damp cloth

[Bill DeShivs]

Bolsters have been soft-soldered on knives for a hundred years. Maybe it won't last...

[stockman]

Bolsters have been soft-soldered on knives for a hundred years. Maybe it won't last...

Bill, years ago I repaired Gas meters. Some of them had parts soldered together. We used the old irons heated in a little furnace,and 50-50 solder. Would this work on knives?

Harold

[Bill DeShivs]

A small torch works better than soldering irons or guns.

[orvet]

Thanks Dale, I appreciate it!
Jeff

Jeff,
Here are the insides of the bolsters that fell off of the Boker folding Hunter. I attached them using 1/16" pins.
I drilled the 1/16" hole into the bolster and then used a tiny ball burr to widen out the bottom of the hole so the pin could mushroom out and hold tight.

I used two pins in the front bolster which was much wider and thicker but only one in the rear bolster.
They are quite secure.

[Jeffinn]

That sounds easy enough, thanks Dale!
I never thought about using a small ball burr to widen the hole at the bottom for the pin. That’s definitely a technique I’ll keep in my pocket for future reference.
Jeff

[Reverand]

That is probably much more secure now than when it left the factory.
I agree with soldering them if there are no scales mounted yet, and pinning if there are. I even mounted some with a thin layer of epoxy, knowing that the pivot pin did more to hold them on than the epoxy.
The only problem that I can forsee is trying to match the German silver nickel. Theirs are often a slightly darker color than the US rods that I use for pins.

EDIT: I just re-read where Dale said not to drill all the way through. Makes much more sense to me now!

[orvet]

I agree with soldering them if there are no scales mounted yet, and pinning if there are. I even mounted some with a thin layer of epoxy, knowing that the pivot pin did more to hold them on than the epoxy.

I actually worked on one German knife and the bolsters were made from a curved sheet of nickel silver, so they were hollow underneath. There was no solder, no pin, no method of attaching the bolsters to the liners other than the pressure exerted on the bolsters by the pivot pins. As soon as I cut the pins to take the knife apart, the bolsters fell right off. I was able to repair the knife and get it back together but it was really a pain!

[Douglasvab]

You can drill and tap it. I would tap it for 2-56 threads, minimum. The bolster isnt heat treated and doesnt need to be annealed. Its 416SS, engravable.

Drill and tap all the way through the liner, as well. Then flush the screw with the backside of the liner to keep it from scraping the blade.

That should do it
Let me know if you have any questions.

[orvet]

You can drill and tap it. I would tap it for 2-56 threads, minimum. The bolster isnt heat treated and doesnt need to be annealed. Its 416SS, engravable.

Actually most bolsters are nickel silver as is the Boker folding hunter I posted.
If you drill through the bolster you will have a steel screw showing in a nickel silver bolster.
Even with steel bolsters, most of the older ones are carbon steel and most machine screws today I have seen are stainless steel, that will also show up in the bolster.

[Meridian_Mike]

You can drill and tap it. I would tap it for 2-56 threads, minimum. The bolster isnt heat treated and doesnt need to be annealed. Its 416SS, engravable.

Drill and tap all the way through the liner, as well. Then flush the screw with the backside of the liner to keep it from scraping the blade.

That should do it
Let me know if you have any questions.

Welcome to the forum....

That is a heck of a first post.

[Jeffinn]

I am working on a Boker right now that popped one of the bolsters. My bolsters were nickel silver and soldered easily.
I glued the stag and hafted it to the bolsters and to the liner but when I picked it up to do a test fitting a a front bolster fell off of one half and a rear bolster fell off the other. I didn't want to pop the stag loose, solder on two bolsters and hope I had everything in the right place. Instead I chose to pin the bolsters. I did that from the inside making sure I did not drill all the way through the bolster.
I also decided I'm not going to work on anymore German knives because of the way they barely attach the bolsters.

I just ran across this today on a Tree Brand knife I was working on. Three of the bolsters fell off and the fourth one was easily removed by hand. Like you, I had already shaped and hafted the bone handles.
The original attachment for these bolsters seems to be glue of some sort which works okay for a one time installation. It’s a cheap alternative to soldering them on, I’m not a fan. It’s the first time Ive seen it.
Like Dale, I’m no longer going to work on Boker knives.
Jeff

[Doc B]

Dale, that's a neat idea!
Douglasvab...that's sounds like a good way to go, too, if you had the technology available. Welcome to AAPK.

[Bill DeShivs]

Bolsters on the German knives were not glued on. Most were soldered.
Some modern ones are spot-welded.
Regardless, the way to do a PROPER repair is to take the handles off, solder the bolster back on, and put the handle back on.