Attaching stainless bolsters to titanium liner

Matt Rochester

Matt Rochester

Joined
Nov 28, 2014
Messages
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I am about to make my first liner lock and was wondering how to attach stainless steel bolsters to titanium liners? I’ve made a few slip joints and just TIG welded the bolsters on. I am making a liner lock similar to the Case trapper. My plan is .100” blade, .050” liners and a .200” stainless bushing. I bought a bushing lapping setup to help dial in the bushing. I also bought precision ground stock since I don’t have a surface grinder yet.
 
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After some more research it seems that you can’t solder titanium and stainless. What are my options? I guess I could do stainless liners or titanium bolsters. It would be tough to pin the bolsters on and have a pivot pin. Maybe spot weld? This is the knife I’m looking to make.
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I screw the bolsters on my liner locks with #0-80 screw's, and have the pivot hidden under the bolsters. I'd personally recommend making the knife disassembleable in some way.
 
I would say from a material/material compatibility standpoint, do Ti bolsters and liners and TIG them together on the sides and the end. The scales will cover the unwelded side of the bolster/liner joint. Bevel the bolsters so the Ti filler has a place to land and grind away the excess Ti. I don’t think you can spot weld Ti and SS. Even if you could, the parts probably would not lie tightly together. Your finished knife will look like an integral.
 
tiguy7 said:
I would say from a material/material compatibility standpoint, do Ti bolsters and liners and TIG them together on the sides and the end. The scales will cover the unwelded side of the bolster/liner joint. Bevel the bolsters so the Ti filler has a place to land and grind away the excess Ti. I don’t think you can spot weld Ti and SS. Even if you could, the parts probably would not lie tightly together. Your finished knife will look like an integral.
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Thanks. I’ll see if I can round up some titanium for the bolsters. Would you hide the pivot pin or just peen it. I’ve never worked with Titanium and am just wondering how it finishes compared to stainless. Also, the knife above has brass liners that I was going to leave out. It has what I’m assuming is nickel silver bolsters attached to brass liners. Can they be soldered? It almost looks like they are spot welded.
 
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View attachment 863691 View attachment 863690 I would make the liners out of Ti and TIG weld them to Ti bolsters. It would be hard to hide the pivot pin in that case. Titanium can take a high polish, but I think it looks better with a matte finish. You can solder brass to “Nickel Silver” which is most likely white brass.
Check the construction the LionSteel Round Head and Shuffler. They have Ti bolsters and liners and are screwed together, but they are lock backs not liner locks. They illustrate the look of Ti.
 
Thanks again. I guess im just going for the look of a traditional slip joint with a lock. Anything I should know about welding titanium?
 
You need a particular purge setup, or a purge chamber to do it in. Lots of info on how to go about that, when I looked into it when building Ti suppressors I just decided to thread everything instead.

I don't know why you couldn't attach the SST bolster to a Ti liner with SST pins that you peened and blended flush.
 
You can successfully spot weld titanium. I've done it many times, without using a glove box. I haven't tried welding it to stainless however. You just need clean, super flat mating surface.
 
kuraki said:
You need a particular purge setup, or a purge chamber to do it in. Lots of info on how to go about that, when I looked into it when building Ti suppressors I just decided to thread everything instead.

I don't know why you couldn't attach the SST bolster to a Ti liner with SST pins that you peened and blended flush.
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I thought of pinning them but thought 3 pins in the bolster would be kind of tight. I may just give it a try. Thanks.
 
javand said:
You can successfully spot weld titanium. I've done it many times, without using a glove box. I haven't tried welding it to stainless however. You just need clean, super flat mating surface.
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I did look into welding titanium and noticed some funky techniques folks were using to do it. I will try just spotting them and see how it goes. It appears in the knife I took apart that the bolsters(nickel silver?) are just spot welded in one spot. Thanks buddy.
 
Matt R said:
I thought of pinning them but thought 3 pins in the bolster would be kind of tight. I may just give it a try. Thanks.
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3 including the pivot? I was thinking 2 1/16 pins for the bolster to liner should leave plenty room for the pivot.
 
Matt R said:
Thanks again. I guess im just going for the look of a traditional slip joint with a lock. Anything I should know about welding titanium?
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When I weld Ti, I use a Thorium electrode, a CP (commercially pure) filler rod, a cup surround (usually made out of an Al beer can on small jobs) to capture and hold the shielding gas around the weld site, and a high post flow (Argon) rate to allow the weld to cool to below 750 degrees F in an Oxygen free environment. Don’t use a blended gas used for MIG welding steel. It has CO2 in it. You want pure Argon or Helium in a pinch. An Argon tent or vacuum chamber is used commercially to weld Ti. Helium doesn’t work as well. It won’t puddle in the cup.
 
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