Soldered vs integral bolsters?

autogateman

autogateman

Rod Braud
Joined
Jan 6, 2017
Messages
180
What are the pros and cons of integral bolsters vs soldered? I have a mill and could pretty easily mill my liners and bolster from one piece and avoid the seam and welding but I figure there has to be a reason so many makers solder their bolsters. The difference in price of thicker steel would pale in comparison to the time savings.
Thanks
Rod
 
I have to imagine there's some warp to deal with when you remove such a significant percentage of material from one side.
 
kuraki said:
I have to imagine there's some warp to deal with when you remove such a significant percentage of material from one side.
Click to expand...
there isn't really,
we are talking about taking some SS flat bar 5/32" thk, the liner remaining is about .09 as I recall.
damn it's been a year since I did a slip joint and I have got to do one next week!
 
I have thought going from soldering to milling liners/bolsters, and came to the conclusion that it has to be harder to make a new design using the integral approach. How the heck do get the hole placement right?
 
Randy3000 said:
I have thought going from soldering to milling liners/bolsters, and came to the conclusion that it has to be harder to make a new design using the integral approach. How the heck do get the hole placement right?
Click to expand...


Drill all holes prior to milling
 
Randy3000 said:
I have thought going from soldering to milling liners/bolsters, and came to the conclusion that it has to be harder to make a new design using the integral approach. How the heck do get the hole placement right?
Click to expand...

For a lot of guys today - program it into the CNC mill.
 
I should have elaborated more. It seems to be that you if have a manually operated mill then you have to have a hole template, and then drill all holes before milling so the bolsters are aligned. To make the hole template, i guess you treat the template stock as a liner when making the spring and fitting tangs. Maybe it isnt so hard...
 
My slip joints are integral, cut out scale profile and build the knife with the steel thick, get everything working right then mill out for the covers and finish the knife.
Spot welding is also another alternative to soldering.
 
I do both. Both methods have their advantages and drawbacks. With multi-material construction, such as damascus bolsters over steel liners for example, you're saving a lot of material by soldering the bolsters, and can potentially use completely different patterns.

Most of my single material bolsters/liners I mill integral these days, but there's a practical limit to how thin you can get the liners. I like my liners around 0.040" thick, and that's very difficult to mill that thin, especially on single ended bolsters, because work-holding the liners gets really tricky. Most people that mill integral bolsters, leave them MUCH thicker.. Once you get down below 0.060, most materials will want to warp up into the cutter, I've ruined many trying to figure out a method of getting them as thin as I want. You can also surface grind integrals, but the same caveats apply, after a point, even the best magnet has difficulty holding the liners, stainless especially.

There are also caveats to getting them lined up correctly, I use a shop built jig to hold my already shaped and fit liners. Either way, it still introduces a lot of stress into the liners, and there's usually a fair bit of warp coming off the mill, right at the liner/bolster transition, and it's a tricky spot to straighten completely, if not completely straigthened, this'll translate to being able to see light around the spring between the liners if held up to a light source.

With spot welding or hard soldering (brazing) you can much more easily go with super thin liners (most people don't do them as thin as me, so it's not an issue), and if setup correctly, I get almost no warp from that process.

However, I do prefer integrals, and you can do some interesting things with different shaped cutters for the scale to bolster transition. I think many customers consider it a feature, but it's certainly not the only or "right" way to do it. Just like pivot bushings, or pin vs screw construction.

Regardless, like everything, if you truly want to have the range to construct anything, from any material, it's advisable to learn to utilize all the tools at your disposal.
 
After having soft soldered bolsters for a couple of years, then getting a mill and doing them integral for 7 plus
years or so I finally do them with hard solder and acetylene. I can grind them blue if I want with no worry about
falling off. Once you get a system set up it cuts milling time in half. 410 ss sheet for liners, 416 for bolsters- no
warps. It took me 2 years to use up my scraps for bolsters after the years of doing it integral. I won't ever look
back.
Ken.
 
kc custom said:
After having soft soldered bolsters for a couple of years, then getting a mill and doing them integral for 7 plus
years or so I finally do them with hard solder and acetylene. I can grind them blue if I want with no worry about
falling off. Once you get a system set up it cuts milling time in half. 410 ss sheet for liners, 416 for bolsters- no
warps. It took me 2 years to use up my scraps for bolsters after the years of doing it integral. I won't ever look
back.
Ken.
Click to expand...


Hey Ken, can I ask why you use 416 at all? I've been using 410 for liners, bolsters, and pivot pins, for 5 or 6 years now, and I gotta tell you, in almost every respect, it's superior to 416. It peens easily and never splinters/galls, it's available in perfect dimensional stock for 3/32 or 1/16 pins (PM me if you want a source), precision ground for bolsters from a few sources. I just don't see any reason in the world to use 416 unless HEAVY (aka non-knife related) machining is necessary.

The added sulpher in 416 makes it free machining, but it is *not* a forming grade, aka it doesn't take to cold forming/forging, aka peening. With 410, I can dome a pin as large or small as I want from any size stock. You can literally peen it for 30 minutes without it work hardening and causing issues, and the rod I use is the nicest, roundest, cleanest finished I've been able to find in any alloy.
 
I should have said that I do often use 410, years ago I bought a couple of sheets of it . I did like 416 over 410 when
I milled my frames integral. Pretty much use all 410 pinstock. I do think the 416 seems "softer" .
Ken
 
kc custom said:
I should have said that I do often use 410, years ago I bought a couple of sheets of it . I did like 416 over 410 when
I milled my frames integral. Pretty much use all 410 pinstock. I do think the 416 seems "softer" .
Ken
Click to expand...

Yeah it definitely machines easier, but I haven't had any issues machining 410 with carbide tooling, however I've got a couple of pretty large mills. I couldn't stand the splintering with peened pins or the track marks and ragged edges with spun 416 though, plus no two batches I got seemed to match color wise.
 
Last edited:
Once the process is down, I think soldering is probably a little faster/less of a head ache for a lot of makers. Not as much fixturing, easier to line up, and no need to worry about warp. That said, I'm sure there are makers that are more comfortable with a millling maching than they are with a soldering torch. Warp, while it can be an issue, can usually be corrected without a ton of effort.

If you have the tools, I say try both, and see which method you like better.
 
You must log in or register to reply here.
Back
Top