Spot welder?

Absinthe

Well-Known Member
So I have heard that people spot weld bolsters. What kind of machine is used to do this? What are the implications? Can I do this with brass liners (3/32) and nickel silver or brass bolsters (1/8)?
Is this still possible when working with SS or Titanium?
 
So I have heard that people spot weld bolsters. What kind of machine is used to do this? What are the implications? Can I do this with brass liners (3/32) and nickel silver or brass bolsters (1/8)?
Is this still possible when working with SS or Titanium?

You can buy purpose-built spot welders. Harbor Freight sells them. $150, I believe.

Another way would be with a TIG welder and plug weld the liner to the bolster. Anyway, you could drill a few small holes through the liner and plug weld to the backside of the bolsters.

I don't own a spot welder, so I couldn't tell ya how well it'd turn out. My experience with spot welding is in automotive applications.

The TIG welder would be a better investment. Not for knife making, but just for general fabrication and repair.

Kinda like how on the show The A Team, an oxy-acetylene torch was always plot critical... yeah. Plasma cutter and a welder. Plot critical for a lot of stuff that I make.

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Just did 5 sets soldered. Didn't enjoy it ... Need suggestions to make it more fun. :)

0727c54bdbe3ad88c0fe44d74a989f5ada9d9ff4.jpg
 
Just did 5 sets soldered. Didn't enjoy it ... Need suggestions to make it more fun. :)

0727c54bdbe3ad88c0fe44d74a989f5ada9d9ff4.jpg
Well, you can grow weed in VA now... I suppose that'd make things more interesting. Going to need to keep food in the shop, though.

I guess I didn't ask. Why would you want to weld instead of solder the bolsters?

If you need higher strength, try some 45% silver solder. Harris Safety-Silv 45 is good stuff. People use it to make brazed carbide tooling.


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A soldering application like this may do well with something like Brownell's 70Pa 430*F tin/silver paste solder.
 
Well, you can grow weed in VA now... I suppose that'd make things more interesting. Going to need to keep food in the shop, though.

I guess I didn't ask. Why would you want to weld instead of solder the bolsters?

If you need higher strength, try some 45% silver solder. Harris Safety-Silv 45 is good stuff. People use it to make brazed carbide tooling.


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But I am in NC :)

All I really want is a simpler way to attach the bolsters'. It looks like the ones I got from the Queen Cutlery surplus were somehow stamped/staked in place. I can grab them with pliers and rotate them.

Right now soldering is not a a comfortable process. Seems too imprecise. Kind of tweaky.

Just want a good repeatable process.
 
But I am in NC :)

All I really want is a simpler way to attach the bolsters'. It looks like the ones I got from the Queen Cutlery surplus were somehow stamped/staked in place. I can grab them with pliers and rotate them.

Right now soldering is not a a comfortable process. Seems too imprecise. Kind of tweaky.

Just want a good repeatable process.
Ya know... if you HAD A MILL you could just make the liner and bolsters as one piece. :D

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Ya know... if you HAD A MILL you could just make the liner and bolsters as one piece. :D

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okay, so that is certainly another use for a mill. So do people make the liners from Nickel Silver too then? I hadn't considered it. I was thinking the liners would always be brass, and the bolsters would be either NS or brass to go with. But, I assume one could also make the liners from NS, or SS and so on?

Of course, I assume I could start from 1/8" or better and use the saw for shoulder cuts and clear out the excess with end cutting mill in the drill press, with overlapping pulls. Or belt grind the middle out as long as the knife is wide enough or the belt is narrow enough, or perhaps small wheel.

I could use my EDM machine :) Or cast the liners/bolsters from bronze...

Single piece, seems like a lot of wasted metal to me. The idea of cutting away more metal than I keep feels like a wrong operation.

While I was roughing up the liners, however, I was considering the possibility of cutting a hard shelf with a mill. Wasn't sure I could accurately do it with the platen and the grinder. Losing a 1/32 from 3/32 in the bolster area would provide a positive fit for a squared off bolster blank.
 
Yeah, just make the entire bolster and liner from one piece of metal on you're wire EDM. :D


I see no reason you couldn't use nickel silver as liner material.

Not sure if you were joking or not about casting them - unless you did something fancy like a ceramic mold or a steel mold, you might have a lot of clean up to do.

Then again, maybe not. You just need to get the inside of the liner flat, the spot the scale flat and square to the inside of the liner, and then the rest is just business as usual.

That'd be a good use for a 3D printer. Make a "tree" with a bunch of your patterns attached to it, all the feeders and vents and whatnot.

I'm not sure about NS or brass, but with cast iron, you want to make your patterns something like 10% larger than your finished casting to allow for shrinkage as it cools.

If you have a 3D printer already and have an interest in casting metal, Google "lost PLA casting". I've seen people make some very impressive casting with that method. It's very similar to lost wax casting.

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Yeah, just make the entire bolster and liner from one piece of metal on you're wire EDM. :D


I see no reason you couldn't use nickel silver as liner material.

Not sure if you were joking or not about casting them - unless you did something fancy like a ceramic mold or a steel mold, you might have a lot of clean up to do.

Then again, maybe not. You just need to get the inside of the liner flat, the spot the scale flat and square to the inside of the liner, and then the rest is just business as usual.

That'd be a good use for a 3D printer. Make a "tree" with a bunch of your patterns attached to it, all the feeders and vents and whatnot.

I'm not sure about NS or brass, but with cast iron, you want to make your patterns something like 10% larger than your finished casting to allow for shrinkage as it cools.

If you have a 3D printer already and have an interest in casting metal, Google "lost PLA casting". I've seen people make some very impressive casting with that method. It's very similar to lost wax casting.

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Yeah, I'm not interested in casting metal yet. First stabilization, then perhaps micarta, some pen turning blanks... Metal casting, can wait...
 
Last year I bought a HF spot welder ( the 240 volt model ) and used it to weld some 0.125" AEBL bolsters to AEBL liners. It worked perfectly after I practiced with some scrap and got the timing figured out. With the total thickness of the parts I was pushing the limits of the machine.
 
Do you just hit it once?
I hit it four times. I relieve my liners first. That way I can spot weld it and have the welds land in the relief so as to not make hard spots in my pivot pad. When I weld on my bolsters, the only finished edge on the bolster is where it will meet the handle scale. After welding I profile the bolster down to meet the profile of the liner.

After spot welding, I clamp the liners up in a vise and use a torch to heat the bolsters up to a red heat. Once cool, the spot welds will be invisible when you grind the bolsters.
 
I have the Harbor Freight 220V spot welder. The advice was that the 110V one would not have enough juice for 3/16" 416 Stainless steel bolsters with 410 liners.

I have not tried it yet on 3/16 416 SS, but have on 1/8: nickel silver and 410 SS liners. The 220V is almost too much juice for that and have to use a light bump touch otherwise blow out the liners.

The Luke Swenson dvd/video on making slipjoints from Chris Crawford suggests the blunt the spot welder tips, esp the bottom one.
 
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