How can I make slipjoint springs?

E

ErikMB

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Jul 27, 2017
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I am trying to enter a new stage of my knife making journey. :) Thus far I have gotten the hang of the Rough Ryder kits and it's time for the next level.

The plan is to purchase blade blanks and make the spring, plates, some kind of bolsters, and scales. I think I can do all these steps except for making the spring. I have a drill, dremel, saws, and a belt sander but nothing more than that.

I figure I will have to buy sheet metal from the hardware store and cut to shape. Is this the right idea? How should this be approached? Do I have to heat treat after cutting it out? How do I do this?
 
Slipjoint backsprings do have to be heat treated, but tempered back further than blades, so no steel from your typical hardware store is going to be appropriate as they will not be hardenable. The spring also has to be the same thickness as your blade blanks, or it could be equal to the blade blank plus the thickness of two washers since you likely won't be relieving the liners on a mill. You could farm out the heat treating to a professional service. I'd also suggest getting a copy of Steve Culver's book on slipjoints it will make some of these steps more clear. Maybe buy a kit with the blade blank and spring and focus on custom liners, bolsters, and scales so you can avoid heat treating.
 
To get your steel back to spring generally you temper in the 1100* - 1150* range. I usually throw my springs back in the HT oven to temper and do my blades in the kitchen oven at the same time since it's not capable of those temps. I do 1140* for all 3 of A2, CPM154 and Magnacut and get a consistent 46 - 48 HRC on my springs. 48 is my target.
 
Note to Eric:
Jason's advice above is for stainless steel backsprings. Carbon steel backsprings will be tempered in the 650-750° range.

As to your steel you can't use the metal from the hardware store. You will need a steel that hardens. 5160, 1095 and 1084 are common choices for carbon steel folders.
A2, 440-C, CPM154, and a variety of high alloy stainless steels are used for stainless folders.
 
Stacy E. Apelt - Bladesmith said:
Note to Eric:
Jason's advice above is for stainless steel backsprings. Carbon steel backsprings will be tempered in the 650-750° range.

As to your steel you can't use the metal from the hardware store. You will need a steel that hardens. 5160, 1095 and 1084 are common choices for carbon steel folders.
A2, 440-C, CPM154, and a variety of high alloy stainless steels are used for stainless folders.
Click to expand...
Thanks Stacey. The steels I mentioned are the only ones I've worked with so far minus 01 which I think I temperd at 900 iirc. :)
 
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