How to temper a 1095 slipjoint spring

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Kessik221

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Nov 2, 2016
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I usually do my tempering in my oven, but what temperature should I temper 1095 at to make a good slipjoint spring? Thanks
 
I used to temper my 1095 back springs in my HT oven at around 670F, but anymore I just heat them evenly with a torch until they turn a purple/blue color.
 
If you have a lead smelter for casting lead bullets, you can immerse your springs in the molten lead until the lead doesn’t stick to them anymore.
That’ll temper them to at least 621, the melting point of lead.
That’s what I do when making springs for the locks on my flintlocks...
 
Do you guys find the springs, when tempered at 675, pick up a permanent bend if they deflect about 10 degrees? I sure did, and started tempering around 550.
 
Randy3000 said:
Do you guys find the springs, when tempered at 675, pick up a permanent bend if they deflect about 10 degrees? I sure did, and started tempering around 550.
Click to expand...
I suppose it depends on geometry. I haven't had any trouble with mine at 670ish (or just a bluish purple torch temper), but I don't think there's more than 10 degrees of deflection in the slipjoint designs I use anyway. That said, I haven't measured.
 
Randy3000 said:
Do you guys find the springs, when tempered at 675, pick up a permanent bend if they deflect about 10 degrees? I sure did, and started tempering around 550.
Click to expand...


Thickness will affect this, 550 is WAAY too low Randy for 1095, you're gonna run a serious risk of breakage.

675-725 is the range I temper 1095, I shoot for 49-50 RC. To me, this is the magic number for slipjoint springs with most steel. Many people go much lower, but I tend to go with thinner, more heavily pre-loaded springs for my action.

If you're getting plastic deformation at 675 Randy, something is wrong, either your springs are way too thick (tall), or something is wrong with the HT/steel. Thinning will allow more flexibility without plastic deformation if everything else is right.
 
I have experimented a lot with how tall the springs are. I have settled on about 5/32" height springs with very small tangs, about 1/8" meat between the 3/32" hole and the radius of the tang (i dont do half stops). The preload is about 0.050". Here is a typical spring i use for a canoe pattern.
ZcTDFF6.jpg


I think that 1095 i had (from jantz) was garbage. I ordered a lot of it when i first started making knives and now, a year later, i ordered my second batch of steel which is O1 from ebay. I can tell a world of difference. I will try tempering hotter with this new steel and see how that goes.

Btw, i know 10 degrees is a lot of deflection, it was just for test purposes to see when it would pick up a bend, i think my designs usually about 3-4 degrees deflection. I like tall springs and small tangs, because i get short tangs and longer blade lengths which i need for the 2 blade patterns.
 
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