Talked to a guy at the scrap yard that made me question my whole steel choice

I was picking up some old leaf springs for $20 and this older smith starts telling me why he only uses coil springs for his knives now. Said leaf springs have hidden microcracks from the temper you can't see until you quench and they fail half the time. Has anyone else switched to coils and noticed a real difference?

2 comments

2 Comments

fox.derek15d ago

Heard the same thing from an old timer at a hammer-in last year and it makes sense if you think about the stress cycle. Leaf springs are designed to flex in one direction under constant load for years, so the steel gets work hardened in a way that creates those microfractures along the grain boundaries. Coil springs bend in a twisting motion, way more uniform stress distribution across the whole bar. Ive tested both myself and my coil spring blades just feel tougher during grinding, less random chipping on the belt. Only catch is coils are harder to get perfectly straight, but a good press or even just hammering them out slow works fine. Pair that with a simple 1084 or 5160 coil and you got a damn near indestructible blade for bushcraft stuff.

seth68315d agoMost Upvoted

Yeah @fox.derek you ever try grinding a coil spring that still has a slight curve in it though? That twisty stress really messes with your angle.