Slipjoint help!

J

jkf96a

Well-Known Member
I'm working on my first slipjoint. I'm using 3/32 CM154 from Aldo. I foil wrapped, soaked 10 min at 1600, then ramped up and soaked 25 min at 1900 then plate quenched. I tempered the spring 1 hour at 450, then 90 minutes at 1150. Tempered the blade 90 minutes at 450, twice. Don't have a rockwell tester.

Got it put together and had a few issues. One, the spring was galling. I'm assuming that means one of two things. One, it could be a geometry issue on the tang. Two, the spring could be too soft. Which is it?

I was using 1/8 canvas micarta, linerless. I was getting almost too much snap/pull on my dry fit, so when I put it together, I used a piece of heat treat foil on each side of the blade when I peened it. I removed the foil after I peened, and it lost its snap. I'm guessing again, one of several things. One, and most likely, I peened to tight. Two, the spring is too soft.

I was using 1/8 416 pins. Is that too soft of material for the pivot pin? Would brass or nickel silver be better?

I went ahead and took it back apart by grinding off the pin heads and tapping them out, and of course cracked the scales in the process.
 
From Crucible site it looks like you did not soak long enough. Here is the data below,

Hardening

Preheat: 1100/1250F, equalize, 1400/1450F, equalize.

High Heat: 1900/2000F, hold 30/60 minutes at temperature.

Quench: Air, positive pressure vacuum, interrupted oil. Cool to 150F.

Temper: 400-800F, hold 1 hour/inch of thickness, 2 hours minimum.
Tempering between 800 and 1100F should be avoided, due to a decrease in both toughness and corrosion resistance.

Cryogenic Treatments: Refrigeration treatments can increase hardness and may improve long term dimensional stability by transforming retained austenite. Refrigeration treatments should generally be performed after the first temper, and must be followed by a temper.
Typical Properties
Tempering
Temperature
°F
Hardness HRC
Air
Oil
Oil + Ref.
AQ 59 61 63
212 59 61 65
400 56 59 62
600 54 56 60
800 55 57 60
1000 58 60 61
 
I would use a pin of the same material you used for the washer so it will hide. I use 1135 on my over for springs and it gets me 47-48. I was getting around 44 at 1150. A corner on the tang that is too sharp can cause it dig into the spring. Could have pinched it a little too tight and kept the spring from being able to move like it should. Check for a PM.

Craig
 
How about finish being a cause of galling?

Was everything nice and polished?

Time at temp should have been OK, I go to 1950, hold for 20, and get 61 to 62 rc regularly.
Pretty sure the high hold times are for thicker material, though one of our metallurgist friends can answer that for sure.
 
The galling issue could also be caused by the thickness of the spring. If the spring is even .0005 thicker than the tang, it will bind. For a proper fit, the end of the spring (in front of the pin) should be thinner than the blade tang by .001 to .0015 to allow the spring to rise and fall without binding.
 
Alright, so I rounded off one more spot a little better on the tang. Parts are polished to 1000 grit. Still galling some, even with lube. I haven't mic'ed the spring vs. blade yet, but by eyeball, the spring is slightly thicker than the tang. Will fix that next. I didn't think about the spring pin being too tight, could be that. All those things aside, I still think my spring is likely too soft. I'm leaning toward either re-making the spring altogether, or trying to re-heat treat the one I have. Didn't use washers this time, but will order some for the next one. Still have it all apart, probably won't peen it up again until I get the spring re-done.
 
Jason,
As for loseing the snap after peening I would say you peened the center pin too tight. What can happen is the pin will bend slightly causing the spring to rise just a little. You just need enough peening to swell the pin in the holes.
I would guess the spring tension was too strong and caused the galling. I always leave the tang and spring at 400 grit, this helps to hold oil in the joint. I also leave the spring
.001 thicker than the tang and use a .002 spacer on each side of the tang when peening. That is how I has taught and it seems to work well, Ive never had trouble with the spring hanging up.

Sean
 
After talking to Craig for quite a while, I had more info than I knew what to do with :) That said, I took some material off the spring to make it lighter, and it now works like a champ dry fitted. Nice snap, no galling. Have to polish it all back up and make some new scales, then back to the peening, much lighter this time.
 
Got 'er done! Has a couple of blems, but has good snap open and closed. Still pretty close to flush at all 3 positions. Blade isn't centered. Nice hand finished blade though.

006-e1295990118227.jpg
 
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