Is this logical thinking ?

[lpspurgeon]

So I just finished HT a new slip joint and waiting for the handle material to arrive. Prior to HT I made sure the Rise and fall was set properly and the lock up of the spring and tang were spot on ( With the correct 3d slope.) Everything was looking great. I was anxious to see how she worked and drilled the liners. Everything went together perfectly. No wiggle in the blade, pins are not bending. When I opened and closed it the first time it worked just as I had hope. On the second time however when the knife was full open there was wiggle?

My thinking and I am hoping this is the right line of thought , is that the hole ('s) of the liner may have stretched? As I am waiting for the handle mats to get here I cannot slap that on to prove my theory and the tracking info has it arriving Thursday. I think the wait is enough to drive me insane.

Dose this at least sound like it makes sense ??


Thanks for any feedback

James

[Don Robinson]

Sounds like the HT for the spring failed and the soft spring bent.

What material was the spring made from?

How did you HT it?

Austenitizing temp.?

Temper temp. and duration?

[SVanderkolff]

What were the liners made of. In order for the hole to stretch that easily it would have to be a very soft material for the liners. Possible but not probable.
STeve

[lpspurgeon]

Thanks for the comeback fellas.

This is the first time I have used 01 for a folder. I know it will rust but it should hold a good edge. ( If I read everything right) and the local knife supplier had it in stock

As far as heat treating I heated the spring to 1450d and started timing 20 mins got to 1500
Pulled it out and oil quenched.
Placed it in 375d oven for two hours
Buffed it up on the buffer
Heated it with a torch until blue.

Please let me know if this is incorrect. I think my designs and fit are getting better but wont know until I get a good spring eh

Oh and for the liner material...... It uh umm is the SS kick plate you get from the box hardware stores. right at .043 thickness

Thanks again

James

[Don Robinson]

I don't remember the temp./color charts, but my guess is that blue temp. was too high for 0-1.

[lpspurgeon]

But everything prior to the torch is correct ? I will double check the color temp chart... Wait lol what temp would you recommend ?
** Checked with the torch / color chart should have been right around 550d

[Crockett]

I've made just a few O1 slip joints, but I've heated the springs to a gray color which is the last color your'e going to see. I thinks it's about 800F. Those knives are still going strong after 2 or 3 years.
Don

[Don Robinson]

Originally Posted by lpspurgeon

But everything prior to the torch is correct ? I will double check the color temp chart... Wait lol what temp would you recommend ?
** Checked with the torch / color chart should have been right around 550d

I don't know what you mean by 550d.

You want a hardness of 40-45Rc for the spring. I don't use 0-1, so someone else will have to provide tempering information. Or google it.

[Crockett]

Well I am a rank armature when it comes to heat treating. Based on what I?ve learned by reading and (limited) doing is this; Tempering O1 at 800 degrees F yields hardness of 49, or some charts say 48-50 Rockwell C. Tempering at 900 results in 46 (45-47) RC.

When using a torch to draw the temper, as you come up through the colors you?ll see brown at 480 deg., brown/purple 500 deg., purple 520, dark purple 540, blue 575 degrees (a bigger jump than the previous color changes), then gray appears at 800 degrees (biggest increase of all). There is no color that corresponds with 900 degrees, the next change you see is the steel begins to become incandescent, giving off a slight dull red glow visible in low light. You just hit 1000 degrees F. I don?t know what the RC hardness would be but I know it?s too soft for a spring.

So while 900 degrees would probably give the best spring temper, if you?re using a torch and doing it by eye you must stop at gray 800 degrees because you have no other reference until it?s too hot. If you had a good HT furnace that you knew was accurate I guess you could get 900 deg.

Edit to add: I just looked at a temp-to-RC hardness table and it says 1000 degrees F. results in a harness of 40-44.

[lpspurgeon]

I guess what I am not crystal on when doing the torch method is the tempering.

I understand to heat it up to the 1500 degrees

Then oil quench

But then I get fuzzy.

Do I do the oven tempering of 375 for the 2 hours

Air cool it

Then hit it with the torch to a gray ?

Seems like this would undo the oven temper ?

Also the blade would have a normal heat treat so it would be harder right ? around 50 RC so wouldn't it cut into the softer spring ?

Again thanks so much for the input guys

[Crockett]

What you just described is exactly the way I?ve done it.

After 1450-1500 and then quench in warm oil, I temper both blade and spring for two hours at 375-400 degrees. The spring will then be the same hardness as the blade, IIRC around 50 RC. Then I sand the spring to get back to bright metal so I can see the colors, and use a propane torch to heat the spring to the 800 deg.

This does soften the spring as compared to the way it came out of the tempering oven. I guess the spring really doesn?t have to be tempered along with the blade, you could just use the torch. But I figure since you have to wait on the blade anyway, why not put the spring in there too. I can?t see how it would hurt anything and might actually help one way or another.