Got some colors

[J.D.]

I hardened a friends lock yesterday, and low and behold, the lock came out with brilliant blue colors. Here is the result, still bolted to the block.

Almost, kinda, sorta looks like I knew what I was doing. The colors are pure blind luck, BTW




God bless,
J.D.

[rich pierce]

That's terrific!  Tell us about your setup.

[J.D.]

There isn't much to it. It's just a charcoal fired furnace made of stacked firebrick covered with an old disc blade, as a damper. Gaps of 1/4-3/8" are left between each brick on the bottom course of brick. The draft is controlled by using  bricks to close off the gaps, as needed. The disc blade is moved to either cover the entire opening, or to provide more draft, as needed.


The crucible used for hardening lockplates is nothing more than a 3 X 3 X 8" steel box made of 1/4" plate covered with a lid of the same material. I made a set of tongs with long reigns and wide, long jaws to handle the crucible. A smaller, 3" dia X 5" tall, crucible is used for small parts.

Please excuse the poor photo.




God bless

[rich pierce]

Thanks, think I can replicate that.

[Acer Saccharum]

That's terrific, JD! Thanks for posting. I like your damper disc!

ACer

[J.D.]

Thanks Acer, this furnace is a close copy of the one you posted on the old board. The only difference is a way to control draft. If anything, I have a problem of not getting parts hot enough. I have had to harden a few parts a coupla times to get them right.

One of these days, I'll find a pyrometer to gauge the temps in the furnace.

The furnace is great for annealing frizzens too. Annealing parts packed in charcoal eliminates scaling, in addition to adding some small amount of carbon to the parts.

Thanks to you, Jerry and a coupla others, I'm learning to harden a variety of parts.

God bless

[jerrywh]

That's the way a lot of the old timers did it. I started out with a wood stove. If you put thicker spacers in between the plate and the lockplate you will get less blue color.

[LRB]

  Can this be done in an electric heat treat oven? Without sooting up the interior.

[J.D.]

Thanks Jerry, I did use #10 SS nuts for spacers. That didn't provide allot of space between the block and plate.

I have some heavy wall, 3/8 ID steel tubing, but thought better of using it, thinking that it was of a too large diameter.

I really wasn't after colors, but will take what I can get. 

I tempered the lockplate at 500 degrees, thinking that resilience with some hardness would be the best way to go.

What do you recommend for tempering temps.

Thanks, and God bless.

[smart dog]

LRB,
Absolutely.  I frequently color caseharden parts in a NeyCraft electric furnace using iron pipe or a steel box as the packing container and bone charcoal as the packing material.  Just leave the door of the furnance open a crack to allow fumes to escape until you reach about 800-1000 degrees and then close the door and continue.  If you use clean charcoal such as that sold by Brownells, there will be no soot.  Below is a photo of a lock I color casehardened using that set up.

dave

[jerrywh]

JD.
  For more space you can just use two nuts instead of one. 450° is what I temper at exsept for screws. I take the screws back to 600°. I have had them snap off when tightened.
 Dave Pearson. Thay lock of yours is about as good as it gets. Fantastic.

[smart dog]

Thanks Jerry,
I basically follow the suggestions you posted on case hardening over the years.  They work.

dave

[J.D.]

Wow Dave, that is nice. While I wasn't after colors, in this case, I plan to color case harden a coupla locks for myself...and I will follow Jerry's instructions. They do, indeed, work.

God bless

[littlefat]

Jd did you get that furnace on Ebay.     nice colors !