new sear bar from A-2

[M. De Land]

Made a new sear bar a couple of evenings ago of A-2 and am about done with it as it is being annealed in my heat treat furnace as I type.
The hardening protocol is.......... wrap tightly in two wraps of brown or target paper,wrap tightly in two wraps of stainless tool wrap and attach a black wire retrieval loop. Heat slowly to 1450,hold for five minutes and then elevate the temperature to 1750 and hold for 30 minutes.Remove and let air cool inside of tool wrap.
The temper draw is 500 degrees for 1 hour, twice, without tool wrap.
This will add approximately 1/3rd more travel length to the cock swing and does make a much better shower of sparks in the frizzen pan.
I think this may do the trick on this guns that has yet to be fired by me after owning it for a year and a half. It had defied me at every turn to get it to spark correctly. Here's hoping! I'll post some pictures of the bar when done so folks will know what I'm trying paint a picture of with words in case they run into the same trouble. MD

 

[bobthemotorcycle]

Good stuff. I have lots of respect for guys who have heat treat knowledge.

There are guys who make steel, guys who machine steel and guys who know how to heat treat steel and the ones who heat treat steel have more knowledge in my opinion.

Its not as simple as heating it up and cooling it down.

I am learning heat treat in college right now. Actually last week but also this week some.

 

[M. De Land]

Well thanks, but the truth is I looked up the dope on the internet and plugged the figures into my digital Even heat oven and it does all the rest by itself.
I do like to discuss ideas with folks and when I pick up some good ones I feel like I found a gold nugget.Always on the search for a better mouse trap than I currently have.
I particularly like folks to challenge my thinking so I can test my ideas against their's to see if it will hold water.The trick is not to piss them off while trying to test the thinking. :grin: MD

 

[M. De Land]

New sear bar on the bottom. Notice the natural case colors on it if it shows up in the picture.
I fit and stoned it up and it works great with a shower of sparks from the frizzen.
I do wonder about the spark focus though lighting the pan powder efficiently as sparks seem to fly all over the lock area. Lot for me to learn about flint lock tuning. It will be interesting to see how long the English black flints last now.MD

 

[M. De Land]

The cam angle on the top back of the sear bar is what adds to the cock travel by about a third and causes a much more active spark shower. It retracts the cam drum rotation probably 5-10 degrees farther, on the inside of the cock, causing it to have more swing. MD

 

[M. De Land]

Learn all you can at school Bobby. I've been making springs,triggers, sears, hammers, reamers dies and all sorts of tools and jigs and etc. now for over 30 years and have just barely scratched the surface of stuff there is to know about it.
The case hardening/coloring has really been an interesting study, mostly in patients and frustration with the many failures but when they start to turn out the way you want then it sure makes the effort worth it all. MD

 

[Vaino]

Nice going w/ the A2...because of the 1750 soak temp, A2 will decarburize if not sealed in stainless steel envelopes. At a 500 degree draw, the piece would be pretty hard...isn't there a lower draw temp for a hardness of RC 57? Think the sharp corner will hold up? Wish I had a heat treat furnace....learned heat treating in the second year of my tool and diemaking apprenticeship....did it for 9 mos. Again. nice work....Fred

 

[M. De Land]

Thanks Fred, funny how you pick up these little tricks over the years and forget where you got them. I like to put two wraps of target paper around the part inside the tool wrap.The paper burns,seals the steel in the ash and the tool wrap holds it all together.
The more I use this steel the better I like it. About a month ago I made a single set trigger for a Low Wall out of it also and it turned out just as well. Good stuff but expensive.
The trigger on my 1860 Colt is 0-1 and it also is very good for these black powder gun applications.

 

[M. De Land]

Oh, I forgot to mention that you are right on about the hardness according to the specs. It should be right about 57-58 rockwell.At 350 for the two, 1 hour sessions it is supposed to yield 62 which you know is file hard. All the edges on the sear bar have been chamfered with a diamond lap except the sear edge which gets only a stone edge break. Mike