New Underhammer project from Muzzleloader builders supply

[gmww]

Well I got an email from Susie at Muzzleloader Builder's Supply that my parts are finally coming. I ordered the Underhammer parts and also asked her to find me a stock. What I asked them to do was cut the stock in half where the underhammer receiver would go. I'll attatch the receiver and also use the front half of the stock for the 1" barrel. They inletted the front stock for me.

Here are my questions for those experienced with heating metal. All the parts are cast. The trigger guard is also cast. It will eventually be the main spring also. She told me to get everything fitted and almost finished. Once I do that she gave me some advise.

The instuctions she emailed me was to heat the trigger guard up to a bright red and quench it in oil. Then re-heat it past the dark brown color to a bluish-purple color which will make it into a spring.

This brings up a couple of questions.

Can I do this with a propain torch?

What kind of oil?

Do I drop it in or hold it into the oil?

Also do I clean off of all oil before I reheat it or is wiping it dry enough?

Once I heat it up to that final color do I air cool or quench it again?

If I need a hotter torch can I buy them a the local super-hardware stores?

What torch?

When the parts come in, I'll start photo-documenting and posting as the project goes along.

 

[John Taylor]

You got a lot of questions. Pick a day to come down and we can do 2 springs at the same time. Most propain torches will not get the part hot enough. There are a few that have added OX that have plenty of heet. You can dip the part in any light oil, oil will not quench the part as fast as water. using water may crack the part. Tie a piece of bailing wire to the part and run the heat up and down over the part heating evenly untill a magnet will not attract it, then dip in oil. I don't use a magnet but I have done enough to know by the color when to dip it. The part needs to be polished before drawing the temper so you can see the color change. Part needs to be heated slow, old blacksmiths laid the part on a large piece of hot iron in the forge and watched for the color. It can be quenched or let air cool after drawing the temper.

 

[SusieB]

There are two types of quenching; water or oil. Water quenching is a common use but the treatment is considered surface hardening and can be improved enormously by adding brine or salt to 50 degree or cool water. You can grind thru water quenched hardened surfaces. Its complicated and takes a lot of text to explain. Oil quenching is deep hardening. It makes a more durable and long lasting part, whether its a spring or a tumbler.Its the type of steel used and the carbon content that makes it good for the job required. But really, nothing beats having someone show you how!
Use 80 weight non-synthetic oil. Its best to use an acetylene torch if available, or two Mapp gas. Its hard to get enough heat to red-orange 1750 degrees for a spring. Stay close to the oil when you get it to the color and immediately immerse and slosh the part in the oil. Let it cool off in the oil, but you need to temper within an hour of heating. Clean the part and bright the finish so you will be able to see the color when you start the temper. VERY SLOWLY heat the part up by waving your propane torch back and forth up and down the part. Watch the colors. When the part gets to mid-brown its hard still, but you are almost there. You want to go to the bluish-purple. Lay it down and let it cool off. Don't dip it.

 

[SusieB]

John is right about water quenching small springs and that dipping in water to cool is okay. But I need to clarify what I was talking about or I'm going to get someone off to a bad start! My reply made John sound wrong and he wasn't. The spring we were talking about is a spring triggerguard and the steel the manufacturer uses is an unknown. Since it is investment cast it is most generally a type requiring oil hardening. Water quenching (best to add a little salt!) is for spring steel like 1095. Air or dip in water to cool is optional. A low tone when you "flip" the spring tells you its right. Take John up on his offer to make a few springs!

 

[faw3]

Remember John has dads spring to do too GMWW might as well do it all at once. Blaine

 

[gmww]

Working it out with John for me to make the 3-4 hour drive to his shop. Right now I've been inletting the stock. :hatsoff:

 

[John Taylor]

I got the lower tang assembled with hammer and trigger, the spring needs a lot of filing but has almost enough pressure as is. It will need to have quite a bit of metal removed before heat treat or it will be way to strong. Also the hammer and trigger will need to be case hardened so they don't wear away fast.

 

[faw3]

dad ended up in hospital before he could do any metal takeing off , he said sorry. ...blaine

 

[gmww]

Well I've spent the last week or so working on the action and rear stock. It has an upper and lower tang that needed to be inletted into the stock.

My tools included a 5/8" chisel, hammer, and sand paper. I also have a dremil. Well I increased my total chisels by 100%. I bought a 3/8" chisel. After many hours and a lot of cussing I got the inletting done. The dremil didn't work out like I thought it would. I ended up chiseling little by little until the tang fit in. I used the small round sander on the dremil to fit the end of the tang.

I ground the extra metal left on the castings with the dremil. I just finished glass bedding the tangs in place to take up the gaps left by over zealous chiseling! :cursing:

I was told by Muzzleloader supply that a 1" barrel was the one needed for this action. So I had them inlet the front stock for the 1" barrel. Last night I took a 15/16" barrel and put it at the endof the action along with the stock to get an idea of what it looked like.

Yowwww! This action is huge compared to the 15/16" barrel. I don't see where a 1" is going to look any better. This thing would probably look best with a 1.5" barrel.

I now talking to John Taylor about finding me a 1 1/4" round barrel. I'm going to have to get another front stock for that barrel. I'll save this one for the 1" barrel to put on my H&A underhammer.

I also picked up an obsolete T/C Venier Tang sight to mount on the rear tang. I'm going to see about getting a fast twist .50 cal. to reach out and touch those plates at 200 yards.

 

[Mike Lea]

There are variety of ways to heat-treat a spring. This is the fool-proof the method I use. Remember it is a two stage process: The spring steel must be hardened first and then tempered or "drawn back" to give it its flexibility. (This is where most people run into problems; the tempering/drawing stage!!!)

Because of the size of your "triggerguard mainspring" only a forge or acetylene torch will heat it fast enough and thoroughly enough. (Assuming you do not have a heat-treat oven) Two MAPP torches won't cut it, I garontee. Prolonged heating will damage the structure of the metal AND allow it to absorb atmospheric sulfur and nitrogen which make it brittle.

FOOL-PROOF SPRING HARDENING and TEMPERING:
Using pair of tongs to hold the spring, heat it quickly and evenly with an acetylene torch. (Use a slightly carburizing flame.) Continue to heat the "raw", polished spring to a bright red color in subdued light or slight shade. (Never heat in the dark nor in direct/bright light. It throws your visual color perception off.) For this size spring, quench in 2-4 quarts of 30W non-detergent motor oil by moving it around until cooled. You will have a lot of smoke and flames erupt when you quench the spring. Its avisable to to does this outside.(NOTE: Some folks use transmission oil, dirty crankcase oil, beeswax, etc. That's fine if you want to chance it, but this a fool-proof method.) Use fresh, clean oil to start with and you won't be buying a second spring from Suzie!! I use a 3 gallon galvanized oval wash tub for quenching, but any clean metal container will do.

Begin tempering the spring by placing it on its side in a flat container, like the bottom 2 inches of a 3 lb. coffee can. Pour in enough of your 30W oil to just barely cover the spring. Probably about 3/4" deep +/-.

Prop your tempering tin on two or three bricks and heat from the underside with a propane torch until the oil ignites and burns on its own. Allow the oil to burn (with the spring inside)until all of the oil is consumed except for a thick, gluey, tar-like residue. (This may take 20-30 minutes and look like a tire fire!!) When the spring is cool to the touch, wipe it off, wash off the carbon and residue with solvent and re-polish if you want. Nothing else need be done from a heat-treating standpoint.

In spite of having an electric heat-treat oven, digital pyrometer, heat-treat manuals, etc. this method has been 99.9% reliable for me. I just heat-treated 300 trigger springs using this method of tempering and not one single spring broke or failed to spring back after flattening three-four times in a bench vise. (My customer has not returned a single one or complained since I switched back to this method.) This method has worked for springs as small as sear springs and as large as huge leg vise springs. (That one burned for three hours!)

Granted, there are other tempering methods which employ watching the tempering colors, dipping in molten lead, touching 50/50 solder to the spring, etc., but this one works assuming that you are using spring steel in the first place.

Suzie's triggerguard-mainsprings are cast either from 1095 or 6150 steel. This method will work reliably for either. I use the same foundry on occasion and these are the only two spring steels they cast.

Some time in the future I can get into using anti-scale compound to minimize de-carburization, clean-up and re-polishing, but for now this will put you on the right track.

Good luck and don't let the neighbors catch you.