How to temper TRS springs?

[jsn]

It has been my experience that the secret to good flintlocks is in the polishing and hardening, especially on early locks that do not have internal bridles. You can double the speed on an early lock by hardening the ****, tumbler and lock plate you can also speed up later locks by making sure the lock plates are hardened. We use 4140 steel on all our lock parts except frizzens and springs which are 6150. These are oil hardening steels, but we don't recommend oil hardening, but you will find that if you case-harden the lock plate, internals, and frizzen then use a water quench it will give you a finer finish and smoother bearing surface. You are not adding anymore carbon by doing this, but you are keeping the parts from losing any carbon while you are bringing the part up to the correct heat range (1650° to 1675° or very bright reddish orange). You will find this especially true with frizzens where carbon content is very critical. A case-hardened and water quenched 6150 or 1095 steel frizzen will spark 10 times better and hotter than an oil hardened one. Always be sure to draw the tail of the frizzen to a deep blue color up into the edge of the pan cover area.

To harden a spring we use a water quench. Use a propane torch or a rich flame on an oxyacetylene torch. Bring the spring slowly up to a very bright red almost orange (1500°), making sure the spring is a consistent color all over, then drop it into a container of room temperature water. Handle the spring carefully, as it is now glass hard. Polish the spring. For tempering the spring use an area where the light is not too bright so you can see the color changes easily. Start heating the spring from the largest end first going over the entire spring and the colors will start out a straw or gold color going into a scarlet or purplish color, then into a shinny deep blue color, continue heating slowly and this blue will disappear and start all over with a clear shinny color, then back into the gold color, then the scarlet or purplish color (approx. 700°), then into a dark blue black (approx. 750°). As soon as you get the blue black color even lay the spring down on a piece of wood an let it cool, when cooled it will be a perfect spring. If you find that it does not have enough tension, re-harden and re-temper to just as the blue black color appears, on smaller springs you can stop at the purplish color (approx. 725°). I have re-hardened and re-tempered some springs 8 or 9 times to get just the right feel. Always polish the bearing surface on the foot of the spring. If you do not want to try hardening your springs just return them after you fit and polish them and we will harden and temper them for you.

The Rifle Shoppe

Can You guys critique or verify this from The Rifle Shoppe?

 

[jerrywh]

First off --- I’m wondering why a company like TRS doesn’t have a heat treating furnace.
Can we agree that a furnace is better and more accurate than a torch?

1650 to 1675 is a temperature for case hardening not hardening a spring. It is possible to case harden spring steel like frizzens. In fact I usually always do. Then temper them.
The rifle shop temperatures are almost exactly what I have been saying. But, Unless he is raising the tempering temperature very slowly he is running the risk of not giving the steel enough time to temper all the way through. His system sounds pretty good though. Especially with springs made of 6150. A very forgiving spring steel.
Bear in mind just because a person sells castings doesn't make him a expert at spring making. That goes for anybody.
In this case I suspect the information is pretty reliable. I read a lot of books with lousy information in them on gunmaking. I know some writers who don’t have the slightest idea what the yare talking about. I have seen more incorrect information on spring making, color case hardening and engraving than any other subjects .
PS-- don't try to case harden a part with gold inlays at 1600° or 1650° or the gold will be gone. You don't need to tell me that gold melts at 1850 or better, I know that.
PS-- I don't need to do mine 8 or 9 times. They are right the fist time. Thats where a furnace comes in or a lead thermometer.

 

[jsn]

soo if i raised the temperature slowly with a propane torch which is what I will be using would that work well? and what would the timetable with that be?

Start heating the spring from the largest end first going over the entire spring and the colors will start out a straw or gold color going into a scarlet or purplish color, then into a shinny deep blue color, continue heating slowly and this blue will disappear and start all over with a clear shinny color, then back into the gold color, then the scarlet or purplish color (approx. 700°), then into a dark blue black (approx. 750°). As soon as you get the blue black color even lay the spring down on a piece of wood an let it cool, when cooled it will be a perfect spring.

 

[jerrywh]

If your detrmined to use the color method I suggest you put the main spring on a large piece of iron or copper and heat the large piece and the spring together very slowly until the proper color is reached. Then let them cool together. the large piece will hold the heat for a longer period of time.
Polish the big piece so you can see the colors.
Don't you have a lead pot?? Lead thermometers only cost about 30 dollars.
You can also use a iron plate on a elctric stove burner. Put the spring on top of the plate.
When the spring turns the proper color turn off the burner. Heat slowly. Don't use your wife's frying pan it might warp it.
Old time gunsmiths called this form of tempering frying the spring.

 

[LRB]

would quenching in used motor oil help with carbon issues?

No. Carbon loss is from prolonged heat soaking, which is required with some steels. There are protective coatings that can be used to prevent carbon loss, and scaling. Motor oil makes a very poor quench oil in any situation. ATF is better, but not ideal. Unless you can do no better, and different steels require different quench mediums to effect the proper cooling rate when the steel goes into the quench. Some steels are subject to crack when cooled too fast, and some will not properly harden if too slow. Commercial quench oils are formulated to have different speeds of cooling, so that one can match the quench to the steel. But they are expensive, and normally just not practical for the home hobbiest, who most often will just have to do the best he can.

 

[Stophel]

Jerry, last I have read, virtually everyone, including Chambers, uses 6150 for their springs.

 

[jerrywh]

I just sent an Email to Barbie to confirm that he is using 6150. A couple of year ago he told me he was using 1095. But it really doesn’t make any difference as far as the heat treating process goes. When I was having lock kits cast the foundry gave me my choice. Now things have changed. I noticed that Jims springs are heavier than they were years ago. maybe that has something to do with it.
As far as quenching goes I agree with Wick Ellerby , Motor oil is a lousy choice but it does work. I quench springs in room temperature water with about 1/8" of transmission fluid on top. The oil breaks the shock of the water. I figure that is the best of both worlds.
Old time blacksmith books used to say mineral oil. 50 years ago I used bacon grease warmed up. When I used a lead bath I had the lead warmed up before I quenched. As soon as the spring was quenched I went right to the lead bath before the spring got to room temp. The burnt oil kept the lead from sticking to the spring. After tempering I would repolish the spring and blue it with a torch just for looks.

 

[Stophel]

I've been using WD40 (the thinnest oil I can find...and the only good use for this stuff I know of!), in a coffee can warmed up on a coffee hot plate. This for springs and O1 Siler parts. Kasenit and Hot water for frizzens.

 

[jsn]

Im 16 soo my mom might get a bit mad if I use the stovetop for springs but ill compromise by fixing supper and at the same time I can cok the frizzen!
I will use mineral oil as the quench I believe since I have that,

Do I need anything on the pan like oil?

 

[jsn]

Could I also do the self clean setting on the oven for 30 mins?

 

[Zonie]

You said, "I just sent an Email to Barbie to confirm that he is using 6150. A couple of year ago he told me he was using 1095. But it really doesn’t make any difference as far as the heat treating process goes..." and I don't quite agree.

6150 steel is an oil hardening steel that under some circumstances can be water quenched (with a risk of cracking). 1095 is a water hardening steel that will not develop its full hardness if it is oil quenched.

I know. Picky, picky, picky. :grin:

 

[jerrywh]

Zonie.
I use a room temperature water quench with 1/8" of transmission fluid on top. Works for both types of steel. It's fool prooffor "MOST"fools.
Besides I find many contradictions to that.
http://www.suppliersonline.com/propertypages/1095.asp#Spec

 

[matt denison]

It's interesting that they describe 1095 as an oil quenching alloy. I and many many others have been quenchiing 1095 frizzens in water since forever. I've never had any problems. I don't use a layer of oil on top because for some reason dogs like to drink from the quench bucket when they come to visit. :youcrazy: :idunno:

For what it's worth I also quench 6150 springs in water too. (and tumblers and sears) Water quenching has big advantages over oil: parts are dead hard so you have a specific starting point to temper from, parts are much easier to clean after quenching, no stinking oil burning smell or smoke. When you do a hundred plus/minus at a time that becomes important.

 

[jerrywh]

Laffindog.
I like your web sight and your guns.

 

[LRB]

Zonie, maybe a year ago, maybe a tad more, Barbie gave the steel type, and it wasn't 1095. It was an alloy that had high shock resistance, which could have been 6150, but possibly even something else. As far as 1095, on thin parts, water, or even brine quenching is risky. Most knifemakers useing 1095 use Parks #50 oil. You are correct in that 1095 will reach full hardness only with a water quench. When a water quench is listed in spec tables, it most often means brine, which is less violent, cools more evenly than plain water,and does a better job of hardening. 1095 requires a quench that will cool from 1475°, to below 900°, in .8 of one second. Brine does this, but Parks #50 oil is a close second at 1.02/1.03. The difference is insignificant as far as real life, and most knifemakers would rather lose a fraction of hardness, than a blade. Parks oil is not cheap, so the next best is warmed canola oil, which does the job under 2 seconds. As far as knife blades, or springs, that should work well enough.

 

[matt denison]

I'm wondering if some of the discrepency comes from most knives (and some springs) being forged from some sort of plate and either ground or hammered to shape where as frizzens and most commercial springs are cast. A difference in the structure? might give different results with water or oil? Or is it the risk factor of cracking the part/knife? Knives are made to be tough, frizzens are made to be hard and only tempered at 350 degrees which isn't really much at all. I'd call it normalizing rather than tempering. So, even though we are all talking about 1095 we are really talking about two distinctly different grain structures. ?? What does Zonie say?

 

[jsn]

We use 4140 steel on all our lock parts except frizzens and springs which are 6150.

This is the type of steel that TRS uses and they say they use a water quench, soo if they do it should I?

 

[Zonie]

laffindog

We are basically in agreement.

I think of 1095 as a wrought material and due to its propensity for developing cracks if fairly thick cross sections are water quenched I can see where the use of a thin oil quench might be beneficial. Although the materials full hardness won't be reached perhaps for a spring which is going to be tempered at a fairly high temperature the maximum hardness isn't important.

The low alloy steels like 4140 and 6150 can be cast lowering the production costs of making parts which need to be hardened.
In my opinion, the random grain structure of castings can never hope to make as good of a spring as wrought material can but for our purposes it does do the job quite well.

 

[jerrywh]

Hey Wick.
I woild like to see some of your knives.
How do you quench a long knife blade without warping it??

 

[LRB]

Jerry, I don't. I seldom get a long one that does not warp. With 01, as soon as you can handle it out of the quench, you have about 5 good minutes that you can straighten by hand pressure. It takes 01 as much as 15 minutes to reach full Martensite conversion. During the first half of that time, you can safely straighten most warping. If you don't get it all, you go ahead and temper, then you polish the blade and determine where you would bend it for it to come straight. Lock it in the vise and carefully heat the spine in that predetermined area to dark blue or more if possible, being careful to watch that no colors go to the edge. Then you hand pressure the blade beyond straight and pour water on it. It will spring back a bit but lock in either straight or close. You may have to repeat to get it where you want it. All carbon steel blades will react to this, the simple steels even more so, but you cannot let the colors run to the edge.