Some Challenging Springs

[mooncoon]

I have had to make a number of springs for my guns over the years but it seems like recently the last 3 have been somewhat challenging. Most flat springs work up and down and involve bending the long arm of the spring. Making a springy piece of metal is easy, it is getting the bends and shape correct is what is difficult.
The first gun below is unusual in that the spring works by pushing fore and aft and accomplishes that by changing the shape of the bend in the spring. The butt end of the spring is secured in a notch in the frame and if the spring is to short it will fall out and if too long the bend is too close to the frame to change shape



The second spring is in a small screw barrel pistol which is double action only. What makes it unusual is that the spring is connected to the hammer by a toggle linkage but that linkage is an extension of the hook which is pulled by the trigger when firing the gun. That forces the spring to slide forward in addition to bending down and to slide back as the hammer falls



The third spring is more or less conventional except that it sort of doubles back into a notch in the bottom of the butt and secures to the hammer with a toggle or stirrup link. The catch with this one is that when the spring at the top of its arc or travel potentially hits a corner in the top of the frame just behind the hammer. Changing the curve of the spring to give it more tension (preload) also changes the effective length of the spring which requires changing the S curve at the bottom of the spring which needless to say changes the angle of the long arm which requires more trial bends and cursing

 

[H Wally]

Good lord you've been having fun eh? I don't envy you on the last two at all

 

[mooncoon]

there was another spring that I did not post partly because I didn't take a photo of it and partly because it was easy and straight forward. What is important though is that it showed me a good way of installing the small spring that you find on the hand of many revolvers. The spring I made was about 1/8" wide and 1/2" long and .014" thick. It fit in a thin slot much like a hand spring but there was a tiny hole drilled just beside the inside end of the slot. The reason for the hole was that the spring had a small bump at its inside end and the spring slid sideways into the slot with the bump fitting inside the drilled hole. Important point is that you cannot pull the spring out of the slot because the bump keeps it in place. It seems to me that that would be a good way of securing hand springs in revolvers. They seem to be factory installed by crimping in place and it can be difficult to keep a replacement from sliding out. A small hole at the side of the slot and a corresponding bump on the spring would keep it in place

cheers mooncoon

 

[Ol' Flinter]

With the skill and patience you have, you should be doing hip and knee replacements!

 

[superted]

If you are not already familiar with them, the Brownell's "Gun Kinks" books have CHAPTERS on various weird and obscure (to anyone not making springs) "tricks of the trade" relating to spring making and its related problems submitted by various gunsmiths/spring makers that may be of interest to you. Also a lot of "gunsmith" related jokes included too... From your previous posts and comments I suspect you would find the stuff interesting and maybe helpful. They are WAY above my PAY GRADE!!!!

 

[NorthCoastBigBore]

Plenty tricky work Mooncoon, great job as always. Always interesting to see these projects.

 

[Magellann]

I tried making a spring a few years ago for an old double barrel hammer gun, I gave up after I broke about 4-5 springs. I couldn't make it without it getting too brittle.
I found a used one at Epps for about $5.00 one day and it fit like a glove.
You seem to have figured out the tricks of the trade.

 

[mooncoon]

I tried making a spring a few years ago for an old double barrel hammer gun, I gave up after I broke about 4-5 springs. I couldn't make it without it getting too brittle.

I have probably posted it before but will go over the basic process that I use. I make my springs from drill rod, usually 3/8" diameter. It is probably 1095 steel but that is a guess. I heat it red hot and hammer it out to about .1" at the thickest point and about .07" at the thinnest. Thickest is usually at the bend for a V spring. While I used to bend the hook into the rod using a hardy and a round edged cold chisel, for the last few years I have been leaving a bump at the end and filing that into a hook. Once I have the spring to rough dimension, I heat it again to red hot and put it in a bucket of wood ash to cool slowly and anneal. When cool, I lightly grind the scale off of the surface and then create a straight edge on one side. I grind the other side to width leaving a tab sticking out for the future pin that sticks out and goes into a hole in the side plate. I also leave a small tab at the end which becomes bent up and pushes against the thickened portion on the inside top of the side plate. After filing smooth, I bend the tab on the end up and also bend the V shape in place leaving the V about 1/4" or a bit more open to create preload when the spring is installed

Bending the V is probably the most critical part because it is difficult to get it in the right location. The tab which becomes the little pin allows me to locate it after bending and to compensate for where I have made the bend. Final stage is to heat red hot and quench in water and then reheat in molten lead to draw the temper. On my high temperature thermometer, that is 720 F to 740 F. That temperature can also be estimated by floating a small THIN piece of steel on the surface of the lead and watching the colours run as the lead heats up. Thin so that you are measuring the temperature of the surface of the lead and not the air a short distance above. The colour you are targeting for is when dark blue/black changes to grey. Pull the plug at that point and make sure that the spring remains submerged in the lead so that it is uniformly hot all the way through. Remove from the lead and tap it a couple of times to shake off most of the lead then a bit of abrasive tape to clean the rest off.

A point of caution; there are several blacksmithing books around and all of them seem to give the same temperatures for the oxidation (colour) spectrum. Those temperatures at least as applies to springs seem to be way off and don't seem to be either Fahrenheit or Centigrade.

Another caution; I have used automotive spring stock a couple of times and it seems to require a significantly higher temperature to bring it to spring temper; I stick to drill rod for just that reason --- drill rod is very predicatable

cheers mooncoon

 

[Aries-]

Friend of my dads makes springs for flint lock locks. And uses the same methos for tempering. But uses basic store bought spring stock. He just has a high quality lead pot and sets the temp and lets it come to temperature and leaves the spring to be in there for a while.

Im not big on some of the methods for tempering out there. Take a bottle lid and put motor oil in it then coat the spring and ignight the oil in the lid. Let burn down and you have your spring. Seems to work well for some people others it does not work. Id rather err on the side of caution and use the lead pot method.

 

[mooncoon]

Im not big on some of the methods for tempering out there. Take a bottle lid and put motor oil in it then coat the spring and ignight the oil in the lid. Let burn down and you have your spring. .

I have made 20 or 30 springs using a burning oil method. I stopped for a couple of reasons; over the last few years, automotive oil seems to be synthetic and does not burn well and second was that if it is raining when you use the method, the rain often puts the flame out. The burning oil method I used was to lay the spring across 2-- 1 1/2" finishing nails in the bottom of a small sheet metal tray ( mine was home made and about 2" x 4" x 1" deep. cover or almost cover the spring with oil, heat with a torch until it starts burning and when the oil burns away, the spring is the correct temper. It takes 15 or 20 minutes for the oil to burn away. Witch craft but it works for me. (obviously harden the spring by heating red hot and quenching before drawing the temper)
I suspect that using used automotive oil might work because of the carbon in it but the molten lead is much easier

cheers mooncoon

 

[10x]

I have probably posted it before but will go over the basic process that I use. I make my springs from drill rod, usually 3/8" diameter. It is probably 1095 steel but that is a guess. I heat it red hot and hammer it out to about .1" at the thickest point and about .07" at the thinnest. Thickest is usually at the bend for a V spring. While I used to bend the hook into the rod using a hardy and a round edged cold chisel, for the last few years I have been leaving a bump at the end and filing that into a hook. Once I have the spring to rough dimension, I heat it again to red hot and put it in a bucket of wood ash to cool slowly and anneal. When cool, I lightly grind the scale off of the surface and then create a straight edge on one side. I grind the other side to width leaving a tab sticking out for the future pin that sticks out and goes into a hole in the side plate. I also leave a small tab at the end which becomes bent up and pushes against the thickened portion on the inside top of the side plate. After filing smooth, I bend the tab on the end up and also bend the V shape in place leaving the V about 1/4" or a bit more open to create preload when the spring is installed

Bending the V is probably the most critical part because it is difficult to get it in the right location. The tab which becomes the little pin allows me to locate it after bending and to compensate for where I have made the bend. Final stage is to heat red hot and quench in water and then reheat in molten lead to draw the temper. On my high temperature thermometer, that is 720 F to 740 F. That temperature can also be estimated by floating a small THIN piece of steel on the surface of the lead and watching the colours run as the lead heats up. Thin so that you are measuring the temperature of the surface of the lead and not the air a short distance above. The colour you are targeting for is when dark blue/black changes to grey. Pull the plug at that point and make sure that the spring remains submerged in the lead so that it is uniformly hot all the way through. Remove from the lead and tap it a couple of times to shake off most of the lead then a bit of abrasive tape to clean the rest off.

A point of caution; there are several blacksmithing books around and all of them seem to give the same temperatures for the oxidation (colour) spectrum. Those temperatures at least as applies to springs seem to be way off and don't seem to be either Fahrenheit or Centigrade.

Another caution; I have used automotive spring stock a couple of times and it seems to require a significantly higher temperature to bring it to spring temper; I stick to drill rod for just that reason --- drill rod is very predicatable

cheers mooncoon

The use of a PID can control the temperature of your lead pot to within 2 degrees F.

 

[mooncoon]

The use of a PID can control the temperature of your lead pot to within 2 degrees F.

OK, I will bite ----what is a PID? There does seem to be some leeway in temperature. In recent years, I heat the lead to 720 F or more and under 760 F and that range seems to work. Much below 700 F leaves the spring brittle

cheers mooncoon

 

[10x]

OK, I will bite ----what is a PID? There does seem to be some leeway in temperature. In recent years, I heat the lead to 720 F or more and under 760 F and that range seems to work. Much below 700 F leaves the spring brittle

cheers mooncoon

http://en.wikipedia.org/wiki/PID_controller

I have built a couple to keep my lead pot at a stable temperature.
No more wrinkled or frosted bullets.
When I set it at 620F it keeps the alloy between 618F and 622F

Cost to build If you are careful - about $25.00 from ebay if you use the Rex C100 PID and are willing to replace the relay in it with jumpers so it will run an 25 amp S.S.R. (Solid State Relay).
the PID runs about $14.00 shipped, a K type thermocouple with a 5" probe is about $6.00 and the S.S.R. adds about $4.00 to the price.

Check out Reloading equipment on Cast boolits....