Author Topic: broken mainspring help  (Read 15502 times)

Offline James Wilson Everett

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Re: broken mainspring help
« Reply #25 on: January 01, 2012, 04:18:29 PM »
Guys,

When forging steel, either high carbon spring steel or low carbon mild steel the temperature can be in the orange hot range, and as the smith forges, the color of the metal cools to the temperature where the steel is black.  At this point the steel can still be forged a little - cold forging, but it is better to reheat at this point.  Heating the steel to much higher temperatures can result in interesting things - like the metal giving off sparks and the metal popping like in welding - it really can misbehave as you found out.  0-1 tool steel is more finicky as it does have a higher alloy content of elements other than iron & carbon.  This alloy is to allow the steel to stay hard & strong at the higher temperatures we find the tool bit is subjected to in modern machining practice.  This is of no advantage to parts for an flintlock.  Personally I like to forge 1095 (a straight carbon steel, iron and 1% carbon) at no more than red hot to avoid things like your adventure.  It does require a short forging time - only a few hammer smacks - and then return to the fire.  The annealing - transition - hardening temperature is much hotter than the forging temperature.

Forging wrought iron is much different than steel as the material is in two distinct parts - pure iron and slag.  If you forge wrought iron the same way as you forge steel it will again misbehave, but not like steel, wrought will split or "broom straw" at the free end.  So wrought iron must be kept at least orange hot and when it cools to red returned to the fire for another heat.  In fact when I forge the small lock parts I always try to allow for some extra length that is later cut back to trim away my inevitable broom straw end splits.

Happy New Year to all
Jim Everett

doug

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Re: broken mainspring help
« Reply #26 on: January 01, 2012, 08:09:33 PM »
Quote
The last time I looked,drill rod was called 0-1
I was going to try to make a spring from 0-1
I tried to make a spring by forging drill rod flat.  It exploded when I hit it with the hammer, flinging red hot globules all over the shop.

     I am sure that I must have made at least 50 mainsprings and a few small springs over the years without any forging problems.  I heat the metal to the bottom side of yellow and stop working it at dull red.  For thin things like springs I water quench and again have never had any problem with either "exploding" during forging nor cracking during quenching.  Most of these springs are for my own guns and many have lasted and been used for a number of years, without problem.  That leaves me to think that what is sold locally as drill rod, may not be O1, assuming that what Dave used was O1.
   I have used the same material occasionally for hollow end mills and quite a few times to make D bit style chambering reamers.  For things like the reamers, I quench spinning into water with about 3/8" of oil on top
    The only time I have departed from using drill rod was to used a piece of automotive leaf spring to make an extremely wide V spring.  It forged OK but drawing the temper to 720F was too cool and both times the spring snapped very quickly in use.  I would not use it again

cheers Doug

Offline Jim Kibler

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Re: broken mainspring help
« Reply #27 on: January 01, 2012, 08:16:05 PM »
There's nothing wrong with O1 for a spring provided it is heat treated properly.  I have used it for springs in the past.  I do agree that other materials may be a little more forgiving, however.

Tony Clark

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Re: broken mainspring help
« Reply #28 on: January 01, 2012, 09:30:13 PM »
I water quench
cheers Doug

Ouch! 

doug

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Re: broken mainspring help
« Reply #29 on: January 02, 2012, 12:42:13 AM »
    The only problem I have had with water cooling was when I made a large twist drill, years ago, and water quenched it.  The drill had deep flutes ground into it and it cracked right down the web.

cheers Doug


I water quench
cheers Doug

Ouch!