Modifying a spring

[Scota4570]

I have a junk box spring I want to modify.  It needs a hook.  Does the bridle hook need to be thicker than the the springs thickness?  I was thinking of using a form die and making the hook under red heat. 

Second issue.  What is the likely material and heat treat for a spring from an old shotgun lock?  I am thinking of a quench in canola oil then draw to 750* in a lead bath.

IF I fail I will need to make the spring from scratch.  I am out of spring stock.  I do not see 1075, but I do see 1080.  Get the 1080 or something else on this page:
https://knifemaking.com/collections/hi-carbon-steel




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[Bob Roller]

That antique spring is made from Unknownium and the likely chance of a succesful cold bend is zero.
1075 can be cold bent into  a tight radius or progressive radius as is seen in early flintlock mechanisms and I made a lot of them until I abandoned that style of mechanism in 1970 in favor of the arm and link system that the best British locks have.To me,the Brits have set all the standards for lock making  and copying proven inferior designs has no appeal to me whatsoever.Your swage/forming die will work and it is similar to the one I used but to bend that old one it should be kept red/orange during the swaging process.
Bob Roller 

[Scota4570]

The plan was to bend the old spring while red hot.

How about the Jantz 1080 steel?  Good spring stock?  Something else from another supplier?

[smart dog]

Hi Scot,
I would think 1080 would be fine.  The claw can be thinner than the leaf but make sure it actual hook or claw is short.  It just needs to grab the stirrup, nothing more.

dave

[Scota4570]

Thanks,

A local outfit gave me a big piece of 1075.  It is only 0.083" thick.  That is thinner than other springs I have which are about 0.100" thick at the bend.

Is my freebie piece too thin for mainsprings?

[Craig Wilcox]

McMaster-Carr has 1075 steel in stock.  They have strips and sheets in thicknesses up to and a bit past 1/8".

[bobw]

I’ve made many springs from both 1075 and 1080, both work fine.  Doesn’t matter to me how you you draw it back but I use the oil bath method.  Just cover the spring with motor oil, heat it from the bottom until it boils and ignites.  Let burn until the oil is gone, I keep intermittent heat on it to help the process along.  Obviously somewhat dangerous so equip yourself accordingly.  The springs I make are for single shot cartridge guns and never had a spring fail with this process.

[P.W.Berkuta]

Dixie Gun Works use to sell 1075 annealed spring steel in different thickness and 1" wide don't know if they still do as I purchased some from them many years back. I just purchased some 1075 from McMaster-Carr <1/8" Annealed (Softened)   item #9071K62   47.83>

[Bob Roller]

Thanks,

A local outfit gave me a big piece of 1075.  It is only 0.083" thick.  That is thinner than other springs I have which are about 0.100" thick at the bend.

Is my freebie piece too thin for mainsprings?

I have made MANY mainsprings from .093 and then went to .125 when I revamped my mechanisms about 40 years ago.I would save the .084 and call McMaster- Carr and get a piece of .125 and then there is plenty to
experiment with.
Bob Roller

[Bob Roller]

Hi Scot,
I would think 1080 would be fine.  The claw can be thinner than the leaf but make sure it actual hook or claw is short.  It just needs to grab the stirrup, nothing more.

dave

The style of the swage indicares a major kink in the end of that spring to be used on a Siler style tumbler.
I may have mine but haven't used it in decades.
Bob Roller

[Dphariss]

That appears to be an orginal Sharps/Spencer spring I and would not turn it into something else.

Dan