anneal or bend red?

[martin9]

I have a pistol triggerguard that's gonna need some bending to fit the curve of the grip.....more than a little cold bending.  It's  a cast steel guard so I'm wondering what y'all thought as to whether I should try to get it glowing hot then bend it or will annealing be sufficient? Or will neither work...can't say I've had to heat bend cast steel before. I broke a guard that looks like it came out of the same foundry and it was very grainy looking at the break.

[Clint]

I would recomend that you anneal the piece and bend it cold. In order to bend it accurately, make two bending tools. One is a simple fork that is held in a vise, a piece of 1/4" x 1" steel with a quarter inch wide slot cut in the end will work well. The other 'wrench is a similar bit of steel with the slot cut into the edge. With the end slot in the vise and the trigger guard in the slot, the 'wrench' can saddle the guard from the top and the metal between the two will bend. go slow and you can get a very close bend that will match the curve of the stock. This system is a mini version of common blacksmith's bending wrenches and there is a lot of power in it.

[martin9]

Thank you, I like the sound of that. I've got a lot of scrap steel laying around I oughta be able to make a couple wrenches out of.
 

[kutter]

If there is quite a bit of bend required, I usually make the initial bend while the steel is at red heat.
That way there's no question about wether it's going to break or crack. It'll just be easy to work.

For the tang to match a pistol grip profile of the stock,,I make a quick cardboard silouette profile that matches the stock.
Then do the bending of the trigger guard while at red heat and use the cardboard profile to compare the tang to.
You can get quite close that way.

I make the bends usually by placing a large dia piece of pipe in the vise and use that to hammer the tang over.
It doesn't take much to bend the metal at red heat so easy does it and a nice smooth curve results.

When it's as close as you think you are going to get it, check one last time for the tang being straight,,they can have a tendency to stray off center when being bent. Heat it a again if necessary and pull the tang back to center.

Heat once more over all and let it cool in wood ashes or warm sand so it ends up annealed.
Then any last little adjustments to the stock can easily be made by hand bending to fit.

The heat scale can be removed easily by soaking in water w/muriadic acid in it.
I only use a couple tbs/ acid per gal of water at room temp.
Takes a while but the scale comes right off.
Saves a lot of polishing.

My heat source is an AO torch clamped in a separate vise to the side so I can easily hold the part in the flame to heat it red and then work it over in the regular bench vise as needed.

[Birddog6]

I've had no luck at annealing investment cast brass or iron. Both of them are made with the cheapest junk
they can make them from & they will crack or break if you cold bend them very much at all.. You might get by
with a very slight bend.  Sometimes they are cracked when you get them, so look at them close when you
buy them. If it is already cracked, you just as well get the wire welder out & start repairing as it will fall apart
if you bend it at the crack.

If I do have to bend one, I heat it red hot where I want the bend & usually bend it over a bolt, rod, socket, etc.
just a tad bit undersize of the bend I want. Then I stick it in sand & let it cool.

[martin9]

I've broken 3 investment cast iron guards. I do have a welder under my work bench and it saved 2 of them. One southern style cast guard broke in 3 different places so I gave up on it. looking close....It was very porous

[Mark Elliott]

I forge my own guards out of both wrought iron and mild steel.  The mild steel can be bent cold.  Wrought iron should be bent hot.  As a general rule,  I bend iron/steel red hot.   I will only attempt very small bends cold.  I don't know about your cast steel guards, but I would assume they are brittle and bend them hot.

[Bob Gerard]

I wish you luck!
I am running away from cast steel trigger guards for the rest of my natural life!