Modifying MIM Hammer

[jimonfly]

I have a 325NG for everyday carry. The only problem I have is the larger spur on the hammer prints noticeably under my shirt. I just purchased a second trigger to play with.

At first I was thinking of just bobbing it. What kind of finish can I apply that will work well and match the original finish closely? Is there any difference in the prep for MIM parts?

Then I though of soldering on a small round spur, similar to a Browning High Power or Colt Commander so I could still use the SA trigger. What is the best method to attach another piece of metal to the MIM part? Can it be silver soldered?

Thanks, Jim.

 

[john traveler]

Silver solder will work well. You will have to use precautions to avoid drawing the heat treatment on the hammer sear.

 

[500 Magnum Nut]

Can't blue it, it won't look that great.
I use a buffing wheel and polish it. It will look original that way, providing it's not flash chromed then nothing will work...

Use a dremel if you have and cut the spur off. Then shape it, then polish what shows.

 

[tomcatt51]

Can't blue it, it won't look that great.

Have to dis-agree. I cut the hammers, from a traditional "bob" to radically lightened and reshape the triggers. I polish and/or cold blue the MIM parts. Birchwood Casey Perma Blue gives them a very dark (almost black) blue.

I also tried TIG welding the MIM stuff. A couple of left over hammer sections. I expected it to bubble and turn to **** but it welded just fine. Surprised me.

 

[jimonfly]

Glad to hear about the Perma Blue because that's what I have and was planning to try first. I was thinking that with enough coats, I could get it dark enough to match the finish from the factory. Still need a way to attach the round spur. I don't know anyone that welds and only have one friend that can silver solder. I know JB weld will do what I have planned, but am also sure it will look like crap after. Maybe I'll just bob it for now and look at the spur later.

 

[tomcatt51]

You can just cut the spur down. It can be made much smaller and still be usable.

 

[Alk8944]

Trim the hammer spur all you want, polish and then use any cold blue. The cold blue will slightly etch the metal and leave it a matte gray which should match the poor color of the MIM parts original finish quite well. Will it match the original finish exactly? Of course not, but if you were so concerned about it looking original you wouldn't trim the spur, would you.

Removing the hammer spur does not impair single action shooting at all. Simply lift the hammer about 1/3 of the way by pulling the trigger. Hook your thumb over the top of the hammer and finish cocking. Once you have the hammer well engaged by your thumb take your finger off the trigger while you finish cocking the hammer!!

 

[tomcatt51]

The cold blue will slightly etch the metal and leave it a matte gray which should match the poor color of the MIM parts original finish quite well.

What brand of cold blue is giving you that result?

 

[500 Magnum Nut]

Have to dis-agree. I cut the hammers, from a traditional "bob" to radically lightened and reshape the triggers. I polish and/or cold blue the MIM parts. Birchwood Casey Perma Blue gives them a very dark (almost black) blue.

I also tried TIG welding the MIM stuff. A couple of left over hammer sections. I expected it to bubble and turn to **** but it welded just fine. Surprised me.

Sure, it's blue-able, I just don't like the look of it.

I found Brownells cold blue the best for what I repair.

 

[jimonfly]

Update

This weekend I bobbed the 2nd hammer for my 325NG and blued it using Perma-Blue. Used a dremel to cut-off, shape and polish the hammer. The perma blue worked well, and came to a nice dark color after 5 coats, but it was shiny compared to the matte factory finish. If I had access to a sand blaster it may have made it closer, but it can all be re-done later.

Had a problem at the range though. The pistol has a Wilson Combat reduced power hammer spring, and 13# rebound spring. Also an Apex extended firing pin. I've put 1k+ rounds with that setup with no FTFs. The first loading with the bobbed hammer gave me 2 FTFs. The primer was dented but they did not go off. I did get one to go off after a few tries in that pistol, and the other fired fine in my 1911. 2nd cylinder had no FTFs. After that I put it away and shot the 1911.

I'm going to put the factory springs back in and head back to the range before I carry it again. My only other concern is the ammo. I didn't think about it until afterwards, but I had to unload a 1911 mag at the range and I think maybe a different ammo got loaded in the first cylinder, which could have had harder primers. Poor planning on my part, but that just means more range time to figure it out.

 

[tomcatt51]

A bobbed/lightened hammer will give better ignition on a centerfire.

 

[jimonfly]

A bobbed/lightened hammer will give better ignition on a centerfire.

Can you explain that to me? I was thinking with less mass behind the hammer it would be worse ignition.

I went back to the range last night using the factory hammer spring. Had no FTF's with 50 rounds. The only problem was trigger reset but that's due to the long length of pull with the factory grips that cover the back strap. They are too long for me. But, I knew that firing multiple rounds with the compact grips would hurt too much.

 

[tomcatt51]

A lighter hammer has more hammer velocity for a given mainspring tension. Centerfire primers like hammer/firing pin velocity. Lightening the hammer (you can reduce the weight of a FMFP hammer by about 50%) is a normal mod to allow lighter mainspring tensions for lighter DA pulls. The lighter mainspring tension then allows lighter rebound springs while keeping good trigger return.

Rimfires are different, they seem to need hammer weight.

 

[jimonfly]

Good to know. Thanks for the info.