Question on hammers for OM Blackhawk with conversion

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Diamondtreo

Single-Sixer
Joined
Apr 7, 2011
Messages
112
Location
Lake Stevens, WA
I recently acquired an OM Blackhawk in .41 mag (circa 1971) that has the factory safety transfer bar installed. The hammer spur is just a bit too high for my liking & I would prefer to have a wide SBH or Mondato-style hammer. Since it has the conversion already & I do not have any of the original parts, I am thinking that I will need to go the whole route, hammer, trigger, etc. Any ideas for this process? I found a Power Custom RSA Old Model 3 Screw Hammer at Grand Masters LLC but their suggested Vaquero-style trigger says nothing about fitting in the OM frame or mechanism. My other thought is finding someone who has original OM SBH parts or the conversion parts with a wide hammer & is willing to sell or trade.

Update: l have found a set of OM parts! Thanks to all. John
 

Diamondtreo

Single-Sixer
Joined
Apr 7, 2011
Messages
112
Location
Lake Stevens, WA
Contender, do you have a source for OM parts? Seems like OM parts are hard to find. Besides Brownells, do you have a suggestion? Thanks, John
 

veeman

Single-Sixer
Joined
Feb 12, 2015
Messages
455
Location
Illinois
Need OM parts? Here ya go.
http://www.rugerforum.com/phpBB3/viewtopic.php?f=41&t=253700

opps sold, but these sets come up fairly regular in the classifieds.
 

Hondo44

Hawkeye
Joined
Apr 3, 2009
Messages
8,041
Location
People's Republik of California
They're sold already.

Things to know about conversion parts and they're use for converting back:

1. Hammer heights vary slightly but here are the four basic size ranges. OM hammer heights measured from bottom surface to top front:

Large frame hammer = 2.370" - 2.380"
Mid-frame = 2.180" - 2.220"
Single six, tall for fixed sight = 2.035" to 2.060"
Super single six, shorter for adj. sight = 1.945" to 1.965"

2. 3 sizes of cyl pin lengths for 3 frame sizes, but the conversion pin can be used with the old parts.

3. cyl hands, two sizes, small frame and mid/large frame. The conversion hand can be used with old parts, it's the same part.

4. The cyl bolt (latch) is the same for all frame sizes; this part must be replaced with an old model.

5. The conversion trigger can be used with old parts, it just needs the transfer bar mounting lever hack sawed off the trigger. All triggers interchange between all three frame sizes. The wider Super BH trigger needs a wide trigger slot in the trigger guard.

PC Bisley hammer for old models:

http://powercustom.com/store/index.php?main_page=index&cPath=12&sort=20a&page=3

If you choose to use the PC Bisley hammer:

MODIFYING BISLEY HAMMER/TRIGGER FOR PLOW HANDLE OR BIRDSHEAD GRIP FRAME:

It's just a matter of dressing down the hump to fit the plow handle grip frame backstrap (as is done with the large frame Bisley hammers on center fire Rugers.)

Before you trace your old hammer, make sure it fits flush with the grip frame 'ears'. If not you'll want to leave the Bisley hammer larger than the original to final fit flush with grip frame ears.
Use the hammer pivot pin to hold the original and new hammers together and scribe both sides, then grind, file, sand and re-blue (if blued), the portion you filed away. If hammer won't cock, the issue is that the back of the grip frame slot just needs a very slight lengthening with a small flat or triangular file.

I "hog off" most of the metal with an 1/8" x 1" Dremel course stone; hammer in a vise, or use a cutoff wheel mounted in a bench top grinder. Then true up the course grinding by 'draw filing' with a small double cut triangular file and then square up the corner at the top of the hump. Finish with 600 grit paper wrapped around a 1/4" x 1/2" alum sanding block with flat surfaces, heat with hair dryer, and re-blue with NU Blue or Brownells OxPho blue. That will match the factory finish which is not a high polish. For a higher polish, follow up with 800 grit and 1000 grit. Polish with a Dremel flannel wheel using white rouge made for polishing stainless steel. Then blue.

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http://www.rugerforum.com/phpBB/viewtopic.php?t=136817

http://www.rugerforum.com/phpBB/viewtopic.php?p=1543606#1543606
Stock Bisley hammer in rear, modified Bisley center and standard hammer in front:
P1010010-6.jpg
(photo by G2)
 
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