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View Full Version : 1911 Bo-mar sight help???????


Eazmo
July 2, 2011, 12:18 PM
I was told this is a Bo-mar sight on this new to me 1911. what i need is the front through pivot pin seems to have broken and a piece has come out so the sight is trying to come apart. I need to replace the front cross pin but not sure of sight type or were to get replacement pin.

Thanks for the help

http://i399.photobucket.com/albums/pp76/eazmo/IMG_20110629_102949.jpg
http://i399.photobucket.com/albums/pp76/eazmo/IMG_20110629_102923.jpg
http://i399.photobucket.com/albums/pp76/eazmo/IMG_20110629_102838.jpg

DnPRK
July 2, 2011, 12:45 PM
I would try a roll pin first. Measure the through hole and get one from the hardware store or McMaster-Carr. The spring in a roll pin will keep it in place under recoil.

If that didn't work, cut a piece from the shank of an appropriate size of drill bit. Put an ever-so-slight bend in the middle so the pin won't slide out.

Scorch
July 2, 2011, 01:08 PM
A roll pin or spring wire will take care of it. I usually use spring wire becasue it won't bind on the sight elevator and the spring wire selection I have has many different sizes in it, allowing me to pick the one that fits best.

FWIW, BoMar sights are very good, and the heavy rail reduces recoil, so when properly repaired your 1911 should be a sweetheart to shoot.

Unclenick
July 2, 2011, 04:15 PM
I don't see a Bomar rib on there. Just the sight. But ditto on the music (spring) wire. You can get it at hobby shops that sell to airplane modelers. They have it in 3 ft. lengths for making landing gear. It is tempered, so don't ding your cutters on it. Use a Dremel cutoff wheel.

Eazmo
July 2, 2011, 06:13 PM
I don't see a Bomar rib on there Not sure what you mean???

This gun is new to me so i only know what i am told. (Family hand me down) one of the claims to fame is the sights have no exposed dovetails. the dove tails were cut down the length of the slide from from front to back not side to side as normal. front sight welded in and rear is dovetailed in from back of slide toward the front. But will get music wire from hobby shop. thanks

Unclenick
July 3, 2011, 08:02 AM
Bo-mar tuning ribs were an addition to the top of the slide that helped control the barrel lock-up. They spanned the length of the slide from front to back. That added the extra weight that Scorch was referring to as a heavy rail, but that's not what you have.

You appear to have a rear sight for which the top of the slide has been relieved, as Bo-mar stand-alone rear sights required to achieve their low profile. That makes it a "Bo-mar style" sight in 1911 jargon, but there were so many knock-offs made that I don't know who your manufacturer was unless it's stamped somewhere on it. Could have been Bo-mar, but very well may not be. I don't recall ever seeing an actual Bo-mar brand sight with the front to back rib, but that doesn't mean there weren't any. I'm just not aware of them. Bo-Mar itself folded up after the principals died (2006 and 2007).

Front sight extensions for target pistols used to have longitudinal dovetails like that and worked fine, but they weigh a lot less than a rear sight. The potential vulnerability for one on a rear sight would be recoiling loose unless a set screw digs in somewhere. Sure looks nice, though.

Front sights being silver-soldered in place was a standard technique to answer the tendency of the traditional Colt staked tenons to come loose. The original Browning designed front sight didn't often do that because it is so small and light, but when target shooting caused front sights to get bigger and easier to see, the issue arose. They would get loose and wobble a little, enlarging groups, and sometimes actually fly off (which they would do almost exclusively in the middle of a match when the owner didn't have a back-up gun with him).

Silver soldering was the solution for a hardball gun. For a wad gun, getting a shallow longitudinal dovetail milled in the front of the slide allowed installation of an extended front sight that increased the sight radius for more aiming precision. Since then, mostly crosswise shallow front dovetails have replaced both techniques. The drawback to silver soldering is you have to refinish the slide afterward, which fewer shops are set up to do these days. It can add significant expense if the gun has to be sent out for that.

GURU1911
July 3, 2011, 09:14 AM
I hate to bust your bubble, but that is not a genuine "bo-mar" sight on your 1911. That is an after-market copy of the famous rear sight. Genuine bo-mars rear sights have the name stamped on the side of the sight base. What you have is a bo-mar "style" rear sight.

Btw: Due to the untimely deaths of several members of the family, the company is no longer making their famous rear sight.

"ed brown products" makes the closest clone to the original bo-mar. Contact ed to see if you can get a replacement pin.


Guru1911

gb6491
July 5, 2011, 04:51 PM
I hate to bust your bubble, but that is not a genuine "bo-mar" sight on your 1911. That is an after-market copy of the famous rear sight. Genuine bo-mars rear sights have the name stamped on the side of the sight base. What you have is a bo-mar "style" rear sight.
Given how that sight base is installed, I imagine it has been modified some, possibly enough to remove any markings on the sides. However, that "Circle R" on the sight body is certainly found on authentic Bo-Mar sights.
Regards,
Greg

GURU1911
July 5, 2011, 08:35 PM
I AM LOOKING AT THE 1973 "BOMAR (BMCS)" REAR SIGHT THAT HAS BEEN ON MY MARK 4 SERIES 70 GM SLIDE SINCE 1973.

(1) ON THE LEFT SIDE OF THE SIGHT, ARE THE LETTERS "PAT" STAMPED (patented) JUST ABOVE THE DOVETAIL.

(2) ON THE RIGHT SIDE OF THE SIGHT, ARE THE LETTERS STAMPED "BO-MAR" JUST ABOVE THE DOVETAIL.

(3) ON THE TOP OF THE SIGHT DIRECTLY IN FRONT OF THE SIGHT BLADE ARE THE LETTERS "UP" WITH AN ARROW POINTING ---->

NONE OF THESE THREE DISTINGUISHING FEATURES ARE STAMPED ON THE SIGHT PICTURED IN THE ORIGINAL THREAD.

ON PAGE 28 IN THE #45 "GIL HEBARD CATALOG", THERE IS A VERY CLEAR PIC OF THE BO-MAR BMCS SIGHT. THE NAME CAN BE CLEARLY SEEN ON THE RIGHT SIDE & THE LETTER "R" IS NO WHERE TO BE FOUND ON THE TOP IN FRONT OF THE BLADE !!!!!

THE PATENT ON THE BO-MAR REAR SIGHT, RAN OUT MANY YEARS AGO. TODAY THERE ARE SEVERAL COMPANIES (take a look in the Brownell's 1911 catalog) WHICH MAKE COPIES OF THE ORIGINAL SIGHT, BUT THE SIGHT PICTURED IN THE THREAD IS NOT A GENUINE BO-MAR----IT IS A BOMAR STYLE CLONE.

I REST MY CASE. THANKS !!!!

GURU1911

Eazmo
July 5, 2011, 09:58 PM
I didn't mean to start a squabble :eek:

I spoke to my uncle today ( thats were i got the gun ) and he says its genuine Bo-Mar. Its not there regular unit because of the end to end dovetail.
He thinks he still has original info and packaging somewhere. gotta do some digging.

anyway i got some music wire today. also the broken pin was .067" what they had was .062" and .076" so i got a piece of each and will try to fix this weekend. when i removed the adjustable part that holds the blade from the base i noticed a very small spring that presses against the Cross pin. i think there might have been a tiny steel ball in there also buy not sure????? don't know were i would find one that small anyway

gb6491
July 5, 2011, 09:59 PM
...BUT THE SIGHT PICTURED IN THE THREAD IS NOT A GENUINE BO-MAR----IT IS A BOMAR STYLE CLONE.
I disagree. As I stated earlier, I believe the base of this sight has been modified to suit the particular way it is mounted on the slide. It appears to have been machined to be more narrow (which would account for no "BO-MAR" on the side) and the ends of dovetail tenon have been undercut. The sight can be identified as a Bo-Mar by the letter "R" inside a circle on top of the sight body. Bo-Mar sights could also be found with this mark on the side of the base opposite the "BO-MAR" marking.
Here's a photo from the old BO-MAR website (the "Circle R" is clearly visible):
http://i52.tinypic.com/de36e1.jpg
http://web.archive.org/web/20080115235114/http://www.bo-mar.com/kevi_001.htm
Here's the same mark on the sight base:
http://1911store.com/browseproducts/BoMar-BMCS-K-Rear-Sight.html
Regards,
Greg

I didn't mean to start a squabble
No squabble, just friendly banter:)

GURU1911
July 5, 2011, 10:27 PM
Well i'll be dipped in shellac---you checkmated me bro.

I will concede defeat in this instance. Maybe both of us are correct & the sights may have been made during different decades & the bomar company changed the sight markings just to screw with our minds. Too bad they had to close the doors to their shop in longview, texas.

To tell the truth, i think we are both correct. How about we shake hands & call it a draw ????? Keep them in the 10-ring.

Guru1911

gb6491
July 5, 2011, 10:44 PM
Maybe both of us are correct & the sights may have been made during different decades & the bomar company changed the sight markings just to screw with our minds. Too bad they had to close the doors to their shop in longview, texas.
I agree on both counts.
Good shooting to you as well.
Regards,
Greg

Hunter Customs
July 9, 2011, 08:13 AM
anyway i got some music wire today. also the broken pin was .067" what they had was .062" and .076" so i got a piece of each and will try to fix this weekend. when i removed the adjustable part that holds the blade from the base i noticed a very small spring that presses against the Cross pin. i think there might have been a tiny steel ball in there also buy not sure????? don't know were i would find one that small anyway

It's been awhile since I disassembled a Bo-Mar sight but I do believe you are correct about the spring and detent.
They are held in place by the transverse pin that holds the sight leaf to the sight body.
The spring and detent is in the sight to hold spring pressure on the pin that rest against the elevation screw.
You are correct about the diameter of the transverse pin that holds the leaf and body together, it is .067.
Best Regards
Bob Hunter
www.huntercustoms.com

Hunter Customs
July 9, 2011, 08:20 AM
I was told this is a Bo-mar sight on this new to me 1911. what i need is the front through pivot pin seems to have broken and a piece has come out so the sight is trying to come apart. I need to replace the front cross pin but not sure of sight type or were to get replacement pin.

By the way I think you will find the reason the transverse pin broke is because the pin is machined to a smaller diameter in the center of the pin.
I believe the reason for this was so the detent could ride in the machined area of the pin to keep the pin from working its way out of the sight during the recoil of gun.
Best Regards
Bob Hunter
www.huntercustoms.com

Roddy Toyota
July 10, 2011, 10:56 AM
Your sight is probably an original Bo-Mar. The serrations on the blade do not cover the entire face of the blade. All of the current Bo-Mar copies are made by Kensight/Champion under various names; and the serrations fully cover the rear face. To my knowledge, I'm the only person around that is removing the serrations to make the blade look like the Bo-Mar. If serrations thru the the sight notch were a good thing, Bob would have put them on his sight. Bo-Mar stands for Bob & Mary.

The horizontal pin is full round and doesn't have any change in it's diameter. It is held in place by staking the ends. The size of the pin is .065"-.066" in diameter. I'd used Bob's sights for 25 yrs on BE guns and used to enjoy occassionaly talking with Bob about target stuff. Anyway, in a pinch I'd use a cut off shank from a #51 drill. To keep it in place you can make it shorter than needed and stack over the hole with a punch. What I would do is to make the pin longer and heat the ends and hit it with a hammer to mushroom the end.

Hope this helps.