Shotgun bead install

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brybenn

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So i shortened the barrels of a spanish boxlock sxs 12ga and filed them to where i like. Now to add a bead. I found the thread pitch on berettas site for their white bradley bead as 2.6x.45. Its easy to buy the bead however ive been all over town in search of a tap to match. Everyone tells me they dont exist. The machine shop says they can order one for about $75.
Is there a basic standard bead that has a thread that has a readily available tap? I like the white bradley style but will settle for something similar
 
Metric is not a common one for gunsmiths..

One of the common small sizes for a bead is 3 x 56
Also in 4 x 40, 4 x 48, 5 x 40, and 6 x 48.

I used 3 x 56 almost all the time for a new bead... and 6 x 48 as the largest.
 
guntech said:
Metric is not a common one for gunsmiths..

One of the common small sizes for a bead is 3 x 56
Also in 4 x 40, 4 x 48, 5 x 40, and 6 x 48.

I used 3 x 56 almost all the time for a new bead... and 6 x 48 as the largest.
Click to expand...

Thank you. Looks like ill buy a tap set and shop for a new bead
 
Buy the tap and bead in one go from Brownells. You could also contact casey from Tacord. He might be willing to sell you both
 
For a one time job it’ll probably be cheaper to get a smith to do it. I know it’s satisfaction to do these type of things yourself but you’ll end up buying a tap you’ll probably never use again.

If you’re going the 6-48 route let me know, I’m mulling a tap purchase myself, lol
 
guntech said:
Metric is not a common one for gunsmiths..

One of the common small sizes for a bead is 3 x 56
Also in 4 x 40, 4 x 48, 5 x 40, and 6 x 48.

I used 3 x 56 almost all the time for a new bead... and 6 x 48 as the largest.
Click to expand...

I have mostly followed GUNTECH' s method for many years on dozens of shotguns. Always works. It also helps if you
stock a selection of beads like Brownells Shotgun Sight Kit . It has 4 different bead sizes in brass & aluminum.
All beads in that kit can be installed with 2 tap sizes . 3 x 56 and 6 x 48 ( common gun screw). You could order the 2 taps
at the same time as the kit & be set for many years if not life ?
 
So i bought a 6x48 bead and searching locally realized this common size is not commonly sold.
Looking online prices range from $5 to $90.
They also come in several profiles. Im assuming i need a bottoming type tap so it leaves a flat to bottom out on?
Is any brand better or better yet does anyone have a Canadian link to what i need
 
You may have different luck than I do. Taps come in at least three profiles - a Start tap usually to get the first few threads good and straight. Then a Plug tap to go most of the rest of the way. Then a Bottom tap to get that last thread or two. Some folks can start a hole with a Plug tap - I never had much luck with that - I am too wobbly, I guess. I have not heard of being able to start and thread a full blind hole - say 4 or 5 or 6 full threads - with a Bottoming tap - not what they were made to do. I have made several usable "bottoming" taps by grinding flat the ends of worn or broken off Start and Plug taps. So, in my case, I do a blind hole by starting with Start tap, then to a Plug tap, then to a Bottoming tap. For a through hole, I have gone all the way through with a Start tap.

Consider that you first have to drill the correct size tapping hole to create your blind end threaded hole. Most every drill comes with about a 120 degree end - so your hole at bottom is not "flat" - is a cone - although, you can grind a bit to cut that last little bit to flat bottom, if really need to.
 
In short holes a starting tap is useless, it is bottomed out before it starts to cut threads... a plug tap works best in the drill press... followed up with a bottoming tap. Many short hole tapping jobs have been screwed up when done by hand... I have flat drill bits to finish the shallow hole up with a flat bottom...
 
I got a 6x48 three tap set of Amazon and it was dirt cheap. Has a bottoming tap, tapered tap and semi tapered. The beads were 12 dollars from Brownells.
 
Sometimes get what you pay for on Amazon. I have a 1955 Winchester Model 70 - someone, at some time, installed a side mount scope base and drilled and tapped three holes through the left side-wall - I could not identify those threads. I had 3 x plug screws from TradeEx for plugging similar holes for European side mount - so ordered a set of three M5x0.8 taps from Amazon - a set of three - start, plug and bottom - I drilled out those holes with correct tap hole drill - 4.2 mm, I think?? - then tried to tap - alternated taps - just barely managed to get the three through holes re-threaded. Those taps are done - as if they were softer metal than the side wall on the receiver on that 1955 Model 70.
 
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FarmerDanz said:
I got a 6x48 three tap set of Amazon and it was dirt cheap. Has a bottoming tap, tapered tap and semi tapered. The beads were 12 dollars from Brownells.
Click to expand...

Brownell's also sell high quality taps. That's where the majority of gunsmiths buy them... I have been since 1966.
 
You are installing the bead on a rib. There will be a bit of space under the rib, between the barrels. You might get away with only a plug tap.
Do you have a #31 drill?
Generally speaking, cheap taps are a bad idea, and not a bargain.
 
tiriaq said:
You are installing the bead on a rib. There will be a bit of space under the rib, between the barrels. You might get away with only a plug tap.
Do you have a #31 drill?
Generally speaking, cheap taps are a bad idea, and not a bargain.
Click to expand...

Yes, cheap taps are good enough to get a few threads into the project, brittle enough to break off and hard enough to be extremely difficult to remove. Murphy’s law at work…
 
brybenn said:
Brownells site isnt accepting my postal code. Ill hit up a machine shop on monday. Thanks for help
Click to expand...

You may get a 6-48 tap at a machine shop, but not the others. They will be special order at big dollars. Guns have a long history of using non standard taps and screws. It’s partly because the walls are so thin that they need an ultra fine thread pitch to get a decent grip. Brownell’s gets the weird taps in bulk which as always far cheaper than a special order. Also you can get tap,drill and bead all at the same time. For the price you probably want to get a couple of beads. Murphy’ law says if you only have one, you will drop it never to see it again. Ask me how I know.
 
brybenn said:
Brownells site isnt accepting my postal code. Ill hit up a machine shop on monday. Thanks for help
Click to expand...

pick up the phone and call their 800 number. I've found that works best every time I've ordered anything from them. Look up the stuff on line, have the part numbers handy, and speak to a person who can tell you whether or not they can ship it to you (because of the border and all that) and tell them your CC number etc. It'll be in the mail the next day, or later the same day if you call early enough - they're on "Central" time like Manitoba and Saskatchewan
 
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