Trapshooters Forum banner

1 - 13 of 13 Posts

·
Registered
Joined
·
2,668 Posts
Discussion Starter #1
I have certainly drilled and tapped holes on virgin stock! However, a trap gun I bought had removed the 3-56 Bradley bead and replaced with a high viz sight. The problem is that the new threaded hole is no longer 3-56! It is something in between the 3-56 and 6-48. I have ordered a new 6-48 bead as well as the proper drill and tap for the 6-48! My quandary is simple! Can I free hand the new drill/bit size safely and will it properly follow the existing hole or do I need to somehow figure out how to level and square and use my drill press? Thanks, Tom Rhoads
 

·
Registered
Joined
·
6,094 Posts
I would level and square it. Use the drill press as a guide and turn things by hand. You have no room for even a few degrees of error. Sometimes trying to correct an existing hole is trickier that a new hole. Any problem with the old will magnify as you make it bigger
 

·
Registered
Joined
·
956 Posts
Bridgeport is just a trade name for the mill.Anygood mill will work.Just remember if it gets screwed up it will be expensive to fix.Get it right the first time.You might need a 6-48 bottom tap to finish the job.
 

·
Registered
Joined
·
148 Posts
There are hand jigs for centering the hole on the rib, this type of tool/jig could be used to center the existing hole for re drilling
 

·
Registered
Joined
·
1,841 Posts
Bridgeport is just a trade name for the mill.Anygood mill will work.Just remember if it gets screwed up it will be expensive to fix.Get it right the first time.You might need a 6-48 bottom tap to finish the job.
I know, I was just funning as you were so specific regarding a "Bridgeport"
 

·
Registered
Joined
·
375 Posts
There are hand jigs for centering the hole on the rib, this type of tool/jig could be used to center the existing hole for re drilling.
I have a jig that is designed for this purpose. It is a Williams shotgun bead drilling jig. Can be used for 2 sizes, 3-56 and 6-48. Available from Brownells.
 

·
Registered
Joined
·
863 Posts
If the needed existing tap size gets boogered up a good machinist can make a bushing the next tap size larger with the needed bead size threads on the inside. Seen it done on a P gun rib and once the bead was installed you couldn't even notice the bushing. Watched the bushing being made on a lathe and I was intrigued while watching the process with such a small bushing with threads inside and outside.
 

·
Registered
Joined
·
10,302 Posts
If barrel has screw chokes, drill all the way through and use a bead with long thread.

I typically rethread guns for the 6-48 if they come in without one or a broken one or if one of mine loses a bead.

Field guns typically have the sturdier 6-48 stem, tournament arms typically have a smaller, more fragile stem on the bead.

New bead might not line up, you might need a bead facing cutter, also available from Brownell's.

SHOTGUN BEAD FACING CUTTER | Brownells
 

·
Registered
Joined
·
2,668 Posts
Discussion Starter #11
All is well that ends well! Bought the correct drill bit and tap from an ebay supplier! Bought the white Bradley bead from Brownells who of course porks you pretty good on the shipping! Anyway, leveled the rib up with proper support and then used a machinist vise and protected the jaws with leather. I used a 1 foot level to level the rib from front to back and used a machinist level to get it level across the rib! Once it was square and level, I chucked up a 3/32 " drill bit to get the chuck centered in the hole! Once I was satisfied the drill bit/chuck was centered, I clamped the machinist vise down to make sure it would not move! Then, I chucked up the #31 drill bit to make the hole! After one last final fretful level and square check, I drilled the hole! I then tapped the hole by hand using good gun oil! It came out perfect and with the naked eye, everything was perfect! Thanks again Guys! Tom Rhoads
 

·
Registered
Joined
·
91 Posts
Could be metric. I would find out what the existing threads are and just buy the right bead. By far the easiest solution with the same result.
 
1 - 13 of 13 Posts
Top