Smith Carbine - Burned out cleanout screw.

[dfbowers]

Hey guys. I'm looking for advice on what to do with a burned out cleanout screw on a Yeck Smith reproduction. I don't what to let this go until the screw ends up in the back of someones head! The shaft of the screw is almost gone and so are the threads that it goes into.

I am contemplating doing a shallow tap for a 7mm screw in the channel, which I feel confident doing, but I'm not sure how hard the metal is in the receiver. Has anyone ever tapped one of these and is the metal of the receiver harder than most taps? Any help is most appreciated!

Thanks..
Don Bowers

[hp gregory]

while at a national i actualy saw a clean out screw come out of a smith during team competition. it passed under the nose of his teammate and hit a guy on the next position in the temple. that poor fellow thought he had been shot in the head. which i guess he had been. as with most head wounds blood flowed freely. it was a scary deal until they realized that the screw had bounced off instead of penetrating. i think the gentleman made a trip to the hospital but im not sure. i think after the smoke cleared it turned out to be a minor incident. it could have been a very bad deal. the smith was a repro. those guns had a history of having thin frames and very few threads holding the screw in. eventualy they would spit the screw out. i think most any decent gun smith could install a larger screw or make a repair that would solve the problem. i always heard the yeck repro frames were made better than the mass produced newer models.

hp

[Lou Lou Lou]

The problem may be with the term "clean out screw". It is a drill access, for making the f lash channel.
it can be permanently sealed. Talk to the SAC as to what they allow.

[Michael Bodner]

I had to fix mine a few years ago. Basically,

1) Place the receiver in your drill press and set the head at the angle that allows a drill to extend into the flash channel. this determines the angle to drill (later).
2) Install a piece of drill rod (or other steel rod) turned down to just fit under the nipple. Trim the bottom to best-fit the curves.
3) Use a center punch to mark the rod at the exact location of the existing clean out screw hole.
4) Remove the rod and place on the drill press. Drill at the angle pre-set from Step (1)
5) Tap this hole all the way thru. On the 'back half' (that will be on the inside of the flash channel) drill it out the same diameter as the flash channel
6) Center drill the rod down to the new cross-channel.
7) Trim the rod to the exact length such that it's just 'under' the nipple.
8) Install into the bolster, secure with screw through the old clean-out hole.

Basically, what you're doing is making a thick 'plug' that you make a new flash channel through and lots of new threads for the screw to hold!

Good Luck!

-Mike

[dfbowers]

I had to fix mine a few years ago. Basically,

1) Place the receiver in your drill press and set the head at the angle that allows a drill to extend into the flash channel. this determines the angle to drill (later).
2) Install a piece of drill rod (or other steel rod) turned down to just fit under the nipple. Trim the bottom to best-fit the curves.
3) Use a center punch to mark the rod at the exact location of the existing clean out screw hole.
4) Remove the rod and place on the drill press. Drill at the angle pre-set from Step (1)
5) Tap this hole all the way thru. On the 'back half' (that will be on the inside of the flash channel) drill it out the same diameter as the flash channel
6) Center drill the rod down to the new cross-channel.
7) Trim the rod to the exact length such that it's just 'under' the nipple.
Install into the bolster, secure with screw through the old clean-out hole.

Basically, what you're doing is making a thick 'plug' that you make a new flash channel through and lots of new threads for the screw to hold!

Good Luck!

-Mike

That seems like the best solution. The only issue I see is that the center of the existing access hole is almost right under the nipple, so making the hole any wider and deeper may interfere with the threads to the nipple. I will have to do a shallow tap no deeper than the existing access hole. I just don't know how hard the metal is.
Thanks Mike!

[marv762]

i gave mine to Lodgwood at a national and he tapped it there. i purchased two new screws from him. this was done about 8 years ago and it is still going strong. easy fix if you have the screw to install. godd luck Marv

[Charlie Hahn]

Master Armoror Notes, Clean Out Screws:

I am sure we have all had to deal with worn or blown out clean out screws. Some times we even get hurt when this happens. Repairing them can even be more of a challenge if you don’t know where to look for the right information and tools to do the job in a way that preserves the integrity of the bolster screw interface.

A little background, threads have several classes of fit, and thread engagement. The fit is the amount of clearance between the flanks of the thread, a class 1, is sloppy, and a class 3 is very close, and has the most metal left for strength. Thread engagement is the other part of the interface. Normal manufactures use 55% of thread to make tapping easier, where pressure vessels usually require 75% to add to the strength of the threaded joint. I am sure there are enough machinists in our group, or other trained folks who will understand this, and others who will have a difficult time with this. What is important is to understand that, using a hand drill and a mystery drill and tap to affect a repair in the area just might not be a real good idea.

Here is a practical approach that should help most acquire the correct tools and a process to make this repair should you not be able to hire the services of a machinist, or trained gunsmith/armoror.

The barrel/bolster should be aligned and clamped in a drill press with a rigid spindle. This will make sure the drill will start and enter the repair sight in a straight path and not wobble and wallow out the hole that will be tapped. In some cases the hole may need to be drilled and reamed, or step drilled in the bolster is hard or the hole in really bad condition. Next, in the same set up you should use the drill chuck and by hand start the tap so it follows the same axis, followed by using a tap wrench and oil to complete the task.

As for tools here is a chart with drill size and tap limits to get the required fits.

Tap Size Tap Limit Drill size % of Thread
6-32 H1 #37 74%

6-40 H2 #34 71%

8-32 H1 #30 69%

8-36 H2 #29 70%

10-24 H2 #26 74%

10-32 H2 #20 70%

The Tap Limit is the tolerance limit on the thread pitch of the tap. These type of taps need to be acquired at an industrial supply house, (Traver’s Tool, MSC, McMaster Carr, etc) Your local hardware store will not have taps of this quality, and “gun style” is the strongest and will give you the best chance to get the hole threaded. The drill sizes I noted are based on years of doing this, and are not necessarily in line with Machineries Handbook, but I think you will see that it will get the job done.

Next the replacement screw. These should be of grade three to grade five, and also bought from and industrial supply firm with know quality levels, (your local hardware store may have these, but not in the value pack). Normal steel with an oxide finish is well suited for this application. Zinc plating and stainless steel helps with rust, however in our carbon/solvent environment will hasten erosion of the bolster thread due to dissimilar metals electrolysis. Always use an anti-seize compound and don’t over tighten.

Respectfully submitted for consideration,

Charlie Hahn

[Eggman]

This thread definitely is worth another look see.

[Bruce Cobb 1723V]

Just a short follow up to to Charlies excellant information. Material screw / bolt grades found at auto stores and those used in the military run 3, 5 & 8. The lowest number is the softest. We used alot of grade 8 in military vehicles. Round headed / slotted screws don't carry any identifying marks to the grade of the screw. You trust the sellers information. Octagonal headed screws / bolts have raised lines on their head to tell the grade. 5 lines, grade 5. ........ This should spark some comments from others on which grade / material / softness is best to use so they won't burn out.

[RaiderANV]

Clean all parts spotless and then use High Temp JB Weld and never worry again. That screw does not need to come back out of the gun once it was installed at the factory. You can even add a tad more JB Weld during the process of putting the screw back in so there is material in the bottom under where the screw goes. Then use a Dremel tool and a small dental drill bit to shape the JB like a slopped ramp into the fire channel. You'll never have a problem with the screw coming out or misfires.