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All Springer/NP/PCP Air Gun Discussion General => Machine Shop Talk & AG Parts Machining => Topic started by: Ronno6 on November 20, 2021, 11:56:09 AM

Title: Crosman Stock Clevis Hole Enlargement
Post by: Ronno6 on November 20, 2021, 11:56:09 AM
I have worked on many a Crosman 766/2100/2200 that have wiggly stocks to varying degrees.
Typically, ANY wiggle signifies a stock with 1 or, more typically both clevis ears suffering fractured holes on the tang clevis.
I have never been successful in gluing them and having the bond hold.
Attempts to enlarge the holes for sleeving have never been successful, either.
The fracture always opens up under the stress of drilling even after gluing.
I am not forming a U-shaped steel strip and gluing over the outside of the clevis ears, and that is helping.
But, I think the ultimate repair will be turning a flange bushing to insert into the hole and securing to the clevis
by JB Welding to the clevis and the U-strip reingorcement.

What is the best way to open these 3/8" holes to an ID of 7/16" ????
Is there a particular bit I should try?

Thanks!
Title: Re: Crosman Stock Clevis Hole Enlargement
Post by: sb327 on November 20, 2021, 12:39:09 PM
Step drills are the beeís kneeís for opening holes in thin metal

Dave
Title: Re: Crosman Stock Clevis Hole Enlargement
Post by: sb327 on November 20, 2021, 12:47:32 PM
I am assuming itís a thin part you are trying to drill, Iím not familiar with the gun.

Dave
Title: Re: Crosman Stock Clevis Hole Enlargement
Post by: Tack Driver 10 on November 20, 2021, 01:01:05 PM
I have worked on many a Crosman 766/2100/2200 that have wiggly stocks to varying degrees.
Typically, ANY wiggle signifies a stock with 1 or, more typically both clevis ears suffering fractured holes on the tang clevis.
I have never been successful in gluing them and having the bond hold.
Attempts to enlarge the holes for sleeving have never been successful, either.
The fracture always opens up under the stress of drilling even after gluing.
I am not forming a U-shaped steel strip and gluing over the outside of the clevis ears, and that is helping.
But, I think the ultimate repair will be turning a flange bushing to insert into the hole and securing to the clevis
by JB Welding to the clevis and the U-strip reingorcement.

What is the best way to open these 3/8" holes to an ID of 7/16" ????
Is there a particular bit I should try?

Thanks!

Here's how I fixed the stock on a chrome 2200.

https://www.gatewaytoairguns.org/GTA/index.php?topic=166335.0 (https://www.gatewaytoairguns.org/GTA/index.php?topic=166335.0)
Title: Re: Crosman Stock Clevis Hole Enlargement
Post by: JPSAXNC on November 20, 2021, 01:11:15 PM
Many plastics tend to crack or craze when being drilled. Using liquid dish soap as a lubricant can stop cracking and crazing in some plastics. hth
Title: Re: Crosman Stock Clevis Hole Enlargement
Post by: Ronno6 on November 20, 2021, 02:12:30 PM

What is the best way to open these 3/8" holes to an ID of 7/16" ????
Is there a particular bit I should try?

Thanks!

Here's how I fixed the stock on a chrome 2200.

https://www.gatewaytoairguns.org/GTA/index.php?topic=166335.0 (https://www.gatewaytoairguns.org/GTA/index.php?topic=166335.0)
[/quote]

Yessiree.
I remember seeing that B-4.
Excellent solution for stocks much farther gone than the ones I am working with.
I have done similar using a sleeve of aluminum.
Title: Re: Crosman Stock Clevis Hole Enlargement
Post by: Ronno6 on November 20, 2021, 02:14:01 PM
Many plastics tend to crack or craze when being drilled. Using liquid dish soap as a lubricant can stop cracking and crazing in some plastics. hth

That's worth a try!

I am looking at trying a 10.5mm counterbore.
I would have to machine a sleeve for the pilot, but no biggie....
Title: Re: Crosman Stock Clevis Hole Enlargement
Post by: Ronno6 on December 01, 2021, 02:49:52 PM
I purchased a 13/32" counterbore w/changeable pilot.
I installed a 1/4" pilot and made a bushing to increase to .330 so it would fit nicely into the original clevis bore.
That setup in the drill press worked nicely!
Made and glued in a couple flange bushings and that stock is FIXED !!

The U-bracket over the outside distributes the stress evenly over the entire outside of the clevis ear to make re-cracking less likely.