No 32 Scope - removing a sheared anti-cant screw.

[paulseamus]

This post is to share the process of removing a sheared anti-cant screw from a No.32 scope.

My recently purchased scope #2707 came with a sheared off anti-cant screw.

My dilemma was how to drill out the screw, given that the centre of the screw was within the outer diameter of the bell of the scope.


Attachment 23468Attachment 23469Attachment 23470

Thanks to the valuable guiding advice of Peter Laidler, I decided to braze an arc-welding rod to a 2.5mm left handed drill bit.

The plan was for the welding rod to allow enough bend to drill without contacting the scope body, and for the left handed drill bit to loosen the screw.


As you can see from the pics below, the plan worked.

The 2.5mm hole allowed the use of an easi-out and the broken screw was removed.

No damage to the scope. Original 4BA threads intact.

Thank you Peter for your guidance.

Now to get the dimensions to machine up a new 4BA anti-cant screw.

Paul

Information

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[newbieDAN]

[xa-coupe]

this needs to be a sticky

[Peter Laidler]

I've had to do this job many many times. The screw doesn't shear so much as be cut off to use the scope on an air rifle in the past. I usually feed a 6" long drill down a suitably sized tube (think brake pipe dia.....) bent to clear the overhang of the erector cell collar. This usually does it plus a bit of judicious clearing with a tap.

This method has failed for several reasons in the past so I've resorted to milling down into the anti-rotation block, into the sheared off screw then lengthwise to mill the complete screw out from above. Then lay a new screw into the vacated slot and back-fill the slot with brass filings and soft solder. It means that the screw is fixed for good - just like the original was meant to be - but once it's in the bracket it ain't goin' nowhere........