Looking for suggestions to machine buggered top strap

[jkallner]

Hi, I have an old version 617 that had been modified to accept a red dot mount in the 90's and I'm trying to find a machinist to fix the top strap so I can put an Allchin mount on it. Anyone know of someone who can do it? Thanks

 

[SweetMK]

Reading your post brings one thought to mind,,,

Go back and delete the negative comment about the gun service.

If someone came to me, and asked for machining service,, and started the conversation by bad-mouthing another organization, I would be VERY apprehensive about helping them.

I would be concerned that I would be the next service that was bad mouthed,,

Positivity goes a L O N G way,,,

 

[jkallner]

Reading your post brings one thought to mind,,,

Go back and delete the negative comment about the gun service.

If someone came to me, and asked for machining service,, and started the conversation by bad-mouthing another organization, I would be VERY apprehensive about helping them.

I would be concerned that I would be the next service that was bad mouthed,,

Positivity goes a L O N G way,,,

great idea - I deleted it even if true!

 

[Alk8944]

Hi, I have an old version 617 that had been modified to accept a red dot mount in the 90's and I'm trying to find a machinist to fix the top strap so I can put an Allchin mount on it. Anyone know of someone who can do it? Thanks

If you would explain, or, preferably, post a picture of just how the top strap of your revolver is "modified" it may help in answering your question!

If it is a matter of using the Allchin mount intended for current D&T revolvers and the screw holes in the top strap are not in the proper position for the new mount then any gunsmith should be able to re-drill and tap the mounting holes in the frame as necessary. Just two screws would be more than adequate on a .22 revolver.

 

[scooter123]

Attached you will find a dimensional sketch showing the locations of the current mounting hole pattern. I will also note that I used these dimensions when I drilled and tapped my model 617 no dash.

Take note the hole above the rear of the barrel is close enough that the tap drill can hit the barrel and snap. So great care when drilling and tapping this hole is mandatory. I'll also note that I wasn't able to find a chart showing the tap drill diameter for a #6-48 thread so I had to use my Machinery Handbook to Calculate the theoretical tap drill diameter and the drill used was a 0.116 inch diameter and it was followed up with a ream of 0.118 inch diameter. Because of this small diameter the mill used to drill and ream the holes must be used for holding the tap and with the mill in neutral you can then work the tap in by hand using a back and forth technique. Snap this tap off in the hole and it will cost roughly 150 dollars to have the tap removed via EDM and you will have to find an EDM shop with an FFL to do the work. So take every step necessary to NOT snap that tap off in the frame.

 

[jkallner]

Thanks - makes sense. I will take a double look to see if there is room left just using 2 holes and shop around for someone to see if they will do that. I had one refusal, but I didn't present the possibility of just using 2 screws to fasten the mount.

 

[jkallner]

Thank you. I appreciate the information.

 

[teletech]

and it was followed up with a ream of 0.118 inch diameter. Because of this small diameter the mill used to drill and ream the holes must be used for holding the tap and with the mill in neutral you can then work the tap in by hand using a back and forth technique. Snap this tap off in the hole and it will cost roughly 150 dollars to have the tap removed via EDM and you will have to find an EDM shop with an FFL to do the work. So take every step necessary to NOT snap that tap off in the frame.

While I do recommend using a tapping-machine, drill press, or mill to guide the tap and try to avoid breaking it, if you do break it, you don't need EDM to remove a broken tap, you can use normal carbide tooling in a mill or diamond tooling in a mill or just in a Demel if your hands are steady.