Woodworking Talk banner
1 - 20 of 29 Posts

· Registered
Joined
·
4 Posts
Discussion Starter · #1 ·
I purchased some custom pistol grips from an eBay merchant to replace the plastic grips. The problem is the counterbored hole for the screws that attach the grips to the pistol is not deep enough for the screws to screw securely to the pistol. The diameter of the counterbored hole is about 8 mm (the diameter of the screw head is 7 mm). I need suggestions about how to deepen the counterbored hole about 1.5 mm without changing the coaxial hole. Thanks.







 

· Registered
Joined
·
1,194 Posts
The checkreing in the bottom of the counter bore is an interesting touch. I think that before modifying the hole I would try to find some longer screws. If that doesn't work, get a forstner bit of the proper size and set it up on a drill press. I'm assuming the screw hole is perpendicular to the surface of the back of the grip. If not, you will have to shim it on the drill press so the counter bore will remain in proper alignment. Of course, if you do it this way, you will lose the checkeing in the counter bore.
Further thinking; could you use a small chisel and carefully shave off the tops of the checkering at the bottom of the hole. Would that be enough?
 

· Registered
Joined
·
29,471 Posts
I think I would be inclined to purchase longer screws. If you start trying to re-bore the hole the bit is likely to hit the sides of the hole and make an ugly mark. Then even with a drill press what happens if you drill it too deep, the grips could easily break off.
 

· where's my table saw?
Joined
·
32,666 Posts
I've never seen checkering in the bottom of a screw hole! That's seems weird since it wouldn't show once the screw is in place.
Chisel it off OR use the same size Forstner bit that was use to counter bore the hole as suggested.
Should be a pretty easy "fix".
 
  • Like
Reactions: ChuckM

· Super Moderator
Retired Craftsman
Joined
·
6,035 Posts
I think the grips were checkered before the hole then a high pressure press punched in the holes. (I've never seen one either).
what model is the gun ?
 

· Registered
Joined
·
4 Posts
Discussion Starter · #8 ·
The checkreing in the bottom of the counter bore is an interesting touch. I think that before modifying the hole I would try to find some longer screws. If that doesn't work, get a forstner bit of the proper size and set it up on a drill press. I'm assuming the screw hole is perpendicular to the surface of the back of the grip. If not, you will have to shim it on the drill press so the counter bore will remain in proper alignment. Of course, if you do it this way, you will lose the checkeing in the counter bore.
Further thinking; could you use a small chisel and carefully shave off the tops of the checkering at the bottom of the hole. Would that be enough?
It never even occurred to me to find longer screws until you suggested it. I just assumed these particular screws were custom for the pistol, but I probably can find some longer screws. I just need to figure out the threads per inch and thread diameter. Thanks for the idea. And thanks to everyone for the ideas and for taking the time to reply.
 

· Registered
Joined
·
97 Posts
Take it to a gun smith chances are a decent gunsmith would have a collection of fasteners kicking around or have the ways and mens to modify the counter bore depth without any trouble at all.
Possibly a place like BasPro could recommend a compentent gun smith in your area.
calabrese55
 

· where's my table saw?
Joined
·
32,666 Posts
Longer screws will indeed fasten the grips to the firearm, but they will not fit flush in the bottom of the hole because of the weird checkering there.
There will be small gaps around the screws that will trap crud and become unsightly. A proper solution would be to remove the checking leaving a flush bottom hole with no means to collect dirt or other contaminants.
 

· Smart and Cool
Joined
·
2,727 Posts
You will need a counter bore bit. Has a pilot that guides the bit from the through hole.

Counter bore:


Longer screws would be cheaper and easier.
 

· where's my table saw?
Joined
·
32,666 Posts
You will need a counter bore bit. Has a pilot that guides the bit from the through hole.
A same size Forstner bit would "self-center" in the existing hole, more common and cheaper if not already owned by the OP.
It can NOT be a saw tooth type bit, must be flush cutting on the bottom.
 

· Registered
Termite
Joined
·
9,499 Posts
Take it to a gun smith chances are a decent gunsmith would have a collection of fasteners kicking around or have the ways and mens to modify the counter bore depth without any trouble at all.
Possibly a place like BasPro could recommend a compentent gun smith in your area.
calabrese55
Agree. Less chance of running his purchase...
 

· Smart and Cool
Joined
·
2,727 Posts
A same size Forstner bit would "self-center" in the existing hole, more common and cheaper if not already owned by the OP.
It can NOT be a saw tooth type bit, must be flush cutting on the bottom.
8mm(5/16") is not a common size in Forstner sets, who knows if the OP even has a typical set, let alone an atypical size?

A 5/16" straight cut router bit is an option as well.

All of this is assuming the OP has a drill press.
 

· Registered
Termite
Joined
·
9,499 Posts
8mm(5/16") is not a common size in Forstner sets, who knows if the OP even has a typical set, let alone an atypical size?

A 5/16" straight cut router bit is an option as well.

All of this is assuming the OP has a drill press.
I thinks if the OP had a drill press, he wouldn't have had to ask.
 

· Smart and Cool
Joined
·
2,727 Posts
I thinks if the OP had a drill press, he wouldn't have had to ask.
I thinks we really have no idea if he does or doesn't, people ask a lot of questions, some have equipment, some don't, the question in no way is a clue to what they have.

Suggesting cutters that require a drill press would require the OP to have one, or access to one.

Buying longer screws wouldn't require any of that, but would require getting the right length, too long and they can interfere with the mag.

Regardless it looks like the OP is headed to longer screws.
 

· Registered
Joined
·
54 Posts
Don't know what tools/facilities/skills OP has on hand but I've done a few of these kind of mods. Success has best come from using a piloted counterbore, preferably with a pilot that can be changed to suit the diameter of the screw hole. This tool can be used in a hand drill so a press, while desirable, isn't a deal breaker. Since it sounds like a one time use I don't suppose investing big $ on a counterbore is a good idea but maybe throwing a few dollars at something like


might be OK?
 

· Registered
Joined
·
4 Posts
Discussion Starter · #20 ·
I think I would be inclined to purchase longer screws. If you start trying to re-bore the hole the bit is likely to hit the sides of the hole and make an ugly mark. Then even with a drill press what happens if you drill it too deep, the grips could easily break off.
Well.. I called the manufacturer to ask for the screw specs, and found out they sell longer screws for wood grips. I had no idea. So thanks again for the suggestion. Glad I didn't spend money on tools to modify the holes and possibly mess up the grips!
 
1 - 20 of 29 Posts
Top