Gunsmithing Grovtec flush cups

[nukebabysitter]

For those of you who have installed grovtec heavy duty flush cups (part #- GTSW-295) did you just drill the .50" hole and epoxy the stud in or did you drill and tap?

Ive found write up on the install but none of them say the person doing the install used a tap, but the instructions say to use a tap.

 

[turbo54]

Drill, tap, epoxy

 

[PCR]

For those of you who have installed grovtec heavy duty flush cups (part #- GTSW-295) did you just drill the .50" hole and epoxy the stud in or did you drill and tap?

Ive found write up on the install but none of them say the person doing the install used a tap, but the instructions say to use a tap.

We run a 1/2" endmill, then tap 9/16X18, coat the insert with Devcon and screw it in. Our tap is ground so the threads reach the bottom. Easy to set depth and run the tap straight with a manual mill and no worries of the gelcoat chipping. Chamfer the leading edge of the hole to keep things neat. We actually do this with another endmill.

If using a hand drill, put masking tape on the stock first and be careful not to cut an oversize hole or chip the gelcoat. Use a smaller drill bit for a starter hole. You might want to break the leading edge with a round file so that the tap doesn't chip the gelcoat. Apply a small amount of Devcon to the threads and make sure to clean up the excess or you won't get the swivel insert to go in or lock.

 

[nukebabysitter]

Any tips if the stock is hollow, like mt savage 338lm with a hs precision? I just dont want the cup in the butt to tear out.