Down and Dirty Adjustable Comb Hardware

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Bob Smalser
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Joined: Sat Aug 24, 2013 11:26 pm
Location: Seabeck, Washington
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Down and Dirty Adjustable Comb Hardware

Post by Bob Smalser »

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The volunteers at our club’s Junior Precision Small-Bore Program have been trying to get out of the duct-tape and carpet-pad business for some time now, the problem being the expense in dealing with a hundred-kid program and dozens of club rifles. Examples include the rifle comb hardware shown on the Match 64 made by a gunsmith in Ireland and marketed on eBay for 75 bucks and the Graco shotgun hardware on the Kimber for 28 bucks at Brownell’s. Both do the job and are adjustable for cast as well as height, although the Irish hardware isn’t always adaptable to thumbhole stocks and while the Graco has more cast adjustment than any, it was designed for shotguns and doesn’t have sufficient height for more than 10mm sight riser blocks. While Warner Tool, Anschutz and the like make the best rifle comb hardware, the cost is out of the question.

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So after arriving at a solution for a donor Valmet with an odd-shaped stock, I adapted it to our other club rifles. While we lose the cast adjustment, we can do 3-4 rifles a day for under 10 bucks each. Here’s how.

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One of our Annie Achievers with off-the-shelf hardware acquired at Tacoma Screw. Three-eighths stainless rod, 10-24 set screw collars to match, and various scrounged knurled-head machine screws. While it has a problem-plagued bolt and (accordingly) was only made for a couple of years, the Achiever target model is probably the best kiddie rifle ever made with excellent barrel, good sights, and adjustable buttplate and trigger. Bolt rebuild kits are marketed on eBay for 39 bucks that will solve the light primer strikes resulting from too-short firing pins and bent striker shafts resulting from heavy use.

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I prefer to index comb cuts to the sight line, and using the top of the barrel channel allows me to easily keep all cuts and holes square and plumb. After laying out the comb cut, I layout hole centers and drill through the stock before cutting the comb, using the bottom of the drill press table as a clamping surface. When cosmetics are secondary, this takes all the fussiness out of the installation, dramatically reducing installation time.

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To make stock cuts level and plumb, I generally cover them with masking tape and fasten them to a sacrificial cardboard jig using spray adhesive and glued-in cardboard shims. Reliable and fast.

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I plug the 3/8” holes with dowels to index the center for a ¾” Forstner bit to countersink the collars, then ream the lower holes to ½” for clearance, as it’s the collars that lock the rod in place, not the holes. Hardware to be glued and sawcuts are made to provide recessed surfaces for the epoxy to lock the steel into the wood.

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Holes for the set screws are drilled and adjusted in a dry fit to insure the screws are plumb, and quick-set epoxy is prepared and dyed for installation. Metal surfaces to be glued are degreased using trichloroethylene solvent, and surfaces not to be glued are coated with paste wax as a release agent. Should you get epoxy where it shouldn’t be and lock things together, touching a hot soldering iron to the metal after the epoxy is cured will release it without harm to either metal or epoxy.

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I assemble everything in the glueup and allow it to cure. While slow-cure epoxy is stronger, the quick-set is more than adequate and allows moving on to other work like pillar bedding in a matter of minutes. Allow to cure for 12 hours before use, however. The last steps are to drill and tap set screw holes from the opposite side of the stock to facilitate ambidextrous use if appropriate, and cut the knurled set screws to the correct length. Running a threading die down the threads and leave it there during cutting and beveling to allow easy thread cleanup.
Bob
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