Rifle Recoil Pad Fixture

thingiverse

UPDATE: 3/13/2023 - the #8 threads in the base portion of this build tend to be weak. They lasted for the entire grinding operation for an old Browning A-bolt I restored. So two ideas here: 1) the base is effectively "disposable" after one or a few recoil pad modifications. PLA is cheap so this option works for me. OR 2) you could embed a long heat set insert to make the fixture base more robust as described here: https://hackaday.com/2019/02/28/threading-3d-printed-parts-how-to-use-heat-set-inserts/ Save $50 to $60 plus shipping by printing your own grind-to-fit rifle recoil pad fixture. Added a new grind-to-fit recoil pad recently to a rifle I am restoring. Fits typical recoil pads available on Midway, Brownell's, and Amazon such as Limb Saver and Kick-Eez. Designed specifically for recoil pad screw separation of 3-1/8". Fusion 360 files attached so you can scale the fixture or alter dimensions. One thing is critical in this design, and that's maintaining the rigidity and strength of the fixture. To do this I did the following: 1) Print using PLA or PLA+ for rigidity. 2) Design incorporates bridges, fillets, and supports around pivot arms to maximize solid material at weak/transition points. 3) Infill density at least 30%. 4) Bumped up hot end/bed temperature to 210/60 5) Wall thickness bumped up to 2.4 mm or 4 layers/0.6 mm nozzle OR 6 layers/0.4 mm nozzle (sliced gcode files for 0.4 mm nozzle) Without these enhanced design features/settings you risk cracking weak points like the pivot arms. Don't over-tighten screws! Additional materials needed: 1) Various length 4 mm or #8 screws. This design uses #8 hardware! Pad screws are M4. 2) Nuts, washers., and lock washers (optional) for screws. 3) Two oversized washers to help stabilize pad in place. 4) Recommend hex head or button head hex for pivot joint so you can get the pivot snug when setting the angle. Post processing and Assembly: 1) Tap the two posts on the base to #8X32 or equivalent. Tap depth to about an inch. 2) Install a 1" or so (as needed) #8 screw with a nut to lock each screw in place. The purpose of these screws is to (a) mark the position of the top and toe angles and (b) secure the down angle travel while grinding in case the pivot shifts. (3) Install pivot nut, screw, and washer. (4) Install washers, nuts, screws, and lock washers for pad screws. Length depending on recoil pad. I used a 50 mm M4 screw for a 1" thick pad. Further instructions for using a similar fixture can be found here: https://www.youtube.com/watch?v=dmUo7lvmU1E Another tip: take your time and freeze the pad while grinding. May need to re-freeze several times but it limits pad melting while grinding on wheel or drum.