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SJC Glock Frame Weight Thumb Rest Kit

Installation Instructions

If you do not understand any of the following contact SJC before proceeding

  1. It is always your responsibility to make sure your gun is unloaded and safe before handling, installation, or removal of parts.

  2. Remove the slide assembly from your pistol before starting

  3. Make sure you have fully backed out or removed the #6 32tpi set screws from the frame weight.

  4. Connect the thumb rest onto the frame weight with the three #6-32 flat head screws making sure they do not protrude through to the inside of the weight. If they do protrude then they must be shortened before installing the weight onto the pistol.

  5. Align the frame weight with the accessory rail and being careful to avoid frame deformation or damage slide on the weight until the unit bottoms out on the frame next to the trigger guard.

  6. The thumb rest pilot hole should be marked using a small fresh drill bit through the hole in the thumb rest but still measure 1.133” to the center of the trigger pin hole. By using this dimension, SJC Glock Sight mounts may use the same bushing location at some later date.

  7. Remove the frame weight from the frame.

  8. Drill out the pilot hole to the exact barrel diameter of the supplied bushing. We normally use a 19/64" bit and use heat for the final seating.

  9. You now need to inlet the sides of the guide rod/spring trough in the frame to accept the bushing flange and prevent any interference with the function of the recoil spring. Proper inletting will place the outer most portion of the bushing's barrel no more than flush with the outside of the frame. Note that the bushing flange outer diameter has flat sides. The inletting process needs to closely match these flats so the bushing will not spin on tightening and loosening of the screws. We use an end mill to bring all of the inletting elements together in a single operation but using a dremel tool carefully will be fine.

  10. Place the cross bar of the included aluminum T-bar insert into the notch on your pistols accessory rail with the short end toward the serial number in the frame.

  11. Re-install the frame weight as before onto the frame and bushing

  12. Install the set screws tight enough to mark their positions on the aluminum T bar

  13. Heavily dimple the aluminum T bar set screw locations with a fresh drill bit. This may be done by hand power.

  14. Use loc-tite and re-install the set screws being careful to not over tighten. Over tightening the set screws will deform the polymer frame or drive the screws completely through the threaded holes in the frame weight. The two set screws over the notch are the only ones required. The others are for back up and additional support.

  15. Minor holster modifications may be required. SJC offers holster modification services and advice on CR-Speed and Ghost holsters.

  16. The SJC Glock Frame Weight is delivered in the white to allow the customer to protect, paint, or coat to each individual’s taste. Maintaining a light coat of oil and avoiding liquids should prevent oxidation until you have applied a permanent protective coating.