Since I need to make the patchbox for the rifle I am currently commissioned to build, I thought I would try and document the process. The box I decide on is a captured lid box with a hidden hinge. The box design was inspired from an original Jaeger sliding wooden box with a decorative surround that just screamed metal box surround to me. The mechanics of the box come from an original cast brass box. Unique to this box is that it is self contained. The springs and the release are all mounted to the box. Anyway, here goes. Hope you enjoy.
David
This first picture is the pattern. I normally draw a pattern on a sheet of copy paper then I glue it to my sheet of brass or steel using regular old carpenters glue. The steel I chose for this box has a thickness of .047" (18 gage).
Once the pattern has been cut out, I form the patchbox to the contour of the stock. This is a time consuming step that is essential to avoid low and high spots after inletting. If the patchbox does not match the contour of the stock you risk having thin spots when you file and sand the patchbox flush with the stock. Now is the time to clean up and draft the edges with a file. Once the prep work is completed, I locate and drill the holes in the patchbox for the wood screws. I then transfer the hole locations to the stock and lightly center punch them. For this box I used 1/2" x 5 flat head wood screws.
This is an end view of the curve in the patchbox. Notice that the curve is smooth with no humps, bends or ridges. You should strive for smooth bends and contours. This will aid in maintaining even thickness during the final filing, sanding and polishing.
This picture shows the use of the gimlet for drilling pilot holes. I prefer using gimlets to twist drills because I can make corrections as I am drilling to ensure the pilot hole is perpendicular to the surface of the gunstock.
With the patchbox screwed into place, I trace around the inside and outside perimeter of the box with a sharp pencil. At this time I also start to remove some of the bulk wood where the patchbox cavity will be. I use a 1" drill and drill each of the 3 holes to final depth in 1/4" deep increments. Drilling in increments helps to keep the drill bit from grabbing at the overlap.
This is the tool I use to ensure the inlet follows the contour of the buttstock. Using a 1/16" drill with a drill stop, I set the drill depth to the thickness of the patchbox.
Using the drill and drill stop, I pepper the area to be inlet with 1/16" holes .047" deep. These holes will be used during wood removal to ensure that the inlet follows the contour of the stock. Once I have peppered the area with holes, I erase the pencil lines and reinstall the patchbox. Next I lightly trace around the outside of the patchbox with a sharp X-acto knife to mark the exterior of the inlet. I then remove the patchbox and remove all the wood inside the scribed lines. I continue deepening the inlet until I have reached the bottom of the drilled holes.
This picture shows the completed inlet. As you can see, all the holes I previously drilled have disappeared and the inlet follows the stock profile perfectly.
At this time I clean up the patchbox cavity. I leave about 1/16" of wood around the patchbox for the lid to rest on. More wood will have to be removed later on for the hinges, springs and door catch.
These 3 photos show the patchbox lid. The lid curve matches the patchbox. The front of the lid and the mating surface have a 45 degree bevel filed on both pieces. The other 3 sides of the lid have a slight draft filed in them.
This is a picture of the hinge assembly. The hinges were bent from the same 18 gage mild steel as the box surround and lid. I made a 90 degree bend in a 2"long x 5/8" wide strip of steel. I then laid out the locations for and drilled the hinge pin and rivet holes. I drilled these holes prior to cutting off the individual pieces so I had a bigger piece of material to hold. The individual hinges are approximately 3/8" wide by 5/16" tall. After tinning the joints, I soft soldered the hinges to the door first ensuring the hinge was perpendicular to the edge of the lid. I then positioned and clamped the door to the box. I slid the hinge pin through the lid hinges and slid the box hinges over the hinge pin. Due to the curve of the box and lid, I had to tweak the 90 degree hinge bends to get a good alignment for the hinge pin and a tight solder joint. The 2 hinges were then soldered to the patchbox. With all 4 hinges secure with no fear of losing alignment, I was able to complete drilling and riveting the hinges to the patchbox and patchbox lid. After countering the holes, I filed the round holes square, leaving the outside diameter of the countersink round. After making some square pins up for the rivets, I riveted the hinges to the box and lid and filed them flush. The reason for using square stock was for added security in maintaining alignment of the hinges should the soft solder joint fail. With the hinge assembly complete, my next step was to provide clearance for the hinges and lid in the stock.
This is a picture of all the components used in making this captured lid hidden hinged patchbox. A total of 18 individual pieces were required to be made for this project.
A picture of the underside of the assembled patchbox unit. The springs were made from 1084 steel. Since I do not make a lot of springs, I like using 1084. It is very forgiving compared to 1095. Screws are made from 12L14 round stock. The thread pitch is 5-40.
A picture of the completed inlet.
The completed patchbox assembly in the gun. A bit more polishing and adjusting the depth of the countersinks and this patchox is done.
