March 12, 2012

Building a Stock-Finishing Rotisserie

A shopping trip to the mall inspired this gunsmith to make a better finishing set up in his shop. Here’s how he did it.

While accompanying my wife on a recent mall shopping trip, I walked by one of the food stores and saw a rotisserie with about six chickens skewered on a rod slowly rotating under several heating lamps. On the ride home from the mall, the idea struck me that the rotisserie (without chickens, of course) might be a good way to apply a run-free, spray-on stock finish. So I built one from used restaurant equipment, and I now have an easy way to apply spray-on finishes.

I started with a used electric barbecue rotisserie, which has a shaft protruding out of the reduction gear box with a 1/4-inch-square recess in the end of the shaft that would normally hold the skewer. On this shaft there is a 10-32 threaded hole with a set screw that’s usually used to secure a skewer.

To make a jig that would insert into stock channels and still mate with the threaded hole, I started with a 36-inch hardwood dowel 5/8 inch in diameter and drilled a 3/8-inch hole in one end of the dowel about an inch deep. I then used plastic electrical tape to affix a 2-inch length of 1/4-inch square cold-rolled stock to the dowel and applied two coats of release agent to the taped end of the square steel stock. After the two coats of release agent had dried, I Acra-glassed the taped end into the end of the dowel with the 3/8-inch hole. After it had hardened, I removed the 1/4-inch steel stock from the dowel and removed the tape. The steel stock now fits into the end of the dowel with ease and some clearance.

Homemade Gunsmith Tools

Courtesy, American Gunsmith

A used electric barbecue rotisserie serves as the drive for a stock-finishing skewer. A 36-inch hardwood dowel 5/8 -inch in diameter attaches to the stock. A plywood box measuring 15 by 15 inches square and 48 inches in length helps control airborne spray.

A 5/8-inch wooden dowel will fit into most sporter stock barrel channels, but if it doesn’t for some reason, it is a simple matter to shave some wood off the sides so it will fit. But for most stocks, all you need to do is lay the dowel into the barrel channel of the stock to be finished and mark the dowel where the two action-screw holes come through. If the stock has a through hole for a front swivel, this hole can be used, too. Drill two 3/16-inch holes through the dowel on the marks and try to keep the holes lined up.

To attach the dowel, I use two 10-32 by 21/2-inch machine bolts with a washer at the head and one in front of the nut. A 1-inch spacer made out of a 1/2-inch wood dowel with the center of the dowel drilled out to 5/16 of an inch—much like a bushing—will elevate the 5/8-inch dowel so that it doesn’t rest on the stock comb. To support the passive end of the 5/8-inch dowel, I fashioned a steady rest with a V-shaped notch at the top. There is also a plastic hold down with a cutout for the dowel to fit into. This part helps keep the dowel from coming up and out of the V notch when turning.

To control overspray, I made a box out of plywood measuring 15 by 15 inches square and 48 inches long. The inside bottom of the box has 245/16-inch through holes drilled 1 inch apart on the centerline to the driver shaft. These holes allow the steady rest to be adjusted for length in case a short dowel might be used to spray a forearm or butt-stock. The back and bottom of the box are permanently fixed to each other at the sides and where they butt. The top and the front are permanently glued and screwed to each other as well. The back edge of the top and the top edge of the back are hinged so that the box can be opened and closed, allowing for dust-free drying.

Homemade Gunsmith Tools

Courtesy, American Gunsmith

A 2-inch length of 1/4-inch square cold-rolled stock fits into a 10-32 threaded hole attached to a shaft on the rotisserie motor.

Once I attach a stock to the dowel and the set-up is running properly, I can spray finish on as the stock rotates. As the stock turns, the finish doesn’t run and it dries smoothly—unless I spray the finish on too heavily, of course.

I’ve tried this rotisserie set-up on composite stocks with some success as well. In the past, when I’ve attempted to get a black wrinkled finish using wrinkle-finish spray paint, I’ve found that to get the wrinkled effect, the paint needs to be applied quite heavily and then before it dries completely, applied again. With the stock in a supine, hanging position, I had too many runs for my liking.

In the rotisserie setup, however, I mounted the fiberglass stock and sprayed the wrinkle finish paint on the stock. As the stock was rotating, I directed the high heat from a hand-held hair dryer onto the paint to speed up the drying and wrinkling process. It worked quite well with nary a run.

Because of the success of my rotisserie, the thought has crossed my mind about schemes wherein I hook up the wife’s vacuum cleaner to the box to suck up overspray, but her catching me could prove fatal. Also, I haven’t told the wife about getting this rotisserie idea as a result of me going shopping with her. She just might think I’m having fun!