I wanted to make a kydex cheek rest for my new M1A, and knew I could do it myself for less than the ones on the market. I thought it would be easy to find a small sheet of kydex, but I couldn't find anything more than .06" or .092" thick. Fine for making knife sheaths, but not thick enough for my cheek rest project.
I called lots of places local to me, and of the few that had it, they only wanted to sell me a $150+ 4'x8' sheet.
Finally, I got the bright idea to check ebay. Again, nothing there thick enough, but I emailed all the sellers to see if they had something thicker.
One did, and I ended up with a nice 12"x12" black sheet, .187" thick, for $15 after shipping.
The company is Harva Plastics, at http://harva.com/
. Amber was helpful and got everything done and in the mail within a couple days. Write them at email@example.com
So I start with a sheet of 3/16"(.187") kydex. To cover the area of the stock I need a 5.5"x10" piece. All white lines drawn with a white colored pencil. The kydex was cut nicely using a bandsaw. You can see the block of wood, which I rounded using a belt sander to make a desireable contour for my cheek. That will be the form onto which the initial thermoforming is done.
Initial thermoforming using the contoured wood block and a black&decker heat gun. Notice the center line drawn perpendicular down the middle. That comes in handy throughout the process to make sure the kydex isn't crooked on the stock as its being thermoformed. Thick leather gloves are a must, because lots of pressure is essential to getting a good mold. To squeeze that hard on something so hot, you need thick gloves. You can tell when the kydex is soft enough, it will blanch ever so slightly as it heats up.
Placed the now rough formed kydex onto the stock, and drew lines to represent the rough bottom edge of the stock. Trimmed the excess off the bottom of the kydex to fascilitate next step, thermoforming the kydex to the stock itself. At this point, mount the stock to your shoulder and get a feel for where your cheek will be hitting the stock. Mark the stock for where the kydex needs to be so you can line it up while forming (mark on stock seen in next pic).
Kydex thermoformed to the stock. You can see the top surface goes from fat to skinny as you go from back to front.
Draw your final contour/outline. I was doodling and trying to come up with something that looked cool, but finally decided on the normal contour.
Upside down belt sander attached to the bench was used to carve the final contour. I decided it was faster and easier than trying to do it with the bandsaw, the coarse belt eats the kydex very quickly, so this step was only 10 min or so.
Some de-burring and sanding and the final shaping is done.
Did some final thermoforming after the final shaping, making sure to have the kydex lined up with the marks on the stock.
Put the gun back together, with the scope mounted, and mount the gun to your shoulder. Move the kydex up and down until you get it right where you have a solid cheek weld where your eye needs to be. Mark the stock along the bottom edge of the kydex, making sure the top surface of the kydex is parallel with the comb of the stock. You now know exactly where the kydex needs to be located. Figure out where you want your holes to be drilled, and mark it.
Here is the nerve wracking part, and where you want to measure 10 times, and drill once. I basically worked from one side to the other. I drilled holes in one side of the kydex, marked the stock through those holes, drilled into the stock, and then marked the other side of the kydex where the holes ended up (making sure it was all always aligned with the marks made earlier). Do your best to drill straight through the stock, but so long as you keep everything aligned on those marks, the important part, your eye alignment, will be maintained no matter what.
You can see my mounting hardware. I think these are actually used in scrapbooking, and are 7/32" wide with a thread of 8x32. I got one 1.5" and one 2". You'll probably want to come up with your own mounting hardware solution, so spend some time at the hardware store, and look at *****'s cheek pieces
Except I'm going to paint the silver ends black to match the stock.
I hope this encourages someone else to make their own. It was actually pretty easy, and could certainly be done with only hand tools. I'm very satisfied with it, for my grand total of $20 invested (and I've got enough kydex left over for a whole other cheek rest).
Once all the hardware is shored up, the thing is surprisingly solid. No wiggle up and down or side to side, and the 3/16" thick kydex has no flex to it at all while mounted. I wouldn't go any thinner than .187", and 1/4" would be too thick.
The placement of the mounting hardware is tricky. You don't want to go too high on the stock, because you want the hardware to go through the thicker area. Some don't want to affect the storage areas in the stock. I compromised, and mine leave the bottom storage area open, but go through the top storage area.
Now, why didn't I do the slotted adjustable like those sold online? A few reasons. First, is that the bell of my scope on the low rings, in addition to the cross screw of the rings, prevents the iron sights from being used while the scope is mounted. If I have time to remove the scope, I have time to remove the cheek rest. Second, because I made it, it was custom fitted to my gun and the height I required for my eye. No adjustment needed. Third, its unique, and I like unique.