Building a locksport box.

15 July 2021

Longtime readers have probably noticed that I have an interest in locksport, or picking locks for the fun of it. As you might imagine, this requires a good deal of buying locks to practice on. From basic practice locks to padlocks, we tend to grab.. well... everything we can find, because there are so many different locks and we try to practice on all of them. While stuck at home waiting for some very long running jobs (multiple hours each) to finish at my dayjob, I decided to keep my hands busy by building myself a lockbox, or a box to hold a full-sized deadbolt lock like you might have on your front door.

At cons you'll often see deadbolt locks mounted into a piece of door or a finished 2x4 on a stand to replicate how they're mounted in real doors. I suck at carpentry (and don't have the tools anyway) so I decided to use a spare project box for electronics that I had sitting around. In case you're interested it's a Hammond 1591 XXS, which has the right dimensions (4.25 inches long, 3.25 inches high, 1.75 inches deep). The lock is a plain old Kwikset deadbolt lock that I picked up at the hardware store for $15us.

Please keep in mind that I am not an expert. This was my first time mounting a lock in anything so I made a couple of mistakes (a few of them I probably don't even realize). In addition to talking about what worked, I hope everyone also learns from my mistakes (so that you can make all new ones).

Step one was to cut the drilling template (local mirror) off of the installation instructions and tape it to the still closed up project box to figure out just how to mount it. The reason I recommended the box I did is because the depth of the box matches that of your average front door exactly. I used a burin to scratch some dots where holes needed to be drilled and more to be used as endpoints for scribing something like a circle for mounting the lock.1 The hole in question doesn't have to be very big, at most 1 5/16 inches in diameter to accept the lock's core assembly. Later in the process I used my dremel to carve a little divot so that one of the mounting screws would reach the mountpoint on the back of the lock body. You may have to do this as well.

I drilled a couple of mounting holes that I didn't need. Don't do that, you'll just waste time. I also thought that I'd need to drill a much bigger mounting hole for the lock body; I was wrong there, too. Also, while taking pictures to illustrate this post, I discovered that the project box in question is tapered ever so slightly from back to front, which might explain some of the alignment weirdness.

The part that worried me the most was that I'd mess up drilling the holes on the side where the deadbolt goes. By taping the strike plate (the metal plate that goes between the door and the doorjam, with a bigger hole for the deadbolt to pass through) to the side, I was able to scribe reliable dots for drill holes and a good oval for the deadbolt hole. A stepped drill bit and a Dremel grinding bit were ideal for drilling that hole.

I used the entire diameter of the stepped drill bit to carve the mounting hole in both the front and back of the project box. By taking the removable back plate of the project box, flipping it 180 degrees (so that the inside of the plate was facing outward), and taping it to the other side of the project box I was able to drill matching holes at the same time to make sure they were aligned. I scratched a couple of little matching lines across the top of the box to make sure that the back plate went back on in the correct orientation. A 1/4" drill bit went through both layers of plastic to make a pilot hole easily enough. Drilling the actual mounting holes for the deadbolt core took quite a while because the bit would get stuck once in a while; it wasn't designed for use on plastic but it worked well enough. Go slow and take your time because you want the bit to carve out the holes, not melt the plastic. If it takes half an hour, it takes half an hour. Go with it.

I know that I should probably take some rattail files or my Dremel and make the edges of the mounting holes look nice (and I probably will at some point) but this is me being real. Don't let Youtube videos and Twitter posts that look perfect dissuade you from doing anything, do it, make mistakes, and learn. It's okay.

If the deadbolt on the guts of the lock is retracted, stick something like a screwdriver into the hole in the middle and turn it until the deadbolt pops out. When I took these pictures I used the lever on a pair of nail clippers, like any reasonable person would. This is essential for making sure that the deadbolt body is aligned properly. Insert the deadbolt body from the inside of the project box and pass the deadbolt through the hole in the side. If the deadbolt body has a little "up" engraved or embossed on it, listen to it. Make sure that side is up.

The back of the deadbolt core has a long metal bar or tube sticking out of it, called a tail. That bar goes through a matching hole in the deadbolt body (when the key turns the lock, it rotates that bar, which pulls the deadbolt back). There is usually a decorative ring or cover that goes on the outside of the door. You don't necessarily have to use it (you'll sometimes see a lack of one on a door someplace) but it really does look nice if you do. It goes from front to back through the cover. There is also sometimes another, more sturdy metal thing that goes around the lock body underneath the cover ring. You can install that if you want (and if you're putting a deadbolt on an actual door you should) but for our purposes you can skip it. There is also sometimes a smaller adapter ring for weird doors. You can ignore that too.

Lay the lock body on its face, with the metal bar sticking up. Adjust the bar a little bit so that it matches the alignment of the center driver hole of the deadbolt body and pass it through. Now, you want to screw the mounty bit (technical term) to the side of project box. Sometimes there's an additional plate that goes on the outside, sometimes there isn't. I didn't use the external strike plate. The screws, however, are usually wood screws so you may have trouble using them on a plastic box. I wound up improvising with a couple of M3 nuts and M3 10mm machine screws. When you insert the tailpiece (the real name of the metal bar) through the deadbolt body, you'll want to make sure that the screw holes on the back of the lock body line up with the matching holes in the deadbolt body, because the lock's mounting bolts have to pass through them.

Put the back plate of the project box back on. If you're feeling saucy screw it in place. It might help, it might not.

That trim piece that goes on the inside with the deadbolt knob? Time to put it on the back of the lockbox. As before, make sure that the shape of the tailpiece matches the shape of the mounting hole on inside of the knob. It helps if you make sure that the deadbolt knob is turned to the "locked" position, because the deadbolt assembly is also in the locked position. Don't try to be too clever, you'll outsmart yourself.

If you can, use the big mounting bolts to line up the two assemblies and them screw them together. If it takes a few tries, it takes a few tries. If you find that you have to grind some bits of plastic off to make the bolts fit, grind the plastic. It's probably not going to fit perfectly, so don't worry if it doesn't. I find that it's helpful to loosen the screw by about a quarter turn to make sure that the threads match up before tightening it. Folks who do a lot of reconditioning retrotech do this to make sure that they don't wreck the screw threads on very old plastic.

Now the fun part: Testing. Does the knob lock and unlock the deadbolt? Does the key lock and unlock the deadbolt? If so, you're done. Happy picking. If not you'll have to do a bit of troubleshooting. Take the lockbox apart step by step and see if something isn't screwed down that needs to be, or if the lock's tail didn't go into the knob on the back.

  1. Scribe a dot in the dead center of where the mounting hole goes. Scribe additional dots around the edges of the circle on the template that match. Measure the radius of the part of the circle that you already have. Measure that same distance from the center to the other edge of the circle and scribe a matching dot. Scratch straight lines from side to side, through the center dot. You now have something like a circle and something like a bulls-eye that you can use to align a drill bit to make a hole.