Installing a flush bolt into the edge or back side of a cabinet door is not an easy task because there’s nowhere to hide any imperfections in the wood-to-metal fit. To make it even more difficult, you also need to cut a mortise into the end grain of the door’s stile. And if you go through all the steps to achieve a great fit, you then hide your careful craftsmanship—literally behind a locked door. Whenever possible, I’ll choose another method of securing a door. But sometimes, you simply have to install a flush bolt, so here’s how to do it.
Before you order a flush bolt, check its dimen-sions carefully. The bolt in this demonstration has a maximum thickness of 3⁄4in. at the top mortise, so that part would have poked through the front of a 3⁄4-in.-thick door. Fortunately, I was working with a 1-in.-thick door (A). Place the bolt on its side on the stile. Using a square, ensure that the end of the bolt is flush with the end of the stile, and mark the lower end of the bolt. Looking at the bolt from the side (B), you’ll see that when I set the router bit deep enough for the groove to house the spring, the mounting post for the screw would lose contact with the bottom of the mortise. To make up the difference, I figured that I’d have to add several no. 8 washers below the post.
Set the fence on your router, and cut the mortise to final depth by making several shallow passes (C). Use a chisel to square the end of the mortise (D). Test-fit the bolt into the mortise, chiseling the mortise wider, if necessary, until the surface of the bolt is flush with the rear face of the door.
At this point, the end of the bolt can’t reach the lower end of the mortise because you need to (Text continues on p. 96.)
A
B
C
D
Catches, Latches, and Locks 96
cut the mortise into the top of the door. Use a sharp crafts or utility knife to scribe the end of the bolt into the top of the door ((EE)).. Chisel the mortise to fit the top end of the bolt ((FF)).. You’ll need an extremely sharp chisel to make smooth cuts into the end grain.
Place the bolt into position, mark the center-points of the attachment screws ((GG)),, and drill pilot holes. Remove the bolt, add washers under the screw post if necessary, and fasten it ((HH))..
After hanging the door, mark the end of the bolt with correction fluid ((II)) and press the bolt against the carcase to transfer the hole location to the cabinet ((JJ)).. Drill a hole that’s about 1⁄16in. larger than the diameter of the bolt. Position the strike plate around the hole, drill pilot holes for the screws, and drive them. Trace the perimeter of the strike plate with a crafts knife to scribe its location onto the carcase. Using a chisel, mortise the strike plate flush with the wood.
E
E FF
G
G HH
II JJ
C
Ca am m L Lo oc ck k
When you buy a cam lock, make certain that its body length suits the thickness of the door stock you’re using. The lock in this installation is adjustable for panels 3⁄4in. through 13⁄8in. thick, so the first step is to screw the flange in or out to match the thickness of your door ((AA)).. The spring-loaded black detents ride up and over the threaded part of the barrel as you rotate the flange. Make sure that the detents rest on the flats of the barrel when you’ve completed the adjustment. For the 3⁄4-in.-thick door I used, I had to move the flange to the full forward position. I chose to use the straight cam (also called the tail) for this installation instead of the cranked cam that the factory attached to the lock.
Use a nutdriver ((BB)) to swap the cams. At this point, don’t worry about which of the four possi-ble cam-mounting positions to use—lightly snug the nut with the cam seated in any position. To determine the mounting position on the door, measure the distance from the center of the mounting bolt to the tip of the cam ((CC)).. With this measurement, you can finalize the design of your door. The drawing at right shows how I positioned the lock in relation to the side of the carcase.
To accommodate the lock body plus the
escutcheon for this lock, use your drill press and a Forstner bit to drill a 3⁄4-in. hole into the stile of your door ((DD)).. Remove the cam so it won’t be in your way as you center the lock body in the hole.
I like to position the lock so the teeth on the key point downward as the key goes into the lock, but it will function just as well if inverted. Partially insert the press-fit escutcheon, and use a ((TTeexxtt ccoonnttiinnuueess oonn pp.. 9988..))
1/8-in. cam slot
3/8-in. deep, 11/8-in. long
3/4-in. hole centered in the width of the stile
3/4-in.-thick carcase side
13/4-in.
stile
1/16-in.
clearance
A
A BB
C
C DD
C
Caamm LLoocckk IInnssttaallllaattiioonn
Catches, Latches, and Locks 98
self-centering punch to mark the centerpoints of the mounting holes ((EE)).. Drill pilot holes and drive screws into the rear face of the stile to fasten the flange to the stile. Positioning the lock over the open vise on your workbench is an easy way to provide clearance for the lock and escutcheon while you drive the screws ((FF))..
As a rule of thumb, you want to position the cam so that turning the key counterclockwise engages the cam ((GG)).. I wanted a carcase-to-stile gap of approximately 1⁄16in., so I taped samples of plastic laminate to the carcase to establish this spacing.
If you can access the interior of the cabinet with the door in place, you can directly mark the posi-tion where the upper end of the cam contacts the carcase ((HH)).. If you can’t mark directly, paint the tip of the cam with correction fluid purchased from an office-supply store. Also make a mark on the carcase to indicate the lower end of the cam.
Using a router or laminate trimmer, rout a 1⁄8-in.
slot 3⁄8in. deep into the side of the carcase ((II))..
I like to rout about 1⁄16in. past each end mark to ensure that there is adequate clearance for the cam. There’s no need to square the ends of the slot. Check the action of the lock to ensure that the cam easily engages the slot ((JJ)).. Finger pres-sure is enough to press the escutcheon onto the lock’s body ((KK)).. The finished lock installation pro-vides good security while retaining an unobtru-sive appearance for your cabinet ((LL))..
E
E FF
G
G HH
II JJ
K
K LL