How To Fit a Mortice Lock

In this article we show you how to fit a mortice lock into a garden gate.

A mortice lock offers stability and durability for reassured safety. A mortice is cut into the edge of the door where the locks fits into.

Fitting a mortice lock can be a more complicated process than fitting a traditional, cylindrical lock. To make this process easier you can use a lock jig. We have used the UJK Compact Lock Jig.

Watch Jason in our Woodworking Basics video where he shows you how to use the jig to fit a mortice lock. Or follow our step by step guide below.

Prepare the gate or door

In this example, we have fitted the mortice lock to a garden gate. But the same will apply to an internal or external door.

The lock jig contains templates for various sizes to help you fit the lock right. Once you have the right templates you can secure your door or gate into a workbench vice and hold in position ready to mark out the position of your lock.

Traditionally a lock should be placed in the middle of the centre of the middle rail. Pay attention to any flaws in the timber such as knots, and try to avoid these as there will be a weaker grain structure.

Mark out the lock location

First mark the lock position on the door or gate of where you want it sit, marking the length of the lock. Then, find the centre point of the thickness and mark using a pencil and marking gauge.

Set the lock jig by loosening the screws and align the centre lines on the jig to your scribed centre lines on the gate. Measure the length of your lock and divide by two to find the lock centre point. Measure and mark this along your scribe line on the gate.

Once the jig is aligned to both your centre lines, you can clamp it in place and fix the guides in place, matching the length of your lock.

Check the width of your lock and select the appropriate lock template of the same width and attach this to the jig.

Set the router guide bush

Use a 16mm guide bush and 1/2in router cutter with the right offset and fit this into your router. This will locate into the template fixed in the gate.

Next, set the depth of cut. First measure the depth of your lock and set this on your router. We used a long kitchen worktop router cutter for the cut.

You can now rout the recess for the depth of the lock.

Rout the lock faceplate recess

Next select the template to match the lock faceplate and fit in place. Next, reset the cutter depth and measure against the lock faceplate to get the correct recess depth. Then rout the recess.

You will need to square up the corners of the cut using a chisel and mallet. Insert the lock to check the fit.

Mark the lock mechanism

Next you will need to mark out on the gate the barrel and key location. Begin by using the slot as a visual marker to mark a central line. Then, measure the distance from the faceplate to the middle of the barrel, using a marking gauge, and mark this on the gate, crossing your centre line. Do the same with the key also.

Don't forget to the measure the barrel bar diagonally across also to know which drill bit to use.

Drill the mechanism holes

Place a piece of backing board in the lock recess to prevent breakout. Once the holes are drilled on both sides, check the barrel bar fits into the top hole and chisel out your key holes.

Assemble the lock by putting in place all the parts and testing the mechanism with the handle.

Drill your pilot holes for the handle and lock and screw in place.

Installing the lock to the gatepost

Once the handle and hardware is fitted to the gate, you will need to install the rest of the lock to your gatepost.

Begin by hanging the gate by its hinges and lining up the lock catch to the corresponding gate post in a closed gate position, and mark where the door catch and lock latch rests. Mark out on the lock plate on the gate post including the length and width to find the centre line to mark out the plate.

Set up the UJK compact lock jig again to the length of the lock plate - we have included a 1.5mm off set at each end for the router guide bush. Clamp your jig in place for routing. Use a spacer if needed.

Set the depth of cut on your router to the thickness of the plate. Rout and check the finished thickness against the face plate.

Next rout the recess for the lock fitment. Reset the lock jig and set the guides to the length of the lock recess with the same offset for the guide bush. Reset the router and measure the lock recess to set the depth of cut. Clamp in place and cut.

Mark and cut the overhang

Mark on the post the overhang as this will need to be rounded off. You can use a spacer with the jig to allow room to rout the edge. Clamp in place and adjust the two stops to the correct position. Reset the depth of cut, again to the thickness of the faceplate, and rout the edge.

Use a chisel to square off the corners and tidy the edges if needed. Use a Japanese rasp to file the edge away to refine the curved edge so the plate sits flat. Test the fit and screw in place

Learn more woodworking skills

If you have enjoyed this article, check out our other useful guides to improve your basic woodworking skills, including how to select timber for your woodworking project, how to cut traditional woodworking joints by hand and how to prepare your timber.