1. Prep the Spindle
Insert your square spindle through the hole in the door so it passes cleanly through the mortice latch inside. Ensure an equal amount of the spindle is protruding on both sides.
2. Centre and Mark ALL Holes
Slide a fixing plate over the spindle so it sits perfectly flush and cantered against the door. Use a pencil or bradawl to mark all the holes:
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The horizontal holes (usually 3 and 9 o'clock) for the bolt-through fixings.
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The remaining holes (often top and bottom, or diagonal) for the wood screws.
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Repeat this marking process on the other side of the door.
3. Drill the Bolt-Through Holes
Remove the plate and spindle. Using a drill bit slightly wider than your bolts, drill completely through the door at the bolt-through marks.
Pro-Tip: To stop the wood from splintering on the way out, drill from one side until the tip of the bit just pokes through the other side. Stop, go to the other side of the door, and finish the hole through the exit point. Ensure your drill passes cleanly through the holes in the latch casing.
4. Drill the Wood Screw
Pilot Holes Switch to a smaller drill bit. Drill shallow pilot holes at the wood screw marks on both sides of the door. Be careful not to drill too deep.
5. Clamp the Plates (Bolts First)
Slide the spindle back through the latch. Place a fixing plate on both sides of the door over the spindle. Insert the long male bolts through one plate, through the door, and thread them into the female sleeve nuts on the opposite plate. Tighten these down first. This ensures the plates are perfectly aligned and firmly sandwiched against the door.
6. Secure the Wood Screws
With the plates clamped firmly in place by the bolts, drive your wood screws into the pilot holes you drilled earlier. This locks the plates down completely.
7. Attach the Door Knobs
Slide the door knobs over the spindle and push them firmly until they sit flush over the concealed fixing plates. Ensure the small hole for the grub screw is pointing downwards toward the floor.
8. Tighten the Grub Screws
Using your Allen key, tighten the grub screw on the underside of each knob. This screw will bite onto the fixing plate (and secure the knob to the plate), locking everything together. Test the knobs to ensure the latch springs back smoothly.
