Best Mortice Lock Jig for Door Fitting: 2025 Expert Review
DR Joinery
Expert Joiner & Bespoke Craftsman
Fitting a mortice lock by hand using a drill and chisel is a core skill for any joiner, but it is time-consuming and leaves room for error. One slip with a chisel on a finished oak door can be a costly mistake. That is why a reliable mortice lock jig is an essential piece of kit for consistent, professional results.
In York's older terraces and listed buildings, we rarely encounter perfectly square frames or standard door thicknesses. A good jig needs to cope with these variables whilst protecting the door's integrity. Whether it is a simple sashlock or a complex multi-point locking system, precision is key for security and longevity.
In this review, I'll compare three tools I've assessed: a budget-friendly marking guide for the DIY enthusiast, a professional routing jig for rapid site work, and an adjustable problem-solver for those non-standard locks we often find in restoration projects.
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Specs vs. The Real World
The Spec: "Universal Fit"
"Manufacturers often claim jigs fit all door thicknesses immediately out of the box."
In older York properties, doors can be warped or have many layers of paint. You often need to clamp jigs tighter or shim them to find the true structural centre of the stile.
The Spec: "Setup Speed"
"Marketing suggests you can rout a lock in under five minutes."
Whilst the cutting is fast, the setup takes time. You must measure the spindle height accurately relative to the handle design. Rushing the setup leads to handles that don't cover the mortice.
My Top 3 Recommendations
Three options to cover different needs and budgets
Decoralin Door Handle & Mortice Lock Marking Jig Set – Template for 45mm, 57mm & 82mm Backset – Edge Center Finder 1–54mm – Includes Pencil & Sharpener – Easy Accurate Door Handle Installation
Decoralin
This isn't a routing jig, but a marking template. For a homeowner fitting a single lock or a joiner needing a quick layout tool, it handles the basics brilliantly. It eliminates the guesswork of measuring backsets manually, which is where most mistakes happen.
The Good
- Extremely affordable for occasional use
- Includes a centre finder which is invaluable for latch alignment
- European manufactured
The Bad
- Does not guide the drill or chisel – purely for marking
- Plastic construction is less durable for heavy site use
Installer Tip:
Use the centre finder to mark your drill point on the door edge, but always double-check with a combination square if the door is warped. Ensure your pencil is extremely sharp for accuracy.
Priced at £6.99 at the time of writing
Check Price on AmazonTrend Lock Jig Kit for Routing Face-Plate Recess and Mortise, 34-58mm Wide Doors, LOCK/JIG
Trend
This is the industry standard for a reason. If you are hanging multiple doors, this jig pays for itself in time saved. The magnetic templates allow for rapid switching between the deep mortice and the shallow faceplate recess, ensuring a perfectly flush finish every time.
The Good
- Extremely robust usage with zero flex
- Magnetic templates make swapping sizes very fast
- Produces a clean, professional finish ideal for high-end joinery
The Bad
- Requires a compatible router with 80mm plunge
- Higher initial investment
Installer Tip:
Ensure you regularly clear wood chippings from the mortice whilst routing. The deep plunge required can clog the cutter, leading to burning on hardwood doors. Take shallow passes.
Priced at £131.99 at the time of writing
Check Price on AmazonTrend Adjustable Trade Lock Jig for Mortice Lock and Latch Faceplates, LOCK/JIG/B
Trend
In restoration work, we often encounter obscure locks with non-standard faceplates. This adjustable jig is the solution. Instead of fixed templates, it uses sliding plates, allowing you to create a mortice guide for almost any size of lock or latch up to 250mm long.
The Good
- Infinitely adjustable for non-standard old locks
- Can handle very long faceplates (up to 250mm)
- Robust construction suitable for site work
The Bad
- Setup takes longer than the magnetic template version
- Requires careful checking to ensure the sliding plates are square
Installer Tip:
Because the plates slide, I always tighten them down and then check the aperture with a vernier calliper before bringing the router near the door. It is crucial to prevent the plates from slipping during use.
Priced at £102.69 at the time of writing
Check Price on AmazonFrequently Asked Questions
Do I really need a router jig to fit a door lock?
What router prevents damaging the door when using these jigs?
Can I use these jigs on fire doors?
Why is the faceplate fit so important?
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