Cam Locks with a Biscuit Joiner: Can You?

Updated November 12, 2026

Yes, you can use a biscuit joiner to cut the slots for cam locks, but it is not the ideal tool for the job and requires careful setup. While a biscuit joiner is designed for creating oval-shaped slots for wood biscuits, a cam lock system requires a precise, flat-bottomed, circular recess for the cam and a separate slot for the bolt. With the right technique and a few modifications, you can achieve functional results, but for production work or high-end furniture, a dedicated drill bit and Forstner bit are strongly recommended.

Understanding Cam Lock Fasteners

Cam locks, also known as cam fittings or cam dowels, are a type of knock-down (KD) fastener widely used in flat-pack furniture. They consist of two main parts: a cylindrical cam (usually metal or plastic) that fits into a recess on one panel, and a bolt (or dowel screw) that screws into the other panel. When the cam is turned with a screwdriver or a hex key, it catches the head of the bolt and pulls the two panels tightly together.

The key dimensions for a cam lock are the diameter and depth of the cam recess (typically 15 mm or 25 mm in diameter, and about 8–12 mm deep) and the position of the bolt hole, which must align perfectly with the center of the cam recess. The bolt head must sit within the recess so that the cam can engage it. Precision is critical: if the recess is too deep or too shallow, the joint will be loose or the cam won’t turn.

How a Biscuit Joiner Works

A biscuit joiner (or plate joiner) uses a small circular saw blade that is plunged into the edge or face of a board to create a crescent-shaped slot. The blade is adjustable for depth and angle, and the tool has a fence that can be set to position the slot at a specific distance from the edge. The slot is designed to accept a compressed wood biscuit, which expands when glue is applied, aligning and reinforcing the joint.

The shape of the slot is not a perfect circle; it is a segment of a circle, with a flat bottom and curved ends. The width of the slot is determined by the blade’s kerf (typically 4 mm), and the length is determined by the plunge depth. For a cam lock, you need a recess that is essentially a blind hole with a flat bottom and straight sides—something a biscuit joiner does not naturally produce.

Feasibility: What’s Possible and What’s Not

Technically, you could use a biscuit joiner to cut a slot that approximates the recess for a cam, but there are significant limitations:

Shape mismatch: The crescent shape of a biscuit slot is not circular. A cam is round, so a crescent-shaped recess will leave gaps around the cam, reducing the contact area and potentially causing the cam to wobble or slip.
Depth control: Biscuit joiners have depth stops, but they are calibrated for biscuit sizes (e.g., #0, #10, #20), not for cam depths. You can adjust the fence and plunge depth, but achieving a precise 8 mm depth with a flat bottom is difficult because the blade cuts a curved bottom.
Bolt alignment: The bolt hole must be drilled separately, and aligning it with the center of the crescent slot is tricky. If the bolt is off-center, the cam won’t engage properly.

In practice, using a biscuit joiner for cam locks is only viable for prototyping or when no other tool is available, and even then, you would likely need to clean up the recess with a chisel or a router.

Step-by-Step: Using a Biscuit Joiner for Cam Slots

If you decide to attempt it, here is a method that can work for a 15 mm cam (the most common size):

Mark the center: On the panel that will receive the cam, mark the exact center point where the cam should sit.
Set the depth: Adjust the biscuit joiner’s plunge depth so that the slot is about 10 mm deep (the cam recess is typically 8–12 mm deep, so check your cam’s spec).
Set the fence: Position the fence so that the slot will be centered on your mark. You may need to make a test cut on scrap to verify.
Make two overlapping cuts: To approximate a circle, make one plunge cut at the center mark, then move the joiner slightly left and right (about 3–4 mm each way) and make two more cuts, overlapping the first. This will create a wider, more rounded slot.
Clean up with a chisel: Use a sharp chisel to square the bottom and remove any remaining ridges, creating a flat-bottomed recess that the cam can sit in.
Drill the bolt hole: On the mating panel, drill a hole for the bolt (usually 7 mm diameter for a 15 mm cam) at the exact position that aligns with the center of the cam recess. Screw the bolt into this hole.
Test the fit: Insert the cam into the recess, align the panels, and turn the cam to ensure it catches the bolt head. Adjust depth or position as needed.

This process is time-consuming and imprecise compared to using a Forstner bit, but it can produce a functional joint if you are patient.

Choosing the Right Tool for the Job

For most woodworkers, the best tool for cutting cam lock recesses is a drill press or a hand drill with a Forstner bit of the correct diameter (e.g., 15 mm or 25 mm). A Forstner bit cuts a flat-bottomed hole with clean sides, which is exactly what a cam needs. You can also use a router with a template and a straight bit, which gives even more control over depth and position.

If you are working with a biscuit joiner, consider that it is designed for alignment and reinforcement, not for creating precise hardware recesses. The time you spend adapting it could be better spent using the correct tool. However, if you are in a pinch and have no other option, the method above will work for a one-off project.

Common Problems and Misconceptions

One common misconception is that a biscuit joiner can cut a perfect circular recess because the blade is round. In reality, the blade only exposes a segment of its circumference, so the slot is always crescent-shaped. Another issue is that the depth stop on a biscuit joiner is not fine enough for the tolerances required by cam locks; a difference of 1 mm can make the joint loose or the cam impossible to turn.

Another problem is that the bolt hole must be drilled perfectly perpendicular to the panel surface. If the hole is angled, the bolt head will not align with the cam, causing the joint to fail. A drill press or a drill guide is essential for this step.

Frequently Asked Questions

Can I use a biscuit joiner to cut the slot for a cam lock bolt? No, the bolt hole is a round hole, not a slot. You must drill it with a drill bit. The biscuit joiner is only for the cam recess, and even then it’s not ideal.

What size biscuit joiner slot do I need for a 15mm cam? You don’t need a specific biscuit size; you need to adjust the plunge depth and fence to create a slot that is about 15 mm wide and 10 mm deep. You’ll likely need to make multiple overlapping cuts to achieve the width.

Is it better to use a router or a biscuit joiner for cam locks? A router with a template and a straight bit is generally better because it produces a clean, flat-bottomed recess with precise depth control. A biscuit joiner is a compromise.

Can I use a spade bit instead of a Forstner bit? A spade bit will leave a conical bottom, not flat, which means the cam won’t sit flush. A Forstner bit is the right choice because it cuts a flat bottom.

How do I ensure the cam lock aligns perfectly? Use a marking gauge or a template to transfer the exact center points from one panel to the other. Always make test joints on scrap wood before cutting into your actual workpiece.

Are cam locks stronger than dowels or screws? Cam locks are designed for quick assembly and disassembly, not for maximum strength. For permanent joints, dowels or screws are stronger. Cam locks are best for flat-pack furniture that needs to be knocked down.

Alternatives and Final Thoughts

If you don’t have a biscuit joiner and are considering buying one for cam locks, save your money and buy a good Forstner bit set instead. For occasional use, a hand drill with a Forstner bit and a depth stop collar is sufficient. For production, a CNC router or a dedicated cam lock boring machine is used.

In summary, while it is technically possible to use a biscuit joiner to cut cam lock recesses, it is not recommended due to the shape mismatch, depth control issues, and alignment difficulties. The extra effort required to clean up the slot and achieve precision makes it a poor substitute for the correct tool. Stick with a Forstner bit or a router for clean, accurate cam lock installation.

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