Bowtie templates for router inlay kits

A brass inlay kit cuts both the recess and the key from one template. Here's how it works and how to make a bowtie template for yours.

How an inlay kit works

A kit has a guide bushing, a removable collar that slips over it, and a small bit, often 1/8". The collar's outside diameter is larger than the bushing's by exactly twice the bit diameter. That difference is what makes the two cuts match:

• Collar on: rout the recess in your workpiece. The cut sits farther inside the template opening.
• Collar off: rout around the same opening in your key stock. The cut sits closer to the template edge, one bit width farther out, so the piece left inside is the same size as the recess.

A kit with a 3/8" bushing, a 5/8" collar and a 1/8" bit fits that rule: 5/8 − 3/8 = 1/4 = 2 × 1/8.

Making the template

Choose Inlay kit in Bowties.cc and enter your kit's bit, bushing and collar sizes. The template opening is your bowtie offset outward by (collar − bit) ÷ 2. The generator simulates both cuts and checks that the key fits the recess, and flags it if your sizes don't follow the kit rule.

Kit tips

• Rout the key stock a little deeper than the recess, then cut the key free on the bandsaw and plane it flush after gluing.
• The key's outside corners come out rounded; the recess's inside corners keep the bit's small radius. With a 1/8" bit they nearly match.
• Measure your collar and bushing. If they're off by a few thousandths the fit changes by the same amount.