How to make a router template for a guide bushing

A good template lets you rout the same pocket or part again and again, exactly the same every time. Here's how to make one that cuts true the first time.

What you need

• A plunge or fixed-base router with a guide bushing set
• A straight or spiral bit that fits through the bushing with some room to spare
• Template stock: 1/4" (6 mm) clear acrylic or MDF
• Calipers, double-sided tape or clamps
• A laser cutter or CNC, or a printer and scroll saw

Steps

1. Measure your bit and bushing. Use calipers to measure the outside diameter of the guide bushing collar and the cutting diameter of the bit. Write both on the template so you never mix them up.
2. Choose the template type. Pockets and openings need a template the bushing rides inside. Parts you cut out need a template the bushing rides around. Inlays need both, with a little clearance.
3. Apply the offset. Offset every edge by (bushing OD − bit) ÷ 2, outward for pockets and inward for parts. Rideline does this automatically and shows where corners will be rounded.
4. Add a frame. Give the opening at least 1 to 1-1/4 in of material around it so the router base is fully supported for the whole cut, and add centrelines to line the template up on your work.
5. Cut the template. Cut it from 1/4 in (6 mm) acrylic or MDF on a laser or CNC, or print it full size and cut it by hand with a scroll saw, then sand and file to the line.
6. Test on scrap. Clamp or tape the template down, rout a test piece in shallow passes, and check the size before you cut the real workpiece.

Picking the template material

Clear acrylic is the favourite for laser users: it cuts with a smooth, hard edge, lasts for years, and you can see your layout lines through it. Cast acrylic cuts cleaner on a laser than extruded. MDF is cheap and easy to shape by hand, but its edges dent and wear, so seal them with shellac or glue. Baltic birch plywood works for big templates where you need stiffness.

The template must be thicker than the bushing collar is tall. Most collars are shorter than 1/4", which is why 1/4" stock is the standard.

Template tips

• Leave enough margin around an opening for the router base. Rideline defaults to 1-1/4".
• Inside corners of a pocket keep at least the bit's radius. Design them that way or square them with a chisel.
• Outside corners of a cut-out part come out rounded to the offset. Use a smaller bushing for crisper corners.
• Engrave the bit and bushing sizes on the template. Rideline does this by default.
• Rout in several shallow passes and keep the bushing pressed against the edge the whole time.