Ryobi Router Circle or Hole Cutting Jig

I created this circle/hole cutting jig for a DIY speaker build to recess and cut the speaker driver holes in MDF. It's made specifically for the Ryobi ERT2100VK Router and is locked in place using the router fence rails. It can cut holes as small as 34mm all the way to 860mm if you reverse the slider and let it protrude from the end of the arm.

Print Settings:

• I chose PETG as it is less brittle
• Use supports for the recessed bolt holes
• I used 4 vertical shell perimeters for additional strength

Required Parts:

• 4x M5 * 8mm Nuts and Bolts to secure the arm to the base plate
• 1x M5 * 20mm Nut and Bolt as the pivot protruding down from the slider
• 1x M6 Bolt and Knob to lock the slider in place (Photo 8, one I had lying around my garage)

Setting the hole size:

I found the best and most accurate way to set the slider is to use Vernier callipers.

• If the required hole diameter is 50mm, lock your callipers at 27.5mm = (50mm / 2) + 2.5mm. The 2.5mm is to compensate for the M5 pivot bolt, you want the measurement to be in the middle of the bolt.
• See Photo 8, plunge your bit out, rotate the bit so the widest blade part of the bit is aligned with the direction of the slider and put your locked callipers around the pivot and bit.
• Pull your slider out against the locked callipers and lock the slider in place with the locking knob when you have a bit of tension against the router bit.
• If the slider doesn't slide smoothly, give it a light sanding or filing on the sides.