The Rockler Interlock Signmaker template description says "The Interlock Signmaker's Kits require either a 3/8'' (#33967, sold separately) or 5/8'' (#30933, sold separately) guide bushing" and (3/8" for 2-1/4" kits & 5/8" for the 4" Kits ).

The #33967 bushing for the 2-1/4" kit has 3/8" ID, 1/2" OD. The #30933 bushing for the 4" kit has 5/8" ID, 3/4" OD.

I have a Bosch 1617 router and a Bosch PR20 Colt router - both with respective plunge bases and the Bosch RA1128 quick-release template guide bushings.

My question: Is the Bosch guide bushing's OD dimension the key characteristic when determining compatibility with the Rockler sign templates? I would think that the ID is only relevant to making sure that the router bit does not contact the guide bushing. I have the centering bit to make sure that the bushing is centered.

Is there any reason why I should use the Rockler brass bushings rather than the Bosch RA1128 guide bushings with the equivalent OD?

Apologies if I am stepping off to one side of the focus of this thread, but the thread has me thinking about moving forward with my wife's interest in being able to route signs.

And ... Matt, I am so very sorry to hear of your loss. I am sure your wife would have wanted you to carry on and be happy. As my wife and I get older this has been discussed and emphasized. --Ken