Sled Center Hole is 1.5" in Temporary and 3" Final Sled, Why?

Hardware Sled
1

I decided to build the “Final Sled” rather than build the temporary sled first as that would take near twice the time. I am a reasonable wood worker and saw no problem build the “Final Sled” first. I made a 18" circle out of a 3/4 inch plywood. I went ahead and drilled the center hold at 1.5" diameter. Then as you do with the “Final Sled” I downloaded the files to CNC the “Final Sled” and then opened up the file: New Sled With Tool Paths.svg in Adobe Illustrator. I printed the drawing to full scale and taped the pages together to get a 1:1 template. I now had a clean template to locate all the additional holes in the sled.

I quickly discovered that the center hole in my “Final Sled” template is 3" in diameter whereas the Temporary Sled instructions tells you to drill a 1.5" center hole.

Does anyone know why the hole sizes are different? Or can I leave the center hole at 1.5" as making it 3" now would be difficult as I have now lost the enter point for my hole saw?

2

The exact diameter or shape of that hole isn’t particularly important. It just needs to be big enough for the router collet to fit through. That being said the larger 3 inch hole is nice because it allows for a little bit better sawdust extraction and provides a larger viewing area to watch as the cutting happens.

3

Thanks so much for the explanation.

I plan to drill a larger hole, but being I already have the 1.5" hole centering the hole will be a difficult. If the hole is slightly off center will that be acceptable?

4

It shouldn’t be an issue other than aesthetically