Making Dowels with New 3/8" (9.5 mm) Router Jig

INTRODUCTION

Recently, I finished making this router jig for making 3/8" (9.5 mm ) dowel. It accompanies the 1/4" (6.35 mm) jig I made and completes a set. They both work great.

If you noticed, I marked info on the jigs to aid when I'm setting up on my router. In addition, I thought I'd attempt to explain the making of it here.

FIG 1

I cut a chunk of 2"x 4" (50.8 mm x 101.6 mm) and hand planed it to 1- 3/8" T x 3" W x 3-1/8" L  (34.9 mm x 76.2 mm x 79.375 mm)

FIG 2

Then I drew  a line 1-1/2" (38.1 mm) up from the bottom and make a center punch mark on center to the width.

FIG 3

I used my dowel centering jig to quickly find the center of the width.

FIG 4

I drew a line from this punch mark around and across the right side. Then another vertical line on center to the right side width and across the top. The intersection of these lines on the right side indicate the tangent point between the input hole and output hole.

FIG 5

Next, I clamped and setup in a drill press drill. Then drilled an input hole from the punch mark made in Fig 1
The size drill to use is determined by multiplying the Finished dowel size by 1.4142.
Therefore 3/8" (.375") or (9.5 mm) x 1.4142 = .530" (13.5 mm) Normally I would use a 17/32" (13.5 mm) Forstner drill bit. But I wanted less meat to shave off on rough stock so I'm used a 1/2" (.500") or (12.7 mm) Forstner bit instead.
I set the depth and drilled to the vertical line made as shown in Fig 4.
Without moving the setup, I removed the 1/2" (12.7 mm) Forstner bit and replaced it with a 3/8" (9.5 mm) Forstner bit. I continued drilling through. If you can't make it through you can swap out for a Brad point or other bit and continue to completion. Just don't move anything until all is done.

FIG 6 and FIG 7

Next I  drilled out the recess for the 1/2" (12.7 mm) trim router bit so it's cutting edge lines up with the 3/8" (9.5 mm) output hole at the tangent point between the 1/2" (12.7 mm) input hole and 3/8" (9.5 mm) output hole.

Here's the completed jig.

FIG 8

This measures .373" (9.47 mm) all up and down the dowel with no sanding. This is a great tolerance for a finished 3/8" (.375) or (9.5 mm) dowel.

Thanks for looking!

Feel free to comment, ask questions, and "thumbs up 👍" if you like it!

Cheers!
Mr Rick