Thread: How Do I Route a 188mm Diameter Hole ?

Clock Overview.jpgGreetings,

I'm in the middle of making a clock as a Christmas gift for a family member, and have run into a bit of a challenge with safely making part of the clock face's structure. The clock is loosely based on a plan that was published in Woodsmith magazine (Issue 89) back in 1993 (see photo at right).
Inner Door.jpg
The operation that is proving to be a bit of a challenge is making the hole in the centre of the clock face panel (it's labelled "Inner Door" in the drawing at left). The panel is 3/4" thick Silky Oak. So, time to find an appropriate method of making that 200mm hole.

The original magazine article says to use a Jig Saw to cut the hole out, and then clean it up with a rasp. So I grabbed a scrap of hoop pine and gave it a go. Maybe it's my jig saw technique (or lack of it), but the resulting hole was very rough. And the jigsaw blade kept bending sideways, so the hole is quite oversized in some places on the underside. I also did a test with a fret saw, and that was quite successful, but my little fret saw doesn't have a big enough throat to be able to cut that hole, and I don't fancy buying a bigger fret saw or coping saw just to do one job.

So, I've started considering different ways of using a circle cutting jig and a router, either hand-held or mounted in the router table, to cut this hole. I normally prefer to use the router table as I tend to feel that most operations are a bit safer on a router table, rather than hand holding the router. But I'm not sure that is the case this time. As it's a hole I'm cutting, it'll need to be a plunge cut.

So, the question is .......

What is the best and safest way to cut this hole.....?

• Use a circle cutting jig and a hand-held router, and plunge cut.
• OR, rig up a circle cutting jig on the router table. Using this approach would entail dropping the workpiece onto the spinning router bit to start the plunge cut. (That's the specific bit that doesn't seem real safe to me !)
• OR, some other approach entirely. Could I do the job more safely using a template ?
• A local Woodie last night raised what he thinks is an issue in relation to using a router to cut a large hole like this. He is concerned that parts of the circle will be a climb cut when using the router - is climb cutting an issue in this case ?

Your suggestions & ideas please .... Including ideas for suitable single use circle/hole cutting jigs ?

Regards,

Roy