Routing and Drilling: What Order?

[woodworker88]

I am trying to make a custom half-round molding on the router table, and then drill and counterbore holes for 1/4-20 bolts. I am wondering what order I should do it in: do I drill first and then rout, risking tearout on the inside of the holes (their about 5/8" dia) or rout the half round and then drill, with the holes possibly shifting from side to side. The holes need to be fairly precise as the bolt connects to a metal bar that doesn't have much leeway, and the wood has to be fairly smooth. Any ideas or comments?

[Lew Hodgett]

Try drilling the holes first, then fill with a piece of dowel and sand smooth, then run piece thru router.

Finally, remove remaining dowel piece with a gimlet exposing counter bores.

HTH

Lew

PS: You can always use some varnish as glue to hold dowel in place while machining, if necessary.

[Phisherman]

[pat]

Chances are good for no tearout over the countersinks. Test on scrap first. If you're using bearing and a bearing might roll over a hole you have no choice but to drill after routing. Notwithstanding, drilling after routing may be a necessity as sanding and such may reduce the pre countersink diameter. And to be sure, if your pre drill 1/4" pilots only and follow with countersinks after routing, (requires piloted countersinks) you will clean up any tearout created during the rout. More on routing and drilling?

[mac davis]

how about drilling the holes first, and "pinning" them to a piece of scrap with dowels or toothpicks... run them through the router using the stock as a jig, then countersink the holes before mounting?

mac

Please remove splinters before emailing

[woodworker88]

The wood is basically a bumper for a metal object, so it needs to be strong. On the other hand, the general consensus seems to be the same: drill pilot holes, then route, then counterbore. I'll try it on a piece of scrap before I run 8 feet of it. Thanks everyone for your advice

[woodworker88]

Anyone interested in the project this is related to should check out either:

or wood will be a bumper underneath the outside metal frame. The frame is 1" aluminum square tubing, 1/8" wall.