ww

"woodworker88"

14/04/2005 8:17 PM

Routing and Drilling: What Order?

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?


This topic has 6 replies

p

in reply to "woodworker88" on 14/04/2005 8:17 PM

15/04/2005 5:50 AM

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?
http://www.patwarner.com

ww

"woodworker88"

in reply to "woodworker88" on 14/04/2005 8:17 PM

15/04/2005 8:43 AM

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

ww

"woodworker88"

in reply to "woodworker88" on 14/04/2005 8:17 PM

15/04/2005 8:48 AM

Anyone interested in the project this is related to should check out
either:
www.lahsrobotics.org or
http://www.eecs.berkeley.edu/~mseeman/photos/robotics/pages/_DSC0108.html
The wood will be a bumper underneath the outside metal frame. The
frame is 1" aluminum square tubing, 1/8" wall.

Pn

Phisherman

in reply to "woodworker88" on 14/04/2005 8:17 PM

15/04/2005 11:20 AM

Bolts in a molding? I'd probably use biscuits, glue and clamp the
molding for a day. Or if you are fastening it to metal use epoxy.
Anyway, one choice would be to drill small holes first, route the
half-round, then countersink.

On 14 Apr 2005 20:17:18 -0700, "woodworker88" <[email protected]>
wrote:

>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?

md

mac davis

in reply to "woodworker88" on 14/04/2005 8:17 PM

15/04/2005 8:33 AM

On 14 Apr 2005 20:17:18 -0700, "woodworker88" <[email protected]> wrote:

>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?

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

LH

Lew Hodgett

in reply to "woodworker88" on 14/04/2005 8:17 PM

15/04/2005 4:39 AM

woodworker88 wrote:
> 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?
>

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.


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