Ask the Staff
Question:
I need to drill a flat bottom screw hole (counterbore). I need a pilot counterbore drill tool. A Forstner type bit in a hand held power drill would be risky. I am building a cabinet carcase from solid pine. Flathead screws near the end grain tend to split the wood when torqued. What can you recommend?
Thank you,
David
Answer:
David,
We do not have a bit to drill both flat bottom counterbore and pilot hole at once. You would first drill with a
Forstner Bit
and then drill the pilot hole for the screw shank next (with a standard bit or a tapered bit with no countersink installed on it).
A 1/2" diameter Forstner Bit in a hand held drill is not too tough. A 1" diameter and larger bit hand held does require more talent.
You could consider making a jig; you first drill through (on a drill press if you have one) a 3/4" birch plywood or MDF. This would act like a bushing for the Forstner Bit to help you drill more plumb.
This
Portable Drill Guide
could help as well for hand held drilling.
CLICK HERE
to watch the video.
Since a flathead screw has the tapered shoulder, this is what wedges the wood near the end grain and causes a split to happen. I don't know if you need to plug the holes with a wood bung or not, but if the look of the screw or the size of another type of screw that has a flat shoulder (like a round head wood screw or a "combo tapping screw", available at most hardware stores) gives you enough room to still plug the hole, then that style of shoulder will be less likely to cause a split.
Regards,
Ed Scent
Highland Woodworking
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