pilot hole

Doug Miller <[email protected]> writes:

> Joe Riel <[email protected]> wrote in news:[email protected]:
>
>> To mount a pull on a drawer front I drilled the two holes, then realized
>> that the material thickness was slightly greater than the length of the
>> machine screw, so a counter bore was required. Didn't want to attempt
>> to temporarily plug the hole, so first drilled a hole through some
>> scrap, clamped that to the inside and used it as a guide.
>>
>> For the remaining drawers I didn't bother with the guide, but instead
>> first drilled a pilot hole, counterbored the inside, then drilled out
>> the pilot hole to the finished size. This was all done freehand with an
>> electric hand drill. While drilling out the pilot hole I wondered
>> whether the bit would track (I was using brad point bits). Apparently
>> they did. Is that common or did I just get lucky?
>
> Either you got lucky, or your pilot hole was smaller than the brad
> points on the larger drills.

The pilot hole was smaller.

>
> When using brad point bits, you should drill the larger diameter hole (the counterbore) first,
> then the smaller diameter hole (the through bore). The point of the smaller bit will self-center
> in the dimple left by the point of the larger bit. Same thing applies
> to Forstner bits.

I don't believe I could drill the through finished hole accurately from
the back with a hand-drill, not without a jig. Marking the location is
also significantly more difficult. This was on a finished drawer.

> When counterboring an existing hole to enlarge its diameter, you should use a twist drill if
> you want to be sure it centers.
>>
>> Presumably it's well known, but a neat trick I came up with to avoid
>> splintering out the backside of the drawer front when drilling the
>> original hole is to put scrap behind it and then wedging it against
>> the front using a stick slightly longer than the distance to the back
>> of the drawer. It's quicker than clamping and can be done with the
>> drawer in the cabinet.
>
> I would think that a clamp would be easier and faster than cutting a piece of scrap to length...

I didn't do any cutting. Just picked a piece slightly shorter than
needed from the scrap pile and added a couple of extra small pieces to
take up the rest of the space. A problem with a clamp is that it can
mar the edges since I was drilling with the drawer in the cabinet; that
is, the edge of clamp would get pushed into the face of the cabinet as
the door slid back. Yeah, there are ways to avoid that, but the wedged
stick was about as simple as it gets. Maybe I need better clamps; that
will be a separate post.

--
Joe Riel

On 7/22/2013 2:19 PM, Joe Riel wrote:
> To mount a pull on a drawer front I drilled the two holes, then realized
> that the material thickness was slightly greater than the length of the
> machine screw, so a counter bore was required. Didn't want to attempt
> to temporarily plug the hole, so first drilled a hole through some
> scrap, clamped that to the inside and used it as a guide.
>
> For the remaining drawers I didn't bother with the guide, but instead
> first drilled a pilot hole, counterbored the inside, then drilled out
> the pilot hole to the finished size. This was all done freehand with an
> electric hand drill. While drilling out the pilot hole I wondered
> whether the bit would track (I was using brad point bits). Apparently
> they did. Is that common or did I just get lucky?
>
> Presumably it's well known, but a neat trick I came up with to avoid
> splintering out the backside of the drawer front when drilling the
> original hole is to put scrap behind it and then wedging it against
> the front using a stick slightly longer than the distance to the back
> of the drawer. It's quicker than clamping and can be done with the
> drawer in the cabinet.
>
Normally you drill the counterbore first then the screw hole.

--
Jeff

Joe Riel <[email protected]> wrote in news:[email protected]:

> To mount a pull on a drawer front I drilled the two holes, then realized
> that the material thickness was slightly greater than the length of the
> machine screw, so a counter bore was required. Didn't want to attempt
> to temporarily plug the hole, so first drilled a hole through some
> scrap, clamped that to the inside and used it as a guide.
>
> For the remaining drawers I didn't bother with the guide, but instead
> first drilled a pilot hole, counterbored the inside, then drilled out
> the pilot hole to the finished size. This was all done freehand with an
> electric hand drill. While drilling out the pilot hole I wondered
> whether the bit would track (I was using brad point bits). Apparently
> they did. Is that common or did I just get lucky?

Either you got lucky, or your pilot hole was smaller than the brad points on the larger drills.

When using brad point bits, you should drill the larger diameter hole (the counterbore) first,
then the smaller diameter hole (the through bore). The point of the smaller bit will self-center
in the dimple left by the point of the larger bit. Same thing applies to Forstner bits.

When counterboring an existing hole to enlarge its diameter, you should use a twist drill if
you want to be sure it centers.
>
> Presumably it's well known, but a neat trick I came up with to avoid
> splintering out the backside of the drawer front when drilling the
> original hole is to put scrap behind it and then wedging it against
> the front using a stick slightly longer than the distance to the back
> of the drawer. It's quicker than clamping and can be done with the
> drawer in the cabinet.

I would think that a clamp would be easier and faster than cutting a piece of scrap to length...
>