For those that haven't been following my saga, I'm a newbie taking an adult
ed class. I've chosen to make a bookcase for my project.
So I have all of my pieces cut to size and am ready to put it all together.
I plan on using woodscrews to attach the pieces. I'm also planning on
"sinking the screw head into a larger hole" (not sure what to call that) cut
with a forstener bit and cutting my own plugs to fill in the hole. So now
on to the questions...
1) What size forstener bit should I use (knowing I need to match the plug
cutter)? Most of the panels are 3/4" x 10.5" x differing lengths.
2) How deep should I cut the forstener "hole"?
3) Sanding - should I sand all my pieces before attaching the pieces with
the screws? I ask because I know I'm going to have some additional sanding
after cutting the plugs off in the screw holes. So do I sand everything
first and then just re-sand the plug areas? Or do I wait and not sand until
the plugs are in?
If it makes any difference, I'm going to need to do some evening on the
panels I glued together (there is a little variation here and there that I
need to make flat) - either with heaving sanding or trying to hand plane to
Thanks for the advice.
3/8" and 1/2" are common plug cutter sizes. get the plug cutter first.
make some plugs and choose the drill bit to fit the plugs. you don't
have to use a forstner bit, though if you happen to get a good size
match that will be a nice way to go. regular old twist drills are
commonly available in 1/64" increments though, should you need to bump
up or down a tad.
whatever tools you end up using, do a mock up of the whole joint and
make sure it's all going to go together well before you make any holes
in the actual project.
not more than 1/3 of the thickness of the board, and not less than you
need to be able to glue in the plug.
I try to do as much sanding as possible before assembly. there will
always be some sanding to do after assembly, but it's sure easier to
sounds like a good opportunity to learn to use a card scraper.
Another method to consider is pocket holes. Essentially, the guide used
makes the process a two-part operation -- drilling the small hole for the
screw to pass through and a larger but shorter hole (partially into the wood
section) to take the screwhead below the wood surface. Yes, that's called a
Screws go in at an angle, which gives them a bigger bite and more leverage
for a clamping action.
Anyway, check out Lee Valley Tools (based in Toronto Ontario) at their
website http://www.leevalley.com and enter pocket hole as the search term.
You should be looking at a half-dozen guides, drill bits as well as hole
plugs. Prices are in Canadian dollars, which convert to about $.75US.
Now don't go leading Corey astray at this point. He's three weeks into his
first, 5-week adult-ed woodworking class, and his friends here have already
filled his head full of semi-useless knowledge. ;-)
When he goes to his first woodworking show, THEN he'll find out how many
ways there are to put two pieces of wood together. And how many ways to
max out the credit card.
who just built a nice garage cabinet, using the best pocket screw
Don't rule out rebated lap joints or dadoes. Screws are strong, but
they're not very rigid. In a class you should be able to improve
things with only a little effort.
Forstner bit is the wrong tool. It's hard to find them that small and
they cut badly. You may also find that it's easier to locate a drill
with a central pilot.
I'd buy a pair of commercial bits (Lee Valley) - one cuts a screw hole
and counterbore, the other cuts a matching plug.
1/4" is plenty for the plug, plus the depth of the screwhead. If the
drill has a shallow angle, then much of this depth will be a
Yes, because it's easier when they're flat. Then sand them again after
assembly. You might just go to your first grit for the first "flat"
Unlike planing, sanding an already-sanded surface is easier than an
I have several different brands that are labeled Forstner and they all have
pilot points, although I have seen some that do not.(maybe the "originals")
If your Fostners are cutting badly they must be dull, I get a nearly perfect
clean hole with mine.
Tiny little spear points though, which will have almost no effect when
trying to start a hole over an existing clearance hole. A twist drill
with a full cone in the centre, or a dedicated screw sinking bit with
a sized pilot, will be easier to guide.
If you have a drillpress, then you can probably use these Forstners
perfectly well. If you're drilling by hand, then it's likely to skid
right across the surface, the edge of the Forstner acting like a
Forstners have a large solid area, and in these small sizes that
doesn't allow space for chip clearance. I'm guessing the OP is working
in softwood here and shifting those chips might be a problem.
if I'm visualizing his project correctly, I's suggest both a forstner
and countersink/drill combo... the forstner would provide a nice flat
bottomed hole to make the plug gluing easier, but you need the tapered
countersink/counterbore for the screw head to seat properly, right?
I always use the forstner 1st, to start the hole, then follow with the
normal or combo drill, using the forstner's spur hole to start the
You might do this if you were using a large plug and a small
screwhead. It's easier though just to drill and pluge in one pass -
the sizes are usually OK
Only if you care what it looks like. Down the bottom of a hole, the
screw will seat fine and you'll never see any gap or broken fibres
around the edge..
Particularly in softwood, you don't need to countersink either.
There's a Stanley combination drill (taping, clearance and head) which
forms a neatly set screwhead by scribing a circle around it, rather
than countersinking. The countersink is formed by compression alone,
but the scribed circle forms a neat edge.
On Sat, 09 Oct 2004 19:43:23 +0100, Andy Dingley
Thanks, Andy.. I'd always understood that the countersink/bore was (in
addition to making it flush in a surface), let the screw be tightened
without cracking the wood... (I use the B&D drill/stop/countersink
You mean the hundreds of countersunk and plugged holes I've done are wrong?
I chose Forster bit because they cut so well and the ones I have do have a
central pilot. (see Lee Valley)
Many ways to accomplish the task but I want as perfect a fit I can get. I
mark the holes and drill a 3/8" dia. hole about 3/8" deep with the Forstner
bit. The Forstners also have a point so locating the bit to the mark is easy
and accurate. Then I use a twist drill or a drill with countersink to make
a pilot hole. After sinking the screw, I can plug the holes with tapered
plugs for a very nice finish. The drilling can be done in one step but I
like the control of doing the countersink on the drill press. I'm not
running a production shop so a few extra minutes if OK.
The tapered plug cutters from Lee Valley do a good job. There is a saw made
for trimming plugs and then just sand or plane as you see fit.
On some projects, like a pine kids picnic table, I used dowels instead of
plugs. They have end grain showing and are not as attractive as plugs, IMO,
but they work. Done right, they look pretty good with the contrast of woods
I would pass them through a planer if available until all are of the
same thickness - regardless of whether they need it or not.
That is, all shelves should be equal in thickness to look ok.
You mean only screws will be holding up the shelves? If so, use at
least 4 screws per side if they are to hold books. Next time, let them
What you will be doing is counter sinking the screw heads. A fosner bit
is the long way around. You can get sets of drill bits and matching plug
cutters that will do the job nicely for you. Then all you have to worry
about is the size of the screw. I like #8's Robertson screws (square
drive) for general usage.
It wouldn't be a bad idea to get the heavy sanding out of the way before
assembly then all you have to do is some clean up sanding when you are
Glad to see you're still going strong on this, Corey.
The answers the others have offered look pretty good to me. Follow their
advice. Keep smiling. And have fun with this.
There are all kinds of adventures in front of you yet.
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