Just when I think I have a little momentum...
For background, I'm building a bookcase with butt joints (no fancier,
stronger joints for this first project). So to reinforce the butts, I
decided to use wood screws to help secure things. I am drilling a 3/8"
forstener (that I will later plug), #8 countersink pilot, followed by
further piloting through the boards with a 3/32" (I think).
Well, I've just snapped off two tops of the screws going into the holes. I
even tried running the threads along a candle on the second one (tip I read
here). So what is my problem - not a wide enough pilot hole? What size bit
should I use for a #8 wood screw?
It is not your holes, probably your screws.
If you are snapping screw heads when screwing #8's into a 3/32" hole you
need to learn a new lesson. Quit using they style screw you are using and
move up to a woodworking screw. Take a look here,
http://www.mcfeelys.com/subcat.asp?subcat .184.108.40.206. And if you are still
using Phillips head screws that will be a good tome to switch to Square head
screws. Most of the screws sold at McFeelys are square drive.
Well, I am using wood screws vs. a woodworking screw (name on the package).
And they are phillips.
I know the experts will cringe. But as a beginner, my sources for now will
come from Lowes/Menards. I'm not ready to move up to specialized ordering
yet. And I don't recall seeing a special woodworking screw at Lowes.
Any other tips for now besides changing screws? Should I try increasing the
pilot hole to 1/8"? Or maybe my pilot hole wasn't deep enough?
Did you get the screws in a small package and at the local Borg? McFeeleys
screw are hardened and seldom break. Yes you are ready to move into
specilized ordering... LOL. You broke 2 screws already right? McFeeleys
screws are probably cheaper than what you are buying now. Typically you can
get 100 screws for about $4-$6. $ to 6 cents each. I pet you paid more
than that for the ones you are using now.
Your pilot hole should be the size of the screw sidth less the threads. You
really should change screws. If you go to McFeeleys, you will wonder how
you got along with out them. They will not let you down.
With a good screw, the pilot hole and size are OK. The big stores carry
cheap screws. In spite of your comment, you are ready for better quality.
No, you NEED better quality or you will frustrate yourself to no end. Go to
McFeelys, or get Spax screws from Lee Valley.
Also, pay close attention to how you are driving them. Too fast or too much
torque on a drill will cause a snap. You want a nice even pressure and
medium speed. If you are using a drill with a clutch, be sure to set it
properly. If you are screwing in with a corded drill, use caution. If you
are driving by hand, just don't go so damned tight.
In all honesty, they're probably really cheap screws. You don't have to go
to specialized ordering, just source out some better quality screws. You've
already had some suggestions from others here. And yes, I highly recommend
square drive screws ~ easier to drive in, much easier to control. They're
called Robertson up here in Canada. Not sure if they have a specialized name
in the US.
Corey, Leon gives you good advice, although you'll have to wait for the
McFeeley's order to arrive in the mail.
Jim has one of the great deals in woodworking for the beginner. $10 gets
you a wide assortment of the types of screws woodworkers use, plus his
catalog. It may even come with a coupon, for reordering. I don't
remember. But the quality of the product, and the quality of the
assortment makes it really worth the $10. Jim doesn't likely make a bunch
of money on these - probably loses some. But he makes a bunch of converts.
If you can't wait, then put a couple of the screws you've been using in
your pocket, and go find a hardware store that says something like True
Value, or Ace, or Do It Best on the side, along with an owner's name. Go
find someone who looks like they remember the 50's, and ask them for some
screws like these, only not made of cheap crap. While you're there, find
some furniture or flooring paste wax (Johnson's, TreWax, Butcher's or
similar) Not only will you use it for screw lubrication, but it's a good
last step in the finishing process for your project.
Congratulations on getting this far in the learning process. Solving these
problems is just part of the fun, and one reason we hang out here.
Much as you don't like the answer, Leon is correct -- the screws you are
using are the problem. You *might* be able to use Borg-supplied screws if
you do not seat them very tight (kind of defeats the purpose though). I
found that I could not use screws supplied from Home Depot for any purpose
without the heads snapping. I think they are able to get away with this
because most people purchasing the screws are drilling them into the soft,
wet, white wood that the Borg also sells. They definitely won't work in
hardwood *at all* -- DAMHIKT. You are only going to cause yourself much
more work all for the sake of saving a couple of dollars.
Agree with Leon, use McFeelys square drive screws and most of your problems
with screws will be gone. However, regardless of the screws you are using
and the wood involved if you proceed as follows you will avoid trouble:
1. Use scraps of the wood involved to first try out drill sizes...same
principle as using scraps to try out a new finishing technique...if you
don't first use scraps them your project boards become an experiment.
2. First determine the hole size needed in the first board so the unthreaded
portion of the screw will go in with little or no force required. You need
a set of drill bits between 1/16 and 1/4 that increase in size by 1/64
increments. Just keep using larger bits until you get the right sized hole.
3. Next determine the size of hole needed in the second board. Start with
a bit about 3/32 smaller than the bit you ended up with in step 2. Try to
screw one of your screws into this hole using a hand driver so you can feel
the amount of torque required. If it is too tight try the next size larger
bit, if too loose try the next size smaller.
4. Once you have the bit sizes, if you intend to drive the screws with a
power driver you need to practice screwing two pieces of scrap together and
get your clutch adjusted so it just barely drives the screws home. If your
power driver does not have a clutch then be sure to stop before the screw
bottoms out. Even with a clutch I like to use a hand driver on that last
turn or two so I can feel when they are tight.
Earl has some very good ideas, especially testing the screws and holes
on scrap of the wood your project is made of.. gotta remember that
What Earl's post reminded me of is that buying a $5 drill index really
helped me in choosing/sizing drills/dowels, etc...
for example, using Earls' advice, try different screws & drill
sizes... but also run your screw through the drill index and see what
"drill size" the shank is...
I just had to do that with my plug project.. I had the plugs cut but
wasn't sure what hole size they plugged... lol
I used the drill index to find that the "small" end of the plug was
21/64, and drilled my holes to that size.. YMMV
Oak is quite hard, especially on brass screws. Wood screws have
a tapered shank and threaded area, so you need a tapered bit.
Find the proper #8 wood screw boring bit and use that. They're
tapered and many also have a countersink/bore built in.
One example is this set
"Given the low level of competence among politicians,
every American should become a Libertarian."
In my opinion you should invest in a good countersink set for wood screws
like Fuller. I had the same problem until I bought my set. Works like a
dream with any type of wood screw from any source. For #6, #8, #10, and
I suspect that you don't have a large enough clearance hole in the
first board. You should be able to drop the screw through the
first board to rest in the countersink with no tools.
Are you using the old tapered wood screws? In very hard woods,
they require a tapered lead hole.
Keep the whole world singing . . . .
DanG (remove the sevens)
I agree with all of the answers above regarding quality screws -- except
that I think that one can get decent screws at the local hardware store and
even at a Borg.
Fasterner quality, substandard products, and counterfeiting is something I
know something about. Commercial and military airplanes have crashed
because of bad quality fasteners -- and those buyers are supposedly on top
of things and willing to pay. The Borgs may have fastener standards for
the buyers and this time a bad shipment came through. Maybe they have no
quality standards. Don't know.
IME, I've had my biggest quality problems with lag bolts over the years.
But I have very rarely had a problem with screws heads snapping -- screws I
bought at local hardware store or a Borg. Now head stripping, as well as
but stripping -- phillips and square -- is another matter, and that also
is a quality issue.
Depending on your time and level of interest, I'd suggest you tell the
place you bought the screws that they got a bad batch and ask for a refund.
I'd get new screws at the local hardware store for now -- with due, honest
respect for McFeeleys.
As for coarse versus fine threads and proper hole size and shape, I defer
to others here.
YMMV. -- Igor
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