Technical how-to's: Drilling safety-wire holes without special tools
Many bolts and screws on a kart need to be safety-wired. You can pick
up the screws and bolts at any hardware store, but to get some with holes
for safety-wire is a much more difficult task. Special tools are offered,
which allow for relative ease of drilling safety-wire holes into bolts
and screws. But they have several disadvantages:
- They cost money.
- They are not readily available in ordinary hardware stores.
- A drill bit can brake, getting stuck in the tool, rendering it
unusable.
Recently, I had to safety-wire-drill some screws on a short notice,
and I didn't have the proper safety-wire drill tool. What to do? I came
up with the following very simple and very cheap solution.
Cost: $0. It should be noted that this procedure will work better
for longer screws or bolts.
I got a piece of hard wood. It does not have to be big nor particularly
fancy. It should be about 2" thick, at least 3" long and 2" wide. The
block of wood I used was a little larger, and I got it simply by sawing off
a piece from a bottom support beam of an unused pallette of a local store.
Make sure, though, that the piece is not thicker than 2" (or the length
of your drill bit).
Now drill a hole which is just slightly thinner than the screw or bolt
into the side of the wood-block. Drill it in at least 2", better
3" or more (assuming the screw or bolt is at least that long). If you
want, you can drill all the way through to the other side, but you don't
have to. Make sure you drill the hole nice and orthogonal to the side
of the block. This hole will later firmly hold the screw or bolt you
need to drill.
Now put the drill bit you will use for drilling the safety-wire hole into
your power drill. From the top of the block, drill all the way through
to the bottom. This hole now has to be orthogonal to the previously
drilled hole for the bolt or screw, and it needs to intersect the first
hole towards the end, right in the middle. This will be the guide hole
for the drill bit. Finding the right point at which to drill might be
a little tricky and may require a ruler and some measurements on the
top of the wood-block. Voila, you now have a safety-wire drill tool!
The screw or bolt you need to drill needs to be inserted into the larger
hole you drilled first. Since the hole was slightly thinner than the
screw or bolt, you will need to force the issue a little. A screw needs
to be screwed in, while a bolt can be hammered in. While doing so, look
through the thinner guide hole. As the screw penetrates deeper into the
block of wood, it will eventually pass the guide hole. You know when
that happens, because your view through the guide hole will be blocked.
Give the screw a few more turns, or hammer the bolt in some more, and
you should now have the end of the screw or bolt a few 16th of an inch
past the guide hole. That should be safe for most safety-wire
applications.
Before you start drilling, you should very scurely fix the block of
wood, now containing the screw or bolt, into a vice. Now insert the
drill-bit for the safety-wire hole into the guide hole. With the power
drill set on low-speed, start to drill your safety-wire hole. The guide
hole should give you enough support so that your drill bit will not wander
too much. Use the usual techniques for drilling safety-wire holes:
- Apply ample pressure.
- Use a slow drill speed.
- Use plenty of coolant. Some recommend WD40, others a special
kind of cutting oil or a silicone powder spray lubricant.
- If the bolt or screw is made from stainless steel, don't
back off the drill bit, or if you have to do so, do it quickly.
If the drill just spins at the material without cutting, the
material will harden.
Once you are all the way through, take out the drill bit and screw and
check out the master piece you just produced.
This wooden drill guide will be good for a couple of holes. I drilled
5 screws that way, using the same guide hole. The last two were a little
off-center, since the guide hole was loosing its shape, but nevertheless
very usable. So what if you need to drill more screws? Just drill
a new guide hole half an inch or so away from the first guide hole,
and continue. It's really that simple.
I used this method in my living room, using an old phone-book as a
supporting base, kneeling on the book, and holding the wood block fixed
with my knees (not recommended!). Very low tech, but very effective.