Drill large holes in wood
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Photo 1: Holes in wood
The best way to cut holes faster is to drill relief holes to
exhaust wood chips and keep the blade cooler.
If you hate to use a hole saw because it's slow, dulls quickly or burns the wood, take heart. We talked to Matt Savarino, the hole saw expert at Lenox
Tools, to get to the bottom of your dilemma. Matt told us
that most DIYers don't need expensive hole saws. In fact,
for occasional cuts in wood, he says the cheapest carbon
steel saws work just fine (see Photo 1). But don't try using
them in metal—that'll destroy the saw teeth in seconds.
Even if you drill relief holes, hole saws take forever to
drill through thick wood. If the holes are less than 1-1/2 in.
in diameter, don't bother with hole saws; use spade bits.
Drill large holes in metal
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Photo 2: Holes in metal
In metal, always use bimetal hole saws and keep the teeth
sharper longer by using lubricating oil.
But if you're cutting a hole in your steel door for a dead
bolt, or cut lots of holes, step up to a bimetal hole saw.
The teeth are made from a harder steel than the shell, so
they last longer. But that doesn't mean they're indestructible.
Always provide lubrication when drilling into
metal. Cutting oil is best, and even ordinary motor oil is
better than nothing (see Photo 2). You can use bimetal
saws to cut through all types of materials except ceramic,
porcelain, granite and the like. For those, you need a
carbide-grit hole saw.