Benefits of a belt sander
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Perfect for scribing
A common use
for a small belt
sander is scribing.
You can gradually
sneak up on a
curved line for a
perfect fit. On a
laminate countertop,
make sure the
direction of belt
travel pushes the
laminate down.
Belt sanders are the big, powerful
gorillas of the sanding world. Few
tools can save you as much time—or
wreck your project faster. If you’re new
to belt sanders or have been frustrated
by yours, read on to find out how to
keep that big ape under control.
Belt sanders are multiuse tools. They
are commonly used for trimming to a
scribed line (photo), sanding very
rough surfaces, leveling surfaces (like a
replacement board in a hardwood
floor) and freehand rounding and shaping.
Because they have a lot of power
and can handle coarse grits, they excel
at the rapid removal of wood. Also,
unlike orbital and vibrating sanders,
the sanding action is linear, so even
with coarse grits you can sand with the
grain and get a good-looking result.
Though a belt sander isn’t an essential
tool in the homeowner’s arsenal, you
won’t find many experienced DIYers or
carpenters without one.
The Top Tool for Rough Flattening
Belt sanders excel at the rapid removal of wood, making them the best handheld
power tool for leveling and smoothing rough boards. Start at an angle to the grain
for aggressive leveling, then finish with the grain. Eighty-grit is good for starting, then
switch to 120-grit.
Buying a sander and belts
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Sanding belts
Both types work well, but many prefer the more aggressive zirconia belts for 80-grit size and coarser.
The best multipurpose belt sander
takes a 3-in.-wide belt. You’ll see
machines designed for wider and narrower
belts, but they’re for specialized
tasks. Within the 3-in. class, there are
smaller tools that take 3 x 18-in. belts,
midsize machines that take 3 x 21-in.
belts and a couple of large sanders that
take 3 x 24-in. belts. The smaller tools
are lighter and easier to use one-handed
for shaping and scribing. They’re
good for smaller work and casual use.
The larger tools
have more surface
area and
weight for
smoothing wide
surfaces. They’re
better for bigger
work and shop
use. The 3 x 21-
in. machines are
a good compromise.
You’ll find 3 x 18-in. sanders for
$50 to $150 and 3 x 21-in. sanders for
$100 to $250.
You’ll also find smaller belt sanders
that take 2-1/2-in.-wide belts. They’re
light and very handy for one-handed
use. Sanders with 4-in.-wide belts are
heavy-duty machines best left to cabinetmakers.
<strong>Pick a belt,
but not any belt</strong>
Personally, I use 80- and 120-grit belts
regularly, and rarely, 50-grit. Grits
coarser than 50 leave deep scratches
that are difficult to remove. And if
you’re doing finer sanding, you’re better
off using a random-orbit sander.
Remember one of the rules of sanding:
You can skip one grade of grit, but it
wastes time and you’ll just wear out
belts skipping two. For example, you
can go from 80 to 120, skipping 100
grit, but don’t go from 50 to 120.
Aluminum oxide is the traditional
grit material. You’ll find it in less expensive
khaki-color form, good if
you need a disposable belt, and longer-lasting,
dark brown premium belts.
However, for grits of 80 and coarser,
many people now prefer zirconia belts
(sometimes called “planer” belts). They
have sharper, tougher cutting particles
that cut more aggressively, last longer
and don’t clog as easily. These belts are
usually bright blue or purple. Zirconia
belts cost slightly more than premium
aluminum oxide belts.
Use Good Technique
Don’t push down on the sander; let its weight do the work. Go slowly, overlap passes
and allow the tool to go past the end without dipping. Be careful not to tip the sander
or change speed or direction. Put the cord over your shoulder so it’s out of the way.
Gouging is the Enemy
This painted panel shows a common problem: horseshoe-shaped gouges at the endof a board. To prevent gouges, use clean, new belts, avoid grits finer than 120, and keep the plate under the belt (the platen) clean and free of dust buildup.
Use your sander safely
Belt sanders are relatively safe tools,
but it’s still smart to take precautions.
- Wear hearing protection—these
babies are LOUD!
- Don’t breathe dust. It’s not just
unpleasant; it’s bad for you. Wear a
dust mask while sanding, unless
you rig up a shop vacuum for dust
collection (photo, below).
- Unplug the tool before changing
belts or emptying the dust bag. I
have a scar that attests to the importance
of this seemingly grandmotherly
precaution.
- If you use the belt sander to sand
metal, you’ll create sparks, which
can start a fire if they mix with the
sawdust in the machine and the
dust bag. Blow or vacuum the dust
out of the sander before you use it
on metal, and remove the dust bag.
- Make sure the trigger is off before
plugging the sander in. Belt sanders
have a locking button that holds the
switch in the “on” position. Sounds
kinda “duh,” but trust me, it happens.
You don’t want the sander to
fly across the room when you plug it
in, do you?
- Belt sanders exert a fair amount of
force on the work. So if your work
isn’t securely held, it’ll slide away
from or right into you. Clamps get in
the way, but a simple stop on the
appropriate side of the workpiece
(photo, “Use Good Technique” above) will keep it from
sliding. Choose a stop that’s a little
thinner than the workpiece so the
sander will clear it at the edge.
Trim After Sanding
It’s hard to keep a belt sander from gouging or rounding over the ends of a board. So if
you can, belt-sand the board before cutting it to final length. You can then safely move
on to a palm sander and finer grits.
Be careful with plywood veneer
Watch Out on Plywood
Belt sanders take off serious amounts of wood, so they can wreck plywood pretty
much instantly. If you have to sand solid-wood edging flush with plywood, draw a pencil
line on the plywood to tell you when the sander starts removing veneer. If you have
variable speed, dial it down.
Tuning up your sander
First, make sure the belt is oriented
properly. Some belts have a preferred
direction, indicated by an arrow on the
inside. Nondirectional belts can be
installed either way. The only adjustment
you’ll probably have to make is
“tracking” to keep the belt centered on
the roller. Hold the sander up, turn it
on, and see if the belt either rubs
against the housing or starts working its
way off the rollers. With the trigger on,
adjust the tracking knob until the belt
is centered on the rollers. You may
have to make a slight adjustment when
the sander is on the wood. If your
sander has automatic tracking, you
don’t need to mess with any of that
nonsense.
Some sanders have variable speed.
You can go at maximum speed most of
the time, but you’ll want to throttle it
back for delicate work.
Keep the Belt Clean
Dirty belts make for lousy work. A belt-cleaning stick will remove the pitch buildup
that happens with all woods, especially pine or sappy woods. Push it against the moving
belt, or for larger sanders, clamp the stick in a vise and sand it.
Good for Rough Sharpening
You can use a belt sander for rough sharpening of tools like axes, shovels, knives and
chisels. Remove the dust bag and remove all dust from the sander (sparks and dust are
a bad combination), then use a zirconia belt for best results.
Soup up your sander
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Better dust collection
The bag on a belt sander provides decent dust collection, but with a little fiddling you
can attach a long, soft hose and a shop vacuum to your belt sander. The payoff: no bag
emptying and almost no dust in the air.
Belt sanders are simple tools that don’t
need many improvements. However, if
you use your belt sander in the shop,
consider these two upgrades.
Dust collection. Belt sanders always
come with a built-in dust bag that collects
most of the coarser dust and needs
regular emptying. However, plenty of
fine dust still gets into the air. If you’re
doing a lot of belt sanding, it’s worth
getting a hose that allows you to connect
your sander to a shop vacuum.
You’ll be able to sand all day with nary
a speck of dust (lower photo).
You can sometimes use the hose that
came with your shop vacuum, but it’s
usually too large or too stiff. The alternative
is a super-flexible, small-diameter
hose designed for dust collection.
You can buy one at a woodworking specialty
store or online (search “vacuum
hose”). I use one made by Porter-Cable
that cost $25. Dust ports vary widely
(some are square, which is a challenge),
so you may have to fiddle around to get
the hose to fit. There are commercial
adapters ($10 to $20; pick one up when
you buy your hose) or you can cobble
something together with—you guessed
it—duct tape. It’s worth the fuss,
though: no dust in your workspace.
Shop-made stand. A handy accessory
if you do much woodworking is a
stand that holds your sander on its
side, upside down or vertical, allowing
you to bring the work to the tool
instead of vice versa. The design of the
stand is completely dependent on the
shape of your sander, so we won’t give
plans. However, it generally involves
several layers of plywood, each with
cutouts to accommodate the parts of
the sander that protrude, plus a couple
of hose clamps or other clamping
devices to hold the sander securely.
Add another piece of plywood to act as
a table, if needed.
Stands like this are particularly useful
if you want to sand lots of small
parts—for example, if you’re making
lots of wooden toys. For inspiration,
search online for “belt sander stand
photo.”
