Marc:The Wood Whisperer is sponsored by: Powermatic, the gold
standard since 1921 and by Rockler Woodworking and
Hardware, Create with Confidence. Without a doubt the handiest
jigs and fixtures in the workshop are the ones you
make yourself, and the one that should be top on your
list is a cross-cut sled. (groovy jazz music) The cross-cut sled is an
incredibly simple device. It consists of a platform
and two hard wood runners that go into
the miter slots as well a front and back fence that
holds everything together. The idea is this movable
platform is fixed at a perfect 90 degree angle so you could
use it to make little cuts on pieces like this, you
can get a stop block, clamp that to the back fence
and you can make repeated cuts, so you can have really
precision accurate milling if you want to batch through something. One of the things I find it handiest for is trimming larger pieces. You know how if you
have a long piece that's longer than it is wide, let's say you're cutting book shelves or something, you never really want to
cut that and make that cross-cut at the table saw
because it tends to move and rack on you and you're going to have
a really dangerous kickback. On a cross-cut sled it's
really not a big deal at all. You put your work piece on here like so. You can clamp it in place if you want, most of the time it's
stable enough as it is. And you could have a
piece that's pretty long. As long as the work
piece itself is supported all the way out there you could just push right through and cut
and it's perfectly safe. Part of the reason is
because the work piece is now travelling on the platform itself, the work piece is not
going to have any issues with friction like it would
if you were moving it across the table saw surface, where
the actual metal of the table saw wants to resist
the motion of the work piece. It's a very safe way to
do these things and it's just nice to know that
you've got something that no matter what you know
it's always cutting at a perfect 90 degree angle,
that's very important. When I first started woodworking
the cross-cut sled was one of the very first things
that I built for myself. At the time I was watching a lot of WoodWorks with Davis Marks and he used a cross-cut sled in just
about every episode. I was fascinated with how simple
it made things and the fact that I can get a dead-on 90
degree cut every single time, it seemed like it would
open up a playbook of opportunities for me that
I didn't have at that time. I immediately built one and it served me well for a couple of years. Since that time I gravitated
away from it a little bit, using my sliding compound miter
saw for a number of tasks. Then once I got the Festool
MFT that really was a game-changer for me in
terms of cutting panels that are a little bit
wider, like this one. And frankly at that
point my cross-cut sleds were a little bit beat up and they needed to be replaced at that point really. I was just a little
bit lazy and I figured, "You know what, I'm just
going to use these other "tools that I have to
accomplish those tasks." I've been doing that now for
the last five or six years and I didn't think I was
missing anything until I took a couple classes at
the William Ng school. William has all his table saws
set up with multiple sleds and it really is incorporated
well into the lessons. It made a light bulb go
off, like I'm really missing out on some simple techniques
and great things that you can do with a
cross-cut sled in the shop. I promised myself that I would come back and I would build one, and then of course show
you guys how to build it, and we'll use it on
projects going forward. Here's my design, and it's
fairly simple to build. Let's review some of the
materials and we'll dig right in. All you need to make
this sled is a piece of half inch plywood for the base, two pieces of thick plywood
or hard wood for the fences, and two hard wood strips for the runners. My fence pieces are going to be made from inch and an eight HDO plywood. This is like regular
plywood but on steroids. The outermost layers feature
a resin-impregnated fiber that provides a smooth,
consistent reference surface. The only reason I'm using
this stuff is because a friend gave me some scraps, so feel
free to face glue a couple pieces of plywood together
to get the thickness you need or simply use a stable
eight quarter hard wood. I'll be using purpleheart
for the runners simply because it's the toughest
wood that I have on hand. Oak and maple would also be good options. Take a close look at the grain here. Wood expands most dramatically across the grain so if we want
the most stable runners possible we should orient
the grain vertically. That way if there's any wood movement it shouldn't affect the fit of the runners. I'll be cutting my
slices like you see here. The first step is to make sure the runner stock is nice and square. Exercise caution if your
pieces are thin like mine are. Using a bandsaw I cut each strip to just over 3/4 inches wide by
3/8 of an inch thick, and that's the rough
dimensions of my miter slot. Although most miter slots are similar measure yours before
your making your cuts. I then test the pieces to
see how much stock I need to remove so that it fits
in my miter slot perfectly. The drum sander is my tool of
choice for getting a snug fit. It removes minute amounts of wood with each pass so it's ideal for delicate work. If you don't have a drum
sander you can carefully dial in a fit with your
table saw or power planer. If you're of the galoot persuasion a few passes with your jointer
plane or smoothing plane should get you where you need to be. The ultimate goal is a
runner that is flush or just a hair under the
surface of the saw top. In terms of width you
should be able to push the runner back and
forth relatively easily. The ideal gap here should be
a few thousands of an inch. To attach our runners to the
plywood I drop the runners into the miter slots and place
the plywood right on top. Notice that the plywood is offset so that there's more room to the
left side of the blade. This gives me more clamping
surface for stop blocks and it's just a personal preference that
works well with my workflow. I make sure that the
plywood is flush with the runners at the operator's side of the saw. The runners will be attached to the plywood using countersunk screws. A large square helps me draw reference lines so I know where to drill. I'm going to configure a
countersink bit for a relatively shallow hole, using the
sled itself for reference. I don't want the screw to
punch all the way through the runner so I set the depth and
the stop collar appropriately. Now it's time to drill. I drive the screw in by hand
to maintain absolute control, we don't want to crack the runner. Once the first runner is secure I repeat this process on the other runner. Now that both runners are
locked into position I can proceed with the installation
of the rest of the screws. Install at least five per side. After the runners are
secure be sure to test the sled for binding,
although there really shouldn't be any problems at this stage. Using a long straight edge I find the flattest of my two pieces of fence stock. Hopefully they're both
flat but honestly the only fence that truly
needs to be perfect is the one that the work registers off of, and that's on the user's side of the saw. You can attach your
fences as they are but it can be difficult to put
pressure on work pieces with your hands if your fence is too tall. I use a French curve to create
a small cutout on each end that effectively lowers the fence height where I'm most likely
to position my hands. The curve here is just decorative. Using a chamfer bit I put a small chamfer on all the edges of the fence. This not only eases the
edges for comfort but also produces a little dust
channel that helps prevent dust from skewing the
registration of your work pieces. Back at the table saw
it's time to cut the kerf. Turn the saw on and
slowly raise the blade. Once a full tooth height is
exposed push the sled forward and extend the kerf, but don't go
all the way through just yet. With the saw off place one of the fences on the sled and clamp it in place. You want the fence to be flush
with the edge of the sled. Countersink and pre-drill and then drive a single screw through
the sled into the fence. To make sure that the fence
is as square as possible I insert an eight inch
thick piece of scrap into the saw kerf that I just
cut and use the largest square that I have on
hand to square it up. I can't seem to find my plastic drafting triangle which would be perfect for this so I use the largest square that I have. Once the fence is as square as you can get it secure it with a clamp and double check to make sure nothing has moved. Make any last adjustments with a few taps from a hammer or deadblow. Countersink and drive another screw to lock the fence in place. At this point it's safe to
attach the other fence as well, only this one doesn't
need calibration so I lock it down completely with
six countersunk screws. Now using a 24 inch by 24 inch piece of plywood scrap I'm going
to make a test cut. Cutting one piece and
checking it for square will get you pretty close but
we can do better than that. I'm going to use the
five cut squaring method. The idea is to make four cuts, one on each side of a test board. After each cut I rotate the
board 90 degrees clockwise, putting the fresh cut
edge against the fence. By the time I make the
fourth cut any error in the squareness of the sled will
be four times as great. To measure how far out it is
I setup for the fifth cut, removing a small strip of wood. Save that off cut and keep in
mind that this is the side of the board that we originally
made our very first cut on. It's important to keep the orientation of your off cut straight so I mark one side F for front and one side B for back. In the perfect world that
offcut would be exactly the same width at the
front as it is at the back. What we have here is .8
inches at the front and .82 inches at the back, for a
total difference of .02 inches, which is just over
about a 64th of an inch. Frankly that's not too bad
considering this number represents the error
over a 96 inch distance. Let me explain. Each side of the board that
we cut was roughly 24 inches, so after four cuts the
total distance is 96 inches, so the error we measured on that last cut is four times the actual true
error. The true error would then be .02 divided by
four, which is .005 inches. In real world terms we're
saying that the error is approximately five
thousandths over 24 inches. Frankly that's close enough for me, but I wanted to demonstrate
how to make an adjustment so I'm going to try to
get even better than that. Here's how we make an accurate adjustment. Since my cutoff piece was
thinner at the front and thicker at the back I
need the left side of my fence to come back
toward me just a hair. I start by clamping a stop block to the sled base right up against the fence. I loose the fence screw
and completely remove it and then inset a five
thousandths feeler gauge in between the stop block and the fence. This is essentially going to push the fence back five thousandths of an inch, which is the amount of error
that we calculated earlier. I use another clamp to make sure that the fence is fully secure to the stop block and then drive a new countersunk screw. Note that this is a new screw hole, you do not want to reuse the first one. I remove stop block and the feeler gauge and repeat the five cut test. This time we have .648 at the
front and .653 at the back, for a difference of .005. Remember we have to divide this by four and the resulting true
error would be .00125. Now that sled's error is effectively about one thousandth of an inch over approximately 20 inches or so. That's what we call crazy good. Remember, I would have
been perfectly happy with the initial results so
this is just a nice bonus. Don't go nuts chasing
down perfection here. Get it as close as you can
with no more than three rounds of this five cut
method and you'll be fine. With the fence dialed in
it's safe to drive some more screws and completely secure
that fence to the base. After firmly attaching the
rear fence here you may find that things have
moved a little bit on you. The runners may feel a
little bit tight now and that's just because as you
drive these other screws things just may move a
couple thousandths one way or the other and that could
cause it to be a little tight. It's very difficult to
look at it and figure out which part of the runner
is causing the tightness. It may just be one of
them, it may be both, it could be one side of the other side. What I like to do is use a Sharpie marker, you could also use a
pencil or a piece of chalk, and I will mark each side of the runner. Both sides of each runner
now have a good marker line. And we can put the sled right
back into the miter slots. Mine is doing just fine at
the front, it's toward the back where I'm getting just
a little bit of rubbing. You can see I can push easily
with my fingers to right about this point here and
then it starts to tighten up. I can still push it through but I want it to be a little bit more relaxed than that. I'm going to push it forward and back, I don't know, maybe ten or fifteen times, just enough that some of that marker is going to start to rub off. Let's see what we can see. It's not going to be very easy
to see but right along here, right in the middle of
that marker line I've got an area where it's
starting to rub away. It starts about here and
ends right about there. That seems to be the biggest offender. I'm going to grab my card scraper and remove a little bit of that stock. I also see a little spot right up here. (scraping) Not too bad, a little bit should do it. Let's test the fit now. Much better. That one little fix was all it took. There were a couple
small points where it was rubbing and that was just
enough to cause it to be a little bit more
difficult to pull back. You want to be pretty
careful with that because if you have to pull really
hard to bring it back to you that's really
going to stress the screws that hold this fence in
place, and eventually it may come loose or it may
knock it out of calibration. (squeaking) Getting a
little bit of noise there. The wax will probably take care of that. But the point is there's no slop and it's fairly simple to push forward and back. Keep in mind there are seasonal movement issues that may occur here. If it gets really humid
you may find that those runners swell up a little
bit and you have to decide whether or not to take a
little bit of material off. The drawback being that
when the humidity goes away those runners can
shrink down a little bit so they'll go back to where they were. That's one of the reasons why we want to use quarter sawn stock. That's very stable so
hopefully we won't have that problem and even if it moves
just a couple thousandths here or there it's not going
to be that big of a deal. (ragtime piano music) Now I think we can take a
moment to review some of the basic operations that we can
perform with a cross-cut sled. Of course you could make
a very simple cross-cut on a piece like this, a
relatively small piece. If you have a pencil mark on
the work piece you just line that up with the kerf cut
in the back here and you should be able to fairly
accurately cut to your line. Nice simple cut, perfectly square. Of course you're also going to want to use this setup to cut larger panels. It's really no different, you just line up your pencil mark with the kerf cut. Let's say it's right there. Turn on the saw and go. Let's say you want to batch out
a bunch of parts and they're all exactly the same size,
so you need a repeated setup. A stop block is what's really
going to make that possible. You could simply clamp the
stop block to the back fence. Now we know that every time we
put the work piece up against the stop block we're going to
wind up with a piece that's exactly the distance between
the stop block and the blade. Generally how you would
do this is of course a work piece needs to be
squared on both sides. In order to have a good square
reference to put up against our block we need to have at
least one side square first. I put it on the right side,
make that cut real quick. Now I could put that nice square side up against the stop and make my cut. Now no matter how many of
these I have to cut they're all going to be exactly the same length because of the stop block. There are going to be times
where your work piece exceeds the fence capacity so if I
wanted to cut a piece that was, say 17 inches long for instance, I won't be able to do that in a setup that involves the stop block
being on this back fence. Here's the great thing. We could use our table
saw fence as a stop. Let me show you how we do
that. Take your stop block. Attach it to the fence. You want to keep it back
toward the front here because ultimately we don't
want the work piece to be in contact with the stop
when it hits the blade. Just adds a little extra safety here. Of course we need to
start out with one square edge so I'm going to
put it on the left side and just trim it so that
it's nice and square. Assuming that I have
measured this distance and I know that this distance
is exactly the repeated cut I want to make I
could take that fresh cut, put it right up against the stop ... Once again I can batch out as
many of these as I need to. Here's a quick tip for you.
If you make your stop exactly one inch wide then all you
need to do is set your fence based on whatever the reading
is and just add an inch so that you don't have to worry
about doing any odd calculations and you won't even have to
measure when a time comes. If I want to cut a 17 inch
piece I need to set my fence for 18 inches to account for
this extra one inch stop. If you can get this to be
exactly one inch you're going to make your life
a whole lot easier. There may be a time when you need to cut really tiny pieces like
this little strip here. The problem is as you make
this cut, you can hold it with an eraser like this and steady
it but it's a little bit scary to think of this little
tiny piece sitting between the stop block and the blade once
it's cut all the way through. There is a little
modification you can make to your stop block that makes
this a whole lot safer. I can use this extra piece that I cut. You can see I just removed material here so that there's a little stop on the edge. What will happen is it will fit right under my regular stop block. Notice I cut this so that it's just protruding a little bit
from the stop block. I'll show you why in a minute. Let's say we want to make
our cut right about here. Clamp the stop block in place.
Tighten it down real good. This then becomes my stop,
I'm not actually using the face of the stop
block. I want to set it so that my cut length is
based on this bottom stop. Once I'm lined up, I've
got my work piece in place, I can actually remove this
so that once I go through and make the cut this off cut is
going to float in free space here and not be wedged between
the stop and the blade. Then when you go to make your
next one bring the stop back in, line it up again and make your next cut. Let me do a couple test cuts this way. You still want to be
careful because these are little pieces and they
could certainly vibrate back into the blade but it's a heck
of a lot safer than having that piece wedged between
the stop and the blade. Those are just a few things
that you could do with a cross-cut sled and that's really
just the tip of the iceberg, there's a lot of tricks and tips. Search on the Internet
and you'll find a lot of great ideas for not only what to do with a sled but also how you can really trick it out and make it that
much more useful for you. Hopefully this starts as a nice template that you could build upon. Of course, send me your
pictures and your ideas. I'd love to see what other
things you do with your jigs to make them work that much
better for you in the workshop. We'll share them with the community. I certainly plan to use
mine on the show a lot more so you'll be seeing this thing again. Thanks for working. (woman singing)
