I "lucked into" thirty or more five foot by nine foot Masonite boards
- dark dense 1/4" thick.
I cut a few with a thin kerf carbide blade and then started having
troubles - blade (on worm drive skillsaw) would warp and could not cut
a straight line - it got "wavy."
I set the depth of cut shallow so as to save the saw horse/support
boards from a through cut. I go slow against an edge guide.
The replacement blade I tried was a 150 tooth steel "Plywood" blade
from Lowes that just aggravated the problems.
Does anyone have any experience cutting this stuff? I'm planning on
covering sixty linear feet of shop wall with it and each board will
reguire at least two cuts to "fit."
direct suggestions, advice, replies to gooeytarballs ATSIGN gmail.com
The biggest problem is that the board is probably not laying flat and is
supported on the bottom. If is is not it can bind and pinch the blade.
Masonite is not particularilly more diffucult to cut than any other thin
I also suggest you stick with carbide tooth but not the thin kerf.
Thanks. I did switch to a new HFT 24T or 40T Carbide blade and found
it a bit easier. But still getting some smoking and wander. Its not a
I'll have to run down to Lowes and see if I can get a (7.25" blade
with more teeth as running these sheets through my table saw is not an
option now absent a helper and a large saw table. I've one more sheet
to cut for this wall, then eight more to cut for the other and I'm
done. Maybe I ought try building a saw table for the task after this
Make yourself a circular saw cutting guide, like this:
I put my Masonite on three or more sawhorses (to support both pieces
after the cut), then clamp my guide on and cut. I've never had any
trouble with wandering, binding, or smoking, and I'm using the stock
blade that came with my Hitachi saw.
When you make the guide, the only piece you have to get absolutely
straight is the wooden guide block. If you use a router, set up your
guide so your saw works on one side of the guide, and your router works
on the other.
I used a piece of MDF molding for the guide block. It's nice and
straight off the shelf.
Maybe I read it too fast, but I didn't see where it mentioned that the
guide strip needs to be straight. Good for you for mentioning that.
I found that it's best to just use a piece of 3/4 finish plywood as the
guide strip, and make it several inches wide. That way you can screw it
down to many sacrificial under-side pieces, or move it back and forth on
the same under-side piece.
This way, when you switch saws, blades, tools, or whatever, you won't
have to realign the guide strip to a straight line, as the plywood guide
strip will stay straight.
"Playing is not something I do at night, it's my function in life"
Yeah, tell me about it.
See my "crappy plywood" post from a couple months ago.
I actually bought one of those $20 Johnson aluminum cutting guides.
The two 4 foot sections are nice to have around and I used one on a
strip of hardboard as a four foot and under cutting guide. I keep the
other piece for quick clamping to whatever for use with any tool.
I would never trust it (with the two pieces attached end-to-end, as
designed) to cut 8 ft. Even if you can get the two sections clamped
together perfectly straight, the slightest pressure against it, pushes
"Playing is not something I do at night, it's my function in life"
I did make such a guide/ I used some very good 7/16" 11-ply plywood
for the guide strip and glued it to a piece of Masonite (the length of
the boards I was to rip) and cut using the worm-drive skill saw I am
using for the job. (I actually made two of these - one long and
another shorter one for cutting the width).
The idea of screwing the two pieces together warrants a revisiting of
the guide making as does the idea of using it with a router and making
one guide serve the two tools.
I do know of a place that sells aluminum extrusions of up to twenty
feet and will look into getting an extrusion to serve as the guide bar/
strip. Maybe some 3/16 C channel about 1/2 inch by 2 inches would do.
But it will be expensive I'll bet!
Maybe, with a router, I cut bevel the edges so each sheet would mate
up better with the previous sheet. Nah, I'm not that good.
Haven't had this problem myself but I typically use a table saw. If I
was having this prob, I would first get something sacrifical I can put
under it, maybe an old piece of 3/4 ply. Then make a zero clearance
cutting runway I can lay on top. Again, maybe a 6" wide piece of
anything with a fence of 3/4 stock screwed along one side. One cut
with the worm saw sets the width. Now drop the runway on top of the
masonite, on top of the sacrificial. Set the depth to cut maybe 1/8"
into the sacrifical. Now the masonite is sandwiched between those and
the cut should be clean.
I built one of those guides by gluing a lone 4" strip of 11-ply wood
(some expensive scrap found outside a sign shop [trash] in Florida
years ago) onto a strip of 15" wide Masonite, then running the worm
drive along the plywood edge to create a saw guide as long/longer as
the boards to be cut.
The first time we tried this, I laid several rough cut 2 by's across
two saw horses and laid the Masonite on top of them. This time, the
saw horses were arranged so that too much of the Masonite hung
unsupported and I added OSB under the sheet to be cut as both a
support and sacrificial board.
I didn't recall as much difficulty the first time as I had this time.
But the wife says we had smoke then, too.
Thanks for the Feedback.
The saw blade is taper ground. Set it deep and it'll be hitting at
just the front and back edges. Set it shallow, and it will hit all
along the buried edge. So it heats up, which is what made it wavy.
Expansion slots would help, but I'll bet it doesn't have them.
Good part is that once it cooled down it was probably as good as new.
Run it deeper, and try to keep it in a straight line.
On Tue, 25 Aug 2009 11:56:15 -0700 (PDT), Hoosierpopi
I don't think the blade has anything to do with a "wavy cut." Most
likely, your tablesaw would benefit from a tuneup. Make absolutely
sure the miter slot is parallel to the blade and to the fence. If it
is off 1/64", that's too much and you will get poor cuts and increase
the chance of kickback. Also use an outfeed table, rollers or another
person at the back to support the stock. Always keep your eye on the
fence, making sure the boards are tightly against the fence at all
He's not cutting with a table saw--he mentioned a worm drive Skilsaw.
If he's going to cut Masonite that way I think he needs to clamp it between
two stiffer boards if he dosn't have a flat table to lay it on.
If he's going to cut Masonite that way I think he needs to clamp it
between two stiffer boards if he dosn't have a flat table to lay it
He sure is - no other reasonable option.
The sheets at 63" wide and about nine feet long.
They were free, but show some wear and tear at the edges.
They are heavy, bulky and difficult to move about - now in top garage,
cutting in barn, my TS is in basement, finished boards are for the
I think that "deep cut" advice may prove the solution. It was avoided
because I had stacked all eight sheets onto the sawhorses used to
support my cutting operations (cut the short dimension of all eight at
once since all were to be cut to the same length) and worried about
nicking the second sheet as I cut through the first. I set the depth
of cut as shallow as I could.
Like I said, I'll have to reset the depth and have another whack at
Thanks for the feedback.
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