Best saw blade to cut LDF?
January 12, 2008 11:43 AM   Subscribe

What type of saw blade should I use to cut LDF (light density fiberboard?)

We're installing new baseboard in our house and the type we've been looking at is made of light density fiberboard (LDF.) We saw some pieces at Home Depot where customers had (presumably) cut with the complementary hand saw and the ends were very ragged. At our Rona store the associate cut us a sample with a power mitre saw and the cut was much cleaner.

So my question is, what type of blade should I use for my power mitre saw to get nice clean cuts? Will the 40-tooth carbide blade (10") that came with my saw suffice, or is there something better-suited to cutting LDF?

If anyone has experience working with this material I'd appreciate your input.
posted by howling fantods to Home & Garden (6 answers total)
The hand saws HD leaves out for customer use are the equivalent of the round-ended plastic scissors they gave you in kindergarten, only duller; it's no surprise that those cuts looked bad. Almost any decent carbide-tipped blade with lots of teeth will be fine. Try to position the stock so the teeth exit on the back/bottom surfaces, so that the visible edges are clean and the fuzz is hidden.
posted by jon1270 at 11:54 AM on January 12, 2008

Probably should've said that 40T might be a little coarse. I'd experiment with the blade you've got before dropping additional cash, but if you do want to upgrade, look for a fine crosscut blade similar to this one.
posted by jon1270 at 12:09 PM on January 12, 2008

Seeing as your blade is new and sharp it might be OK but, as a rule, more teeth per inch work better on cross-cuts with real wood and probably more so with LDF baseboard, though I’ve never used the stuff.

Here’s a handy way to find bevel angles for corners. Lay two pieces of baseboard at least 18 inches long on the floor, pushed hard to the walls so that one lays across the other at your corner. Then use the top one to scribe a pencil line across the bottom one. Take that to your miter saw and use the blade to find that angle. For a “90 degree corner” you should get nothing to just a couple of degrees. That is your deviation from 90 degrees. Now add or subtract that from 90 degrees, divide it in half and cut the bevel. Always make it a degree or two sharper for outside corners and a degree or two less sharp for inside corners.

Always cut long from inside corners to outside corners and scribe the boards with the walls to get the true cut.. On inside to inside leave it a fat sixteenth long and spring it in.
posted by Huplescat at 2:35 PM on January 12, 2008

Use a 80 tooth (for a 10" saw) ATB carbide blade. Often sold as a melamine blade. Composite materials like fiberboard are hard on edges but easy on tips so buy a cheap blade unless you plan on getting the blade resharpened a lot. You don't need a blade with any kind of fancy coating because the LDF doesn't have any pitch content.

Make sure you buy a chop saw blade rather than a table saw blade. The mitre saw blade will have a negative hook angle and the table saw blade a positive hook angle. If you get a table saw blade it'll tend to pull the stock off the fence resulting in an inaccurate cut.

Also if at all possible cut this stuff outside. The dust is very fine and will get everywhere. A shop vac hooked up to the vent on the saw will help but won't come close to getting everything. The molding should be supported as much as possible for best results so rig up some kind of table if you can. I've had good luck fastening a 1x10 laminated shelf 8-12' long right to the table of the saw then using a couple pieces of 2X4 as legs about 1/6th from either end. A full table like that is much superior to the mitre saw stands that only support the stock in three places (table and two rollers). If your saw doesn't have holes to attach an auxiliary fence/table you can use double sided carpet tape. I've also just drilled and tapped my saw for flush bolts.

I can't seem to find a picture of what I'm talking about but there is a picture of a fancier one here from woodweb.
posted by Mitheral at 5:34 PM on January 12, 2008

Response by poster: Thanks for the tips everyone. Some good advice here.
posted by howling fantods at 11:33 AM on January 13, 2008

Of course howling Fantods, or any other normal person for that mater, could care less... but I’ve been getting dust collection that can’t be beat with a Fein vacum hooked up to my 10 inch Hitachi.
posted by Huplescat at 8:31 PM on January 13, 2008

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