Cutting Veneered MDF on a Bevel
Lately, I've used an 80 tooth blade (Avenger Brand) which does a good job crosscutting or ripping these panels. But when I tilt the blade to 45 degrees for bevel cutting, I'm getting a fair amount of chip out, and quite a bit of drag, which pulls the work piece away from the fence. Applying blue painter's tape on the cut line eliminates the chip out, but the tape's adhesive accumulates on the carbide teeth, making drag even worse.
After looking at Freud's and Dewalt's selections of blades, I'm getting confused, as they make blades recommended for veneered plywood, some for melamine and laminate, with similar but also differing characteristics. MDF + veneer seems to be a cross between laminate and wood. At this point, I'd just like to know whether I should be using TCG or ATB, low angle hook or high. Would thin kerf be better, or will it flex too much? Maybe there's a problem with the blade height? Or some technique to improve results? Of course, any specific blade recommendations are appreciated, but I would prefer to stay in the $50 range if possible.
From contributor K:
I would lean toward the low angle ATB. I would avoid adding the tape gum to the mix. Sometimes a 1/4" difference in blade height can make a huge difference. If you are sure that the fence is perfectly aligned, yet chips when beveled, I have found that some saws need shim washers between the table and trunion or base to get the back of the blade aligned when tilted to a 45*. Inspect the scoring marks on the finished cut to determine if the back of the blade is causing the chipping. If you are cutting on a sled or whatever, maybe a weighted scrap of MDF will reduce the chip out.
From contributor F:
For half of my woodworking career, I did table saw beveling with the parts between the fence and the sawblade. I can now testify that doing it that way is the hassle way. It is difficult to set the dimension because the hair sight curser is way off when the blade is tilted, and also difficult to keep the edge being beveled flat on the table on wider panels.
The method I now subscribe to is cutting all my soon to be beveled parts to "net" size with 90 degree edges. Then I crank the saw to the required bevel angle and using an auxiliary fence with a rabbit at the bottom and the blade elevated to where it cuts into the auxiliary fence. I adjust the fence and the blade height to a setting that bevels the entire thickness without removing any of the width or length of the panel on the upper face or long point of the bevel face.
With this method, you can bevel the edges of parts that have differing widths and heights with a single fence setting as long as the parts are the same thickness and, of course, need the same bevel angle.
The rabbet at the bottom of the auxiliary fence is there to prevent the triangular scrap from binding between the fence and blade and shooting out of the front of the saw. This method also works great with a power feed.
From the original questioner:
I've seen that method for beveling done before, but have never tried it. I always assumed it would be difficult to get the blade and fence set to give perfect bevels, without removing any additional material which would alter the finished dimension. Maybe I'll try this on my next project. I'm still pondering the best blade for this type of work, though. The 80 tooth is definitely causing too much friction... A 40 tooth blade cut more easily, but didn't give the finest edge on the veneer. Maybe a combo 50 tooth blade would be a good compromise, with the raker tooth clearing out the MDF, and the rest of the teeth giving a smooth veneer edge.
From contributor F:
Try this technique. Just use a small piece of scrap from the material you will be beveling to get the fence set to where it bevels just to the edge without taking away dimension; it's not difficult. As to the blade, any sharp alternate top bevel blade with 60 to 80 teeth of good quality will work fine.
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