Burned wood solved by propper cutting technique

[paulhtremblay]

My brand new TS55 created burn marks in 19mm MDF when I made narrow cuts with the parallel guides. It did not create burn marks when using the other side of the parallel guides, or when using the rails by themselves.

I contacted Festool support. At first, Lester suggested the toe was out of alignment. He suggested I could test the alignment myself, get a replacement saw, or return it. When I told him the burning only occurred with the parallel rails, he changed his original diagnosis, stating that there was nothing wrong with the mechanical workings of the tool. He put me through to applications.

The guy there (sorry I forget his name), asked me if I used my left hand when I made the cuts, and if I cut behind or beside the saw. I told him I used my left hand (thought I am right-handed) and and walked beside the saw. He told me I must be tipping the saw, and that the saw was meant to be pushed from behind.

Since the cord and hose were getting caught in the rail, I first had to make a jig to keep them out of the way. (I hope to post picts of this device.) I wanted to have both hands on the saw so I could concentrate on the cut.

Tonight I tested the saw using Festool's suggestions. At first, the saw struggled to cut 19mm MDF. It made growling noises and acted as though I cut through 8/4 hard maple. I saw burn marks in the thin strip of MDF. The burn marks were lighter in color and did not run the entire length of the board, but I could still see them. I tried a few other techniques, such as removing the dust plate, making sure the bevel was at 0 degrees (and not -1), and having the MDF hang over the edge of my cutting table. The burn marks seemed to lessen.

Then I put the dust plate back on, and cut with the MDF completely on the cutting table. I noticed that the if I put my body behind the saw, it did not struggle to cut through the sheet.

Finally, I bent my torso so it was squarely behind the saw. My head was directly over the saw, as if the saw were a gun and I sighted it. The saw glided through the wood. The burn marks completely went away. I ripped 18 pieces of MDF 50 mm wide. With the right technique, the strips had no burn marks at all and the saw moved easily along the cuts.

The proper technique seems to be to really get your full weight behind the saw, so you sight over the top of it. Doing so makes a huge difference.

 

[Roseland]

My TS55 goes through MDF like a hot knife through butter.  Which blade are you using - the 48 tooth?  Is it sharp? Is it in the right way?

Andrew

 

[Wenyce]

Thanks for the technique tip, I've been noticing some burning on melamine, I searched around and pretty much was told everywhere it's normal but I do see that sometimes it's barely ever there then some other times it's like burnt toast, I'll try to be more consistent with how I push the saw through.

 

[paulhtremblay]

Well, I thought I had the problem solved, but it has returned. I ripped some 19mm Birch plywood and got considerable burning again. The saw seemed to really struggle cutting through the wood as well.

My blade might be dull. I have only had it a month, but have cut quite a bit of MDF with it (enough to fill two bags with MDF dust in my vacuum.)

I note that the burning occurs at the start and end of the cut, where the plywood is not supported. My plywood cutting table is only 6 feet long, meaning the plywood hangs off a foot on each side.

I hope a new blade or a better supported table fixes the problem, because otherwise, the parallel guides work fantastic, and the saw makes a cut so fine it does not need any further finishing.

 

[semenza]

You might want to get the blade sharpened after cutting that much MDF. Which vacuum (how much capacity) ? But also the unsupported ends may be causing some side twist do to flexing. Which would explain the burning at the beginning  and end.

Seth

 

[tjbnwi]

Clean the blade, see what happens.

MDF kills blades and bits. You may need to get a 4 or 5 blade rotation going if you cut that much MDF.

Where in the U.S. are you located?

Tom

 

[grbmds]

I don't cut much mdf. I don't have any burning problems. I can't say that I always push directly from behind the saw. It seems that, in many cases, this wouldn't even be possible. However, I've made cuts while I'm standing on the right side, the left side, and as behind as I can get. Since I use the boom arm with my MFT I find that where I stand depends on what I'm cutting and where the vac/arm are in relation to my cut. Anyway, no burn marks unless I move the saw too slowly. Can you support the pieces with portable support tables at the ends. That might help solve your problem although it does not seem as if that is the whole solution given your description.

 

[BMH]

Using good technic with the TS 55 is important but using the standard blade on all your cuts and not having it sharpen is a big problem. Using just one blade is like sanding everything with 120 grits and not changing the paper.  I have 4 different Festool blades and use them on the appropriate material or type of cuts, the difference in the quality of the cut is amazing.

 

[grbmds]

Using good technic with the TS 55 is important but using the standard blade on all your cuts and not having it sharpen is a big problem. Using just one blade is like sanding everything with 120 grits and not changing the paper.  I have 4 different Festool blades and use them on the appropriate material or type of cuts, the difference in the quality of the cut is amazing.

BMH . .. What is the best blade to use on MDF? I, too, have other blades, a rip blade and a finer blade (to be used for crosscutting when I want a fine finish on the end grain), but would have thought that the standard blade that comes with the saw would be acceptable for MDF.

 

[BMH]

I find that the solid surface 48 tooth saw seem to last longer and give a better cut in these composite material. MDF is denser then plywood (http://en.wikipedia.org/wiki/Medium-density_fibreboard) and the resins and other fabrication process can dull the blade very quickly. When I am starting to get those burns mark and/or feel that the TS55 is working harder at cuts I know it is time to get the blade sharpen or changed.

Bruce

 

[amt]

If the burning is only at the beginning and end, then I would first get the supports worked out before trying a different blade.  Since you only have a 1 foot overhang, I would get a few 2x4's that are very straight and put them between the table and the plywood, running parallel with the saw's track/your cut, with one right before and right after the "cut" line you are about to make, and a few more spaced farther away to support the plywood completely.  In fact, I would just screw the 2x4's to the table.  These will serve two purposes:  it will give you the support you need at the ends and it will allow you to plunge the saw fully without cutting deep in to your table.  Getting the saw blade fully plunged should make it far easier on the saw to cut the plywood because it reduces the number of teeth actually cutting.

 

[paulhtremblay]

A bit more info on this:

I made a plywood cutting table out of a grid of 2 X 4's, but I made it 6' by 3 1/2 ', thinking a little overlap would not matter, and wanting a smaller table to save room. I am using the blade that came with the saw, which I believe is the 48 tooth blade, and the best for cutting MDF. The blade is pretty dirty (as I realized late last night), so I have ordered some cleaner from Rockler.

I use the Fein Vacuum. (The Festool dust collection is spectacular, by the way; so much dust gets collected, I don't even need to vacuum when I am done.)

I will get another 48 tooth solid blade (there is only one such blade, right?), and rotate that in between getting it sharpened.

I am surprised that the parallel guides work at all, because they really trap the wood. When I finish my cut, I really have to pull out the cut wood, firmly between the parallel guides and kerf. Yet once I got the technique down, I cut dozens of MDF with no burn.

The burn side is always on the right side (opposite side of motor) of the wood. Maybe I am tilting the saw in that direction.

 

[paulhtremblay]

A further update: I cleaned my blade with Rockler cleaning fluid and now have a clean blade. The blade cuts much easier when cutting MDF on my mft3 table, and seems to cut square both ways. However, it struggles when cutting through plywood, and produces a cut completely out of square, with the corner against the cutting rail longer than the rest of the cut.

I use the same setup: I check my fence for squareness, cut a piece of MDF and get good results. I lift the guide rail and insert a piece of plywood and get unacceptable results. I lift the guide rail and insert a piece of MDF, and get good results.

I know when I used my circular saw (Milwaukee), I experienced the same problem, with a sharp blade cutting straight, and a dull one not cutting straight.

I have ordered two 45 tooth solid surface blades and will see what happens when I get them. (Obviously I have to send my current blade out for sharpening.)

 

[duburban]

Interesting issue your having. At least your results are consistent which will help find a solution.

 

[tbellemare]

If it helps, every circular saw I've ever used, including Festool saws, want to walk sideways when the blade is at all compromised.

It can happen when dirty, dull, or missing teeth/portions thereof.

With a track saw, that can manifest itself as binding and burning. With a typical circular saw, it wants to run away.

Tom

 

[semenza]

Assuming that you are not raising and lowering the MFT rail mounts between cutting the plywood and MDF. Could this be caused by the MDF being a true 3/4" and the plywood being undersized allowing a little more flex?  ???

Seth

 

[Birdhunter]

Do you clamp the wood/MDF to the MFT before cutting?

 

[rst]

Take a dial caliper and check the distance from the blade body and the inside guide slot.  If this distance is not equal, you will get burning.  I use took possession of a recon TS55REQ and in the process of making sure that the kerf of it and my TS75, I discovered that the blade was angled to the slot.  It was an easy fix...use the supplemental guide for the process.  Just a note to Shane and company, the saw was a 20% off and looked perfect and had a blade that had to be brand new and there was no sign of dust or wear any place.  However, the bade was not square to the base.  This I also corrected by attaching shims into the base.  My saw was off square by one degree, checked with a knife edge engineers square.  Fortunately, I just discovered today that the brand new 55" rail furnished with the saw runs off two mm from 32" to the end.  I haven't contacted Bob yet, but am certain that he will correct this.