Rating of saw blade manufacturers

rdewinter · Post by **rdewinter** » Thu Jun 21, 2007 2:23 am

I bought a 50 tooth Freud blade for making fine sharp cuts on birch plywood. After the 3rd cut, I got burned or black marks only on the waste side of the blade and on the plywood. The good side had no burn marks.
Can someone explain why?

Ed in Tampa · Post by **Ed in Tampa** » Thu Jun 21, 2007 9:47 am

rdewinter wrote:I bought a 50 tooth Freud blade for making fine sharp cuts on birch plywood. After the 3rd cut, I got burned or black marks only on the waste side of the blade and on the plywood. The good side had no burn marks.
Can someone explain why?

Burning comes from friction and if everything is set up correctly there shouldn't be enough friction to cause burning. If you look at the construction of a blade the teeth are wider than the actual body of the blade. That mean only the teeth should be contacting the wood. If there are rub marks on your new blade this is a clue something is wrong.

If your saw is set up correctly the teeth should only be a one spot in the wood momentarily as they make the cut and later as the wood leaves the blade. Time and amount of friction this involves shouldn't be enough to burn your wood. Well perhaps I should saw ply as Cherry and a few others will burn if you look at it funny.

That means something is wrong somewhere. You didn't say whether you were ripping or crosscutting. If your ripping I would suspect the fence is forcing the wood against the blade after the initial cut. If you cross cutting I would suspect technique or the splitter. If you cross cutting you should not be pushing at all on the cut off piece if you are then that is the problem. If not then double check your splitter either it is allowing the wood to pinch the blade or it is causing the cut off side of the wood to make contact with your blade.

Some other things that can cause burning is too high or slow a feed rate. Blade depth not set high enough (the gulley of the teeth must clear the wood), too slow or high machine speed. On the feed rate try adjusting it and see if you can reduce the burn, do the same for the speed keeping the dail in the saw range.

On my saw if it is burning it is because of the splitter or my feed rate or my blade needs to cleaned or sharpened neither of these should be your case.
Ed

james.miller · Post by **james.miller** » Thu Jun 21, 2007 2:07 pm

I would like to add one more thing to Ed in Tampa's reply. Check the blades run-out. If you change blades on the arbor when you put it back on the arbor it could be in a different position with could cause greater run-out. If your only using one arbor then mark each blade to the position of the arbor set screw hole once it has been adjusted for minimum run-out. This will also help the blade cut smoother.

I use an arbor for each blade and once set up keep the blade on the arbor.

I have an Irwin Marathon 40 tooth thin kerf blade I use as my everyday blade and by adjusting it for minimum run-out (.006") it gives me a decent cut when I don't want to use my expensive blade.

Jim in Tucson

fjimp · Post by **fjimp** » Thu Jun 21, 2007 7:35 pm

Shortly after buying my 520 I read an article extolling the Forester Blades. I bought one that has never been used. I really do like my Shopsmith blade. Perfect cut every cut. I agree with the comment regarding the standard (larger) arbor. It is more stable. I did try a 5/8 plywood blade for one project and didn't like the flex. Jim

rdewinter · Post by **rdewinter** » Fri Jun 22, 2007 1:31 am

Ed, friction may very well be the problem. BTW, I was doing a ripping operation with my rip fence.
Your thoughts on the following: I checked the alignment of the blade with a dial indicator guage-with the infeed side of the blade set to zero, the outfeed side was +.003, or tilting right by that amount on the outfeed. Then using the same dial indicator I checked the alignment of my rip fence. Infeed side of fence set to zero, the outfeed was -.005, or tilting left toward the blade. Since these tolerances were so small I thought all was well. Do you think the combination of the two amounts of out of square could cause the burning? I don't think I could even see such small amounts.

rdewinter · Post by **rdewinter** » Fri Jun 22, 2007 1:31 am

Ed, friction may very well be the problem. BTW, I was doing a ripping operation with my rip fence.
Your thoughts on the following: I checked the alignment of the blade with a dial indicator guage-with the infeed side of the blade set to zero, the outfeed side was +.003, or tilting right by that amount on the outfeed. Then using the same dial indicator I checked the alignment of my rip fence. Infeed side of fence set to zero, the outfeed was -.005, or tilting left toward the blade. Since these tolerances were so small I thought all was well. Do you think the combination of the two amounts of out of square could cause the burning? I don't think I could even see such small amounts.

Ed in Tampa · Post by **Ed in Tampa** » Fri Jun 22, 2007 10:56 am

rdewinter wrote:Ed, friction may very well be the problem. BTW, I was doing a ripping operation with my rip fence.
Your thoughts on the following: I checked the alignment of the blade with a dial indicator guage-with the infeed side of the blade set to zero, the outfeed side was +.003, or tilting right by that amount on the outfeed. Then using the same dial indicator I checked the alignment of my rip fence. Infeed side of fence set to zero, the outfeed was -.005, or tilting left toward the blade. Since these tolerances were so small I thought all was well. Do you think the combination of the two amounts of out of square could cause the burning? I don't think I could even see such small amounts.

RdeWinter
I'm thinking of writing a book titled "The Day I Made Myself Crazy with a Dial Indicator". I hear all this talk of setting up machines using dial indicators and more than twice now I have proven to myself I can get a better setup/cut using the Shopsmith alignment procedure than I can trying to set every thing to a dial indicator.

That said.

Rdewinter inspect where the burning is occuring. As the leading edge of the blade enters the wood it should cut a kerf that is wider than the body of the blade. As your cutting you should be able to see this clearance on both sides of the blade. At the back of the blade the teeth should be ever so lightly but evenly touching the wood on both sides. Push the wood through enough to have the back of the wood past the blade and splitter and stop everything and inspect what is going on.

Since your ripping and the burn is on the waste side I assume the keeper wood is between the blade and fence. If so then I suspect the spitter, is it adjusted wrong or your pushing against the waste wood forcing it into the blade.

Where does the burn occur at the beginning, in the middle of the cut or at the end of the cut? Or is it the length of the cut. Again begin your cut after the blade is well into the blade and past the splitter stop your machine and inspect where the burning occuring. How long of a piece of wood are we talking here. 6-8 foot? If so I suspect your twisting the wood. Remember the slightest swing of the end of the wood will equate into tremendous movement at the blade more than enough to over come .005 tolerances.

Try this using the feather board placed forward of the blade so it applies pressure to wood before the blade cuts it, run your wood through using little or no directional input simply feed as straight as you can. Does the burning occur?
Ed