Suggestions for Preventing Burn marks

[judaspre1982]

I have new SS carbide tipped saw blades I have been using to rip a variety of hard woods. I cant seem to prevent from getting burn marks on the wood and have resorted to cutting pieces wider then jointing to finished width. I have made sure the rip fence and blade are parallel,tried different feed rates and blade projections and waxed all surfaces including the saw blade. Just cant seem to totally prevent burn marks. I am using an older machine with the 3/4 hp motor. I have no problem with the cuts except the burn marks. The blades have recently been cleaned of residue also. I have cut a lot of pine and fir without any burn marks, only happens with hard woods. Does anyone have a suggestion as to what may be going on. My cuts come out with even and parallel sides and there appears to be no binding going on during the cut. Happens with combination and rip blade equally. Suggestions Please-------Dave

[charlese]

Dave, I was able to stop most burn marks on edges by ALWAYS using the upper blade guard and splitter. Also not ripping oak at speed "P" slowing the blade to the lower side of speed "O" helped quite a bit.

Cross cuts and miters have never been a problem with Speed "O".

I think blade speed is a major contributer here.

[judaspre1982]

Thanks for the reply Charlese. I had to stop using my blade guard and splitter setup as it is the old metal guard and is for the old SS 9in blades. I have a newer lower saw guard that fits 10 in blades. I will have to see if I can get the upper saw guard to match. I was going to buy the saw guard upgrade back in the summer but chose not to after finding out you had to cut some of the aluminum off the main table tie bar to accommodate the lower saw guard. I will try to at least come up with some kind of splitter to see if I can stop the burn marks. Thanks again-----Dave PS----I will try the slower speeds tomorrow

[a1gutterman]

Hi Dave,

It has been my experience, when ripping oak, that the pieces tend to come together after passing through the blade. When that happened, I got burn marks. The splitter will help prevent that. For the purposes of preventing burn marks, the upper saw guard is irrelevant, but do use a splitter, even if you make your own like dusty has done.

[judaspre1982]

Thanks for the info Tim, I will search Dusty's many posts to locate the splitter he made. This may take a while as Dusty has 25 pages of posts. :D I think I remember someone making a splitter from plastic but I cant remember if it was Dusty. Thanks again----Dave

[a1gutterman]

While you are looking, check this thread out: http://www.shopsmith.net/forums/showthread.htm?t=1515&highlight=splitter

And actually dusty made a riving knife, knot a splitter. Here is the link. Be sure to look at the attached picture in the first post: http://www.shopsmith.net/forums/showthread.htm?t=1658&highlight=riving+knife

[judaspre1982]

Tim, thanks for the links. I have been finding so much info on this subject. I see this subject has be discussed before. The advanced search feature helped locate many hours of reading. Thanks again for taking the time to post----Dave:)

[reible]

Hi,

It sounds like most of this has been covered and I'm not in the mood to go back and read all the older posts so this might have been mentioned somewhere else but just in case it wasn't.

When you make a rip cut and then look at the two pieces are they burned at the same places? Also do you see a lot of blade arc's on the wood, one or both sides?

Several things can be happening. If the wood has not been jointed to a smooth edge and that is against the fence, the lack of a true edge will show up in the cut some times as burns.

If things are moving, fence, quill is not locked or can't be locked, loose arbor, bent or bending blade, table is flexing or tipping... lots of things can happen.

If you are seeing burning and it is on the part next to the fence and the other side is not burning it means the fence is not square to the blade.

If the arc marks can be checked to see if it is the mark is made by the initial cutting or by the the blade as the teeth pass on the out feed side.

So this is either a repeat of new material but that is about all I can add.

Ed