Troubleshooting Blade Wandering
Tooth set and tension are factors to look at when a blade wanders shortly after entering the log. October 25, 2006
Question
About 3" to 5" after I enter a cut, the board will show a ripple (washboard) which only lasts for another 3" to 4" and does not show up again. What is going on?
Forum Responses
(Sawing and Drying Forum)
From contributor L:
We need a little more info. What kind of mill, blade, wood, current tension you're running, set and hook angle of blade?
From contributor K:
I get a similar washboard when entering the cut, but not three inches in. I expect this is a blade tension issue. Are you picking up speed at that three inches? Are you running into this when the blade is sharp or dull? Does this affect the market value of the lumber? When I get the dip and dive blade action at the start of the cut, I consider it trim. If it occurred farther into the cut, I can see how a woodworker would not appreciate the extra passes through the planer. What do your customers say? I have asked in the past if cutting from the butt up the stem is more likely to cause this effect. I see the butt portion of the log more dense and the grain of the butt as less uniform. I wonder if you have noticed this on your logs? What species are you into? That will tell us a lot about the density and grain pattern as well.
From contributor R:
At the beginning of the cut, is it climbing in the cut just once, like a hump, or is it several up and down waves? Was this just on one or does it happen most of the time?
From contributor T:
Your mill manufacturer should be able to guide you on tension of the blade. However, there many factors that can cause your problem. How old are the logs, and what species? Some old logs will be very dry and hard on the ends, but still green in the middle. This can cause your problem. If your logs are old, try cutting off a foot as a test, and see if your problem goes away.
From contributor K:
Good call. That may be a factor for me when I get sloppy and do not cut a fresh face on the log.
From the original questioner:
Primary specie are Ponderosa pine and incense cedar. Logs can be both fresh or aged. Mill is a woodland vertical, blades are Suffolk new and sharp. I don't run blades more than 4 hours and will always change if I notice any wandering or other indication of dullness. The washboard could be as I speed up the cut, since I enter the log slowly. I'll try getting into the cut and do repeated slow-fast to see if this happens all the way down the log. The washboard only goes along for 2 1/2 to 3 1/2 inches, then disappears.
From contributor L:
Just a thought... It sounds like your blade is trying to stabilize and find its place when you enter the cut. Once it settles in, it cuts smooth? I guess if it were happening to me, I would try to increase my set in the blade. I'm glad you're running Suffolk's blades... they make a good blade and have done a lot of research in blade performance. One thing that I learned from them is that a blade doesn't necessarily get its stability and tracking ability from blade tension, as many would think. In fact, one of the first things they ask you to do when you begin running their blades is to decrease your tension. Am I correct? When I began using their blades, I had a WoodMizer LT40 and found that even with much less tension, if I would widen out my set, my blade would cut smooth and stable even through very hard woods or knots. This would take into account the ends of logs that may have a head start on the drying process and thus be a bit harder. Try a wider set with a consistent feed rate. By the way... How long and how wide of a blade are you running?
From the original questioner:
The blades are 13'9" long by 1 1/2 by 7/8" for softwood and 1" for hardwood. This is a new problem and I'll try increasing the set on one to see. Thanks.
