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Re: wavy cuts - baker scragg-mill

From: Irwin Post
Date: 3/19/99
Time: 4:55:33 AM
Remote Name:


With respect to wavy cuts using 1 1/4" blades in a Baker scragg saw:

In my experience, wavy cuts are usually caused by one of the following: 1. Defective blades (varying set, poor alignment at welds, twisted, etc.) Wood-Mizer blades are generally good in this respect, though it is possible they've been damaged in shipping.

2. Too high a feed speed. I don't have experience with Radiate Pine, but in working with Eastern White Pine in Vermont, USA (the local wood closest to Radiata in hardness & other properties) I've found that cut quality generally deteriorates at feed speeds that give over 60% to 70% gullet fill. See my article in the Dec/Jan 1999 issue of "Independent Sawmill & Woodlot Management" (Vol 2 issue 2) for a discussion of gullet fill, feed rates, cutting accuracy, etc.

3. Teeth too dull. Sawing deviation tends to increase as the teeth dull. Also, damaged teeth (from shipping and/or handling -- I've even seen teeth broken off!) and burrs on the teeth can cause sawing deviation. I examine teeth with a 30x microscope for sharpness.

4. Not enough set. Most of the Wood-Mizer blades have sets in the range of 0.020" per side. I've found that the amount of set needed for best performance in Eastern White Pine varies with temperature. At higher temperatures (over 25C), I've found that sets of .025" to .030" give better performance.

5. Problems with inner bark. (Assuming you are not debarking the logs.) Again, with Eastern White Pine, I've experienced problems with the inner bark not cutting cleanly. The fibers tend to "mush" and push the blade to the side and to get dragged over the gullet. This seems to be a function of temperature and growth stage of the tree, being particularly troublesome in the early Spring. I've read of a possible solution used by Laurance Kiesman ("Independent Sawmill & Woodlot Management" Feb/Mar 1999, vol 2, issue 3, talked about in a portable sawmill review article beginning on p. 10). Larry uses a high pressure air/water "blast" to remove the buildup in the gullets.

I hope this helps; please let me know your solution.