This is a first for me. I have a Lucas 825 and suddenly the blade is diving, but only when I take a full cut. 2x4 cuts are not a problem, it's only when I cut 6 or 8 inch that the blade dives, and sometimes it moves up. It's very frustrating. I have checked for loose bolts, alignment, etc. Any ideas?
I had a flat decked log, and by moving the power head back and forth, I was still getting sawdust off the flat of the log. I thought that it would have cut once and then not cut on the second or third pass. If the saw is in one place too long, it will leave the circular cut in that one spot. Go figure.
(Sawing and Drying Forum)
From contributor P:
Without knowing more, I am suspicious of your blade's tension. Have you swapped blades to try to solve it? I have six blades for my Peterson 10" and one of them is contrary right now. It needs some special attention.
If the log is not sagging due to its own weight, you may want to make a thin adjustment cut. Band mill operators would flip the log and take a cut off of the other side to relieve stress.
Finally, I never take a full bite with the horizontal cut. When I do, the mill often tries to move side-to-side. You may want to try cutting half of the horizontal cut on the first pass. Pull the blade out of the cut, return to the starting point, and cut the remainder of the horizontal cut. I hope I understood your question.
Let me throw one more at you: In the past, I have had a log set on scrap, wedges or what have you, which was on a thick layer of saw chips - on a spongy layer. As I cut off the weight of the log, the log was actually rising up. The "ground" was springing up, as the weight was reduced, lifting the log. Since you are probably set up on some fine bunks, this is not a probable cause, but I did have it happen. (Now I try to act like I know better.)
Now, however, I am curious. You have the full gamut of possibilities. What turned out to be the real issue ? Inquiring minds want to know!
I will know more when I get back to the saw on Tuesday. I adjusted it a bit and it still dipped, but not as bad. My next adjustment is the front slide block and the roller. Thanks for all the input. One of the logs was way tensioned, so I tossed it off to the side until I get this adjusted correctly.
Do you have any of the heads of the bolts that hold the saw blade to the hub? Do any of those heads protrude just a smidge? I replaced those bolts and I have two of them that are protruding a smidge. They are not flush. I cleaned and inspected the bolt holes and surfaces.
My thinking is to buy a new blade and save it as an inspection/standard to insure that the blades aren't out of tension or whack. My 5 blades have been re-tipped say 12 or so times.
I'm cutting Monterey pine. I tried an experiment - air dry the logs and see how much lumber I get after a couple years. Interesting that on some logs, which have been down for 3 years, I get about 75% of the good wood out of them, and some logs are less than fire-feeder. I have determined that with proper air flow around the log, without the bark on them, the 2-3 year old trees are still of some value. If they have bark and are closer than 6 inches to the soil, then the tree is junk.
Comment from contributor J:
The biggest problems I have run into with climbing or diving blades is how sharp the blade is. For some woods like oak or ash, you need to touch them up after a couple of logs, especially if they are knotty. I know it sounds excessive, but believe me it works. I was first told of this by a friend of mine. I refused to believe it at first as well, until the mill would bind so much after a couple 16' oak that I couldn't even push it forward and it actually jumped off the rails. After a couple of minutes of touchup, she was cutting clean and straight again.
For all you guys looking for a saw doctor, we quit sending them off at $40 a pop and now we re-tip our own. A soldering kit to do this doesn't cost a whole lot, and tips are only a couple of bucks. Just make sure you get the right solder or the blade tips will instantly come off. Now we only need two blades to keep sawing all the time instead of the four we used to have on rotation to and from a saw doctor.