I have a friend who runs a 60" saw with, I believe, 57 teeth. He's had nothing but problems since he started. Doesn't de-bark and uses carbide. I told him the carbide is probably the better bet, but he should be running a 56" saw. I have found that the extra 2" means the whole world. I have found the 56" will cut truer, pull less, heat up less than the larger saw. What is your experience?
(Sawing and Drying Forum)
From Professor Gene Wengert, forum technical advisor:
I used to manage a mill that had both 60" and 54" saws. The tension for the two 60" saws was difficult to obtain... That is, the person that hammered our saws (a traveling saw doctor) never did a great job on one of these large saws. We did have one time when it was hammered correctly and worked well for a while. (Of course, any heat will quickly change its operating parameters, so avoiding heat, even a small amount of heat from the mandrel bearings, is critical.) We finally had it cut back to 54" and then we had it tensioned correctly and it worked like magic. So, the bottom line is that 60" saws work well if properly tensioned and if there is no heating, but the skills to tension these large saws seem to be in short supply.
Incidentally, 60" saws allow easy cutting of a 34" diameter log. That is why they were used in the first place. Of course, today, we do not need such a large saw. A 52" saw can only cut a 26" log! What many mills have done is cut the large saw down to a smaller saw, which is much more stable indeed. Then if large logs are sawn from time to time, a top saw (a second saw on top of the main saw and a few inches behind) is used.
The tooth width (and therefore the kerf) is wider with the larger saws. With 56" and smaller, we can use an inserted "F" style tooth which is 9/32" wide. I believe that we always will have an even number of teeth. A 56" saw will have 54 "F" teeth; a 54", 52.
Regarding carbide, the carbide is quite brittle, so with logs that still have the bark (and sand and debris in the bark), I think steel would be better. When you hit a small stone with carbide, that tooth is no longer very effective.