ON THE CUTTING EDGE

EVERYONE DOING THEIR PART

By John Hebert

  In the year 1814 (189 years ago), the first circular saw in the US was patented by a blacksmith in New York. The trade of sawfiling was at the grassroots stages; hammering a saw and getting it to cut straight was considered to be somewhat of black magic. Much has changed since then, the doors to the filing room have opened up and knowledge is now being shared between filers.

   Technology has come a long way; with improved manufacturing of saws, premium saw steel available, benching practices, machine centers and saw sharpeners. Industry wide we are now able to run with much thinner saw plate, faster feed speeds, higher rpms, and at the end of the day produce more quality lumber, and hopefully make a profit. With the many changes in technology to our trade, filers have been able to reduce the plate thickness and kerf of the saw. We have been able to produce much straighter lumber, therefore reducing target thickness of the rough lumber we produce in the mill, which in turn increases lumber recovery, producing lumber instead of sawdust, shavings or chips.

   Quality of product starts in the forest with logging practices. Occasionally we can see damage on the logs due to aggressive spikes from log processors. The biggest bone of contention for a filer is the mud and rocks caked on, or embedded in the logs; we all know what that does to sharp saws. Unfortunately, there is not much we can do about it, other than to suggest the processors use chained tires as opposed to spike rolls, and hope the logging truck drivers keep their mud flaps in good repair and the loader operators don’t store or lay the logs in mud. The debarkers at the mill remove most of it, but quite often cannot clean off the end of the logs without trimming the ends of every log. I personally prefer winter sawing best, when the logs are frozen with the temperature around minus 5. When the ground is frozen, the logs pick up very little sand and mud from the roads and log yards.

   The byproducts from sawmilling; shavings, sawdust, and bark also have an important role in manufacturing. A representative from a pulp mill ask if we could “increase our tooth bite of the saws to give them a larger piece of sawdust”.

I put the question to the plant manager; “Which is preferable, high quality sawdust or high quality lumber?” The answer is obvious; we are in the business

of making quality lumber. Sawfilers strive to design saws to cut the most efficient, based on the rpm, feed speed, tooth design, species etc. Whatever falls out the bottom of the machine, Sawfilers are not overly concerned about (the less sawdust the better).  There is an increasing interest in shavings for animal bedding, packaging material etc.; even the bark or hog has a value. As long as it is not too large, it can be used for landscaping, burnt to heat dry kilns or fire co-generation plants.

  By cutting straighter lumber this allows the planers to do a much better job and are able to have a higher-grade output due to less skip. A Head Planerman once told me, “I think we have reached the limit on our minimum rough lumber thickness. Sometimes a change in the weather can dictate how much skip I see on the boards because the weather is hot.”  Not only does weather have an adverse effect, the kiln operators also need to keep an eye on the drying process when kiln or air-drying. Before making any target reductions, much thought, research and feedback from everyone involved must take place.

  Typically the first area looked at is the filing room; but when the thickness of the lumber gets to this critical point everybody at the plant must focus to do the best job possible in his or her particular area.

   The saw is only as good as the machine it is put into and vice-versa. If maintenance on either the machine center or saws are poor, the lumber will also be poor. If the product that is being fed into a machine is improperly fed or off square, wedging or mis-match on a gang edger is almost a certainty. If the mill doesn’t give the planer a good product to run, they struggle with their set up to minimize the amount of skip due to mis-manufactured lumber or over drying.

   When we look at the sawmill and planer from a “distance”, you don’t see all the small details. That is why it is so important for everyone at the plant to do their job to the best of their ability. But as we take a closer look with a trained eye, it becomes obvious that it only takes a couple of things to go wrong to have a big impact on the lumber and grade recovery at the end of the day.

  If you have any comments, ideas or questions that may be of interest regarding the sawfiling trade that we can use in this column, please send me an e-mail;

jehebert@telus.net