Fall is here and intense cold weather for many parts of the country is right around the corner. While this may not be a challenge for many industries, for those sawing lumber, cold weather means some tough days ahead. So now is the time to prepare if you want to make cutting frozen lumber much easier this year.
When cutting in frigid cold weather there are many things to consider: work attire, hydraulics, lubrication systems, fuel, blades, logs, etc. All of these factors will be much tougher when the bottom drops out of the thermometer. Now here you are preparing for old man winter.
First you need to see that your machinery will be ready; your engines running properly with lower viscosity oils for colder temperatures, the hydraulics full and functioning properly, and your cables should be in good shape not frayed with cable tensioners doing their jobs. The lubrications system should be set up and functioning properly with a lube that will not freeze, maybe diesel fuel or my favorite, a good windshield washer fluid with dish soap in it.
The blades you choose will make a big difference as well. You should choose a blade with a quality edge and the proper tooth spacing to clear the cut. For example, if you are working with 3½” boards you can choose a 1/2" tooth space but if you cut more of the 5½” boards you should go with the 3/4" tooth space and if you are over 6", try the 7/8"tooth. For cuts that are over 12", go with a 1" or 1 1/8" tooth space. As a general rule you want your blades to clear the cut well because winter conditions can be tough.
The gauge of your blades is important. A thicker or harder tipped blade will cut longer but be careful you don’t want to go too thick because the diameter of your band wheels will dictate how thick you can go. If you have band wheels that are 16" or under, you will need to stay with a .035" gauge blade. If you have 18" to 25" wheels, you can go with a .042 – .045 gauge blade. And if you have 30" or larger wheels, you can move up to a .050 – .055 gauge blade. Your type of band wheels are important as well. On steel wheels, if they have a crown see that the crown is within specs or your blade will not track well, and you should run a hardback or bi-metal blade. If you have belted wheels the belts should be in good shape and you can run a flex-blade or bi-metal band.
The width of your blade will be mostly dictated by the wheels you have, but most wheels can have a little play, most 1" wheels can also run a 1 ¼” blade and most 1 ¼” wheels can run a 1 ½” blade and so on. Be aware though a wider blade will stay more stable in the cut because it has more beam strength. Having too much of a blade off the wheel or too wide of a blade may not allow your guards back on the wheel shrouds without cutting into them.
The hook angle of the tooth face on your blade can be modified as well. A hook angle of 0 degrees would be perpendicular, or 90 degrees, from the body. If you have a lot of horsepower or smooth cutting wood, you can run a blade with 10 degree positive hook on the face; but if you have lower horsepower, really hard or frozen lumber cutting back on the hook will help the blade run more efficiently try going back to 7 degrees positive hook or as low as 4 degrees positive hook for the really hard stuff.
The profile of your tooth can be modified as well. Some manufacturers make a frost notch type of blade where the tip top of the tooth is cut out. This helps because of the way sawdust collects in the gullet of a tooth. In perfect conditions the gullet functions by forming a swirling pattern of chips that are cleanly expelled from the gullet upon exiting the cut. But when the lumber is frozen, the chips become dust and instead of exiting the cut they become lodged in the gullet. Or if it’s cold enough the dust slides right past the gullet and down the body of the blade, baking on the sides of the saw and increasing the thickness of the blade. This buildup reduces the effectiveness and function of the set on the teeth. The frost notch changes the vortex in the gullet of the blade making a smaller swirl that is ejected from the gullet upon exiting the cut before it gets lodged in the gullet or has much of a chance to bleed down the side of the blade.
When lumber freezes, it is also helpful to decrease the amount of set on a blade. This helps by giving the fine dust of a frozen cut less room to bleed down the side of the band.
Blade speed can be changed as well in harder cuts if you can slow the blade speed down.
Your tension is going to be very important in frozen lumber. The tension range for carbon blades is between 18,000 – 32,000 psi band tensile strength. In perfect conditions on straight grain logs on a nice day, you can run at 18,000 psi. But on tough days, sloped grains, frozen logs your tension will have to increase, or it will push your blade back. Since a band is a band not a string, it will cock one way or another in order to move backwards. Then it will follow that line in the cut till it gets tighter and tighter and finds that tension it is searching for. Then it corrects itself and dives back down the other way creating wavy cuts. If you are uncomfortable with the tension it takes to cut straight, always make sure you un-tension your band when you walk away for anytime at all. By letting the band and the mill cool down without tension, your wheels, bearings, and bands will last longer because they all cool down at different rates. As a rule assuming the blade is sharp and your feed not too fast the proper tension on any blade is, with the backup guides set at 1/16" away from back of blade. The amount of tension needed is the amount that it takes to keep that blade off of the guides while you’re performing the cut.
In these colder months your sawdust will go from chips in nice weather, to slush in semi-frozen logs, to dust in fully frozen logs so you have to manage that weather impact. Stay safe, try to stay warm and know if you need any help quality advice is only a phone call away. Bring on winter, we have work to do!
Editor’s Note: Country Saw & Knife supplies a full line of circular and band saw blades as well as sharpening services. Steve Mercer is an expert on cutting technology. He can be reached at sales@countrysaw.com or 800-253-7379.
Testimonial
“We’ve been fortunate to have lived close enough to Country Saw for years and pick up our blades from their facility, many times on short notice. We have never had a problem. Blades were waiting for me by the time I got there, and their expert advice in extreme cutting situations has made easy work of nasty situations.”
– Jerry Grace of Grace Services
Quick Tips for Better Winter Weather Performance
1.) Choose blades with a very sharp edge. My personal preference is a bi-metal blade. Look for one with less set. You can buy one with a frost notch from the manufacturer, or you can cut one in for yourself when you sharpen it. Make sure your tension is right for the density of the cut you are making. The tension ranges for carbon blades is between 18,000 – 32,000 psi band tensile strength.
2.) Inspect the equipment regularly. The machinery itself needs to be regularly inspected for signs of improper operation. Make sure your machine and wheels are functioning properly. Make sure your cables are in good condition, tight and free of ice. Give your engine and hydraulics time to warm up each day just like you do with a truck before running it on the road.
3.) Seek shelter. Having protection from the cold can significantly help mitigate the effects of harsh winter weather. Work under roof or inside when at all possible. Stage your logs properly. You may even want to pile sawdust on the next logs to thaw them a few days before cutting.
4.) Inspect other parts of the process. Make sure your de-barkers and lube systems are working properly.
5.) Listen for problems. Slow down your blade and feed rates. Listen to your engine. If it loses RPM and bogs down in the cut at any time, stop the feed till it comes back up to proper RPM’s.
