best bandsaw for metal
You just cut along straight lines making it necessary to have a board which has one square side and an edge. Unfortunately majority of woodworkers dont seem to be aware of how to go ahead with it. Successful resawing necessarily demands a suitable blade selection sufficient tension right operational level and the right stock control. Selection of Blade: When you saw a thick stock the blade is subjected to much of pressure with each of its teeth shaving and throwing out waste. Using a blade with three teeth to an inch (TPI) has large gullets to facilitate plenty of waste. The blade is supported on its top and bottom on thrust bearings. During the real process of cutting its only the stiffness or the "beam strength" of blade that keeps the cut going straight and prevents its drift.
The reason there is not a side load is the angle of the side of the tooth. The tooth is bent or set at such a sharp angle on the side that only the top corner of about.010 touches the wood fiber. Of course if you run your band excessively dull it does take on more side load. Now compare the gullet stretch per tooth. Remember both band bodies are .042. The set tooth has the total kerf stress divided between 3 teeth. The swaged full tooth carries the entire kerf stress per tooth plus the side load on 2 sides per tooth. It is easy to understand that the full tooth carries twice the load just because of the top width of .084. Then add the 2 sides of load and we have at least 3 times more tooth load per square inch than the set tooth bands have. What does this mean? From my experience the set tooth pound for pound will perform 2 to 3 times better than a full tooth of the same band width and thickness. This is true even if a special steel is welded to from the full tooth. Let me talk about the body of the band for a bit here. I have spoken of the distortion and how it changes the middle portion of the band to dish on the log side.
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If a sawyer runs the band too hard or too dull he will distort the front. Then when he sends it out for repair the sawfiler has no choice but to distort the middle and the back to make the blade equal everywhere. He can make the blade saw and appear as if it is restored it to original but it is not. Of course the tooth sharpness can be restored but I am speaking of the body distortion. Now after 3 or 4 runs the band has been distorted by the sawyer and then distorted by the sawfiler and the molecules pulled apart (cracks in the gullets) and the sawyer or owner asks what is the sawfiler doing wrong. It is not the sawfilers fault. It is a matter of stressing the blade more than it can stand. If you want this cracking to stop then you have to lower tension which in turn makes you slow down and pull the band for sharpening more often. Or leave the tension the same and just sharpen much more often. All in all keep the tooth load lower.
It is only when the prescribed amount is exceeded that it becomes distorted and loses strength. Think of valve springs in a gas/diesel engine. They operate within their ability to extend compress and return every time and run almost forever under harsh conditions. They do not exceed their steels ability to stretch and return. A good understanding of the above two paragraphs is very important to understand an accurate comparison between the swage tooth band and the set tooth that we will discuss below. Now let us look at a set tooth band of .042 thickness: The Kerf of a set tooth band is also two times the thickness. Usually .084 (sometimes more sometimes less). The difference is the set tooth shares the tooth load between 3 teeth. Each tooth is only .042 on the top or the leading edge. The most any tooth can cut is.042 wide. The average that the 3 teeth cut is only .028. The right and left tooth only cut the set amount beyond the body width. Only 2 of the teeth cut on the side and they only have 1 side to create side load which is very minimum. It is so small that I do not consider it to have a side load.