Here are a few trouble-shooting suggestions for our sawyer Jack Pine.

We all know in the business that Jack is a proud individual and usually is the person in the mill which knows the most about the art of making a circular head saw run trouble free. Another important person in the picture is the individual which hammers the head saw for the hand and revolution per minute at which it runs on the mill. Having over 30 years of experience behind me on maintenance of circular head saw and adjusting them on the mill, I think that Jack would be pleased that I share with him some of the tricks of the trade I learned over the years.

The first trick of the trade is when everything works we, don’t try to fix it.

When everything goes well the teeth on your saw are sharp, especially on the corners of the tooth. The shanks are in good condition and centered with the tooth. The mandrel, the collars, and the bearings are in good condition. The lead is OK. The guides are adjusted properly. The splitter is where it is supposed to be. The track is straight and level. The carriage wheels have no play on the V side of the track and of course the saw is hammered properly for the RPM and hand it runs on the mill.

Now, if you have problems, one or several of these things are not right.

On of the most common problems I’ve seen over the years is the teeth corners rounding up on the carriage side of the saw. At the beginning, it is barely visible when this happens, the saw will run out of the cut and the teeth will rub on the log more and more the saw will run out to the point where the log will rub on the center of the saw blade which causes it to warm up on the center. In no time you have to stop sawing. It is possible at that point that the saw needs to be rehammered, especially if you notice that the saw has one or several blue spots. So it is very important to keep the teeth of your saw very sharp especially at the corners.

A worn shank will not clear the saw dust properly in the cut and will cause problems especially in the winter. Keep the shanks centered with the tooth.

Here is a procedure to check if the collars on the mandrel bend the saw in or out. Clean the collars with a sand paper. Install a straight saw blade with a clean center on the mandrel. Install the outside collar and the big nut. Tighten the nut slightly by hand. Put a chalk mark on a tooth on the saw. Adjust the guides on both sides at 1/16 from the blade at that marked tooth. Then take the big wrench and tighten the big nut as you normally would do. When this is done take the marked tooth and move it back to the same position it was when you adjusted the guides and see what happened. If the collars are in good shape the guides should be on both sides at that 1/16 you had adjusted them to.

If the blade has moved toward one side or the other, your collars bent the blade. That means problems. A blade bent on the mandrel will run toward the cup side it is bent. The solution then is to take the mandrel out with the collars and have them remachined by a qualified machinist. Many collars get damaged by running the saw with no dowel pin. In that case the damage is on the mandrel side collar. Keep pins installed. It is very important.

The bearings on the mandrel should be check regularly. If the bearing which is the closest to the saw heat up, the heat will run along the safe and go in the collar and then to the saw. This will affect the tension in the saw and in no time the saw will go out of control. If you notice that the saw is hot in the center, check if the heat is coming from the bearing or if it is the log which rubs against the blade.

About the lead? That’s a tricky question. There is no sawmill which runs with exactly the same lead. In theory, you should have around 1/16 lead on a 48" saw, but in practice this can change to 1/32 or 1/8 according to how the saw sits on the mandrel. If the collars bend the blade toward the carriage the saw will need less lead. If it is the opposite way you may need more lead to compensate.

One way to adjust the lead on a saw without an elaborated string system, is to make a cant on a 6" long, 10 to 16 feet long. Then lay that cant flat on the carriage and with a sharp saw, cut slowly in the center of the cant until you reach the center of the log. Then shut the mill down with you saw right in the middle of the log. You should then be able to see how much lead you have on the part of the saw which is close to the splitter. If your saw has too much lead you should see more than 1/8 space between the saw tooth and the cant on the carriage side. If the saw has not enough lead, the saw tooth on that same place probably is in contact with the cant on the carriage side. When adjusting the lead, always do it on the bearing which is the furthest away from the saw. That bearing is usually around 4 feet from the blade and it needs very little movement one way or the other to change the lead. When adjusting the lead that way, always make sure you do this with a straight saw and a new set of teeth. Also us a straight log. A bent log may have some timber bind in it.

When a saw runs out of the cut in pitches saw dust in the air at the splitter. When the saw runs into the cut it will, just as it finishes the cut, bounce away from the log on the carriage. The guides on the sawmill are very important. They should be made out of lignum vitae or fibrous material, but not with any metal, including brass. The guides should be as high as possible. Every inch you move the guides up under the cut you will gain an easy 10/100 capacity of sawing. The guides should be kept as close as possible without being in contact with the blade when it runs at full speed.

Remember this, the splitter has only one function. That is to open the cut so as the saw blade does not come in contact with the slab. The splitter should be adjusted after the lead is correct. The inside of the saw teeth on your saw (no more). If the splitter is too far inside toward the carriage it will push against the cant and wear a curve in the track. If you want trouble let this happen.

As we said at the beginning, the tack should be straight and level and no play in the carriage wheels on the V side of the track. It is no use to do any adjustment before you’re sure the track and carriage are OK.

An average saw blade has a diameter of 44" to 48" to 40 teeth. Smaller is the saw, the easier it is to control. If you need a saw bigger than 48", you would be better off to install a top saw. The average RPM of the head saw is betwwen 600 and 1000 PRM. To know if your saw is a right hand or a left hand, place yourself (facing the track), between the saw and the log deck. If the log deck where you load the carriage is on your right, it is a right hand saw (RH). If the log deck is on the left hand side, it is a left hand (LH).

In conclusion Jack, there is no mystery in running a sawmill head saw, only a few common sense things to take care of. Hope this will be of help to you and if you any questions, just call us the (807) 623-3171. It is always a pleasure to help our customers.

Your Saw Doctor,                      

Andre Ludwig