By Tim Ard
Ah, those little guys on the front of the saw chain tooth. With only a little swipe of the file, I can make this chain saw really cut!
Some call them Rakers, some call them Drags, others, like I do, refer to them as Depth Gauges. Whatever you technically want to call them. Some people abuse them, some confuse them, and some just dont realize how they work and what they do for you.
I often hear, "they are to be left alone". "Dont mess with them." Others say to, "take them down first thing on a new chain." Most common exchange of thought is, "you really dont have to do anything with them. They will wear down as you use the chain."
In answer, first I would recommend if you dont understand them leave them alone but, take them and the rest of the chain, to a professional shop for sharpening and depth gauge settings.
You have to adjust them. Look at the chain tooth. The top plate area, as you file it back, goes downward toward the end of the top plate. As you file the cutting surface of the tooth back, the depth gauge will grow. Maybe not grow, but stick up past the tooth point. The results, you will either have to set them properly or you will have to apply so much pressure to the saw to get it to cut, it will be dangerous for the saw, saw chain, guide bar and You.
Taking the depth gauges down on a new chain or at any point of the chain life, below manufacturers specs is not a good idea. Check the specifications on your saw chain and make sure you use proper tools to maintain the settings as close as possible. With hand tools its hard to keep everything perfect, but dropping them too much below design can mean a lot of grabbing, chatter and possibly loss of control.
Well, finally the last statement is somewhat true. They will possibly wear down a little on their own in abrasive conditions. Nevertheless, under normal cutting of wood, not rocks, etc., the hardened surface of the depth gauge is not likely to wear very much. At least not wear to the tune of an exact thousands of an inch.
Proper Depth Gauge checks and adjustments during the filing/sharpening process are as important as having two-cycle oil in your fuel mix. You can cause a lot of damage taking them for granted.