Hi all! I have a problem about the gears used in a winder as hown in the picture. You can see right in the front view of the picture, there is a counter, which is a pair of worm gear. The engineering drawing of this pair of draw is as shown in another picture. My question is, in the prespective of the mechanism of the winder, it seems that the winder will still work if only one worm gear with great thickness instead of a pair of worm gears is used. So what is the reasons for using a pair of worm gears instead of one only? Second, the pair of worm gears are of different number of teeths (one with 100 teeth, and one with 102 teeth). What is the reason for this? And it seems to me that when the pair of worm gears are glued togather. And when the pinion rotate, there may be a mismatch of gears' teeth...(one with 102 teeth, one with 100 teeth) Could you address me the problem? Thridly, the pair of gears are designed a bit different from ordinary spur gear, right? There is some inclination of the gears so that when they are glued togather, the entire gear looks like a "turbine" as showed in the last figure. What is the reason for this? Sorry that I am really an idiot in the stuff. Thanks for your nice help!