FILENAMES: GearDT1.jpg GearDT2.jpg GearDT3.jpg GearDT4.jpg GearDT5.jpg GearDT6.jpg DESCRIPTION: These are pictures of and instructions about a gear depthing tool built by Mike Fendley . Mike provided the following description: ----------------------------------------------------------------------- Gear Depthing Tool If you're a salvage yard machinist (I am), you get parts where ever you can. Sometimes you need gears for a small project: power hack saw, small winch, etc. You may pull them off some machine, small engine, cam & crank combo, etc. Yes you can calculate the center to center distance for where the gear shafts should theoretically be placed. However, if your gears are used and have some wear you will end up with a noisy gear box and sloppy gears. If the gears are new but weren't cut just perfectly, you may end up with too tight a fit. Hence the gear "depth-ing" tool. After appropriate bushings are made for the 2 gears you are meshing, the gears are placed on the gear depthing tool's parallel 1/4" shafts and the retainer collars put on. (The shafts are drill rod hardened with one end ground to a 60 degree point. The above bushings are machined to be a tight hand press fit to the gear hub and reamed .250 for the drill rod shafts.) Using the main adjustment knob on the underside of the left leg will adjust the span of the depthing tool to mesh the gears. The fine feed knob under strong spring pressure and 1/4 x 40 threads (on the right leg) then adjust the gears tightly to where they begin to bind. Slowly spinning the knob with your thumb while continuing to rotate the gears with your left hand will bring you to the point where the gears run smoothly and quietly with no binding. Go too far and they get sloppy and noisy. Going back and forth with the fine feed knob eventually brings you to the optimum distance. Once that distance is adjusted to, the depthing tool's protective plastic guards are taken off the hardened points and the tool is laid down on the piece that will take the gear shafts. (Do both pieces at the same time if you can.) A scribed line on this piece will show where the points are to be aligned. A light tap of the hammer will put two pips on the line at the proper gear depth. Indicate off the pips in the piece and bore your holes for bearings. One picture is included of the beginnings of a small 10" power hack saw transmission. (GearDT6.jpg) The outer brass gear revolves around the shaft it is placed on (it is not attached) and also will have a pulley attached to it with a belt from the motor. The gear depthing tool gets used a lot in my shop and was a simple project. If you're into gears - build one for yourself . . . you'll use it and love it. Chips and prayers, Mike (Other projects: See AtlasAsy.jpg and SteadyR(1-9).jpg & txt) GearDT1.jpg - Gear depthing tool with two helical gears off a small engine. Various gear hub bushings off to the side. GearDT2.jpg - Close up of the adjustments for the tool. Main span adjustment knob under the left wing. Fine adjustment knob on the right wing. GearDT3.jpg - Underside of tool showing one plastic cover removed to expose hardened 60 degree point. Span adjusting knob on the wing. GearDT4.jpg - Gears removed to show 1/4" parallel shafts for the gears. Shafts are adjustable up and down via a tiny set screw in the hubs of the wings. Note that one hub is taller than the other to make up the height difference since the two wings are just cold rolled steel overlapped at the pivot point. GearDT5.jpg - Shows the proper way to hold the gear depthing tool. The left hand would be spinning the gears (but in this case was pushing the button on the camera!) GearDT6.jpg - Shows the beginnings of a 10" power hack saw transmission. The smallest gear and the brass gear were made in my shop by a person just wanting to see what machining was like. (His first time ever machining.) I like to teach as well as build. The ball bearings are 1/2" bore junk yard specials. The strokes per minute of this saw will be about 150spm. However, the 1/4HP motor will have a variable speed pulley to enable the saw to go above or below this 150spm speed. The brass gear will revolve around it's shaft and not be attached to it. A pulley will be attached to the brass gear and then a belt to the motor. I'll post a picture of it when it's done.