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  • Tom--Since this is only a "for fun" project I will probably keep one primary drive for both the saws and the feed rolls. What you are saying certainly makes a lot of sense, but making the drive for the rollers separate and adjustable adds a level of complexity I don't really want to deal with. Those boards I edged in the video were just 1/8" strips sawed off the side of a spruce 2 x 4. I have found a speed for both the saws and the rollers that seems to work very well, and I doubt that I will switch out to a different wood. All I have to do now is design and build a dual output gearbox that satisfies both saws and rollers and cuts down dramatically on friction points. I would still like to drive this thing with one of my gas engines.---Brian
    Brian Rupnow

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    • So what does a design engineer do if he's bored?--Well of course--He designs something. In this particular case, a custom designed reducer to work with the edger. This will do three things, which may all be good. With full ball bearings on every shaft, this will cut way down on friction, and use up all the weird ball bearings that have been collecting in my tin of goodies. It also may give a far greater chance of the edger being powered by one of my gas engines, and it will keep me from totally forgetting how to cut gears with my mill and rotary table. It will also get rid of the towers and overhead shafts on the edger. I had accumulated six "bastard" ball bearings, some of which are metric and some of which are imperial, but they are all good bearings.--More will follow, tomorrow.
      Brian Rupnow

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      • I dug around in my "someday I might use that" box, and Voila!! Not only did I find all of the orphaned bearings that I will use on my new gear reducer, but I also found a set of timing pulleys and a timing belt, which were rescued from a dead appliance?? One shaft from my reducer is going to extend from the reducer and sprocket side to the opposite side of the edger, where they will drive the sawblades.
        Brian Rupnow

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        • Okay---Version two!! This is a much cleaner version. The overhead towers and shafts and pulleys are gone. All of the gearing to get from 1000 rpm to 60 rpm is done by the gears inside the reducer I will build. This will dramatically cut down friction and noise. One of the gears which is running in the opposite direction in the reducer has it's shaft extended through to the far side of the edger, where a timing belt drives from the extended shaft to the saws.

          Brian Rupnow

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          • Originally posted by brian Rupnow View Post
            Okay---Version two!! This is a much cleaner version. The overhead towers and shafts and pulleys are gone. All of the gearing to get from 1000 rpm to 60 rpm is done by the gears inside the reducer I will build. This will dramatically cut down friction and noise. One of the gears which is running in the opposite direction in the reducer has it's shaft extended through to the far side of the edger, where a timing belt drives from the extended shaft to the saws.

            The highest level of reform is simplicity! I like it.

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            • There are a couple of 14 tooth gears in the new gear reducer I an building, and it is actually simpler if I make the gear and the shaft that supports it all from one piece. This picture shows the first blank, ready to have teeth cut in it. I used the auto feed running in reverse on the turned down area closest to the chuck. It worked fine, but felt very weird watching the cutting tool and carriage moving from left to right.
              Brian Rupnow

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              • So---It's been a long and uneventful day, but I have two shafts turned to size and ready to have gear teeth cut into them tomorrow. Turning shafts to fit bearings is not one of the machine shop jobs that I really like. I have ruined so many pieces of shafting by trying to get that last thou off the diameter and then ending up undersize. Steel is funny stuff. Unless the lathe tool is razor sharp, it won't cut that last thou--it just burnishes the shaft. Then when you turn it in one more thou, it digs in and takes off more than you wanted it to. I generally take shafts down to about 0.002" oversize, and then work the final bit off with carborundum paper strips until it is a "perfect" fit. Sounds good if you say it real fast, but my thumbs are sore tonight from holding sanding strips.
                Brian Rupnow

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                • I've had a very gearish morning. We have one set-up shot and a shot of the three finished gears. No real excitement, I have the entire procedure written down in my "Gears" notebook. I don't do this very often, so it's nice to have something written that I can look over before I start machining. There is one more gear, made from brass, but it's a big one, over 4 1/2" diameter. I called my metal supplier to ask how much it would be, and he said "If you have to ask, you can't afford it!!"I have a good size piece of 1/4" brass plate that some kind soul gave me a few years ago, so I am going to laminate two pieces together and cut my gear from that. Now I have to go shovel the front step and go for my fat mans walk.

                  Brian Rupnow

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                  • Whenever I cut a pair of gears, I always drill and ream two holes the exact calculated distance apart in a piece of scrap material and insert the gears and shafts, then turn them by hand to test how they mesh. Most times it works alright, but I have been fooled in the past. I can generally live with a bit of extra "lash" in the mating gears, but when they are a bit oversize, it gets ugly pretty fast. If they are a bit oversize, you can either set them back up in the lathe and recut them, which is a pain in the $#@%, or you can change the design of the housing a bit to accommodate them. Also, you can see my two pieces of 1/4" brass plate, rough cut to 4 3/4" and joined with J.B.Weld, then clamped. I will also bolt them together after they set up for 24 hours.

                    Brian Rupnow

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                    • So here we are, ready to cut the 108 tooth gear. The two pieces of 1/4" brass plate were "glued" together with J.B. Weld, clamped and left overnight under a heat lamp. The outer circle of bolts hold the two plates together permanently--I don't trust any adhesive in an application like this. The inner circle of bolts pass through the plates and are threaded into a 1.5" diameter steel stub-shaft that is held in the jaws of the chuck on my rotary table. Before the stub-shaft was bolted in place, the brass plates were set up in my lathe 4 jaw chuck to drill and ream the 1/2" center hole. The stub shaft was also drilled and reamed for a 1/2" shaft, and you can see the end of it sticking out past the face of the brass plates. The big deal here is to achieve absolute concentricity before I start to cut the gear teeth. A dowel with a pointed end was first secured in the chuck, and then the center of the cutter was adjusted to be perfectly horizontally in line with the point on the dowel. Then the table was fed towards the column in the Y axis until the major diameter of the brass just touched the major diameter of the cutter. Then with the table cranked back out of the way in the X axis, the table was advanced 0.089" in the Y axis. This is the depth of cuts to be made. The table stops were set so that the cutter just cleared the brass part in each direction on the x axis. I am now ready to start taking full depth cuts every 3.333 degrees. This rotational distance is set by using the divider plates on the front of my rotary table.
                      Brian Rupnow

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                      • So, here we are with the completed gear-train for my new gear reducer. I cut the 108 tooth gear this morning, and after finishing it I set all of the gears up in the correct relationship to each other, and took it for a test drive on my milling machine.
                        https://www.youtube.com/watch?v=AX3ZXzG1Wck
                        Brian Rupnow

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                        • The two main outer plates of the reducer have the exact same outer profile. Of course they have different cavities machined in the in facing side because of the mish mash of bearings I used. The easiest way for me to do this is to extend the small diameter of the blind bores completely through the plates. That way I can pick up on the bores when I flip the plates over to mill the cavities. There will be no pressure in the reducer, just lots of gear grease, so if I do extend the bores all the way thru each plate, I can glue in plugs after the fact. This makes my job a lot easier, and takes nothing away from the functionality.
                          Last edited by brian Rupnow; 12-07-2019, 07:06 PM.
                          Brian Rupnow

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