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  • Model Woodsplitter

    As far as I am able to determine, no one has built a model wood splitter. A google search on wood splitters show two main types, either hydraulic (which are not suitable for a model, in my opinion), and electric screw type which might hold some promise. Then of course there is the cone shaped threaded splitter which bolts to a tractor wheel and screws itself into a block of wood, bursting it to split it, and the heavy revolving flywheel with an axe head mounted on it, which looks like a total suicide machine. I have seen one example of a steam driven wood splitter, which worked well, but I doubt that it would scale down very well.
    Model engines simply don't have much torque. One of the primary things that a model woodsplitter would need would be a huge torque multiplier, and with torque multiplication, things slow down dramatically.
    I have a couple of ideas floating around in my head, one involving a rack which is pushed forward incrementally by a sprag driven from an eccentric, and one which had a heavy flywheel with an eccentric on both sides driving "pusher arms".I want to split wooden logs 1 1/2" long, and prefer to split them in one full movement of the splitter, not incremental units.
    Brian Rupnow

  • #2
    Of course, the wood splitting action would have to be controlled by a hand lever mechanism, so it would only split "on demand", and then only one cycle. Nobody wants a finger chopped off while removing the split piece of wood and putting a new piece on the splitter.
    Brian Rupnow

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    • #3
      Have your sprague clutch turn a differential screw as a torque multiplier. Two sprague clutchs on the same shaft will use both strokes of a crank pin to turn the shaft which speeds things up. . To picture this, put two boxend ratchet wrenches on a hex dowel, put one in each and, then move both hands up and down at the same time as if they were attached to a push rod. If the crank pin that drives the spragues comes off the cam shaft then both will moved on the power stroke.

      Hey - I found the old drawing I made...

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      • #4
        http://www.youtube.com/embed/40sCGb678sQ

        Hope the link works. Just another method. I've seen variations on impact splitters.
        Look to be dangerous at best!

        Sid

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        • #5
          How about an inertia type, using flywheels, rack and pinion:

          https://www.youtube.com/watch?v=C4_Oze0-Cy4

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          • #6
            Both of the above two designs will be safe as long as you wear gloves!

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            • #7
              that DR model barely works. not enough oomph . i would be quite disappointed. the rotating wedge is scary as heck. almost as bad as a buzz saw.
              i would think an air over hydraulic pump driven with a steam engine would be a really involved project. but a master piece when finished. hydraulics don't need to leak

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              • #8
                I really like what Nicholas posted. I hadn't seen that type before. I have been setting designing in my head for two hours, and have decided that even though model engines don't have a lot of torque, they can spin a massive flywheel, and generate tremendous inertia. If one can then gear down the rpm of that big flywheel and use a dog clutch to engage/disengage an eccentric with pusher arms, that will work, and yes, it will use much the same principle as the one posted by Nicholas. DP---I also thought about what your sketch shows, and haven't ruled it out, only reversing things get a bit tricky.
                Brian Rupnow

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                • #9
                  Whats wrong with hydraulics for models?


                  I have a similar little unit to this, works surprisingly well. I have little doubt the model would snap like a twig somewhere before the hydraulics blew.

                  Also have one similar to this:


                  Both work just as you would expect them to!
                  Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.

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                  • #10
                    BlackMoons---I have already had a go at a mechanical gear pump. Although it did work, it developed very little pressure, nowheres near enough to drive a hydraulic splitter.
                    Brian Rupnow

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                    • #11
                      You make some neat stuff! It would be cool to see a mini hydraulic one!
                      Feel free to put me on ignore....

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                      • #12
                        Brian, what scale are we talking about? An inch and a half length of wood 3/4 inch diameter will split with a sharp edge quite easily with the grain.


                        I just cut an inch and a half off a dowel 7/8 in diameter, tried a 1/2 inch double bevel chisel with the tip of the cutting edge on center to keep the proportions in line. Well, with just my strength behind the chisel I couldn't split it. I think if I imposed a bathroom scale into the action, I'd probably break it. So my perception of quite easily was biased by the use of my trusty mallet, I fear. Yup, you're going to need inertia to help.
                        Last edited by Gary Paine; 01-29-2015, 03:35 PM. Reason: I tried it

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                        • #13
                          Yes Gary, that's the size I'm talking about.
                          Brian Rupnow

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                          • #14
                            I have used a Super Split which the DR one is a copy of. It was the best splitter ever. With just a 5 horse motor it would split anything we stuck in it. Even 18" diameter logs. For the big ones, you just do one side and start working around like a pie if it doesn't split in half the first time. If I still had a need for a splitter I would get one of those in a flash. The flywheels are doing all the work and it's way faster than a hydraulic one.
                            Kansas City area

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                            • #15
                              Adding to the above post, I have an old model of the Super Split, from some time in the 1980's, which I still use, having had it for many years. It has a 3/4 horse (yes, that's not a misprint) 120 volt electric motor. It is nearly silent, wickedly fast, the mechanism is dead simple, and it will split nearly anything you can lift onto it in one stroke, and absolutely anything in multiple strokes, even across the grain. I don't know about the DR, but the Super Split is still made, I think.

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