This Motorless Pull-Behind Mower is Made From Junk

Cutting a field of grass is a straightforward and satisfying process, given a suitably powered mover. A tractor with a rotary topper to hang on its three-point linkage and power-take-off will make short work of the task.

[Donn DIY] had an agricultural quad-bike, but when it came to mowing its lack of a power-take-off meant it wasn’t much use. When he saw a home-made mower for a quad-bike online he had to give it a go himself, and came up with his own take on a mower made from junk.

He started with the rear axle and differential from a Russian built Lada, which he reconditioned, before mounting in a wooden jig with its input shaft pointing upwards. He then made a frame for three mower shafts, onto which he mounted his custom-made rotors and their machined bearing housings. Some pulley machining, and he could then link the rotor shafts to the differential with a series of V-belts and a further shaft to step up the rotor speed.

He wasn’t finished there, after the rotors came a lever mechanism for lifting the cutters off the ground, and a pair of weight baskets to ensure traction was maintained. The result is a mover that takes its drive from its wheels, and cuts grass very effectively when towed behind the quad-bike. The unguarded blades would probably give a farm insurance assessor an apoplexy, but for the purposes of the video below the break at least we can see everything.

We’ve had quite a few mowers here at Hackaday over the years, almost too many to pick highlights. This unholy marriage of mower and hedge trimmer did catch our eye though.

19 thoughts on “This Motorless Pull-Behind Mower is Made From Junk

  1. I love a good scrap metal job. I may have missed something, but the belts look like they’ll be a pain to tension and replace and I really hope he tightens those blades up well.

    1. it looks adjustable at the center pully, looks like the whole assembly slides back and fourth to tension the 2 blade belts. the power input on the other side of that shaft looks like it has a tensioner pully. the connection between diff and the large pulley looks like its roller chain.

    2. If you look at a commercially made brush hog, the short blades are all left loose on purpose. Less chance of flinging anything solid the blades might hit.

    1. Actually he’s doing everything right there. You have to hold the file so your arm isn’t over the chuck (unless you want your sleeve or armpit hair ripped off). Worst thing that happens is if the end of the file somehow gets hit by the chuck, the file is just kicked back in your direction. However, what normally happens is the file just rides up on the chuck jaws.

      I’ve done it many times and was actually taught that method when I studied machining in high school.

      1. “what normally happens is the file just rides up on the chuck jaws”

        This is a probability based safety assessment. It seems that every one assess safety this way now and I assume that has been the influence of the insurance industry.

        Here is a scenario –
        There is a large ball bearing (ball) that has been sitting in the pocket of a cupboard for three months since it was lost. Today due to the vibration of the workshop activity and an unusually high breeze if decides to roll across the floor ending up under one foot.

        The lather operator falls to his left and instinctively releases the distant end of the file to free his hand to grab the lathe above the chuck rather have his hand end up *in* the chuck.

        Unlike all the other times – the file is in an unusual position and hits the jaw perpendicular and does *not* simply rise over the jaw.

        His right hand has also instinctively loosened its grip in preparation of falling.

        Now his left chest is aliened with the chuck and the file penetrates his heart like a speer and kills him instantly.

        Now, lots of people will say – what are the chances of that happening to which I will answer that the chances are very high as an eventuality if they have the attitude to safety that gets sloppier as time goes on.

        Safety assessments should always be weighted towards the more sever outcomes.

        A lathe has an extremely solid tool holder for a reason.

        If you used a lathe at school then you’re probably as old as me! We do things differently today as the high death rate for males in manual industries is no longer acceptable.

        Infortunately we also wrongly base safety assesment of the probability of outcomes rather than the severity of outcomes.

  2. He turned his own double-pulley! Great job making your own farm equipment. :)
    Please stay safe [Donn DIY], those blades…
    bah blah blah safety-I’m worried about when it hits a large rock.
    I assume a guard or something will eventually be added, even if it’s just wood.

  3. In addition to the ‘lift’ mechanism, it should also have a method to disengage the drive from the axle. A simple hitch pin that can be inserted to lock axle output flange to the pulleys together would suffice.

    But overall a creative build.

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