MadInventor

Grapple Skidder scratch build

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My kids and I have been following this build!! We are in the middle of forestry country in SW Arkansas. We are covered with logging equipment around here. Awesome job!!

I would call you more of a "real" inventor than a mad one!

Could you pack the tires with foam to help with the compression??

Now you need to build a log loader to pull around on the back of a Globeliner or the such!

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My kids and I have been following this build!! We are in the middle of forestry country in SW Arkansas. We are covered with logging equipment around here. Awesome job!!

I would call you more of a "real" inventor than a mad one!

Could you pack the tires with foam to help with the compression??

Now you need to build a log loader to pull around on the back of a Globeliner or the such!

Thanks, I might be able to put some foam in the front tires, but I have a suspicion that they have been superglued on so that the wheels don't slip inside the tires.................

Bit more progress today, I've made the rear frame that the roller block fits in. I still need to make something to hold it in position though, as at the moment it's only held up by the friction in the mounting joints that attach it to the chassis. The frame is made from 12mm steel box section and 1.5mm steel plate. The steel cable looks nice, but it's nearly 3mm diameter and I've got no chance of winding it onto a winch drum. As others have suggested in another thread, I think I'm going to have to use braided fishing line for the winch rope.

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I've also made one wheel cover from 1.5mm steel plate, to help protect the wheel rims from damage.

img33435_08032015190219_4.jpg

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Its a real pleasure to watch your project come together.

It makes me think you might work for the likes of Roger Hunt building equipment for The John Deere equipment he sells.

My family are in Hampshire and Wiltshire, Next time I'm home id love to see your set up. i used to run a Full machine shop. CNC mills and Lathes. May have to go back to the job part time

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Its a real pleasure to watch your project come together.

It makes me think you might work for the likes of Roger Hunt building equipment for The John Deere equipment he sells.

My family are in Hampshire and Wiltshire, Next time I'm home id love to see your set up. i used to run a Full machine shop. CNC mills and Lathes. May have to go back to the job part time

Thanks Dave,

I work in software now, but many years ago I had a part time job in forestry. My workshop is very basic, just a tired old warco hobby mill, a couple of vices, and a rotary table. I also have access to a small warco lathe.

On with the build :)

I've been working on the winch for the last few weeks, I've made a winch drum and drive shaft, and one bracket for mounting the drum into the chassis. The winch drum is made in 3 parts, a central hollow drum made from aluminium, and 2 side plates made from 6mm thick steel. Massively over engineered and too heavy as usual, but it was the metal that I had to hand :).

The winch 'rope' is 0.38mm braided fishing line, with a quoted breaking strain of 100lb. No idea if this will be strong enough for what I want, but the seller I bought it from on Ebay also does 1mm diameter line which has 300lb breaking strain.

The mounting bracket is made from 15mm thick aluminium plate, I needed the thickness in order to get the mounting bolts where I wanted them, the bracket will be bolted to the main rear bulkhead and the floor, to stop the winch ripping itself out of the chassis.

The drive shaft the winch sits on is 8mm steel, and will run in 2 16x8x5 roller bearings. The drum is driven by pin through the main drive shaft, which sits in a recess in one of the steel side plates.

The plan on the winch is to have the gears on the opposite site of this bracket (where the steering isn't in the way), and have another 540 mounted behind the drum to drive the winch. I just ordered the motor, which comes with a 139:1 reduction box, and also the gears to give it a further 4:1 reduction, giving the winch a total reduction of 556:1, which should give it fairly good pulling power on 3S.

img33435_31032015194826_1.jpg

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I've got a bit further with the winch. As usual, it's taken me a lot longer than I thought it would. <_< When I tried the mounting block above in the machine for size, I didn't have the cab fitted as I was in the middle of fitting the wiring for the winch. Once the cab went back on, I found that the main drive gear fouled on the cab at full left steering lock, so I had to reposition the winch drum. This meant that the mounting block above was now useless. So, I plodded on with building another one. I've now got the new one done, and also the block for the other side, and am about half way through building the gearbox:

Nice new symmetrical right hand mounting block. This one will only be secured to the bottom of the hull, but I'm going to use M4 bolts for a bit of extra strength.

img33435_31032015194826_5.jpg

The left hand block has been recessed to give me room to fit a manually operated dog clutch, so that I can pull out the winch rope by hand. I didn't want to have to wind the rope out with the motor.

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The tight fit of everything is evident from the photos, I was only just able to get everything in

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The motor connections are very close to the hull side, I think I've got 1mm clearance. Still, fitting 1980's radio gear into hotshots has been good experience for cramming stuff into a small enclosure :)

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Just so impressed by the immense stature of this thing, everything looks bulletproof! If all else fails I bet you could plow this beast through forests at wide open throttle and it wouldn't bat an eyelid lol. Love it Martin! :D

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More progress:

Making the hex drive for the clutch from round bar:

img33435_26042015175045_2.jpg

Main drive shaft with hex fitted, main drive gear with dogs fitted, and the clutch mechanism machined from delrin. It was quite a challenge to machine the internal hex...

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Side plate to support the drive gears. A lot of hours went into this. There are roller bearings on the opposite side to support the gear shafts.

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Clutch engaged:

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and dis-engaged. It operates smoothly and easily, which is a relief, as I was concerned that it might drag and not slide smoothly. :)

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Overall view:

img33435_26042015175045_6.jpg

I've nearly finished this now, just waiting on some stronger winch rope to arrive and I can fit it in the model. The only thing left to do is either machine a plastic dust cover for the gears, or see if I can get one 3D printed. However it will work fine without it so I'm now going to press ahead with the wiring to get it working, and then I've just a couple of brackets to make to hold the rear winch arm in a solid position, and some strengthening brackets for the cab, and it's more or less finished. I'm going to try and get it finished before August this year, and then it will have taken less than 2 years to complete.

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Test run:

very pleased, apart from the wobbly rear wheel where I didn't have the wheel nut done up

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That is ridiculously powerful, fantastic! :)

And that's only 3S, the main motor is capable of handling 6S B)

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A couple of final pictures of the skidder. It's more or less done now, the only item left is to make a small bracket to mount the speed controller for the winch motor (a HobbyKing 1060ESC)

I managed to get a gear cover 3D printed, the clutch engage and disengage works well.

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Just a few more shots of the finished article.

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Steel gears were supplied for this build by HPC Gears (www.hpc.com)
540 motors with bolt on reduction units for the steering, blade movement, and winch power were supplied by MFA COMO Drills (www.mfacomodrills.com)

I'd also like to thank everyone who supplied me with materials and cutters for this build, you know who you are, thanks very much, and also major thanks are due to Mike for designing from scratch and building the custom steering controller module that transformed this from an unwieldy beast into a very tame and easy vehicle to drive.

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awesome build.. but.. where's the "grapple" part of the grapple skidder? This is (albeit awesome) a winch skidder :)

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9 hours ago, ChILd_ReBoRn said:

awesome build.. but.. where's the "grapple" part of the grapple skidder? This is (albeit awesome) a winch skidder :)

It was originally going to be a grapple skidder, then I found that the mechanisms I would need would be too complicated / weak for the available space, so went the winch instead

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12 hours ago, ChILd_ReBoRn said:

never dabbed in hydraulics? With enough funds.. one can make marvels..

Didn't have the funds ;)

 

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