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1:10 scale farm machinery scratchbuilds 6 years 7 months ago #45231

:woohoo: sorry un truc de dingue!!!
You made tractor wheeles. I love them. Congrates Jonny.
Like always :p

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1:10 scale farm machinery scratchbuilds 6 years 7 months ago #45252

Rear axle bears a lof of similarities to the front of the Fiat tractor - again starting with an F103 front upright set. Wheels get a simple 30mm OD, 14mm ID cover plate ... tyres need a bit more work :whistle:

Obviously there's a huge difference in height between the front & reat axles - I did look at my untouched pile of aluminium L- section (15 800mm lengths :whistle:) before deciding that putting the necessary S-bends in them was well beyond my skills & equipment, so 3mm styrene sides braces with something thinner top & bottom look to be on the cards. I'm determined to use that aluminium on something though ...

:)






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1:10 scale farm machinery scratchbuilds 6 years 7 months ago #45328

I'm not going to build a full card mockup of this, but I did do a 2D version of one side to help me work out the chassis rails ... DT02 Grasshopper is there for scale - size isn't too intimidating at the moment ...




Chassis rails are 3mm thick strips, just on the outside (with internal supports) on the flats, angled bits are four layers. Clod gearbox is only held on at two points at the moment (M4 screw through a spacer where the steering shaft/saver should be, plus M3 screws either end of a long spacer attached to the braket that usually breaks). I did try taking extra support from the steering knuckle to the chassis rails, but it added no stiffness/support - and the wheels flopped around all over the place :S






I still think the hardest bit will be the drive in the cutting head, so plan to do that next... I spent some time measuring up the cutting head on the 1:32 model & ordering the basics for the drive (M8 studding {allthread}, nuts, washers, skate bearings, plug a couple of pulleys & a toothed belt), the only bit I could do while waiting for all that to arrive was the 5th wheel. For that I used the usual method - a bunch of squares of various thicknesses, turned down in two stacks to the ID of a Scorcher front tyre (39mm) and the ID of the seat part (33mm), re-stacked to make a wheel. It's a pig to get the tyre on so I'm quite sure of my measurements & machining - but the tyre will spin on the wheel if provoked, so will need gluing ...

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1:10 scale farm machinery scratchbuilds 6 years 7 months ago #45335

If you can't fix it with a hammer, you've got an electrical problem mate :)
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1:10 scale farm machinery scratchbuilds 6 years 7 months ago #45438

Very little progress on this ... made some bearing holders (complete with preemptive helicoil inserts), but still waiting on toothed belt & pulleys after the first shower I ordered them sat on my order for the best part of a week, only to admit when pushed that they hadn't had them for some time (despite showing as in stock). Saying they should be able to send them in a "couple of days" seemed a bit unlikely, having seen "in stock" change to a lead time of 3-4 weeks on their website :whistle:

2nd lot do at least appear to have sent me something, though they're not what I wanted ... there was only one permutation of pulleys and adequately wide endless belt that would cover the required gap, so it was either that or make my own aluminium V-pulleys & use a suitably long o-ring as a belt - though that didn't work on my Sand Rover, and I don't suppose it would work any better here. Shouldn't whinge too much though - overall price was 40% of the previous (now refunded) bill :)

I really don't know why it has to be so difficult ... throw in lots of different (and completely incompatible) small toothed belt standards, suppliers that initially appear to have a near infinite range of belts but only one size of (incompatible) pulleys, or vice versa, or are non-specific about which standard their pulleys are, me being committed to 8mm shafts, a distance between centres constrained by this being a scale model, _and_ needing an endless loop belt (rather than sold by the metre, cut your own length intended to be closed only by a big metal clamp on a print head) & it becomes a massive time suck trying to get anything at all :S

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1:10 scale farm machinery scratchbuilds 6 years 7 months ago #45514

After losing my bearings - quite literally, I'm always losing things in plain sight & had to order some more, then found the original bag :whistle: I started on the cutting head ... probably a bit elaborate for a proof of concept, but I was reasonably confident & cutting all the teeth & the silhouette ends seemed a reasonable bet.

Obviously a huge amount of work to do in boxing out the left side end fence & detailing the other side, plus the reel & auger, but I'm happy so far - although it has to be said that clearance is such that the only "crop" this is even going to work on is carpet (I'm assuming it would be unwelcome on bowling greens ;) ). Studding will need cutting down a bit, should be hidden completely on the left, but will stick out a bit on the left, dome/acorn nuts will make it a bit prettier.

The next most difficult bit will be making the grain evelator / articulation/joint to the chassis - but it just needs to be attached firmly, and provide a bit of up/down movement, the idea of having the head lift up somehow has gone out the window - the cutting head as it stands already weighs over 900g so the torque needed would be probitive - not to mention needing to weigh down the rear end to balance it. A quick guess suggests 1.5kg or so would be needed, that's a lot for those little Grasshopper tyres to cope with ...





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1:10 scale farm machinery scratchbuilds 6 years 6 months ago #45628

Conveyor box finished & attached after a couple of tweaks, setup allows for a lot of lift (though if I hit a bump 250mm high as pictured, I'm pretty sure it won't be the 5th wheel that's the first point of contact) but no droop - deliberate to stop the cutting head falling into a dip & getting stuck on the other side. Rear wheels lifting could well need some added weigh to remedy, further down the line.

I thought the field opposite had been cut at the same time as the other 4 adjacent fields with the same crop (some sort of pea/bean - I didn't look too closely as they've been full of Pea Weavils in the past & I don't like the bites) but I guess not ... I hope that thing is air conditioned as it's been filthy hot & humid today & I wouldn't want to be in a sealed glass box ...

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1:10 scale farm machinery scratchbuilds 6 years 6 months ago #45629

:woohoo: :woohoo: :woohoo:

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1:10 scale farm machinery scratchbuilds 6 years 6 months ago #45726

Making progress, but still can't point to any more aspects & call them done yet ...

Reel is (so far) a collection of machined discs, tube, and a couple of templates:





Auger(s) will have to be modified/shortened so I can fit a couple of additional bearings - the M8 studding is bending under the weight :whistle:




Added 3mm to the inside and outside of each bump stop:




More torque/less speed needed so as I couldn't find an HPI reduction unit in stock anywhere, I bought an RC4WD one instead for twice as much. No instructions (would be nice to know what depth the motor pinion should be fitted at, rather than having to trial & error it. Some design decisions have been made for side (very narrow gears), others look to have been made purely on cost grounds without reducing the RRP (mount/motor fitting screws pass through the entire unit instead of having threded inserts soyou could use your existing screws + they reallt should have provided a couple of short ones to fix the motor, reduction gear looks like one is simply pressed over the smaller). Some are just plain boneheaded (hole for the bearing that sticks out of the end ouf pretty much every 540 motor ever is 11.2mm on the reduction unit & needs to be machined out to 13mm):

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1:10 scale farm machinery scratchbuilds 6 years 6 months ago #45733

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Jonny Retro Inspired by these wonderful works I bought some ABS plates and methylene chloride. When I received the methylene chloride packaging I was a bit scared ... it says it is for industrial use only and by authorized professionals suspected of causing cancer, it causes eye irritations, skin irritations, respiratory irritation, drowsiness, dizziness ... use only in ventilated spaces, and protective clothing, facial protection ...
I confess that I have some fear of using it. I think that's what you use to stick ABS, have you had any problems?

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