Komatsu HD785-5 100 short ton dump truck

[Will Vale]

Hi all,

 

I posted some pics of this kit in the box a few weeks ago, and I've been quietly fiddling with the parts since.

 

 

I picked it up at our local model railway show from a stall with a huge pile of exciting yellow machines in HO scale. I was a bit wary as model railway kits aren't always the best (and often the tooling is ancient) but it wasn't too expensive so I took a punt. 

 

It's actually quite a nice kit - simplified but good lines, although it was let down by tooling that hadn't been cleaned up very well, huge attachment pins, and lots of ejector pin marks. I started off by building some sub-assemblies - the chassis and forward superstructure.

 

 

It's a bit hard to see against the yellow, but I've done various bits of filling and cleaning where e.g. the hole for a part was bigger than the pin where I attached the cab safety brace thing. The equipment boxes on the chassis also needed some gaps filling, and then I had to remove the ends of their mounting pins where they came through the chassis rails, and clean up after.

 

Similarly, I've trimmed and filled a mix of peg-ends and ejector pin holes under the superstructure as the wheel arches are huge and there's a chance they'll be visible.

 

 

The best bit is obviously the dump body, provided as one big piece in the box. It was obviously slide moulded so I had to hunt the mould lines quite carefully, and it needed a lot of ejector pin holes filling on and between the ribs underneath.

 

 

That's most of the parts cleaned up and fitted, except for the exhaust (it's not very good) and the cab which I'll build up separately. I also need to decide about the railings - the kit provides them but they're heavy on the flash and will probably be difficult to clean up well. On the other hand the complex shapes mean making them out of rod will be difficult too.

 

 

I need to add some detail now, hydraulic and electrical lines and whatever else I can think of which will enhance the appearance. Oh, and make some new steps for the ones I removed under the bumper and up the front of the superstructure, as the kit ones are very thick and clunky.

 

I'm probably going to weather it to look like this:

 

Komatsu PC2000 & HD785-5 by Jose Sarmiento, on Flickr

 

because it looks awesome  

 

Cheers,

 

Will

 

 

[Bengalensis]

This will be most interesting to see coming to life.

[Andy Moore]

Great start. I was wondering if those Claas logos on the sticker sheet meant that they licence built it or at least re-badged it? Can't find any photos of one, but it would look great in Claas colours. Probably not as fun to weather as yellow though.

 

Andy

[Will Vale]

13 minutes ago, Andy Moore said:

I was wondering if those Claas logos on the sticker sheet meant that they licence built it or at least re-badged it?

I suspect it's a one-size-fits-most sticker sheet to cover a whole range of Kibri stuff? They do some Claas tractors in the same scale. I know what you mean about the Claas colours, my only encounter is the Lego model which is awesome

 

I haven't found a non-yellow HD785 yet, apart from an orange one used in the Huntly mines in NZ, but it's a much earlier version. Euclid mining trucks are lime green though

 

I think I've got enough reference now so I'll start fiddling with some details, lines and such.

 

W

[Alan R]

I'd love to put that next to my ERTL 1/25 Payhauler 350 ...

[Will Vale]

I've made a start on the details by filling in the large mounting holes for the kit ladders and building my own:

 

 

They're from 0.5mm brass and styrene rod and slivers of styrene strip. Still over-scale, but they have the right section (the kit part has square section rails) and are a good bit lighter than what was provided. I also added a couple of missing hand grabs on the bonnet.

 

I did a couple of other filling jobs at the same time, for the mounting holes for stairs on the right equipment box, and blanking off the underside of the bumper where the mounting pins for the bonnet fit in.

 

I may have painted myself into a corner with the cab - mounting the frame means I can't drop it into place inside the railings, so I either need to add those last, or cut the frame away and put it back. I think I might do the latter - if I drill up through the mounting posts into the frame and then cut flush with the mounting plates, I can pin it exactly back into place and keep the work I've done to fill around the joins.

 

I also need to decide about the mounting holes for the railings - they're a bit big but the real ones do protrude.

 

Cheers,

 

Will 

[JeroenS]

Not bad at all, those ladders.

[Will Vale]

Thanks Considering they're largly eyeballed I thought they came out quite well. I guess I did use the kit part as a template for bending the first rail.

Not 100% realistic - the rear rails should be proud of the surface - but should probably look OK under paint and some rust

 

I need to make the lower steps (below the bumper) which might be suspended on chains in some photos. Or maybe the rods are just easily bent?

 

W

[JeroenS]

8 hours ago, Will Vale said:

I need to make the lower steps (below the bumper) which might be suspended on chains in some photos. Or maybe the rods are just easily bent?

Well, now I became curious myself... I'd say, the lower steps are from thinner material, not chains. I've never been near one, but I think that steps suspended from chains are pretty uncomfortable to step on (and off) the truck. 

[Will Vale]

1 hour ago, JeroenS said:

I'd say, the lower steps are from thinner material, not chains. I've never been near one, but I think that steps suspended from chains are pretty uncomfortable to step on (and off) the truck. 

I was curious too and went back to look at my reference. On a lot of trucks, the steps look to be made from stiff cable - you can see the strands. I think maybe because if they were rigid below the bumper they'd probably get irreversibly bent, so it's better to have something which doesn't snap after being bent back and forth a few times.

 

But in the pic I linked above of the weathering I was planning, they're definitely chains I do have some etched chain somewhere, I dunno if it's fine enough though.

 

Will 

[JeroenS]

It definitely makes sense to make them of flexible material, I think visibility is somewhat limited from the cab 🙂 

[Andy Moore]

Definitely looks like stiff cables, although I've seen a few photos with what looks like retro-fitted custom-fabricated steps. I suppose the quarries fix or replace parts with whatever they've got to hand.

 

 

 

 

Andy

[Andy Moore]

Forgot to add, I love the steps, especially the wire hand rails 👍

 

Andy

[Will Vale]

Cheers! There's another detail in that picture I was thinking about how/whether to make - the indicators. On the HD785-5, they're in what looks like a diagonal cutout so they're visible from the front and side, with a bar in the angle. On the kit they're flat.

 

It might be possible to file out the diagonal recess and add the bar, but there's not much room to work there and it might be too risky?

 

You're right about the users adding stuff, almost all the pictures I've seen have some kind of firefighting system above the engine, they vary a bit but basically I need a stack of red or blue bottles with some pipes That master cutoff button or whatever it is just above the bumper is cool too.

 

W

[Bengalensis]

Judging by the fine work on those ladders and rails this is going to be very nice, just as I thought. 👍

[Will Vale]

Thanks Jörgen, I just hope that I cleaned up the surface well enough after filling it. The yellow plastic is quite translucent and hard to read, I was holding it up to the light to see what was going on.

 

I guess weathering will help, and they do get dinged up in use.

 

W 

[Will Vale]

I've been downloading a load of HD785-5 pictures from bizarre sources like a Russian site listing replacement part numbers, and what I think is a Malaysian heavy plant school  

 

All of which makes me want to add more details, but because I haven't really planned things too well it's been a bit haphazard.

 

 

I started with the oil tanks because I had a good pic of those already. I just added the bolt heads today which may have made things a bit messy - maybe 1/87 is too small for that kind of nonsense? 

 

The scribed line is standing in for a raised bead between the brake oil and hydraulic oil tanks, I need to fill it and have another go as it isn't straight, or maybe replace with a stretched sprue bead?

 

I also added the bracket for the oil filters on the left, which turns out to foul the mudgard. I'm not sure if I should remove it (it is a bit messy) or move the whole box up? I suspect the former as there's not a whole lot of room on the right next to the dumping ram.

 

I also removed the engine baffles as I haven't found any pictures of them fitted. That committed me to doing something about the engine lump. The block is about the right shape, but lacking detail, and the "transmission" section looks to be completely fictional. It should be further from the engine (there's a prop shaft at each end of the chassis) and shaped more like a transmission More or less two fat cones stacked up, with mickey mouse ears at one end which I think are the oil pumps.

 

 

Just baby steps so far.

 

Will

[Will Vale]

I filled the rubbish scribe line and stretched some sprue instead.

 

(you might need to click & zoom in, sorry)

 

That gives a nice rib between the tanks, and I was able to add the ones on either side too. The bottom edges look quite nice, but the top is getting rather messy and I don't know quite how it'll be under primer. The yellow plastic is quite irritating.

 

If it does turn out that it's all a bit off I can probably sand or pare away the top edge of the rod where it attempts to wrap around. There's enough detail up there that it may not be too obvious.

 

I also thinned the ends of the brackets a bit. They should really be U-shaped but I don't know if I'll go that far. Oh, and removed the extra oil filters. Nearly done with this bit now, apart from some more piping.

 

Cheers,

 

Will 

[Will Vale]

Did a bit more last night, stretching a load of sprue then trying to find some consistent-diameter sections to make the lines which run along the front frame and are very visible through the wheel arches.

 

 

I think these might be grease pipes, I'm not really sure. They're long, thin and metal. At the front they terminate in a diagonal line like that and connect to flexible hoses which either go through the frame or up over it into the engine bay. Thankfully there don't seem to be any on the right side as it was quite a fiddly process to line them up and glue them without creating a mess. Well, without creating more mess than I did - I had a false start and ripped it out again.

I think it looks OK now although everything aft of the frame strut (above the wheel mounts) is made up as I don't have pics of that area. The grease nipples are all clustered under the rear lights (above the diff housing, assuming it is a diff and not just a couple of bevel gears) so it's not impossible that the lines would run all the way along, although inside the frame seems more likely that outside it?

I also added very basic representations of the sight glasses on the oil tanks. They should be hexagonal with little hoods over, but needs must - I don't have any hex rod. When dry I'll drill them out which I think will make a difference.

Will

[Will Vale]

Actually going through the maintenance section of the operator's manual they're probably something else. No idea what though.

 

[edit] Unless it's the auto-greasing system, in which case the lines would terminate at a rack of injectors on the frame behind the front left wheel.

 

W

[Bengalensis]

Looking very nice, good detail work.

 

I'm thinking these pipes are hydraulic lines (connecting to pressure hoses at some ends), some of them possibly for the hydraulic steering. Not 100% sure though, this sort of thing is a bit out of my usual 1/1-scale tinkering...

[Will Vale]

Another friend suggested the same thing, I'm pretty sure you're right as it definitely has hydraulic steering. In which case the back ends of the cables would probably run up over/into the frame just forward of the oil tank since the hydraulic pumps are on the transmission in that general area. 

 

So what I've got is probably OK in lieu of better pictures Phew.

 

Will

[Frah2o]

Not my model genre, but it' really cool build. I follow very interested!

[Will Vale]

On 12/14/2019 at 9:18 PM, Frah2o said:

Not my model genre, but it' really cool build. I follow very interested!

Thanks! It's not my genre either really - I usually build sci-fi models and figures - but the real things are awesome machines.

 

I didn't have much time this weekend - lots on, plus I spent Saturday night playing videogames - but I did get a couple of hours last night.

 

 

Most of which I spent trying to cut down a couple of cleats from the Tamiya T-55 to make the tow hooks and variously dropping and picking them up again. I didn't get them entirely even but I was worried I'd end up trimming them away to nothing if I kept going! I've installed one very slightly at an angle so they line up and I'll run a little CA in there to form a fillet later.

 

 

I also added some basic detail/texture to the suspension mounts and started the front engine bearer. It's a bit of a caricature at the moment, the real thing is an inverted U of thinner steel flush with the frame sides, with a cranked U beam across the mounts supporting the engine in a cradle shape. I might fill in the backs of my profiles with CA and file it all to shape so they're solid, I think trying to do the correct solution is too hard. Likewise the cross-piece I added to support the uprights may stay rather than getting cut away as it's not very visible.

 

I really need to find my misplaced etched saws since there are several things they could help with. In particular, slitting the suspension mounts either side of the A arm would make them look more like an arm in a yoke and less like the one-piece moulding they are.

 

Cheers,

 

Will 

 

 

[Will Vale]

Found the saws, they were on my desk right under my nose! So I was able to slit through those parts and do a bit of carving to make them look a bit more separate.

 

 

I also filled in behind the engine mounts and then filed them into shape, I think they look OK now and I'm going to get some details into the engine and hopefully move on to something else.

 

 

Apologies for all the tiny changes, normally I don't document enough but I think the pendulum may have swung too far the other way.

 

Will