More Madill Madness

[Beekster]

Apr 11, 2021 17:10:28 GMT -6 dogfish7 (R.I.P.) said:

It might be easier to add shims, to raise it slightly above the drive wheels.

It would be the outer piece with the drive sprocket molded in that would have to be shimmed in order to raise it.  Doing that would raise it above the upper track support rollers, which I would like to avoid.  Adding some thin material to the top of that part would ensure that the bottom of the chain sits on the support rollers, but would raise the overall profile.  I might be able to get away with something like .015" without it being too noticeable.  I'm sure it will take a combination of things to solve the problem.

While I puzzle over this, I will also work to solve the size problem with the front rollers and figure out something to mass-produce to make rollers for the bottom of the track frame.  Getting those in place will tend to hold the bottom run of the chain parts in place, which will (I hope) help with working out a solution to the height disparity on the top surfaces.

[Beekster]

This just keeps getting weirder. One would thing that turning a diameter on a lathe would be simple, right? Make an axle shaft to chuck in the lathe (brass & styrene superglued together), sand down so the wheels fit, tack wheels on with drops of superglue, and carefully turn them down and sand smooth. Done it many times, and will do it again on this very project to make the Wichita brakes and clutches just like I did on the first Madill. Fixes there are in progress, BTW.

So this is what I get after the lathe work:


All that tan/grey stuff is residue from the superglue de-bonder. That stuff always makes the superglue sticky, but it seems to have reacted with the material the wheels and chain parts are made of (some kind of nylon?). I used up a LOT of debonder and scrubbed and scrubbed with blue shop towels to get the goo off as best I could, and washed the parts in hot soapy water. What's left here will scrape off with fingernail or scalpel blade or file, so it hasn't completely re-bonded with the base material. Not does it seem to have affected it otherwise; the wheels haven't gone all rubbery or anything. It's just strange, and more work than I had hoped for.

If you search eBay for "1/35 Excavator", you will come up with a lot of hits for die-cast collectibles like this one. This was the least expensive option. You would be forgiven for wondering if I ought not have waited on this, saved more money, and sacrificed a model that cost two and a half times as much but which had real metal tracks.

Oh well. The challenge is in doing it all ourselves, right? A retired guy like me has all the time he wants to tinker with this, yes? I keep telling myself that...

[JCON]

You've got this Beekster!!!

[Beekster]

OK gentlemen, time for consultation. This is the engine I plan to use for this, and just how much of it will be seen is unknown at this time. It's provenance is uncertain, and I sawed off the wretched solid disc "fan" up front and the transmission that isn't needed. I have a duplicate (unmodified, for now) in gray which came in the AMT 1/32 Snapfast Coca-Cola Volvo tractor-trailer kit. I believe the tractor is an N10, if that gives anyone ideas about what this engine actually purports to be. This is the left side:


Sure looks like a diesel injection pump in the middle. Would I be correct to assume that the horizontal manifold above is the intake manifold? Seems to me exhaust heat probably isn't something you want close to a precision high-pressure pump.

Here's the right side:


I see a starter to the left, a couple of lame fuel filters in the middle, and other unidentified stuff to the right. Above it all should be the exhaust manifold, yes?

The reason for wanting to figure this out is that practically all such large diesels are turbocharged, which means I ought to build one and make some attempt at proper intake and exhaust routing. And how that turns out has an impact on where I eventually locate the exhaust stack. Comments on my reasoning; other useful ideas?

[dogfish7 (R.I.P.)]

If you search it has a down loadable Manual.

[Beekster]

I will definitely look into that!

Edit:  Looks like these N9/N10 engines are newer (circa 2014-present) than the block I have here, which was from a 1990s truck.  But the layout is the same, with intake and exhaust sides as I surmised.  The new engines have twin sequential turbos and diesel catalytic reduction for the exhaust.  I think I can work with this to make a mash-up that looks roughly correct.

[Beekster]

OK, so no real progress to report since other projects consumed the weekend hobby time. That said, my usual habit of occasionally picking stuff up to stare at it and then go off thinking has clarified matters, I think, with respect to those chain drive parts. If I am honest about it, that inside run really doesn't have to be intact at all. I have to stop looking at the track frame, chain drive, & wheels in isolation out in the open and visualize what it will look like with tracks on. As the rudimentary test photos here show, the inside of the track run will be very close to the hull side, and the hull extends well beyond the length of the track run. There will be no way at all to see the top of the inside chain run without a dental mirror and a strong light (and everything will be black anyway, with some dirt added for flavor). Two ideas derive from this: One, I can probably swap sides with the inside pieces and put them on backwards so that the chain drive detail is visible on the inside of the assembly. That is, the chain detail could be seen from outside, at least on the bottom. The track run will obscure the totally bare surface that faces the hull. Two, I can section the top of the chain drive and get it to sit down closer to level with the outer piece. The chains probably won't line up quite right on top, but visibility back in there will be close to nil. Figuring out what to permanently affix the sectioned pieces to will be the challenge; that and determining how much I might have to still shim the outer chain parts to get a level surface for the tracks.

[JCON]

I have faith you will sort it out just fine buddy!!!

[JED]

I sure you sort something out Beekster

[Beekster]

Yeah, long time; no report. I haven't been the happiest of campers lately...problems with M911 and trailer (they don't want to sit wheels on the ground now, for some reason), Madill #1 (track breakage and paint problems), a week lost to tweaking my shoulder (long story that begins with getting slammed by a sneaker wave a decade ago). On the upside, a new battery lawnmower, electric pressure washer, and other yard tools which I am quite happy with.

Meanwhile, still thinking on this project. The problems with the chain drives still has me wondering about the best way forward. This morning I decided to count the sprocket teeth that I could see, and made an estimate for how many would make up the circumference. I came up with 19. I don't know of anything that uses a 19-tooth sprocket, but what about 17? I have a Dragon Sexton II kit in stock, so I pilfered the correct sprue and cut out a sprocket ring:




Well now, isn't that interesting? Sure looks about right to me. Or perhaps, right enough; at least the overall diameter is right in there. Working out how the real thing works from images, I count 21 or 23 teeth that cup the hinge pins on the track shoes. So what that tells me is that the detail on the die-cast is not only simplified, there might actually be more than one sprocket design on these things. So what of this? Well, I found two of the correct parts trees from the Sexton on eBay and they are on their way. I can play around with them and make a few of the chain drive links to see how things work out. If I can come up with something that works, casting my own chain links to make a workable track might be possible.

[JCON]

That does look way better!!! As to the shoulder that just confirms that old adage that things happen in threes... you, Jim and AG... ouch fella!!! Get well soon!!!

[Beekster]

Already in pretty good shape again, Joe. I got plastered by a sneaker wave in Lincoln City about a decade ago, and dislocated the right shoulder. ER docs popped it back into place, and I was lucky--rotator cuff wasn't torn. With months of physical therapy I regained nearly complete range of motion. But I've been careful with it ever since. Unfortunately, I am a rotisserie sleeper...I roll around a lot. And apparently, I rolled just wrong a couple of weeks ago and woke up barely able to move it. Took nearly a week to get better, and I slept with the arm in a sling for a few nights to keep from aggravating the injury.

[JCON]

I understand those sneaker waves as my Coastie son in law is forever rescuing Californian's in Eureka Ca who get swept out to sea by them when they get knocked off their feet and the undertow gets them!

[Beekster]

Fortunately, I was several yards up the beach from where the waves were, and atop a large log. The sneaker came in much farther than previous waves had, and knocked me off and carried me straight up towards the high tide line. Yeah, I shouldn't have been there...lived in Oregon all my life (and around 48 years old at the time), so I ought to have known better. Much more careful nowadays.

[jimrichards]

OK, now I know what a "sneaker wave" is. I lived in Kansas 7 years then lived in Arizona for the last 40, so been awhile since spent anytime at the ocean, then that was the Atlantic when I grew up in NJ.

Hope your shoulder is getting better again, that makes three of us with busted up top ends, here.

But the real issue is your model projects. They are both awesome.
I was a fan of the AXE Men show, so this yarder is one of the best model projects I've ever seen.

But I gotta say, even though your weathering is top notch, I'm a shiny side up guy, and this also would have been pretty cool if it were built as a brand new rig being delivered to the site. New and shiny would have really highlighted your great scratch building.

Regardless this is probably more realistic as a used rig.

Keep up the good work, the education you are giving us about these rigs, we are all gonna end up certified mechanics on these, LOL.

Jim

[Beekster]

Thanks, Jim! I followed the first couple of seasons of that show too, when the logging outfits were local. I always wanted more technical commentary about the industry though; the manufactured drama of those reality shows turns me off. And while you guys may be impressed, the truth is I have nothing to do with the timber industry. Whatever I'm spouting is information I've gathered online and from talking with a few guys who really do the work. And as I've mentioned before, I'm happy to share all this material for anyone else who fancies tackling one of these projects.

Assuming I can get the running gear sorted for this second project, I have thought about finishing it in transport mode and pristine or nearly so. When a company goes to the trouble of disassembling the major components and torching it off the old Sherman running gear for a new excavator frame, they tear everything down and rebuild it like new and of course that means new paint. Like this bedplate, disassembled & primered, that I saw in a rebuild shop a few years ago.

[Beekster]

Nothing much happening with this as I work out problems on my first 071 build. The brass sheaves I ordered from RB Model in Poland arrived late last week, and this is a look at how they will be arranged around the spar:

I decided to take a chance on the brass rather than scratchbuild the sheaves this time, and these ought to work fine. They are a little thicker than they need to be, but when all is said and done they will spin more freely on their shafts and won't wobble, so running the lines will be made easier. I've got enough sheaves to do the four powered guyline blocks, too.

[rustybaer]

Scratching track links? Wow......

[dogfish7 (R.I.P.)]

Pretty amazing, huh.

[Beekster]

Stay tuned, fellas...there's a major change coming for this project. Suffice to say that the die-cast excavator frame idea is being discarded, and I'll return those bits to the die-cast that I purchased. Should be a couple of weeks or so before I can report on the new direction, but I'm very hopeful that I will have the solution I really want.