I suppose that this is just about the most radical Sherman conversion there is. After years of research, I've finally started cutting plastic on this one. There are many miles to go, since this thing has to be almost completely scratchbuilt.
This is the sales brochure for the beast; it was a piece of logging equipment built on Sherman chassis.
These are images of what I've got so far. The hull is together and modified, and I have started on the big bedplates which support the five main winch drums. I have also made a good start on the main spar, which is half an inch in diameter and over thirteen inches long, as well as the hydraulic lift cylinder. Needless to say, there is an immense amount of work to do yet, including scratchbuilding the whole engine, but slowly but surely I'll get there.
"You could probably use some armor. A Sherman can give you a very nice...edge!"
Thanks! This will take damn near forever to finish. The sheer number of subassemblies to be engineered is immense. Fortunately, I have hundreds of images and accurate measurements of a surviving machine that I've taken myself, and an operator's manual. There will have to be some concessions to scale because of the materials being used. The spar is one; it should be .518" in diameter but an even half inch is as large as Evergreen or Plastruct makes. I briefly considered wrapping it in .010" sheet, but discarded that as insane...getting it to lay down evenly would be impossible over that length.
I'll have to find three different sizes of really small thread to rig this thing, and turnbuckles too if I can find them. Then there's that M123 tractor and scratchbuilt lowboy to put it on...
"You could probably use some armor. A Sherman can give you a very nice...edge!"
Despite being distracted by the arrival of prototype castings for my M60 HMGG conversion this weekend, I have made some progress on various bits for the Madill. Dealing with this is like peeling an onion; each layer (or assembly) reveals another layer (an interrelated assembly) beneath it, to an almost infinite degree. This is the latest: This image shows the entire spar lift mechanism, mostly mocked up. Left to right are the spar mounting points, the hydraulic lift cylinder, the spar stiff leg, and the stiff leg mount which will be fixed to the forward winch bedplate. Beneath the joint of the stiff leg and lift cylinder is the stiff leg support which will be affixed to the differential cover.
This shows the bottom of the spar, and the spar hinge which will be fitted atop the forward winch bedplate. There is still detail work to do here, and the spar retention bracket for the rear bedplate and the retention pin itself have yet to be started.
This shows the underside of the spar at the business end. I've added two brackets for some of the fixed guyline wires, and I've added the main and haulback sheaves. The sheaves rotate within their housings, and their axle swivels within it's three bearing tubes just like the real thing.
The skyline sheave at the tip is removed here; I'm working out how to fashion the mounts for the powered guyline wires. I think that I've got that conceptually nailed down; not finished building them yet. And I'm not sure about the running blocks that attach to those mounts, either. I might try to scratchbuild one and have duplicates cast; it doesn't actually have to function even for rigging the model. Or I might try to find something similar from the likes of RB Model in brass, though the shape wouldn't be quite right.
"You could probably use some armor. A Sherman can give you a very nice...edge!"
This project is awesome,there is or was a show on Discovery about loggers in the US and there i saw a type of logging machine build on a Sherman chassis(i think most of you have seen that show or know the Sherman logger i am referring to),only I forgot the name of the logging company. And when i saw that one i sure would love to build it,one of these day,s i must start collecting reference,s on the one i saw,if only i could remember the logging company name,one of the company,s was called something like Rydders?? Now I come to think about it i believe there was more than one of such Sherman based logger?!
Butt i will for sure be following this build and kudos for you to take on such a cool demanding project.
Boely, I've been interested in this use of the Sherman chassis for many years now. You're right that there have been several different yarders using Sherman parts; Madill themselves did at least two. The Model 071 used the Sherman chassis or a soft-steel copy of the same dimensions; the larger Model 171 used a purpose-built soft-steel hull with HVSS spaced about like an M4A4. I photographed one years ago, but haven't located a 171 machine near enough to go measure it up. The show was Ax Men, and Pihl Logging did use an 071. I believe that they still have it. Other operators in the Pacific Northwest also still use these machines. Sadly, though, many are being scrapped. Sherman parts are getting more scarce and expensive; some operators have scrapped the whole machine while others have transferred the yarder works onto a more modern hydraulic excavator chassis--far easier and cheaper to maintain.
I've developed quite an archive on these yarders; it fills three CDs: Photos, a document that breaks down the machine into pieces with measurements taken by me, hundreds of images (my own and scoured off the internet), a customer list with serial numbers, an operator's manual, and a document on cable yarding practices that is helpful in understanding how these things are rigged and operated. The machine I measured resides in Tillamook, OR, and at my last visit had been sitting unused for several years. The caretaker of the wood yard did tell me at that time (last June) that the owner had gotten a new timber contract, and was considering overhauling and re-rigging the old girl for work in the woods once again.
"You could probably use some armor. A Sherman can give you a very nice...edge!"
Ax Men that was indeed the name of the show,these Sherman based logger vehicle,s are indeed very interesting. Thanks for the information,these variants are as said indeed very interesting,i did not know there were that much of them. It is great that you have acces to take photograph,s,i will be following your project for sure.
I guess with that much reference,s you will be building more of these Sherman based logger vehicle,s,maybe I will be doing one of these someday, i already have so much projects going and on my wish list to last me for years haha.
It would be cool to putt these machine,s in somekind of museum,to preserve them for the future.
Thanks again for the interesting information and as said I will be following this project for sure,keep up the good work,
Jelle, I probably won't be building more than one of these things. It is really about two dozen models in one, when you break it down. Perhaps more than that, if you count the various fittings on the spar, the fuel & oil tanks, the engine, and so on. It takes some really sustained creative effort, and that effort comes and goes. When I think that I've got some assembly worked out conceptually, construction proceeds in a pretty orderly fashion. But there's also a lot of time devoted to staring at images, staring at the model, working out measurements, and figuring out how to build something. And sometimes the first couple of attempts don't work out as I would like. That's the nature of scratchbuilding.
The Madill 071 was in production between 1975 and 1985, and some 250 were built. As far as I have been able to determine, all were built with VVSS. I've seen a single image of a one-off machine that used 071 components but rearranged the placement of some things and used HVSS. It's unknown how many were built on actual Sherman chassis, and how many were built using Madill's own mild-steel hull to save weight. The Tillamook machine has a mild-steel hull, and was built in 1977.
"You could probably use some armor. A Sherman can give you a very nice...edge!"
So, I've gotten back to this one again lately. I've installed the hydraulic actuators for the transmission; those are resin copies of the brake boosters from the Trumpeter Chinese 50-ton tank transporter. There will be more of those gizmos needed for the winch brakes when the time comes. I've also got a lump coming together for the engine block, and another for the fuel tank. I will sand that one to refine the shape and then skin it with a big slab of .015" sheet. It looks sorta gruesome, but I wanted a stiff structure so I just kept adding Evergreen structural stock until it was pretty solid. I don't care if it's heavy. I'm also about done with the rotating guyline ring for the Skyline sheave; I can't count how many pieces of plastic are in that little monster and you don't want to know how long it took to make it. As for the engine, I've got a service manual on CD which is quite helpful, but a parts book would be better. I'm scoping out a couple of options for that on eBay. The engine pretty much has to be the next thing done, so that I can work from that to do the big PTO shroud (which extends out to the side up against the rear winch bedplate) and the drive shaft. At least the thing is orange, so it doesn't have to be painted separately from the rest of the model.
"You could probably use some armor. A Sherman can give you a very nice...edge!"
Most interesting indeed. A project you don't see very often or not at all.
Don't give up!
Jeff
Thanks, Jeff! I won't give up, don't worry. This is just one of those projects that moves in fits and starts because you find that in order to build Thing 1, you really have to build Thing 2 concurrently and both of those are influenced by how you do Thing 3 and Thing 4. I just have to plug away at bits and pieces until they coalesce into larger subassemblies.
"You could probably use some armor. A Sherman can give you a very nice...edge!"
Ya know, sometimes this scratchbuilding thing just makes one want to shriek and never stop. At least it makes me want to. That engine block you see a few posts up? Gone. That's #1; and the more I compared it to images the less I liked it. Too tall and too wide across the cylinder banks, and too narrow below the cylinder banks. Trying to sand it down created some less than straight lines and angles so I started #2. That one was shorter, and the end-on proportions looked much better. But the calipers told the true tale, and it turned out only fractionally narrower so not really solving the dimensional problem wich was overall width. So that one's been discarded as well. I just sliced and glued heavy strip stock to start block #3, and made sure that the core is significantly narrower than the first two iterations. Tomorrow, once it has cured, I can sand it square and dial in the length before starting again on the angled cylinder banks. Of course this also affects the rough assembly for the Roots blower which lives atop the block in the Vee between the cylinder banks, and the dimension of the head & valve cover parts, too. Just started Roots blower #3 and will wait on heads #2 until I'm satisfied with the size and shape of the basic block.
At least I got the skin on the big fuel tank, and that is wrapped tightly in tape while the glue sets up. The seam won't be too hard to fill & sand smooth, and it will wind up on the lower inside face of the part, facing the engine bay where it will be least noticeable.
"You could probably use some armor. A Sherman can give you a very nice...edge!"
Oh the joys of scratch building. I have never tried an engine before, like what you are doing. Keep it up!
So far so good on block #3. While it's only about .047" narrower overall, the proportions are better than before and the width of the cylinder heads themselves will be narrower by about .050" compared to the parts I had started before and about .020" shorter vertically. That in turn will drive the valve cover portion (not started) smaller and that ought to keep the proportions looking right. The third blower housing also looks more appropriate, though it's a little short yet. I haven't cut and fitted the base and top plates for it yet, nor started on the intake trunk on top. Fuel tank is looking good for shape, so now I need to examine images and add stuff like the mounting straps, filler neck, and outlets for lines to the eventual fuel filters to be mounted somewhere.
"You could probably use some armor. A Sherman can give you a very nice...edge!"
Allllrrrighty then! Now this is looking better. I'm much happier with the block/heads/valve covers/oil pan lump now, and it's seen mocked up in the engine bay with the roughed-in blower housing on top. I like the size and proportions much better now. The oil pan from block #1 is re-used here, but cut down to be shallower. The blower housing is #2, which after some sanding on the bottom and cutting to length (more or less) looks more like it should. There are miles to go on this with details, but this is what I wanted to see. The channel-stock frame rails are set in place on the hull floor, and I'll eventually make engine mounts for this thing so that it can sit properly. Right now the oil pan sits on the floor; I'll want maybe .020" of clearance. The flywheel housing is in process now, and I can get going on the accessory bits on the back, belt pulleys in the front, the rest of the blower housing and intake trunk, and the exhaust manifolds and eventually the turbo. Once I have this pretty well squared away, I can make the oblong PTO housing which will fit behind the engine in that notch in the hull and up against the rear winch bedplate. And the dimensions of the PTO housing will be influenced by where the back edge of the bedplate is, so I need to think about adding the various details to the inside faces of the bedplates and building the supporting structure to make them a unified assembly. Puzzles within puzzles...isn't this fun?!
The last two images show where I'm going with this. Some of the details on the block will be simplified or omitted, since viewing angles will be rather restricted when it's in there for good.
"You could probably use some armor. A Sherman can give you a very nice...edge!"
Puzzles within puzzles! I've gotten the basic engine in shape, with exhaust manifolds and flywheel/PTO clutch housing roughed in. Decided the blower housing was too short and not tall enough, so another is in progress and mocked up here. You might thing that the PTO housing itself might be next, since aside from it's irregular sorta teardrop shape it's a simple construct. But you would be wrong. That's one of those gizmos that could only be photographed, not measured, so it's dimensions will be whatever fits and looks good. But to do that, I need to know where the back end of the rear winch bedplate will sit when all is said and done. To know that, I really need to get to where the two bedplates are made into one solid structure with the various things that connect them. And to do that, I need to detail their inner faces where the winch drums go. So what you see here is all that mocked up and in progress. There are lots of detail bits to add yet. For example, the two shrouds for the Main and Haulback drums on the rear bedplate need treadplate on them, so I'll be ordering an Archer Surface Details sheet for that. The guards on the back side of the front bedplate need retaining tabs, bolt heads, and nuts added to the triangular stiffening gussets. And finally, a shot of this monster with the spar set in place almost dead on where it will eventually be placed. Note that this barely fits in the lightbox. The Sherman hull is about six inches long; the spar itself over thirteen...Definitely a long load for the lowboy!
"You could probably use some armor. A Sherman can give you a very nice...edge!"
A few more bits and bobs beginning to take shape. In these shots are the unfinished examples of the air cleaner, Roots blower for atop the engine, and the turbocharger. Not shown is the angled intake trunk for atop the blower, because I wasn't happy with the first one and have a second in process...needs to be a little shorter and with shallower angles. The wheel hubs make great turbine wheels; too bad they'll never be seen as intake and exhaust trunking will cover them up. In these shots, the compressor side is in the foreground and the exhaust side is in the background. The open tube is where the exhaust pipes from the headers will be routed, once the turbo is on the intake trunk, the intake trunk is on the blower, and the blower is on the engine.
The ruler shows the rather diminutive size of these things.
And it now prompts more thinking about process to percolate in the back of my brain. How to assemble all this and when to paint? The engine will have to be finished and installed in the hull before I can build the rear superstructure, which will support the big fuel tank on one side and the air cleaner on the other. The top deck provides a ceiling for this, and it appears now that the deck along with all its fittings and the operator's cab will have to be a separate assembly. Otherwise I won't be able to get in to mount the air cleaner somewhere (location and method varies on these beasts) and make the connections between the air cleaner and the engine, to say nothing of figuring out how to do the radiator & plumbing and feed lines from the fuel tank to fuel filters and over somewhere towards the engine. And I'll have to have the upper deck fairly well along and able to be placed atop the support structure before deciding how to route the exhaust pipe through it.
"You could probably use some armor. A Sherman can give you a very nice...edge!"
Hey there, fellas! Long time no see...I've been buried in house remodeling for months, and not working on my various projects. I've tinkered with this one again lately, and need to shoot a few more images, but this one ought to whet your appetite. The spar can now be fitted to the mounts, and when this was taken the fit was tight enough for it to stand on it's own. It won't do that any more; I've had to put a bit of slop into the fit to make everything fit. Those images of the engine can be dismissed, as I've started on another. The one I posted is too big, as I discovered when I bought a MiniMan Factory M911 HET kit (which will be the tractor for this model, eventually). The M911 used a slightly different Detroit Diesel engine, and it was clear mine was too large. I had an idea that might be the case, since other things weren't fitting quite right.
"You could probably use some armor. A Sherman can give you a very nice...edge!"
Just have to keep plodding as inspiration strikes, Dogfish. This is one of those where you get to a point that you're stumped on a solution to something, and have to set it aside (but visible) so you can stare at it now and again while your mind works on it in the background. Eventually an idea surfaces. So I'm on to engine block #4, it seems. When it warms up a little, I will shoot some paint on the inside of the winch box and the three big winch drums, and install those permanently. Need to make sure they rotate freely so that they can be rigged later. I've made some progress on the six Wichita clutches and brakes, and that's another piece that needs it to be warmer in the garage so that I can do more lathe work on them. They will have issues with concentricity, but that isn't much of a concern as they won't be rotating parts.
Moving forward, some of the little things still need solutions, preferably working ones. Like snatch blocks and shackles. RB Models of Poland makes shackles in brass, and I have some, but finding the right sizes is challenging. All of their snatch blocks are much too small, and the ones found for wooden ship models are the wrong style. At least model ship rigging thread will be correct for the winch cables. More images soon...
"You could probably use some armor. A Sherman can give you a very nice...edge!"
Been busy on this the last few days, and this shows where I'm at. All this is incomplete and mocked up, but it's getting there. Image 8062 shows the engine and lower base of the PTO housing in the engine bay. I used the resin 8V-92 from the M911 as a dimensional template, and my engine is a good thirty thou shorter front to back than the resin one. Even so, this is still too long in there. I will have to saw off the flywheel housing and sand it down by .030"-.040" inches to shorten things up. I have no room at the front for the accessories and belt pulleys there, so I need to figure that out. I've already extended the tray on which the radiator mount will sit, so that that piece (not shown) will shove the radiator aft a bit more. The PTO housing is already fifty thou narrower (1.75" in scale) narrower than it ought to be, and I may need to shave it down another fifteen or twenty thousandths.
Image 8063 is a bit blurry, but shows the completed guyline outrigger attached to the front winch bedplate, and also shows how tight the engine bay is. The Roots blower/turbocharger assembly may be a bit too tall, but I have room to shave it down about twenty thousandths on the bottom if need be. Actually, though, taller is better as it will fill the space. Image 8064 shows the front of the thing, with the A-Frame support for the spar stiff-leg installed on the diff cover and the triangular mount for it on the front of the front winch bedplate. The drive shaft way down there is now complete back to the plane of the rear winch bedplate. It will probably never be seen, but better safe than sorry.
Image 6065 shows my Wichita clutch & brake drums ready for milling in the lathe. Each of these six drums has three circles, each one three pieces cut from .020 sheet stock and glued together, and twelve pieces of .060"x.060" stock in between the three layers of circles. That's 33 pieces each, and we're not done. These are about .690" in diameter, tacked on to the brass tube with superglue. Tomorrow I will chuck this up and mill them down to .628". This is my second try at these; the first ones were wildly non-concentric and didn't mill well. This time, I made a fixture using a small piece of .125" brass tube superglued into a thick styrene base, carefully mounted so that the shaft was vertical and square to the plastic surface. I can tell already that these are far more concentric than the first batch. Not prefect, but probably close enough.
The engine will have to be largely complete and painted separately before installation, and therefore so will the inside of the hull tub. I will mask off areas where assemblies will land and touch up after they are in. Everything will then get slathered in black, oil, grimy goo. I may paint the inside surface of the bottom plate black and not orange to begin with, since virtually no trace of the original color can be seen with all the oily grime. It will also absorb light, making flaws less noticeable if there is any sort of sight line down there. I'm not sure there will be, but once again better safe than sorry.
I decided to mock things up this afternoon to check for interference, and I'm happy to say there is none. So let's walk through these, shall we?
Image 08066 shows things from the right rear quarter. The engine is mocked up, as are the Wichita brakes for the Main and Haulback drums (down low, white things). Low on the left is a cut-down Sherman idler wheel as a flywheel on an idler shaft. I milled it down as far as I dare, and it's still oversize and really should have eight spokes but I'll live with it. I don't have any eight-spoked wheels a half inch in diameter lying around. Up above is the Tag drum with a Wichita brake on the end.
Image 08067 shows the side view. I didn't put the big winch drums in between the bedplates, but the Straw and Tag drums are visible on their common shaft with their Wichita brakes. Also visible is the gear for the Haulback drum, with a Wichita clutch. All these front clutches may be replaced, since they do differ in detail from the brakes and I can make them more accurate now that I have figured out the fixturing to make it happen. In the forground is the guyline outrigger assembly.
Image 08068 is a front view. It shows the relationship of the gears & clutches for the Main and Haulback drums, and the little gear on the main PTO shaft. No, these are not accurate with respect to tooth count but they are about the right size. Extending into the foreground is the Spar Stiff-Leg, with the inside piece of the hydraulic actuator sticking out towards you. The Stiff-Leg is secured to the A-Frame support on the diff cover, and pinned to the triangular hinge point on the front of the winch bedplate. Out of focus above is the brass axle for the spar mount, with the triangular spar mount with a big hole for the retention pin.
Image 08069 is a left rear quarter view. All the engine bay bits mentioned earlier are visible, as is the Spar Mount and the Spar Saddle where the spar sits when the spar is erected for operation. You'll never see things quite this way when this is done, since the huge fuel tank gets mounted on the left side adjacent to the engine.
Mocking things up this way confirms that I have squeezed things dimensionally just enough that I will be able to get the radiator and mount in there and still have some representation of the gizmos mounted to the front of the engine. It also makes it clear that I need not get my undies in a bundle about the accuracy of the gear case and accessories at the back of the engine, since they will be all but invisible. There will be a solid deck above at the level of the top surface of the bedplate, the fuel tank will block views from the left side (along with masses of fluid hoses coming from under the deck), and there will be a large door on the right side extending from the rear bedplate to the back of the yarder. That is a simple frame of .060 square stock with etched brass screen on it.
So, some progress was made over the weekend as shown in the photos below. I've got the PTO case on the engine finished, the cam gear case at the back roughed in, some details on the front finished, and bolt heads on the engine mounts to finish them up. Pictures 08071 and 08072 show the engine now, with supercharger assembly mocked up, at higher magnification. This thing is less than 1 3/4" long...
The next two show the engine mock-up back in the hull with the winch box structure. A completed Wichita 218 brake can be seen, and the Skyline band brake. That one is #2, as the first one inadvertently got swept off the bench and crushed under the wheels of my office chair. There's more Wichita stuff to finish, and that will take time and some tedious lathe work: Another 218 brake, a pair of 218 clutches, a pair of 216 clutches, and the 318 Main clutch. They're all the same diameter, but differ in their front appearance. I will go ahead and do the ones for up front, even though sight lines to them might be nearly nonexistent. I'll know they are there, and if I manage to have an opening door on the front enclosure they will be visible.
Finally here is a scan from the 071 Operator's Manual that shows a general schematic for the winch drums, engine, and transmission. I won't have all the gears installed, but a few of them can't be seen anyway. The little drive gear on the intermediate shaft for the Skyline drum might be visible inside the winch bay, so I'll have to see about that. The gears I'm using are all nylon gears from Plastruct, intended for RC stuff.
"You could probably use some armor. A Sherman can give you a very nice...edge!"