Madill 071 Mobile Tower Yarder

[dogfish7 (R.I.P.)]

Looking fantastic! I can see why this rig was so top-heavy.

[Beekster]

Feb 11, 2021 16:04:14 GMT -6 dogfish7 (R.I.P.) said:

Looking fantastic! I can see why this rig was so top-heavy.

Yeah.  The spar itself wasn't the problem, especially once the fixed guylines were snugged down.  With that done, no problem driving it around or on and off a trailer.  When either of those things happen, the big lines and powered guyline wires are all spooled in and tied off so the center of gravity isn't all that high.  A few thousand feet of 5/8" to 1.25" wire rope weighs a lot, and the bulk of that sits right about dead center on the yarder.  What gets these rigs into trouble is when they are rigged out for yarding and a log turn that is either too heavy or hung up on debris meets up with an inexperienced or impatient operator who pulls too hard.  When that happens, the narrow tread of the Sherman chassis isn't stable enough and the operator can pull out the powered guyline stumps and topple the whole rig as seen in the images further up the thread.  That's why outfits that re-manufacture these things use a big hydraulic excavator chassis: 






This one was rebuilt by an outfit in Eugene, OR back in 2017.  Notice that the original chassis was retained, which for most of these machines was a mild-steel copy of the Sherman hull.  The VVSS is gone, and a new stiffener plate added covering most of the side panels.  The excavator frame emerges from the center of the chassis.  It has a much greater track width than the original VVSS running gear, and probably a lower center of gravity.  This machine has the optional fourth powered guyline drum and one of the fancier optional cabs.  It would be possible to model one like this, too, if you could find a 1/35 excavator model to use.

[dogfish7 (R.I.P.)]

Some definite improvements!

[Beekster]

Oh, definitely! More stable, easier maintenance, and more, though I expect all-up weight goes up considerably. There's nothing wrong with the yarder itself, which is why it remains popular even though the original manufacturer has been out of business for some time. The machine is robust and capable; only the chassis was a problem if the operator was ham-fisted. And the Sherman bits have become something of a maintenance nightmare, since parts are quite scarce eighty years on from the war and what parts there are still available, are bid up in price by military vehicle collectors with deep pockets. Interestingly enough, I've only ever seen images of one Madill 071 with HVSS running gear, though that would have been as easy to source and would have improved stability. Madill did use HVSS on the larger 171 yarders, which were much larger machines on a longer chassis. Building one like the modernized version above would pose its own challenges, like having to use a die-cast excavator just to get the running gear. And those tend to be the collectible sort, and rather expensive if you intend to part it out.

[JCON]

Amazing work you are doing with it!!!

[Dukemaddog]

Stunning work Beekster! I am most impressed!

By the way, there is a 1/35th scale excavator announced for release soon...

[Beekster]

Feb 12, 2021 14:36:20 GMT -6 Dukemaddog said:

Stunning work Beekster! I am most impressed!

By the way, there is a 1/35th scale excavator announced for release soon...

How big?  Hasegawa has a small-ish one, but from the looks of the cab it would be much too small.  Just what I need...an excuse to build another one with a boxed-in engine bay and a fourth powered guyline drum.  At least I could dispense with the engine stuff.  And have I ever mentioned this?





That thing was impounded in British Columbia a few years ago for being a rolling Superfund site.  Hardly surprising, since that M26A1 Pacific under there had chain drives with constant oil-drip lubrication.  There are very few images of this beast, and no documentation whatsoever.  I've pieced together that it apparently had a stretched frame, a Skagit yarder, and a Madill spar and was converted in the early 1960s.  Yes, I have a Tamiya M26 in the stash and a very rare Trakz M26A1 soft-cab conversion set, just in case I go completely insane and try to tackle that project.

[reserve]

Having spent alot of time on the logging roads on the Olympic peninsula when I lived out there I can only say that that thing looks like a good way to die. Surprising it lasted long enough to get impounded rather than rolled a hundred times or so down some steep mountainside.

Impeccable work on an unusual subject; I can only guess at the time spent researching and measuring

Regards,
Mark

[Beekster]

Feb 12, 2021 18:15:19 GMT -6 reserve said:

Having spent alot of time on the logging roads on the Olympic peninsula when I lived out there I can only say that that thing looks like a good way to die. Surprising it lasted long enough to get impounded rather than rolled a hundred times or so down some steep mountainside.

Impeccable work on an unusual subject; I can only guess at the time spent researching and measuring

Regards,
Mark

Agreed! The big Pacific was a brute and even the soft-cab tractor weighed something like twelve tons empty.  What this yarder weighed, I can't even venture a guess.  Same goes for my research time.  I've been collecting images for at least a couple of decades, and some of mine were shot back in the days of 35mm film.  Actual measurement of S/N 70097 was done over three or four trips, and I typically spent about four hours measuring, making notes, and taking related photographs.  When I returned home I would write up my findings in a more coherent form, and I have a Word document that runs to eighteen pages that resulted from the measuring trips.  The original sales brochure has useful dimensional data, as does the operator's manual (I was given an electronic copy by another enthusiast).  The internet also provided me with a .pdf copy of a 200+ page handbook on cable yarding practice from the British Columbia Worker's Compensation Board.  That is an invaluable reference for understanding how these machines are rigged and operated safely.  Much of what I've gathered simply couldn't have been marshaled in any serious fashion before the internet age, at least not by anyone not involved in manufacturing these things.

If anybody else wants to tackle one of these I can be prevailed upon to burn CDs with all the documentation and a whole lot of photos.  In terms of variations in features and appearance, what I've presented here barely scratches the surface.  To quote myself from an unpublished manuscript:

The Madill 071 exhibits just as much variation above the tracks as the original Sherman on which it was based. The yarder could be fitted with either three or four powered winches for the guylines, three types of cab (standard or Deluxe, which was wider and longer, and yet another style with an angled cab front), a skylight that could be specified for any of the cab styles, and two types of spar; even air conditioning was optional. Over time these machines show many differences in placement of various fittings like exhausts, cooling water tanks, hydraulic oil tanks, guyline anchor points, tow lugs, and more; even a top deck that was extended above and beyond the radiator on one example. While it might be extreme to claim that no two are exactly alike that characterization probably isn’t far from the truth, particularly now that most if not all of these yarders have been passed down through multiple owners all of whom probably made modifications to suit their operations or save money.

[Beekster]

Small stuff going on in the background on this one. Did some touch-up of the orange last week, and next week I will hit that with flat clear. I am working on finishing the construction of the turnbuckles for the fixed guyline wires, and this morning started on the lines themselves. There will be five of them:


This is the finished end of one line, plus all the ferrules for the other end and the other four lines. I won't build up the other ends until I get to final assembly, when I can judge the appropriate length. The rigging line is .020" diameter, and the ferrules are an eighth of an inch long. To get the chamfer on the ends, I chucked up the .093" Evergreen tube in my Dremel and used a needle file. Then chopped to length.

This is how they will be rigged to the spar. I need to find more blackening chemical so that I can age the brass on the shackles. The other ends of the guylines attach to the top deck, the outrigger, and one lug on the differential cover. That's where the turnbuckles will go.

[JCON]

Looking good!!!

[Beekster]

And at the other end of the guylines will be these turnbuckles. The bodies are made of brass strip superglued to stainless steel nuts. The threaded ends are stainless steel screws used for eyeglassses repair. The slotted screwdriver ends were cut off and nuts threaded on the ends and soldered in place. The U-shaped ends are brass strip, drilled out .030". Meng plasticnuts with protruding threads are superglued to one side, then drilled out from the open side to make room for the shaft. The retaining pins are Meng bolt heads, drilled through and with brass rod superglued in and ground flat when cured. There's more primer needed on these bits, then I will airbrush them a steel color to look more or less like galvanized metal. These have to be fully functional to properly tension the fixed guylines, and they are indeed fully functional. Securing the spar by putting the lines under tension will wear some of the paint off the threads, but the eventual steel paint color ought to disguise that. Ruler in the background for scale.

[JCON]

Those look really good!!!

[Beekster]

Mar 5, 2021 17:48:39 GMT -6 JCON said:

Those look really good!!!

Thanks!  Fabricating them was a major challenge, especially ensuring that the open jaws were all about the same and all the holes were more or less centered.

[JED]

Superb work Beekster...

[DPNM]

This is truly incredible craftsmanship Beekster. From your research to your desire to build as close to what a real one is is inspiring. I can tell this is a labor of love for you.

Your work is top notch.

[BUCKY]

Those turnbuckles look fantastic! A lot of tedious work, there!

[Beekster]

Mar 6, 2021 19:06:49 GMT -6 DPNM said:

This is truly incredible craftsmanship Beekster. From your research to your desire to build as close to what a real one is is inspiring. I can tell this is a labor of love for you.

Your work is top notch.

Thank you, sir!  It is indeed a labor of love, and after more than ten years fiddling with it it will probably be finished within the next year.  It has been a tremendous learning experience and has really stretched my fabrication skills.  Well, this project and others.  I'm a very logical and linear thinker, generally speaking.  I've been told I think like an engineer, and that's true to an extent.  I couldn't tolerate the math required to be an engineer, but I grasp the essential concepts well enough..  But over time I've come to terms with the reality that the creative process isn't always linear or logical.  Part of why this project has taken so very long is simply the time it takes, consciously or otherwise, to work things out.  It has often been the case that something comes to mind that I think might be a solution to a problem for this project, but also applicable to another one.  And while this project might have dozens of such problems to solve, that other project has only one or two.  So I work on the other project (sometimes even completing it!) to work out techniques before returning to the yarder and applying those methods. The end result is better than it would otherwise have been, I think.

My predilection for detail accuracy and functionality has not, in retrospect, always been an asset.  I could have saved myself considerable effort by choosing a different engine bay configuration that left much more restricted views into that area.  I could have decided from the start that the spar would be either up or down, and not tried to engineer it to be both.  That realization has been slow in dawning, as I am now gravitating towards a spar-up finished configuration that isn't disassembled to lower it.  I suspect that doing so more than once or twice would break things.  That would still work with the transporter, since it seems probable that the spar was secured in the up position before driving off this kind of trailer.  Otherwise the end would dig into the ground as it went down the ramps, and the operator's manual says nothing about partially raising the spar and holding it there under hydraulic pressure while driving the thing.

So perhaps I will do a second yarder, with some elements eliminated for ease of construction and the spar fixed in travel position.  If that rumored 1/35 excavator kit is large enough, that might be a catalyst to start the planning process.

[Beekster]

Well, well, well...what have we here?



Uhhh...yeah. You nailed it. That is what you think it is, two slabs of laminated styrene sheet and an engineering drawing of the winch bedplates. Yes, this means a second yarder will someday follow the first. If you are asking yourself, why today? There's method (of sorts...) to my madness. The catalyst was my current bottle of Testor's liquid glue, which is getting down to the dregs. Usually I open a new bottle and pour what's left of the old one into it and put the glass bottle aside to dry out and toss it into the glass recycling bin. But today it occurred to me that if I was going to pour the stuff anyway, I might as well do something immediately useful with it. So I cut enough rough, oversize sheets of .030" and .015" sheet stock (three each of the thicker stock and one each of the thinner stuff) to make two bedplates, and commenced to pour liquid cement on one piece and quickly smear a second one on top and line them up. This didn't take much time, but it did pretty well fume up the war room so windows were opened and the door to the rest of the house closed behind me. I let things air out for about an hour and shot Dullcote on the trailer wheels during the interim. This method is messy, but I'm not worried about surface damage since there will be much sanding, shaping, and drilling to follow. I suspect that this will result in stronger pieces than the set I used on the current project, where I just used a small brush to flow the cement. Here, the entire inner surface has been covered so the whole thing is melted together, not just the edges and a little bit of penetration deeper inside. These will dry now for a few days, and I'll start trueing them up with the True Sander after that whenever the mood strikes.

[JCON]

Waste not, want not!!! Good job!!!