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Big Rigs, Multi axle, & Tracked Vehicles The place for "Semi" talk!
Tamiya and Wedico Tractor trailers!
Tamiya and other brand R/C Tanks and Tracked vehicles. And any vehicle with more than 2 axles; 6x6, 8x8, 10x10, etc!


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  #16  
Old 01-14-2020, 07:00 AM
dremu dremu is offline
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not sure what you are using for printer and/or software, but I can set fill density from 0% all the way to 100%. Granted, i rarely use 100%, as I have found that around 75% is usually plenty, but the option is there if I want it.
Sorry, that was a gross oversimplification for those who aren't familiar with printers My experience is that folks assume, based on what they see on TV, that they would get a solid plastic piece suitable for making guns to pass through metal detectors (rolls eyes.)

Been using a Flashforge clone of a Makerbot for some time, using either their software or MakerWare (which I know is cheesy, but it's quick and simple) and then lately a bigger Qidi, whose software uses Cura as the slicer AFAIK.

I don't think I've ever gone much over maybe 40% except for the flexible filament when I did the wheel chocks, and yeah, those were like 80%.

-- A
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  #17  
Old 01-14-2020, 09:50 AM
dremu dremu is offline
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Very impressive already!

I have multiple 3d printers, but have not done anything quite like this! LOL
Oh, and to this point: I think it's a matter of "run what you brung", using that with which you're most familiar. For example on the 1:3 HMMWV, the ladder frame is done in 2" channel steel because it's cheap and I can weld passably. Prolly slight overkill, but it won't come apart any time soon.

For an RC though, steel would be too heavy and bulky, and the aluminum rails are easy to get. Unfortunately I haven't a clue about welding aluminum and trying to *bolt* up crossmembers in aluminum just seemed like it was begging for trouble, too many holes and not enough strength. The plastic lets me build structural shapes and seems to gives enough strength.

Fiddly detail bits are trickier and sometimes force me to learn new styrene skills beyond the gluing-my-fingers-together. As I go through my backlog of pix you'll see there are some pieces that came out pretty well, and others I kinda mixed and matched printed pieces and pre-cut styrene (learning to love Evergreen Models )

-- A

Last edited by dremu : 01-18-2020 at 12:34 AM.
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  #18  
Old 01-14-2020, 04:55 PM
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I totally get ya! (especially on the *rolls eyes* thing, hehe)

I run several modified Solidoodle 4 models (all purchased used), a larger kit printer that I built - the Folgertech FT-5, and I have a relative newcomer to the scene - kinda high end, but I am a beta tester for them - PrintIt Industries Horizon. Quite the machine. will run circles around most other printers, speed wise, and still put out high quality prints.

I do run RC stuff for a local guy, he builds custom racing RC's - mostly "monster trucks" but he also does pullers, and a few other things. He has, and knows how to use, Solidworks, so his stuff is usually good to go.
I also do prototyping and stuff for a few others, as well as my own "oh, this looks like fun" stuff, lol. My current project (when I am not printing stuff for others) is the 3D printed Rancher Jeep - some of the parts are a challenge.

Anyway, looking forward to seeing more of this build, I am really intrigued by the scale you chose to go with and all the 3d printed goodies to make it happen. =)
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  #19  
Old 01-14-2020, 06:24 PM
dremu dremu is offline
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I totally get ya! (especially on the *rolls eyes* thing, hehe)

I run several modified Solidoodle 4 models (all purchased used), a larger kit printer that I built - the Folgertech FT-5, and I have a relative newcomer to the scene - kinda high end, but I am a beta tester for them - PrintIt Industries Horizon. Quite the machine. will run circles around most other printers, speed wise, and still put out high quality prints.

I do run RC stuff for a local guy, he builds custom racing RC's - mostly "monster trucks" but he also does pullers, and a few other things. He has, and knows how to use, Solidworks, so his stuff is usually good to go.
I also do prototyping and stuff for a few others, as well as my own "oh, this looks like fun" stuff, lol. My current project (when I am not printing stuff for others) is the 3D printed Rancher Jeep - some of the parts are a challenge.

Anyway, looking forward to seeing more of this build, I am really intrigued by the scale you chose to go with and all the 3d printed goodies to make it happen. =)
I gotta Google that lot -- I suspect you're outta my league on the fancy-o-meter -- but the great thing about technology is that what's state-of-the-art (and expensive/esoteric) today will be run-of-the-mill (and cheap in a coupla years.

Holee carp, just Googled the Rancher Jeep. You're gonna print the whole bloody vehicle? Yeah, I can see where that could make you crazy, even on a fancy printer with high-density good material.

Donno what's so odd about the 1:10 scale. It was picked as a Goldilocks sort of thing. Much smaller and you get into "model" territory, where the parts are so fiddly you have to put them on with tweezers, and my arthritic fingers don't like that so much Any bigger and the dang thing requires two people to move.

As regards the printing, I'm hopeful that the scale is also a sweet spot. Parts can be made big enough to be strong but small enough to be detailed. ..shrug.. We'll see. I certainly can't say it's "done" by any means, but the basics are all in place. It moves under its own power and does what I wanted it to... prolly take some tweaking yet, but that's to be expected.

-- A

Last edited by dremu : 01-18-2020 at 12:35 AM.
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  #20  
Old 01-14-2020, 07:54 PM
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I used this body set and modified it for my mk48 build. I did use steel frame to weld in crossmembers. I also went with a walking beam style leaf suspension since that was how the 1:1 works. Gotta love the multi axle builds.


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  #21  
Old 01-14-2020, 08:29 PM
dremu dremu is offline
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I used this body set and modified it for my mk48 build. I did use steel frame to weld in crossmembers. I also went with a walking beam style leaf suspension since that was how the 1:1 works. Gotta love the multi axle builds.


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Oh dang, yeah, forgot to mention the LVS's. Doing the pivot is gnarly, that musta taken some doing. Sweet truck!

-- A
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  #22  
Old 01-14-2020, 10:01 PM
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yes, printing basically the entire vehicle - aside from screws and bearings, lol

Solidoodles are pretty much run of the mill cartesian style but the 4 is fully enclosed making printing with ABS a cake walk. the company went belly up a few years ago, so no new ones available, only used. They can be made to be super reliable tho.

99% of the printing i do is in ABS - which is why the Rancher is such a challenge.. large parts = long print times = tends to warp with ABS. But, ABS will also hold up much better than PLA will, so yeah.. I am a glutton for punishment, LOL

most of the "big rig" type stuff tends to run in 1/14th scale.. smaller, but not too small - that is why i mentioned being intrigued by the scale. Have often thought about building a 1/10th version of the other half's work truck.. just for kicks.
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  #23  
Old 01-15-2020, 12:13 PM
dremu dremu is offline
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yes, printing basically the entire vehicle - aside from screws and bearings, lol

Solidoodles are pretty much run of the mill cartesian style but the 4 is fully enclosed making printing with ABS a cake walk. the company went belly up a few years ago, so no new ones available, only used. They can be made to be super reliable tho.

99% of the printing i do is in ABS - which is why the Rancher is such a challenge.. large parts = long print times = tends to warp with ABS. But, ABS will also hold up much better than PLA will, so yeah.. I am a glutton for punishment, LOL

most of the "big rig" type stuff tends to run in 1/14th scale.. smaller, but not too small - that is why i mentioned being intrigued by the scale. Have often thought about building a 1/10th version of the other half's work truck.. just for kicks.
ABS is my go-to filament for most everything, but I'm lucky here that most of the pieces are relatively small. I had some trouble finding a nice OD green in ABS for a while, so I was stuck using PLA, but then I also had printer problems. Also, as we'll see later, the lift mechanism for the flatrack was too big to print in one piece.

Interesting on the scale; you look at the numbers and think "Oh, 1:14 doesn't sound much off 1:12." (Or 10.7:1 or whatever this crazy Chinese cab kit worked out to.) But when it's a 30-40' long 1:1 like a Kenworth or a HEMTT, yeah, it makes a difference. My wife laughs at me as I tote Frank around the house for testing or photo ops, 'cuz I have to crab-walk sideways through doors.

More to come as I organize pix.

-- A

Last edited by dremu : 01-18-2020 at 12:36 AM.
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  #24  
Old 01-18-2020, 07:18 PM
dremu dremu is offline
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As previously discussed, The Plan for Frank was for it to be an M1074, which is equipped with a compound lift arm arrangement to load a so-called "flatrack", a NATO standard for logistics interoperability. The flatracks not only allow carriage of a conex as you've seen here, but bulk cargo, vehicles, basically anything. More random interweb photos:



There's also a gizmo that connects the arm directly to a conex, the Container Handling System:



I debated building this, but doing so in scale with the right strength would have been tough. In retrospect I'm glad I didn't try, might have discouraged me to the point of giving up. The scale conex is like seven or eight pounds and I fear the leverage of it would either break the CHS, or the conex :|

While I've seen scale cranes and construction equipment with hydraulic cylinders, I've done hydraulics in the real world (built a mini skid steer) and loathe hydraulic fluid and plumbing. I figured there had to be a way to do this electrically -- again, how hard can it be? (shakes head)



What I wanted was a linear actuator, basically an electric motor that goes straight in a line instead of circularly. However, for this we'll need fairly small ones, though still fairly strong ones. After much Googling, I found a Canadian company that makes exactly that, Actuonix. They have a wide range of sizes and flavors, including controllable units. See, some actuators just have a stop on each end, so you feed them voltage one way and they go until the end, or you reverse the voltage and they go the other way until the other end.

For this purpose, finer control is required, so that you can say "go to 40% and stop" or whatever. I did find some with potentiometer feedback, so that, yeah, you could drive them with an Arduino or something ... but it would be a metric ton of code and wiring and work. Or there's some with USB, great for robotics or home automation, but less handy in a small environs like an RC truck.

But then I found Actuonix has some that use RC servo inputs. Bloody amazing, simple, and interface right to your rx. You just feed it a 1000uS-2000uS pulse. At one end it stays retracted, in the middle it extends linearly, and at the far end it extends all the way. No messing about with the Arduino and can just use the auxiliary dials on my TX. Could just as easily use a spare stick, but I had plans for those.

In the end, after much, MUCH pain, this was the net result:



That's the flatrack being unloaded off the truck. With me at the controls, it looks like this:


There's some starts and stops as I'm used to being on the left side of the truck, so I was turned around here and moved the dials the wrong way.


And loading the rack is the same, only reverse. As before, it's trickier than it looks to keep the thing level while manipulating two dials. The GIF above assumes linear matching movement for both sets of arms, which actually isn't optimal (you'll see the flatrack can be angled off the horizontal more than necessary.)

-- A

Last edited by dremu : 01-18-2020 at 08:11 PM.
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  #25  
Old 01-18-2020, 08:08 PM
dremu dremu is offline
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I say "much MUCH pain", as modelling the movement of the arms was hairy. One, they're compound, so the lifting of one affects the location of the other. Two, I'm using the same CAD software for modelling the truck, and for designing parts, so it might be a factotum thing, jack of all trades but master of none. And finally, and most critical, it's been YEARS since I was in school and my geometry was really, REALLY rusty. Took me a few days on and off to sort out how to deal with non-right triangles with known-but-variable sides and unknown angles (mmm, the law of cosines!)



The far side is the left side of the truck (front to upper left), and you can see all sorts of triangles and pins for hinge points and measuring. It was a triumph for me, anyway, when I figured it all out. I did have to retract my question from high school though, when I asked my teacher, Miss Simms, "When will I ever use this crap again?"

The answer is, now, decades later. Miss Simms, you win



Kinda hard to visualize, though the animation and videos above should help. The black and grey gizmos are the actuators in question, basically like hydraulic cylinders, but square. Front of truck is to the bottom right, by the green hook. When designing I tend to use multiple colors so I can distinguish parts or sections from one another, so forgive the garish colors

Extending the short, upper set of actuators results in movement like this:



Moves the hook up and back, pushing the rack with it.

Extending the longer, lower set of actuators looks like this:



Again, it's a compound thing as the lower actuators move a base a-frame (with a cactus-looking center pole), and then the upper actuators move off that to the hook.

While working on the a-frame it looks like this (again with the garish colors). Rear of truck to bottom left.



And then rendered for export to the 3D print software.



That's actually cheating, as the part is too big to print even in my big printer and has to be split into two, then glued and bolted together. This is an early test print of the lower half.



Because 3D printers print from the bottom up, if you have a piece that has empty space underneath, the printer has to support that bridged area (again, gross oversimplification but you get the idea.) You can see on the right side a bunch of vertical lines that aren't in the render; they're the supports in question. They're thin enough that you can break them off, maybe with some sanding and/or chemical treatment, to get your desired part.

There's also some random strings of plastic hanging off which are to do with temperature settings not being quite right. Not only does each TYPE of plastic require you to tune your printer to it in terms of movement speed and feed rate and plate and extruder temperatures, but different BRANDS of the same kind of plastic will vary, as we'll see later. I wasn't kidding about printing being more a dark art than a science. At the least it involves a lot of trial and error, or as my buddy says, "It's an iterative process"

The big focus with the lift mechanism was that it's what defines this truck, right, it's the whole point, but at the same time it has to be strong enough to actually heft several pounds of flatrack and conex reliably. Not only did this mean multiple actuators, but I had to fiddle with their angles as well to get the right lift. Again with the trigonometry and geometry, ugh.

The 1:1's hydraulic cylinders can exert tremendous force, so the lower set is very close to horizontal. When I tested the actuators at such an angle, I found they wanted to just break the plastic holding them rather than lift the aframe They ended up about 10* up from horizontal so that they'd start lifting, but still had enough travel to move the thing over the complete range. This in turn jacked up the floor of the flatrack a bit more than I'd like. If you look closely, you'll see that Frank's conex rides a bit high as compared to the 1:1's.



I did the math, however, and surprisingly it's only about 6" higher scaled, so I call it an acceptable compromise to make this truck work. I really wanted Frank to be more than just a truck that drives around, wanted it to be a truck where all the parts work.

Next up, more working parts, more geometry, more me tearing out my very limited supply of hair.

-- A

Last edited by dremu : 01-19-2020 at 12:23 AM.
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  #26  
Old 01-18-2020, 10:34 PM
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Impressive!
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Old 01-20-2020, 04:21 PM
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Awesome project!

I think I would have printed most parts with 100% infill, drill holes and insert brass threads.
They work well and fits with help of a soldering iron.

And for glue, try some sort of bondene and styrene.
The glue is like water and you can't glue your hands together lol. it's impossible.

I'm not that precise when it comes down to cutting, due eyesight.
Styrene is fun and for a box shape you can make the plates a tad to big, and then sand down.

For me the biggest drawback is the lines in the prints.
And if there is one thing I hate, it's sanding.
I do have a printer, but its set up wrong and the display won't work, so I haven't been able to print anything at all.

One thing I do know, it would have taken me ages as I would have printed most parts with 0.1 layers as I hate print lines lol.


I'm intrested to see the rest of this build.
And I do like pictures
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Old 01-20-2020, 06:17 PM
dremu dremu is offline
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Thanks all for the good words!

100% infill would be tough, IMO. Warp like crazy, never mind the amount of material and time. I've never had to go that far for traditional filaments. (The flexible stuff is another matter entirely.) The brass nutserts are a great idea, though. Dangit, wish I'd thunk of that. Maybe my next build ..scratches chin..

I'm doing better with styrene now that I've had some experience. Trying to get out of my comfort zone of PRINT ALL THE THINGS!, but in the end we do what works for us.

The lines on printed surfaces, though, totally with you. Doesn't help that PLA is basically un-sandable, and even ABS and printed styrene are as you say tedious. Careful planning of what side is up or down in the print helps, as does breaking up a part into multiple pieces. And ABS can be cleaned/surfaced chemically, or so I hear. I've only messed with it a bit.

One piece I think I forgot to mention is on the back end. It's simple, but critical to the movement of the flatracks. The 1:1's have a set of rollers on the back, which not only hold the flatracks, but guide them into position:



See highlight. The outer, angled rollers help center and align the rack going either direction, and then the rearmost level ones hold it up. It's hard to see in the photos as they're printed in black:



kinda underwhelming, I know, but when CAD'ed:



Gotta admit, with this project I've gotten way more adventuresome with the CAD. Was an absolute bloody necessity to scope the movement of the racks, the animation above, but even the little things like the bolts and heads in this part. I can plan ahead and countersink the one set so the rack doesn't trip on the heads. And going back to the bit where I had to move the flatrack up to get leverage from the lift mechanism, having this in CAD was priceless. Coupla mouse clicks and it moves up, oops, too much, coupla more clicks, move it back down until it's right. Can't say I got everything right the first time, but certainly avoided a TON of rework.

-- A

Last edited by dremu : 01-20-2020 at 06:53 PM.
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  #29  
Old 01-20-2020, 09:18 PM
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Gotta admit, with this project I've gotten way more adventuresome with the CAD. Was an absolute bloody necessity to scope the movement of the racks, the animation above, but even the little things like the bolts and heads in this part. I can plan ahead and countersink the one set so the rack doesn't trip on the heads. And going back to the bit where I had to move the flatrack up to get leverage from the lift mechanism, having this in CAD was priceless. Coupla mouse clicks and it moves up, oops, too much, coupla more clicks, move it back down until it's right. Can't say I got everything right the first time, but certainly avoided a TON of rework.
And that is the beauty of learning how to work with stuff in the 3d world. =)
I will say, you have gotten a lot more adventurous than I have with the CAD work, but yeah, it does pay off to learn how to do it.

Really enjoying seeing this build come together, and how you went about figuring things out.

as for the chemical smoothing of ABS - yeah, it can be done. I have only tried the "cold" method myself.. soaking paper towels in acetone, attaching them to the sides of a container (i have an old steel pot - used mini magnets to hold the toweling in place), and putting the piece in/under that to let the vapors do their thing.. it does work, but timing is everything.. not long enough, and it doesn't look like anything happened, too long and it is a "melted" mess, LOL. One of those "use in a well ventilated area" kind of things, too.
it is easier to do a little sanding, then brush acetone over the surface to "melt" in the sanding dust.
Acetone also makes a great "glue" when connecting two ABS pieces.
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Old 01-20-2020, 11:28 PM
dremu dremu is offline
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Heh, that's almost exactly my experience, save that I used a gallon paint can. Mini magnets, paper towels, either we're both geniuses or we both read the same web page

For glue I've had very good luck with this stuff

https://www.tapplastics.com/product/..._16_cement/132

It bonds dang near any plastic to dang near any plastic, similar or not. The "gluing my fingers together" bit was a joke ... well, sort of. CA glue and I don't get along, though I'm finding the newer gel types to be manageable. My eyesight and finger grip aren't what they once were, so maybe that's why the runnier CA glue is so tricky ..shrug.. I'll have to try the acetone + sanding thing, though, that sounds fairly straight-forward.

As for the build, yeah, it's mostly been fun. Before I got the Cross kit I very briefly messed with building an Arduino quadcopter, and VERY quickly discovered that I don't like flying things. They crash. All the time. Repeatedly. Self-levelling my fat hairy ... well, anyway, they aren't self-levelling. They crash, and it's expensive and a ton of work to fix each time.

RC trucks, on the other hand, are simple, especially slow/large stuff like this. You let off the throttle, it slows/stops, and sits there. As long as you're not stupidly off-camber, you're golden -- and face it, a PLS is not a King Of The Hammers sort of truck.

-- A
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