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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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  #46  
Old 01-23-2020, 02:42 PM
dremu dremu is offline
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Originally Posted by caprinut View Post
Speaking of printers..

Which can print nylon, or what do you need to change to be able to print nylon?
Thinking of making suspension parts etc..
Depending on the size of the part, you might not need nylon for suspension. Denser-infill ABS might do fine. Or if you wanna do weird filament, there's CF-infused ones that would be stiff and light, right?

That said, IIRC, it's higher temperature and/or more abrasive, so you use a stainless nozzle instead of the more common brass, and I think a metal or some other more solid tube to the nozzle in place of PTFE. My Qidi came with a second head set up for nylon, but I only did a few parts in it. Specifically, I wanted to do the drive gears for the crane rotation mechanism in something that could handle the face wear more than PLA or ABS.

Guess it's as good a time as any to start into the description of the crane setup, but as relating to this topic:



That's the big "spur" gear that the crane turns on (upside down, as it rides on your basic fidget spinner/skateboard bearing.) Rightside up it has a slot for the crane to glue into:



It's driven by a worm gear which goes sideways against it:



The CAD is often more exciting and easier to grok than the real world, as black things bolted to other black things tend to be hard to make out. But, just to prove it happened:





And yeah, that's just your basic servo ... sort of. It's what's called a "continuous rotation" servo (hereinafter "coro" as the full name is hard to type). You see them all the time in Arduino and robotics projects but aren't as common in RC, I don't think. They aren't limited in arc the way a regular servo is, so if you move your rx lever or dial one way, the servo just turns in one direction. More lever or dial turns it faster, but it won't stop. Move the lever or dial the other direction, the servo turns the other direction. In a perfect world (and it takes fiddling), a centered lever/dial makes the servo stop turning at all.

Coro's are great, then, for situations like this where the wormgear has to turn a bunch of times. I've got the gearing at about 1:10, and I may actually need more. As with regular ring/pinion setups, juggling the number of teeth on the gears gets hairy as the teeth get too small and you lose strength (and in this case, the piece gets harder to print.) The worm gear was a challenge as it is; ended up printing it in two halves and then gluing them together. I did my best to align the teeth, but it wasn't perfect and there was some flash. Took me forever to file out the goobers and get the worm teeth nice and spiralled. Nylon does not like to be filed

Sure, you COULD use some other type of motor, especially with an Arduino. I just like servo motors 'cuz they connect directly to the rx (or to the servo board, in this case) and don't take much work.

You could do a traditional DC motor, and have the Arduino trap the rx control, translate it to an analog up/down speed, then convert to PPM or whatever and drive it with a motor shield or something. I've done that, I have network-enabled motorized blinds at home I built that do it. But that's a lot of pieces to stuff into an RC, versus the servos are small and simple and work like all the other stuff.

More to come in another post.

-- A

Last edited by dremu : 01-26-2020 at 05:04 PM.
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  #47  
Old 01-23-2020, 03:00 PM
dremu dremu is offline
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Originally Posted by heartless View Post
print temps are basically the same as for PLA, but yeah, you would probably want at least a hardened nozzle - it could eat up a standard brass one in no time.

I got a sample of the copper (their first offering) at a Maker Faire a few years ago and tried it out (did not get it sintered, however) and it was basically pretty easy to print with, altho kind of brittle, so no hard bends going into the hotend, unless you use a warmer to preheat it a little to make it more flexible. Had to slow the speed down just a little, too - kind of like using PETG - a bit more viscous than standard PLA.

Printed a chess piece just cause.. it didnt come out too bad. Pic is straight off the printer.

My setups use an overhead spool holder, so it was no problem for me on the open frame printer, but could be for those that hang the spool off the side, or sit it next to the printer.






quite the imagery, lol
Yeah, I learned early on that overhead spools are the way to go. Means I have to keep a stepstool in the garage to get up there, but the feeding is sooo much smoother.

I chuckle when you say "this is straight off the printer." Again with the what-people-see-on-TV preconceptions, that 3D printers just magically spit out a perfect piece. Well, no, you generally gotta file or sand or tune them. Be like casting in acrylic or something, I think (not that I've done so), but there's flash or support or whatever that needs a bit of love. Though yours came out awful nice, especially if you didn't try 37 times to tweak settings like I always seem to have to.

Also good info on fiddling with the settings. Last coupla days I've been trying to get my Flashforge to do duplex color prints, and while they're both ABS the two colors are from different vendors (it's what I had handy), and while I *thought* I could make it work ... ugh. One of those things where Brand X likes a temperature or speed or whatever slightly higher or lower than Brand Y. Teach me to get the cheap stuff just because they were out of tghe brand I know, from now on I'll wait for it come back into stock. (Historically I've had good luck with Hatchbox; the Gizmodorks underwhelmed me.)

As for Frank, it saddened me slightly that what's taken me however many months to put together ... could be taken down in basically a long afternoon. And that was with carefully separating all the fasteners for each section: all the stuff for each axle in a bucket, the crane, the body, etc etc.



End up with a LOT of those plastic buckets, and then a bare frame:



Which is truly underwhelming to look at unless you know the amount of work that goes into that. Also the number of fasteners. That is a metric buttload of M3, I tell ya.



Primered it and then a coat of ultraflat OD, and things look better. That OD is REALLY dark and doesn't quite match the printed OD, but I'm not gonna tear down the aframe and eleven wheels and whatever else to paint them. Close enough

-- A

Last edited by dremu : 01-30-2020 at 07:50 PM.
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  #48  
Old 01-23-2020, 04:11 PM
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I know the feeling.

Most of my builds takes years to complete, but only hours to tear down..

Regarding Coro's as you call them, is known in the crawler community as winch sevo.
There is several brands selling internal and external winch servos.
I have personally converted several servos to winch servos in the past, but these days I use a normal winch.

Thanks for the nylon tips.
I need to read up on that.
Even saw one chap printing nylon on a stock Ender 3, but that seems to come out too soft and bendy for my liking.
I think Ender 3 is too cold even at 255 degrees.

If I only could get my free FLSun Delta working, I would at least have a starting point..
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  #49  
Old 01-23-2020, 05:37 PM
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Quote:
Originally Posted by caprinut View Post
Speaking of printers..

Which can print nylon, or what do you need to change to be able to print nylon?
Thinking of making suspension parts etc..
Any printer can be made nylon capable.. it is not the printer so much as the hotend that makes the difference.

you want an "all metal" type hotend - there are a few out there, so look around.
I personally use E3D v6 hotends on my printers and can do most materials with no issue. I have a good friend that prefers Microswiss.

Any hotend that uses a liner will not be able to run hot enough to print nylon. Liners limit the temps to 245C or less - all metal units can go up to 295C with no worries, higher if you swap out the thermistor for a thermocouple. Thermistors get damaged at 300C or higher.

Taulman 910 Nylon alloy is pretty easy to work with, and a good all around product. prints beautifully if you can get to the required temp - somewhere around 275C.

Plain Nylon is fine thru a brass nozzle for occasional use - unless you plan on printing a lot of it, all the time, i would not worry too much about the nozzle.

it is "filled" filaments that will destroy a brass nozzle quickly.. things like wood fill, carbon fiber fill, or metal fill.. those are the ones you want the hardened or stainless nozzles for.
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  #50  
Old 01-23-2020, 06:03 PM
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Originally Posted by dremu View Post
Yeah, I learned early on that overhead spools are the way to go. Means I have to keep a stepstool in the garage to get up there, but the feeding is sooo much smoother.

I chuckle when you say "this is straight off the printer." Again with the what-people-see-on-TV preconceptions, that 3D printers just magically spit out a perfect piece. Well, no, you generally gotta file or sand or tune them. Be like casting in acrylic or something, I think (not that I've done so), but there's flash or support or whatever that needs a bit of love. Though yours came out awful nice, especially if you didn't try 37 times to tweak settings like I always seem to have to.
yeah, most have no understanding of what "straight off the printer" really means. LOL I have been playing with these infernal machines for several years now (since feb 2015), and have #1 set up and tweaked so well these days that it is pretty much a "turn it on and print" machine now. #2 is pretty close to that.

Quote:
Also good info on fiddling with the settings. Last coupla days I've been trying to get my Flashforge to do duplex color prints, and while they're both ABS the two colors are from different vendors (it's what I had handy), and while I *thought* I could make it work ... ugh. One of those things where Brand X likes a temperature or speed or whatever slightly higher or lower than Brand Y. Teach me to get the cheap stuff just because they were out of tghe brand I know, from now on I'll wait for it co come back into stock. (Historically I've had good luck with Hatchbox; the Gizmodorks underwhelmed me.)
I can highly recommend the Veracity brand. I use it a lot these days. Used to buy Octave brand almost exclusively, but they folded last year. You can get Veracity from filastruder.com - based in Georgia. I do use Hatchbox for certain colors - their red is the best looking red i have found. Another brand I use fairly regularly is Inland, from Microcenter. I have had issues with their red, however, so I tend to stay away from that one (too dark anyway).. the blues, green & yellow are all decent enough.

Quote:
As for Frank, it saddened me slightly that what's taken me however many months to put together ... could be taken down in basically a long afternoon. And that was with carefully separating all the fasteners for each section: all the stuff for each axle in a bucket, the crane, the body, etc etc. End up with a lot of little plastic buckets, and then a bare frame:

Which is truly underwhelming to look at unless you know the amount of work that goes into that. Also the number of fasteners. That is a metric buttload of M3, I tell ya.

Primered it and then a coat of ultraflat OD, and things look better. That OD is REALLY dark and doesn't quite match the printed OD, but I'm not gonna tear down the aframe and eleven wheels and whatever else to paint them. Close enough

-- A
LOL, yeah, it is amazing how many fasteners end up in a custom built RC..
not sure if you know about them, but boltdepot.com is a great resource! Trying to find a good selection of metric screws around here is an exercise in futility.. found boltdepot one day and have never looked back. need just one? no problem need 1000? also no problem - and all shipped direct to my door. =)

the frame is underwhelming? yeah, no - i dont think so.. not when I look at the thing knowing the time you spent making all the bits & pieces to put it together.

now you get the real fun of putting it all back together! LOL
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  #51  
Old 01-23-2020, 06:08 PM
dremu dremu is offline
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Quote:
Originally Posted by caprinut View Post
I know the feeling.

Most of my builds takes years to complete, but only hours to tear down..

Regarding Coro's as you call them, is known in the crawler community as winch sevo.
There is several brands selling internal and external winch servos.
I have personally converted several servos to winch servos in the past, but these days I use a normal winch.

Thanks for the nylon tips.
I need to read up on that.
Even saw one chap printing nylon on a stock Ender 3, but that seems to come out too soft and bendy for my liking.
I think Ender 3 is too cold even at 255 degrees.

If I only could get my free FLSun Delta working, I would at least have a starting point..
Oh yeah, "sail winch" was a term I saw for the RC's. Guess the boat guys use them too. Didn't know they were common for cars.

250+ seems hot even for nylon; I think my Qidi says 240. Also depends on the brand of filament, as I've had PLA that wants 180 and PLA that wants like 220. Which sure sounds more like ABS to me, but what do I know.

Speaking of winches, back to the crane...





Bunch of challenges here. One, the M1074's crane is hard to get pix of to work from. I cheated 'cuz pix of the HEMTT crane are more common. However, two of the hydraulic cylinders have greater travel than the other two, so the mounting points are asymmetrical. Compare the two smaller ones to the left vs the larger to the right.



(another random interweb pic.)

That drove me crazy for a while until I gave up trying to duplicate it and did mine with the same offset top and bottom. Not accurate to the 1:1, but it's not immediately obvious. Went round and round (see what I did there) deciding on gear options and finding a good library for OpenSCAD to do them, and eventually settled on the worm/spur arrangement you see above. Like the Arduinos, lots of folks have written libraries for OpenSCAD to do (fill in the blank), so you don't have to reinvent the wheel (or in the case, the gear.)

Fitment was also a trick. The actuators only come in such-and-such sizes, gotta work around the main aframe and the cab, etc. For being a meter long, there's surprisingly little room in this thing!



Once again the CAD was key. Even though I'm not gonna print all the pieces, there's a model of the actuators and the servo and the bearings in there. From that I can say, yep, it'll all fit, barely. Printed a platform for it



(this is the bottom side, with hexes for nuts) and put a piece of styrene sheet on the top to make it look nice. As pointed out, printers have a hard time doing a nice flat surface.

Ends up looking like



There being cat scanned by HRH Princess Irulan Corrino Atriedes aka "Faith." It passed the sniff test.

And then with all the parts assembled on. Yet another complex thing to tear when the time comes to paint, sigh.



Again, the CAD kinda looks better than the real thing, hard to see. The four lift actuators -- red and blue in the top pic -- are set to have three positions. One is all the way down. The other two positions are like 80% lift, and full lift, to allow the main arm to clear the aframe hook as the crane rotates. Did I mention it's a tight fit?



That's down, and then mostly-up is



If it goes all the way up, the actuators come so far forward they interfere with the hook in the rotation. If I scoot the crane forward on the truck to clear the hook, it runs into the cab. Thus the 3-position thing (that and I had a three-position switch going unused on my tx, so it wasn't a hardship.)

That main arm is in turn a longer actuator, so it can extend out to the side of the truck, or almost halfway down the flatrack. The crane isn't strong enough to pick up a vehicle, say, it's not a wrecker, but can do cargo like tires and the like and move them to the flatrack. Once I get Frank back together and have some good lighting I'll have videos of that.

And finally, circling back to the winch, there's a baby coro on the end.
Kinda see it all the way at the back, but it's the blue thing. It's actually attached to the actuator, so it moves in and out, necessitating its wire being curled to expand and contract. Sooooo many wires on this thing; whose idea was it to have all these motorized parts??

Made its capstan from a coupla the circular servo arms, because printing a spline that small is dang near impossible, then printed a tube between. A hook from some other kit, put heatshrink one the end of some silver string, and it looks like wire rope.

Finally, the rotation servo and its worm gear sit in a bearing on the other end, some little 13mm thing I had laying around. Printed up a pillow block of Just The Right height



The rotation mechanism is an M8 bolt down through the spinner bearings into this base



Notice that the mounting is slotted, so that the gear mesh can be adjusted just a smidge.

Okay, that's the crane, demos to come. Not quite as proud of this as I am of the larger-stronger-oh-my-god-so-much-more-work a-frame, but it's still clever and fun and surprisingly close to the 1:1.

-- A

Last edited by dremu : 01-24-2020 at 12:37 AM.
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  #52  
Old 01-24-2020, 12:00 AM
dremu dremu is offline
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Oh oh, and one other simple thing. The hook on the 1:1's is a fold-down so that the trucks are air-transportable. Now, I have ZERO intention of ever owning a 1:10 scale C-130 (refer to the crashing above), but in the interest of the slight accuracy Frank has (plus 'cuz it's fun), his folds too:



Hinges on a piece of spring steel pin, aka a paperclip (those things are stout!)



and is held in place by what I think is called a lynchpin:



I coulda printed something or done styrene or whatever, but an inch or so of brass tube and a paperclip and ten minutes with the Dremel, and I have the exact thing I needed. Sometimes simple is best, even for me =))

-- A

Last edited by dremu : 01-24-2020 at 12:38 AM.
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  #53  
Old 01-26-2020, 04:30 PM
dremu dremu is offline
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Okay, Frank is out of the paint booth and is running and mostly what I wanted. Took him out today and put him through his paces, found some stuff that needs tweaking, but basically there.




And whether on or off the road, Frank drives basically the same. Gotta love 10 wheel drive!



I'm jumping WAY ahead of my write up here, I know, forgive me. There's lots of intermediate pix, many with cats, yet to go through.

Today's exercise was to unload the conex and load up the M809. Let's see how Frank did (and how his operator did!)


Outrigger feet go down, and the arms do their thing. I'm still learning to do it; there's a trick to moving the big arm one direction, the little one first the same direction, then the opposite, then the first direction again. This keeps the load closer to level, which I don't always manage.

Then unlatch the hook, lift the outriggers, and off we go.

A magic invisible crane (me) then removes the conex, and the M809 comes around to be loaded. Remember on that truck I did the sound board. Cute for 30 seconds, then annoying. But listen for the airbrakes hiss off at the end.


Was tough for me to back up when looking at the truck sideways as I was behind the camera for this. Guess I shoulda been outside of shot, left of camera == behind the truck.

Then came time to load. I have some little chains and stuff, and as always,



-- A

Last edited by dremu : 02-06-2020 at 06:49 PM.
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  #54  
Old 01-26-2020, 04:38 PM
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So first I chained around the axles and just wrapped the other ends around the flatrack, figured it would hold the fiver.


Apparently not.

Then I strapped the fiver down with a coupla cargo straps (again ahead of myself, those will show up later)


And the fiver goes for a roll again. Doh.

Okay, four straps, as tight as I can get them (they don't ratchet, just friction hold), and success!


Lift the arms, back up to the flatrack. Latch, lower the outriggers. Then pull, carefully dialling the knobs this way and that (and still not getting it quite right; I gotta practice!) But the M809 is loaded, so we raise the outriggers -- watch the back end sink under the weight. That's with the high density tire foams I haven't discussed yet.

-- A

Last edited by dremu : 01-26-2020 at 08:06 PM.
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  #55  
Old 01-26-2020, 04:51 PM
dremu dremu is offline
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Finally, some bits and bobs of videos while Frank was out.

General running around loaded:


When the crane, lift arms or outriggers are in use, the lights strobe. This is the front end, with rotating beacon effect and the traffic director on the cab brim. Yes, the passenger side orange LED got unplugged.


The rear traffic director:

In normal operation, the rear has a center brake, and the turn signals are sequential:


And in reverse, the rear and side lights strobe to warn passersby to exercise caution. I have miserable backup skills


Lots more to come on the light front, including an explanation of how it only takes one wire to do all of that (well, one wire plus power and ground). I like lights, especially blinky lights.

-- A

Last edited by dremu : 01-26-2020 at 05:06 PM.
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  #56  
Old 01-26-2020, 07:26 PM
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wow... just.. WOW
awesome stuff!
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  #57  
Old 01-27-2020, 11:23 AM
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Awesome :nice.
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Old 01-27-2020, 05:10 PM
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Nice to see it run, what no emergency brake in the 6 x 6

Well done
pep
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Old 01-27-2020, 07:34 PM
dremu dremu is offline
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Nice to see it run, what no emergency brake in the 6 x 6

Well done
pep
You know, I'm kicking myself because I have a set of wheelchocks I printed in the flexible filament for just this purpose. Nice and heavy, dense, fairly good traction (think tire rubber.) Coulda used them, didn't think of it.

But yeah, even in gear, you tip that 6x6 and it rolls. Kinda surprising.

And thanks. For a first scratch build I think it came out okay. Still some tweaking, and lots to write up here, but not half bad.

-- A

Last edited by dremu : 01-27-2020 at 07:56 PM.
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Old 01-28-2020, 06:02 AM
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"tweaking" that is always part of it, even straight up kit builds require it. That and the builder having a desire to dial things being the motivator.

There is a lot going on with that loader, slick model and unusual.


How many servos at work in there ?
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