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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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  #91  
Old 02-12-2020, 06:20 PM
dremu dremu is offline
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Now, there's two racks (the flatrack with the conex and the box rack with the drop sides), but the truck can only carry one of them. The next logical step, then, would be some way to carry both. Hmm, what would that be?



Why, an M1076 trailer of course. Put on the CAD hat again...



Obviously wasn't remotely that easy nor that quick, but was certainly simpler and faster than the truck. Also, from my Googling it seems like there's actually a coupla manufacturers for the 1:1's with different designs, so I could get away with deviating a bit from the 1:1. The trailer is also shared with the HEMTT, further fitting into my Franken-Oshkosh motif.

The trailer can carry any rack that fits on the truck, and it doesn't need a load/unload mechanism of its own as it shares with the truck. You drive with both, then unhook the trailer, drive off and unload the truck. Come back, hook the truck back up to the trailer and slide *its* rack onto the truck. Unhook the trailer again and go and unload. Loading is the opposite: load onto the truck, transfer to trailer, load onto truck again.

I'll do some videos of this in due course.











There's different views and some visualizations with the two different racks.

The M1076 is complicated in that the front axle is on a turntable, as you see in the first render, to assist in turning. However, when backing up, you *don't* want it turning, so you gotta have a lock to hold it in place.

Correspondingly, when towing you want the lunette far enough out that the trailer and load don't hit the truck on corners. But when transferring from the truck to and from the trailer, the trailer has to be close enough for the hook to grab. The lunette is therefore on a telescoping arrangement with lock points for the two positions. The 1:1's have a pneumatic leg for the front a-frame because it's so heavy; I decided to forgo that as I had enough trouble fitting in all the other detail.

Of course it has lights, in an approximation of the 1:1's lights and reflectors, that run off Frank's turn signals, brake, reverse.

Here's Frank fully loaded:



--A

Last edited by dremu : 02-14-2020 at 01:20 PM.
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  #92  
Old 02-12-2020, 06:24 PM
dremu dremu is offline
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And the aframe with the lunette and various other details:



That's with the telescoping part stretched out for towing, and yes, those are metal tow chains in case the lunette fails. Which it did a coupla times, so the chains paid off, or else we'd have lost a trailer at approximately 3/4MPH

And finally, turning the trailer:



-- A
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  #93  
Old 02-12-2020, 06:32 PM
dremu dremu is offline
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As with the truck, the trailer is aluminum channel frame with 3D printed crossmembers.



That's not quite finalized; later it got the horizontal sliders for the racks down the sides.

There isn't an actual suspension; in the future I may do either metal or plastic leaf springs with separate leaves, but for now they're just solid, faux springs:



That's the rear tandem, front has similar "springs" but flipped 180*. This is the front turntable, which rides on fidget spinner / skateboard bearings:



-- A

Last edited by dremu : 02-13-2020 at 03:04 AM.
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  #94  
Old 02-12-2020, 06:40 PM
dremu dremu is offline
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As with the truck, was challenged to find an appropriately military tread tire, further challenged to find one slightly smaller than those on the truck (the truck 1:1's use 16.00R20's while the trailers have 15.50/80R20.)

Finally found some fairly close, though they had their issues which we'll go through in a minute.

The one place with the trailer where I could really cut loose was the wheels. Since the trailer isn't driven, the wheels need not have beadlocks, so I went for as much cosmetic accuracy as possible. Here's the 1:1



and my final iteration



Dang close IMO.

These have a hub cap that pops off, covers a nylock inside to hold it to the axle (M4 threaded rod.)



and then a brass bushing inside to ride on the axle



As previously mentioned, 3D printing is not an exact science (not even a science at all.) Used the wrong temperature profile once for this brand / plastic / phase of the moon, and this is the sort of thing you get:



Left, good; right, not so much. Doh.

-- A

Last edited by dremu : 02-13-2020 at 12:33 PM.
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  #95  
Old 02-12-2020, 06:47 PM
dremu dremu is offline
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The tires came as a set with wheels (not that I cared), but were really cheap, and when I got them I found out why. Yes, they have foams inside...



Just utterly useless ones.



That's the same pressure on a test wheel with a new foam inside... a nice new stiff foam made from an oversize pool noodle!



Got me a hot wire cutter and went to town slicing up that pool noodle. Ignore the top one as its center is cut way too far; see the comparison pic below for where I got the inner diameter dialled in.



Left, the foam that came in the trailer tires, bah. Center, obvi my new ones, and right, the foams that came in Frank's tires. Those were much better than the cheap ones that came in the trailer tires, but I still ended up replacing those with pool noodle slices as as the pool noodle is stiffer yet.

Frank's factory foams:



and the noodle:



As before, same pressure, visible difference. Frank needs all the help he can get holding up all that weight.

-- A

Last edited by dremu : 02-13-2020 at 12:35 PM.
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  #96  
Old 02-12-2020, 07:03 PM
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2redrovers 2redrovers is offline
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Awesome work as always
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  #97  
Old 02-12-2020, 07:14 PM
dremu dremu is offline
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Dad was out this weekend, and after some initial trepidation and confusion with both why I as a grown adult would play with toys, and the sheer size of them ... we all had great fun, three generations out playing with (I mean, carefully testing ) Frank.



There's a little playground, with sand and gravel and rocks, highway made from roof shingles and a bridge I made out of a busted up pallet.



There's actually a bunch more of those big river rocks I gotta add in yet. Pile didn't look so small until I got the truck in there. While obviously Frank's not a crawler, he got in and out okay as long as I picked a decent line.



The bridge goes over a 4x6 -- you've heard of the Bridge Over The River Kwai. This is the Bridge Over The Railroad Tie (groans.)

It's a good think Frank is 10x10, because the suspension doesn't have enough droop on the (admittedly steep) bridge. Axle #5 isn't remotely touching.



Finally, Dad wrangling the thing over the bridge. He's got the truck facing him so the steering is backwards, and it took him a while


-- A
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  #98  
Old 02-12-2020, 07:24 PM
dremu dremu is offline
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Finally, eagle-eyed viewers will have noticed some of these in the last few posts, but teasers of what's to come:





-- A
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  #99  
Old 02-12-2020, 09:46 PM
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i gotta admit, I log in daily to see what new & fun stuff gets posted.. and this is one of the threads I get excited to see updates in.

the trailer looks great!
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  #100  
Old 02-13-2020, 12:52 PM
dremu dremu is offline
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Thanks all for the kind words! I'm generally pleased with the results, though sometimes I look at what I did and just shake my head, throw it out, try again. Sometimes I say "Well, poop, now I know how NOT to do that, and I'll do it [different|better] next time." Sometimes I just accept that my work is that of a novice, and hopefully I'm gaining skills and patience. I take a lot of guidance from y'all and your threads here. Lots of work that's far better than mine

Frank also is an intentional compromise by design. He coulda been closer to the 1:1, but I had to diverge as I wanted it to be functional as opposed to just a static model. And my habit of 3D printing things (vs eg styrene fab) sometimes makes pieces kinda rough, or look more like toys than models ... but ..shrug.. I enjoy it, and I suppose in the end that's the key.

I'd started building the truck long before I started posting because I wanted to make sure I could finish it. More than once I've seen folks start a build thread and get overwhelmed or flat give up, and I didn't want to be there. Once I was pretty sure it would happen, I went back and started organized the photos and started the writeup.

Points being, (1) the breakneck pace is misleading, and (2) I'm almost done with the photos, so sadly there's gonna be a slowdown, at least until the next project comes along.

Though I already have several ideas for next projects, some simple and some "Oh My God what was I thinking" complicated

-- A

Last edited by dremu : 02-14-2020 at 12:34 PM.
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  #101  
Old 02-20-2020, 07:44 PM
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Coming along nicely

Tips for future build.

You could do like a mate of mine did with his excavator reinforce bits like a crane with a matal plate on the outside of the prints to make them stronger.
1:10 winch motor and their small garboxes can also be used to move a crane, simply by have a allthread axle and a nut side.
Big cranes can be built using strong servo with the same allthread and nut system.

My brain just spins after the fact you have coded everything.
And so glad that we see new people in this hobby now and then, it becomes rarer with time.

And I like your trailer
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  #102  
Old 02-21-2020, 07:28 PM
dremu dremu is offline
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Thanks!

Took me a while to sort what you meant about the allthread, but you mean like a small version of



where the rod turns and the brass (or whatever) in the middle moves up and down. Oddly enough, these are the key mechanism to 3D printers and I still don't know what they're called. "Linear motion screw" seems to get them on the Google though.

As for the coding, it would either be hours and hours of tedious measuring and mouse-clicking, or hours and hours of tedious measuring and typing. All comes down to what you like to do.

And yeah, I'm surprised at how few folks are doing stuff, but maybe drones are more popular. We know how I feel about flying, so here's to hoping I have a few more years of making things ahead of me

-- A
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  #103  
Old 02-21-2020, 09:45 PM
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root shingle highway ........ keep that a secret, we do not want the city grabbing that idea, cause we would be driving on it LOL

I make a joke but it has a realistic road look about it. How are you keeping them from separating ?
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  #104  
Old 02-22-2020, 08:14 AM
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Quote:
Originally Posted by dremu View Post
Thanks!

Took me a while to sort what you meant about the allthread, but you mean like a small version of

where the rod turns and the brass (or whatever) in the middle moves up and down. Oddly enough, these are the key mechanism to 3D printers and I still don't know what they're called. "Linear motion screw" seems to get them on the Google though.

-- A
Allthread is any threaded rod that can take a standard nut - it is threaded the entire length of the rod & comes in standardized sizes, both metric and sae

the picture you shared is of a "lead screw". It uses a specialized nut to move the length.

there are also "ball screws", which are similar to the lead screw, but use more ball bearings in the "nut" to handle moving a load
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  #105  
Old 02-22-2020, 08:21 AM
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caprinut caprinut is offline
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Quote:
Originally Posted by dremu View Post
Thanks!

Took me a while to sort what you meant about the allthread, but you mean like a small version of



where the rod turns and the brass (or whatever) in the middle moves up and down. Oddly enough, these are the key mechanism to 3D printers and I still don't know what they're called. "Linear motion screw" seems to get them on the Google though.



-- A
Yep allthread is basicly a rod that are threaded all the way, like a really long bolt without the head.
The dump truck guys have made their own system for years doing so.
And more recent years used on printers.
If don't remember wrong, the printers seems to use fine pitch M5 or so.

A normal allthread can be bought at you hardware store, at least where I live.
I'm using 3 or 4mm allthread to make my own links on my rigs.
Saves a bunch of money vs buying link kits.
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