First Tamiya truck build, MACK Dump truck 6x6
 

Hey guys I just purchased a abandoned bruder dump truck conversion from a fellow modeler and I decided to give it new life with a 3d printed MACK Cab. I have already done some body work to the cab which includes a few coats of high build primer and sanding it down, making body mounts and adjusting everything to line up and look correctly. the chassis I painted a redish orange color to match the full size rigs I see pictures of on google "I know really fancy" lol. I think I will go ahead and make it a 6x6 with a driven front axle. This is where I run into a question for you guys. If I put a TLT axle in the front can I get the ride height back down to where it is with the solid axle? It doesnt look like it will work mounted above the spring and mounting the axle under the spring would raise the ride height alot. What have you guys done to make it work Im curious?

Thanks

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Re: First Tamiya truck build, MACK Dump truck 6x6
 

Nice to another Mack being built

Re: First Tamiya truck build, MACK Dump truck 6x6
 

Since your using the stock 3 spd, rails and the axial trans for a transfer case you'll have issues with front driveshaft routing. You'll either have to space the 3 spd up as high as possible or ditch it for a planetary type transmission. And that's just a start to the issues you'll encounter.

Re: First Tamiya truck build, MACK Dump truck 6x6
 

gotcha, I was planning on moving the trans toward the back of the truck and extending the output shaft so it will stick out the front of the trans and use that to drive the front end. I have no parts gathered yet so I havent checked fitment of this. I was just looking at ride heights the other day and realized with a driven front axle it would be difficult to match the ride height of the solid stock axle.

With the Mack cab I have it lowered as much as possible, I actually cut the cab in the front to sit lower on the frame to get it to look right. So Im not sure if its worth it to jack up the whole truck to gain 6x6.

Re: First Tamiya truck build, MACK Dump truck 6x6
 

It can be done but it takes a lot of modification to do it. Based on the wheel base your working with, moving the 3 spd back and modify it is going to take up space needed for you dump mechanism unless your going hydraulic, then you might get away with it. I would ditch the 3 spd before I'd get rid of the driven steer axle idea.
I'm on this kick about replacing all my 3 spds because they are a pain to keep adjusted and pretty much worthless in the big picture. They also take up way to much space that can be used for other stuff. Good luck and keep the pictures coming it'll be nice when its done.

Re: First Tamiya truck build, MACK Dump truck 6x6
 

Thanks for the advice man I do appreciate it. I will keep going with it and see how it ends up. If the 6x6 isnt meant to be it wont be the end of the world, I just want it to look a certain way Im sure we all know that feeling.

Re: First Tamiya truck build, MACK Dump truck 6x6
 

Nice cab and extended hood! Are they for sale?

Re: First Tamiya truck build, MACK Dump truck 6x6
 

Well, everything is for sale for the right price but it will definitely not be cheaper than buying brand new if that helps your decision at all. Specially once the RCP dump bed gets mounted

Re: First Tamiya truck build, MACK Dump truck 6x6
 

Understand! Was wondering if the cab and fender/hood assy. were for sale somewhere and then I found them at Shapeways. Is this cab the one with the non opening doors?
Looking forward to this build, as I might have to change plans on my 6x6 tractor build from a Globe to a R model. Spent a lot of years/miles in R models.
I hear that sanding these printed bodies down smooth for paint is a bear...

I'm using the F350 powered steer axle with F350 springs with factory holes drilled in them, and it does lift the front end up some. But so are the 1:1 6x6 trucks. I've seen some guys redrill the rear suspension mount holes lower down to get the frame to ride level. OK for a straight truck, but a tractor will be too tall to hitch up to stock trailers anymore, just like the 1:1. You just put blocks under the landing gear legs.

Re: First Tamiya truck build, MACK Dump truck 6x6
 

Looking good!

Re: First Tamiya truck build, MACK Dump truck 6x6
 

Yeah shapeways is where I got mine, I also got a few extras like MACK emblems and the bulldog for hood ornament. The prep work is a little bit tedious but really not that bad. Just take a couple days to get plenty of high build primer built up and sand after 2-3 coats seemed to work the best. I think I have a total of about 8 coats. I plan on using a nice automotive clear and helps hide alot of imperfections that aerosol clear coat cans doesnt.

https://www.shapeways.com/product/SJ...=user-wishlist
https://www.shapeways.com/product/DQ...=user-wishlist

Re: First Tamiya truck build, MACK Dump truck 6x6
 

Well this thread is kinda old, PB wont show my pics, so Im going to post pictures directly attached here.

I have not lost interest in this project and I am trying to build this a little differently than standard practice. Which is probably not the smart way, but I am tying this with my other hobby of casting and forming metal along with my 3d printer and design ability. So I am actually attempting to cast the majority of the dump bed from aluminum which is going well, although it is a pretty heavy dumper I think it will still work fine, I will modify my pattern to make thinner castings and maybe even make the walls shorter and use a piece of wood at the top like some full size truck do.

I attached some pictures of the process, the bed is cast from aluminum with traditional sand casting methods using petrobond sand and 3d printed patterns that I finished with primer and sanded down, the casting duplicate the patterns finish almost exactly, as this petrobond sand is MUCH finer than standard water bonded sand.

Re: First Tamiya truck build, MACK Dump truck 6x6
 

Some more pictures of the dump bed.. This file uploading sure does take a long time!

Re: First Tamiya truck build, MACK Dump truck 6x6
 

Well, Im sorry guys if this isnt working but Im not seeing the photos.. Im hoping maybe they're pending approval by a moderator or something but here are more pics of the bed sitting on the truck.

Re: First Tamiya truck build, MACK Dump truck 6x6
 

Pics don't work

Re: First Tamiya truck build, MACK Dump truck 6x6
 

Well that pretty much figures.. That sucks I got some cool stuff to show you guys too. too bad photobucket had to take a crap

Re: First Tamiya truck build, MACK Dump truck 6x6
 

PB for now, works, IF you have the fix installed on your computer to make it show the pics.

I use Flicker, as it's...........................free, FOR NOW. Just upload your pics there. When you want to share the pic, click that pic. It'll pop up, with some weird looking icon things below on the rioght hand side. Click the one that looks similar to a right turn arrow. Select BBC option, & MEDIUM for the pic size. COPY the BBC it generates, then paste it here into your post. Hope this helps ya
I'd really like to see your progress with the casting attempts.

Re: First Tamiya truck build, MACK Dump truck 6x6
 

Here's a link that'll walk you through how to install the patch so you can see ALL of the pics again, EXCEPT the ones that were delted &/OR moved.
http://www.rctruckandconstruction.co...ad.php?t=12878

Re: First Tamiya truck build, MACK Dump truck 6x6
 

Believe some have to move to other pic servers such as flickr to post pics or start albums. I'm still using PB, but was new when the bs happened so I guess I slipped through a crack or didn't have enough used on their site YET.

Re: First Tamiya truck build, MACK Dump truck 6x6
 

Wow that link totally worked for me! but that doesnt mean everyone that visits the page will install that patch to see them. I really really dont want to upload all my pictures to a different server. but, in the interest of being a good sport and mainly the interest of shared knowledge between all of us I better just get started making a folder of all my project pictures, in hopes everyone else will do the same. Its a small community and if we all stop sharing experiences because of some inconveniences that would be a shame.

Re: First Tamiya truck build, MACK Dump truck 6x6
 

Ok, sorry about all the junk posts guys. Lets try some Flickr uploads here.

https://farm5.staticflickr.com/4480/...3749aa51_z.jpg20170326_140310 by Scott Kositzky, on Flickr
https://farm5.staticflickr.com/4475/...79bb2a9f_z.jpg20170325_151141 by Scott Kositzky, on Flickr
https://farm5.staticflickr.com/4511/...81ea4a71_z.jpg20170325_151144 by Scott Kositzky, on Flickr
https://farm5.staticflickr.com/4499/...a49ed4ae_z.jpg20170325_155251 by Scott Kositzky, on Flickr
https://farm5.staticflickr.com/4489/...28037f21_z.jpg20170325_161953 by Scott Kositzky, on Flickr
https://farm5.staticflickr.com/4449/...699449f6_z.jpg20170325_164925 by Scott Kositzky, on Flickr
https://farm5.staticflickr.com/4460/...c8161950_z.jpg20170913_192954 by Scott Kositzky, on Flickr
https://farm5.staticflickr.com/4449/...1df1a24d_z.jpg20170921_000050 by Scott Kositzky, on Flickr
https://farm5.staticflickr.com/4457/...1cf5cb7f_z.jpg20170921_000058 by Scott Kositzky, on Flickr

Re: First Tamiya truck build, MACK Dump truck 6x6
 

Here is some of the trickier stuff. The dang split rims! I couldnt bear to pay the price for 3d printed plastic wheels so I designed them myself and still thought the plastic was pretty hokey. Took quite a few revisions of these rims to get them fairly close scale wise in the design and prototype phase. Then to get the scale correct AFTER they are cast and still fit the hex drives and bearings without machining was tough. but the first go around turned out pretty decent, had issues with the kiln during burnout which gave me some surface finish issues but I think I know the reasoning behind that.

Anyway these are designed by me, I 3d print them in house as well, the 3d print is mounted on a sprue tree, which is then encased in a plaster mix called investment, then put in a kiln to burnout the plastic and you pour molten metal in there and bam, metal wheels!

These will be 2 piece as you can see, I am drilling and tapping 2-56 threads and using brass hex bolts to hold them together. I think I may try to cast the centers out of a brass alloy for extra weight, and I can either paint or polish that, figured Id polish the rim at least. I am excited to try a few different things on the next batch and increase the surface finish quality for quicker cleanup. but it really only took about 1.5 hrs to clean these up from raw casting to how you see it now, just hand files and belt sander.

https://farm5.staticflickr.com/4493/...8b1897f3_z.jpg20170508_220809 by Scott Kositzky, on Flickr
https://farm5.staticflickr.com/4491/...ccbcc1d9_z.jpg20171022_195507 by Scott Kositzky, on Flickr
https://farm5.staticflickr.com/4468/...c6744ac9_z.jpg20171021_141651 by Scott Kositzky, on Flickr
https://farm5.staticflickr.com/4476/...50b2d18a_z.jpg20171022_165425 by Scott Kositzky, on Flickr
https://farm5.staticflickr.com/4491/...ca9cf174_z.jpg20171022_165435 by Scott Kositzky, on Flickr
https://farm5.staticflickr.com/4491/...cdde0870_z.jpg20171022_230149 by Scott Kositzky, on Flickr
https://farm5.staticflickr.com/4487/...08e4fe89_z.jpg20171024_122705 by Scott Kositzky, on Flickr

Re: First Tamiya truck build, MACK Dump truck 6x6
 

Totally awesome! Great work!! More pictures please.

Re: First Tamiya truck build, MACK Dump truck 6x6
 

Nice rims! I believe that's the FIRST time I've seen them style rims for 1/16 semi trucks. I see a LOT of them on the 1:1 container trailers near the port of Tacoma, as well as the port of Seattle.

Re: First Tamiya truck build, MACK Dump truck 6x6
 

For the detail hungry guys, if you look close the picture of the cast aluminum tipper bottom sitting next to its pattern you can see the amount of shrinkage that occurs with casting! its is very noticeable in a casting this long, but it also important with the wheels. I had many experiments in scaling and revisions to accurately cast the drive hex and bearing bores. I know it would be easy enough to machine the bearing bores but with the accuracy of investment casting you shouldnt HAVE to and I can now push the bearing in by hand with a good fit into the cast hole with minimal hand finishing. but I think I have a great model to use now and can start really knocking out some wheels!

I have ordered a automated 3d print smoothing machine in a attempt to get a better surface finish. So hopefully soon I will have more updates for you guys with better parts, and assembled wheels on the truck.

As for the tipper, I have some engineering to do on that guy, it is a heavy box! I am going to remake the patterns for thinner walls and probably shorter walls altogether because I feel this would make the truck top heavy the way it is. but for now I will finish this heavy box and figure out a tipping mechanism probably similar to RCP's setup with a threaded rod on the box.

Re: First Tamiya truck build, MACK Dump truck 6x6
 

Why buy a smoothing machine? You can save $ & just do an acetone bath.

Re: First Tamiya truck build, MACK Dump truck 6x6
 

Will you be offering them wheels fir sale?

Re: First Tamiya truck build, MACK Dump truck 6x6
 

I am using a filament from overseas designed for investment casting which doesnt react to acetone like ABS does. I have used PLA before too and that also doesnt react to acetone.

This material dissolves in isopropyl alcohol which is waay better to work with than acetone. and the machine is just to make things easier on me, it makes a nice fog and rotates the part at the same time so I dont have to babysit the whole time.

In the grand scheme of things, its not too difficult to clean up the raw casting the way they are, but what fun would it be if I wasnt trying to make it better all the time. and this might lend itself well toward future projects if I make sand casting patterns out of the material I can smooth those out faster. and it also makes them water tight! which is a plus in investment casting.

Re: First Tamiya truck build, MACK Dump truck 6x6
 

Wow, that dump bed could take some abuse, and you shouldn't have to add any weight for traction ever.

The rims look great! Can you print the sprue like that, or is that print first then assemble?

Re: First Tamiya truck build, MACK Dump truck 6x6
 

That sprue is a 3d printed part actually, I designed it specifically for these wheels. Alot quicker to sprue them up that way when compared to using wax, they are pinned on one side and a hole on the other so I can stack as many as I want to. I also have a huge 6" diameter flask I am hoping I can fill up with a whole bunch of wheels and centers and lug nuts.

yes Im hoping I can offer the wheels for sale. I would like to have some more confidence in my castings before doing so, and I think alot of people would like to see these cast in brass for extra weight/traction. Which should not be a problem, just more money for material.

I have no idea what the cost would be on a set tho. I'd have to see how long it takes to even make a full set and if I would be cleaning them up and machining, or just selling the partially machined castings.

Re: First Tamiya truck build, MACK Dump truck 6x6
 

Sorry I misunderstood the question, I print the wheels separate from the sprue and then melt it together. IT would take alot of support material and time to print them as 1 big piece. There is probably about 70 hours of printing right now that goes into a full set, and I bet it would be double that if it was printed as 1 piece.

Re: First Tamiya truck build, MACK Dump truck 6x6
 

Thanks for the info. I WASN'T aware that PLA won't
react to acetone bath. I'm glad I read that, before I tried doing it!

Yes, workingn with alcohol is much gooder then acetone!

There's ALWAYS fun times trying to improve upon our projects!

Re: First Tamiya truck build, MACK Dump truck 6x6
 

Little update with the dump truck. I ended up purchasing a RCP dump bed for the old Mack. This cast bed is just plain TOO HEAVY and the weight is up high making it a losing battle. The long thin cross sections coupled with thick sections would create a difficult scenario to cast consistently. AND since I probably only make 1 or 2 of these things I decided it wasnt worth the time and effort re-tooling the patterns, to just buy Reg's product and be done with it. He has a awesome product and I already have it installed and working, what a great piece it is! thank you Reg.

I have made a little progress with the wheel castings, fueled by my motivation with completing the rest of the truck, I have a new batch sprued up and ready for the casting process, I plan on using silicone broze for the wheel centers to add weight down low, paint the centers, and using aluminum for the outside portion of the wheel so I can polish it like the real truck wheels.

I will try and get some updated pictures added to the forum, it is now painted and working!

Re: First Tamiya truck build, MACK Dump truck 6x6
 

Here is a link to the post I made on the RC trucks and construction FB page.

https://www.facebook.com/groups/rctr...2%3A%22O%22%7D

Re: First Tamiya truck build, MACK Dump truck 6x6
 

That thing looks AMAZING! Very smooth, bright, & shiney too.

Re: First Tamiya truck build, MACK Dump truck 6x6
 

That thing is awesome man