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Lot of Marui stuff those times...

Last time printed the three parts of the chassis to test it. I had to check 2 dimensions : one requiring the 3 parts (body mounts positions), second one being the rear rigid axle position...
I printed all on the same plate, not in an optimal position, and without using the mutimaterial capabilities of the AMS system, as I still have 2 rolls of Amazon basics filament to finish. That makes the case for this. Once those 2 rols are depleted, I will use PETG as interface support for PLA prints, and that will be much better... In the meantime, the quality is not that good, but the target was not really quality...


The 3 part printed (NB:I removed the antenna supports to get the rear flat on the bed).


With the orientation I used for the print, I'm almost sure the nut pockets are not that good quality either due to supports, but nut and bolts were not required for the test fit...


The rigid axle take place perfectly, and it is moving as it should. I'm happy with this. I have no doubts on the front side, and it is not even critical on front side...


One thing that I absolutely needed to check was the position of the body rear body mounts... I checked with both CJ-7 and Big Bear bodyshells, and it is lining up...


This means it is very good

After having spend a day fixing my diff design issue (coming from a mistake on the bevel gear on the top of it, I'm now thinking about pulling a Big Bear and a Super Wheelie for next week-end vintage event...

For the Super Wheelie, the bodyshell will be rough, but beside this, I have everything needed... For the Big Bear, I have a lexan bodyshell to paint, and all the parts to be able to make one... Except tires and rims, and there is no way I'm getting 4 molded tires by that time (24 hours cure for each), plus finding a way to glue them, which may need anothe 24 hours to cure... Easy sourcable tires are Lunchbox tires, and I know from a friend that makes the Big Bear working quite well... I have ordered 4 Lunchbox tires for this purpose... Remains to define rims easy and quick to print...

Went for a very simple design this time... And since I don't want to use supports, it is a two part design, using 4 M4x16 screws to do the assembly...



And just to make an idea of how large the Big Bear tires are compared to a Lunchbox one...


I launch the print tonight. I reserve the printer for small ABS or nylon print for adjustments and chassi reinforcement as both chassis I intend to use may require this...

Among the chassis I have, about 2 on 4 have issues with the body mounts, and one of them is pretty damaged at the front...

For the rear body mounts, I will print some parts. I made one version to reinforce the ones which are still alive, and one to repair the one broken... As matter of fact having a chassis modeled in CAD is making those kind of mods/repair very easy...


Launched some prints to complete 2 of the chassis. I start with the ones in worst state : those two cars I build will be runners...

About 3 minutes to design the parts... About 50 minutes to get the 6 parts needed for the 2 chassis...

The small repair on a Big Bear chassis front... Easy, fixed with a M4 screw... This will be circled by some springs to maintain a bumper...


On the same chassis, the body mounts are alive. I put a reinforcement, and no rework required...


On the other chassis both body mounts are broken... I put the second version of the body mounts reinforcement which includes the top part, and this is perfect...



And both chassis are now good to go...

I launched the rims print last night...


Fresh of the printer, mounted the rims with M4 screws and we have rims... The Lunchbox tires are not yet there, but worse case scenario, I can pull the tires of my daughter's lunchbox : they are the only one not glued yet...

Rebuild starts...
First a few minutes print to get some shim washers printed in ABS for 1mm to complement the ball bearings which are thinner than the original oiless bearings (that is where I love again my X1C printer)


Then real things can start... With a small issue here : the modern 540SH which I wanted to push here is too large for the motor mount, and additionally it doesn't line up with the holes for the contact at the end... And worse I can not remove it from where it is. Thanks I have a gearbox in addition which will save me for the time being... I rewired the original 480RS crossing my fingers it is in working state...


I put everything in place and got my diff in place (with the new big bevel gear I corrected and printed in Nylon PA12 on the BambuLab X1C)... It works smoothly and pass the 3V test...




Next step is the chassis itself... The instructions indicate a part which you never find with a car you get without the box, so I redesigned one and printed it...


While printing, I prepared the front arms


And then mounted them... The printed part is good an allow to validate the parts around as well...


Then the rigid axle comes in.


I needed a ESC and a servo. The Big Bear wheels are usually heavy, my rims are heavy as the Lunchbox tires are lighter than the original Big Bear tires... This will make up for the motor test, but it needs a bigger servo. I have one oversized in the DT03 I don't use anymore, and it has as well an ESC with no RX... I vampirized it (nb : yes the 20 kg servo is totally overkill for this build )


Remains to do :
- motor connectors
- tires to put in when they arrive
- bodyshell
- front chassis body mount fixing...

Well, there is a Lunchbox with unglued tires in my daughter's room, and she is not using it a lot... I'm quite sure she will be unhappy when she will see this, but I had to try (and as soon as new tires arrive, she will have new tires)...


I tried to reuse one of the diff main gears on which I remove some material, but it gave too much lateral play to the main gear when running and it resulted in hitting the 9T of the idle gear badly. I replaced both main diff and idle gears and it is now fine : each time you have an issue with a transmission, it is the weakest point that takes it all first... Now the real question is how long this gears will last, specially on a Big Bear, and I have no clue of this...

I hope to be able to paint a lexan bodyshell some evenning this week, but I'm not sure at all it will be possible... In the meantime, I have a hard bodyshell


I raided another car which is missing a RX to build a Super WHeelie chassis...

And another print in ABS...


And here is on the car...

The bumper came out nice , have you tried acetone smoothing with ABS ?

Dadio wrote: ↑Sun May 14, 2023 4:34 pm The bumper came out nice , have you tried acetone smoothing with ABS ?

I've not done anything : it's fresh out of the printer... I could eventually do smoothing with acetone, but I still need to do other stuff to finish my cars for next week-end... And I still want to build a Super Wheelie, and I'm back to work tomorrow... The week will be hard, athough there is only 3 days of work this week in France (because many of us are bridging Friday)...

The Lexan bydshell was trimmed yesterday...



Few others elements printed in ABS for the Big Bear... Normally, they should be the last ones... Those are the parts you can find on Thingiverse from tahustvedt and threesixty31 users. I could have done some parts myself, but I was lazy


They came out super nice. The front of the search lights will be paintad white, but that's all, beside this, all the parts will be taken directly like they are out of the printer... The only ones I'm not sure to use are the mirrors...
I'll prepare the fitting on the bodyshell before I'll take care of the paint...

On the Big Bear, everything is set for the bodyshell. Left over are the masking and the paintjob.... I'm quite clear on what it will look like, and it won't be boxart... There is 3 days left (and in practice that really means 2 evennings and one day) before the packing and departure for the first vintage event of the year I'll be going, not sure when I'll do the paint job, but accordingly to the weather forecast, it won't be easy.

In the meantime, I started to sort the parts for the Super Wheelie:
- 7.2V repaired chassis should normally have a white cj-7 or blue Landcruiser bodyshell, and black arms...
- a full transmission in mod .8
- gearbox parts
- red or black arms - have to decide (normally the red arms should go on a 6V chassis with a black CJ-7 body)
- a black CJ-7 body, in okish state, with lights I must test, and eventually replace...
- ball bearings...

I put everything on my desk and started... To stop almost immediately : the axis are too large of something of .1mm to go through the bearings... I need to shave them, but this means noise, and it's too late for this... We'll see tomorrow...

silvertriple wrote: ↑Mon May 15, 2023 5:20 pm On the Big Bear, everything is set for the bodyshell. Left over are the masking and the paintjob.... I'm quite clear on what it will look like, and it won't be boxart... There is 3 days left (and in practice that really means 2 evennings and one day) before the packing and departure for the first vintage event of the year I'll be going, not sure when I'll do the paint job, but accordingly to the weather forecast, it won't be easy.

In the meantime, I started to sort the parts for the Super Wheelie:
- 7.2V repaired chassis should normally have a white cj-7 or blue Landcruiser bodyshell, and black arms...
- a full transmission in mod .8
- gearbox parts
- red or black arms - have to decide (normally the red arms should go on a 6V chassis with a black CJ-7 body)
- a black CJ-7 body, in okish state, with lights I must test, and eventually replace...
- ball bearings...

I put everything on my desk and started... To stop almost immediately : the axis are too large of something of .1mm to go through the bearings... I need to shave them, but this means noise, and it's too late for this... We'll see tomorrow...

Good luck , sounds like you'll be busy this week !

I got some bad news from Norway : I sent a gear set to a friend there as he was possibly having a chance to test it in real long before me. And the result is that the Nylon PA12 Glass filled is too much brittle for gears and the experience turned short (very short)... On my side, I'll test the Nylon version this week-end, and I'll have as well a regular V1 gearbox ready, just in case, so I'll be able to run the Big Bear even if the gears break too fast (we'll see). 

On the super wheelie, the red arms and wheelie bar are not complete : one the wheelie bar side is uncomplete. I decided to print arms and wheelie bar in ABS... And they turned so nice I'm now contemplating the idea of getting the gearbox and the chassis printed, although I'm not sure I'll have the time for the chassis...