TOPIC:

I started the front to create a derived part from the rear right wheel carrier... Then I set the upright from there. I could have done something different with bearings inserted in the wheels, but this way, I can just do a simple design working for both front and right and giving the possibility to use printed nuts (I really want to play with this).



Then I started to work on the master part of the front train... I have the idea to let people play with the caster angle, and if we want to do this without any impact on the wheelbase, that requires to set the caster setting axis lined up with the wheels center...


Then I prepared basic clamps...


And now that I look at it differently, I'm thinking to change the way I thought the pivot between uprights and the C part : having the ball bearing in the uprights is probably much better, so I'll amend the holes and design accordingly...

I modified the upright : bearings are now inserted in the uprights and the screws are in the main arm.


The front train is now complete...


Next activity is related to chassis plates... I will target a wheel base around 200mm in this first version.  I may also add provisions for longer and shorter chassis plates to give room for longer and shorter wheelbases...


I'll need to position the steering servo, esc and battery, for which I'll include more holes, and as well define the bumper fixation area, body mounts and other small elements. I'm also questioning the need of an upper deck or not : i'm actually open to any ideas

A quick test print to ensure it is printable, and the clamp works... (and yes, I added some cryptic message on some parts )



I will just modify the master part of the front train in order to make it easier to position within the clamps wihout the risk of it being slightly right or left...

The clamp works perfectly. At the exception of the uprights, everything was printed without supports. Upright were printed with a top spacing over supports of 0.3 mm, which allows an easy removal. I'll think about modifiying those parts to make it better, and eventually without the need for supports...

As the Hirobo parts are ready to get ordered, I'm contemplating the idea to add diff, wheel carriers and nuts in my order to save on the shipment costs: those are the parts where I believe it makes sense to work with powder base process for this project. Others will be printed using filament.

As usual, and just to make it more convenient, I grouped the key parts in clusters. The wheel nuts are going to be printed with a 0.05mm offset. The idea is really to confirm the right offset to use, so I will add a set of nuts in 0.1mm offset as well. That's the first time I'm trying to print threads in MJF, so it promise to be interesting. I saw some experiments of threads printed in MJF and I believe it should work as per this experimentation...


Let's see...

I ordered those parts while ordering for the Zerda, so they arrived as well...


I did a mistake when doing the order : I completely forgot to use the right nuts version. Nuts are wrong.
But the rest is fine.


As expected (and that what I wanted to check), I'll need to add something to make it right with MJF (the FDM printed parts add some imperfections here and there, which at the end makes a bit of difference when they are added in chain, like in this case...

I spend a bit of the day today on this project, with the overall idea I want to be able to make it quite versatile in terms of battery configurations, and I also planned for mini and standard servo (mini servo is better, though), with a bit of flexibility as not all servos are exactly the same size.


I still need to deal with the Bumper and bodyposts but the overal idea is here...

I'm questionning myself about keep the chassis the way it is now. I intend to use the same holes than for the Bumper as mounting points for the front bodypost (I may even think about include them in the Bumper design, using some magnets to fix the bodyshell).And for the rear, the original idea was basically to use the front top of the motor pod (where I have holes already set in order to deal with the bodyposts fixations)... And since bumper and bodypost will be bodyshell dependant, it looks like chassis design could be frozen...

I also made sure there is enough material around each holes so they can be countersunk as it will be definitely nicer to have them this way...


Next will be to get two (maybe three) chassis cut in G10 2.5mm thickness. I've check everything twice, it should be good. Hope I don't forget anything important...

Just received chassis parts today thanks to Jeff from Factory Works
I will have to print my parts in final mode soon so I can check everything and make them available...

I thought I could move on the Zerda soon, but I did a miscalculation for the belt length, apparently. Ordered new ones, longer. And in the meantime, this mean I need to do something...

A friend has fed me with ideas in my reflexion, and he will work with the red parts for the chassis he is going to build. On my side, the target was to make another color...

I printed the parts today, and in particular for 2 parts, I allowed me some fun


I lined all the key parts on the table. I have the ball bearings and the RX (not on the picture). I'll need to take care of the ESC and motor. And remains the hardware : normally, I should have everything I need, but I still need to check. In the first test, everything will be assembled with button head screws. I'll change for countersunck screws once I have the possibility to rework the holes. And there I few sleeves I need to take care for the front shafts, but nothing too difficult...

Time to check the assembly is going to go easy...

First front train bar... I straight away noticed that I need to review the bottom part of the clamp either to introduce the nuts by a pause during the print or either reviewing the design to make it easier to insert (it was a bit too hard to my taste. Almost everything is mounted with M3x8 machines screws (not yet countersunk, but that would not change the dims required). 4 M3x8 screws + 4 M3 nuts


One of the exceptions to this is the screws required when using a mini servo (M2.5x8)


Rear train is also mounted with 4M3x8 under the chassis and 4 M3x8 countersunk for the rear side


One of the things I needed to absolutely check was my rear axle : the flat area of the hex is at equal distances on both side (an adjustment will be made to the design of the hex as I did adjust that therorically after the initial mount of the diff - I'll adjust that once I have the motor and pinion in).


I also mounted the carrier on the knucles... 2 M3 Nuts, 2 M3x20 screws (used as shafts)


The initial design I made includes a sleeve 3x4x11 which one would need to cut to be able to mount both carriers. Maybe this is a bit too much of DYI for most (I don't know, I'm not sure, but I doubt most would be happy to do this). I'm considering to remove this and replace the sleeve and the ball bearing by another simple ball bearing. Don't hesitate to shime in, especially if you are interested by making a derivative of this project...



Next is the battery mount : 6M3x8 screws and 2 M3 nuts for the center part (which is going to be removed more often as it is the battery retainer). I noticed I made a mistake on this part, I'll review it...


I still need to deal with the steering links (but that will be easy) and then it will be wheels, bumper and bodymounts...