TOPIC:

I checked on the chassis and the servo I had in the car. I did not have a chance to drive it before tear it down, but I remember the front wheel were not lined up properly.

I had a look at the standard servo and the way it should be to have the head centered: in the case it is centered, it does collide (slightly) with the bottom chassis. I could gain slightly by reviewing the profile of the sides of the chassis, but it would still collide a bit, requiring at minima to file something (either the chassis or the servo holes extension)... I'll review the side profile, the top deck and will call it done .

A very important advantage of working in a start up development is that one gains more experience than in an established company, and also that startups can fail, but there is always a chance that it will be successful, and even if it is not, one will gain unique experience.

Long pending update...

The model did not correspond perfectly to what I had in hands... I had few review of dims, more than once without finding the culprit...


In the car I had some standard servo which I'm used to have on many cars. This time I took the servo (Graupner C505) and measured it... And in fact, the servo I used as a reference is not proper. Servo length is too long (about 1.5mm) and the servo head is in real more closed about the left end by 2mm...

I'm assuming I searched for nothing and my model is correct...


Few details remain to do : making sure the walls of the gearbox are printable (I need to make sure I have always 1mm thickness everywhere), and review the diiferential case as I have a small doubt (I need to make sure it is right as it is the same for both Zerda and 44B (I don't have one yet, but I hope to find one at some point)...

Once this will be done, the files will go on Thingiverse after some prints for checks...

I don't know why I got this appearing in my items proposals on Amazon, as I did not searched for that whil looking for some cables for the printer... But it appears that pulleys are easy to find in 20T and 16T GT2, and it is the same for timing belts in GT2 in different dimension... That may be a very good reason to consider doing another diff and another Pulley in GT2 format for our Hirobos...

The gearbox halves were not printable in their original state if I refer the minimal 1MM thinkness requested by most of the printers


I reviewed the walls to get that proper.

And once done for the first half, I did it for the second one...


There is few remaining notes in my todo list :
- review the diff case : I have 1 mm doubt on the pulley position I will need to recheck
- find a solution for the top shaft bearings : initially the bearing (no ball bearings) are 5x13x5 6x15x5. There is no ball bearing of this size. I woulld think to do a 1MM thick printed washer (6x15x1) to complement a ball bearing

I'll do this later within this week, and once done, I'll extract all the stl files, unelss I decide to do a Powergrip GT2 version of the transmission, which means it will take slightly longer before I come to the stl extraction stage (not too much longer, that said
 

MR695ZZ/W5 is indeed 5x13x5mm 

Yes, found that out later on... but yikes, they are expensive...

What if you make a adapter so you can run 5x10x4 bearing?
3mm thick ring with one side being 1mm?

because there is only one bearing, and there is therefore only 5mm to guide the axle. I have thought a bit, and thought about two small bearing with 2.5mm width. It would probably work with the same flanged bearings as used for the Spirit FF or the Samurai, with an adaptor (someone on rc10talk also highlighted the same idea). That being said, that won't change anything in terms of guidance, and therefore the only interest would be to reduce the cost... And taking in consideration of the cost of a print, that would not worth the effort...

 

and to remove all possible confusion :
- ball bearings for the shaft in the gearbox 4x13x5
- ball bearings for the rear wheel axle : 6x15x5
- ball bearings for the diff : 9x17x5