Another guy making custom 3D printed axle housing (lots of large pictures)

[T_Tank]

Ok I'll admit I'm impatient waiting on people to release their custom housings so I grabbed myself a set of new axle housings from my LHS and measured for a few hours while messing around in tinkercad to the end result of this little feller.




Now you may ask yourself whats so special about these housings compared to the others that are being worked on? Well if you look closely in the first photo there is nothing limiting which what the ring gear goes in, yup thats right you can put the ring gear in anyway you want!

Also these feature a diff cover instead of splitting the whole axle in half its secured with 4 2mm bolts and 2 3mm!

Lower link mounts/shock mounts are also interchangable with either side an removable and modular

Works with stock mrc servo plates/link mounts will revise the included design for a modular one

Now sadly being the first prototype I made a couple of goofs... I undersized the bearing outer diameter to much to compensate for printing tollerances from shapeways >.<
Secondly I also made the removable lower link mounts to shallow so even a mrc ball end won't fit

Luckly already fixed those two issues though keeping protype1 around get a new bit for my dremel to let the diff rest correctly so I can check pinion depth/mesh maybe Ishould just use 2 3mm grub screws to let you set how far the pinion rests...

Anywho here are what the axles look like assembled!




Don't have a picture of it mounted to anything as these are for a project I'm working on but will likely put these up for anyone on shapeways once I get it where I feel I don't need to update it anymore.

Like to think I did pretty good using only a 4" digital caliper an eyeballing!

[89redranger]

Those look awesome!

[T_Tank]

Can you believe I designed these in dead simple tinkercad in 2 days XD?

here is it rendered with a micro servo (i know not torquey enough I'll make so the upper plate can be adapted easily)

[MRCrackhead]

Very cool design.

The mini board is on fire lately with new and innovative products.

I really like the reversible diff idea you have going here.

My Losi Insane motor is a fixed can motor and it goes faster in reverse, than forward.

I have the tranny flipped so it's running backwards, and that's always bugged me.

I'd like that extra wheelspeed that's not being used.

Your idea would make it very easy to capitalize on motors like this, which are all that are available for these rigs anymore.

Nice work

[FocusMiah]

Nice work man!

[T_Tank]

Thanks for the positive remarks I'm didn't think about fixed direction brushed motors but glad these give a option. The original idea was for a IFS SRA mini that uses a mini lst front with a mrc rear, issue is the mini lst has the ring gear flipped and there isn't a option to flip it around.

Update with some pictures.
Longer link/shock mounts the lower links are close to the stock geometry the shock mounts are a bit inboard though you can mount them on the other end of the mount or flip the mounts all together.

Also new servo mount thats setup for the 1/16 traxxas sized servos though direct drop in for sure is the savox sw-0250MG.





Gotta say 3d printing has revolutionized the hobby in a big way!

[89redranger]

These parts keep looking better and better man! Keep up the awesome work. As you know, I also have alternate uses for the MRC/MLST/Exceed gears, and 3D printing has made a lot of these ideas possible. Beyond just production parts, a guy can now design and produce anything that they may need without having to resort to massive production runs. BTW, if you're turning parts out like this with TinkerCAD then I can only imagine what you could do with Fusion 360 (my favorite thanks to Dravpnir) or another high end program. Shoot me a PM if you need any help getting started in another program.

[T_Tank]

Thanks for the info for the other program but I'm so used to tinker it's like building with primitives in a multiverse game called secondlife that I've been building in since 2007! I still have some builds on there that people ask if it was made in maya or 3ds max.

Now what I would love to have is a depth micrometer or a depth measuring tool so hard to scratch my noggin figuring out pinion depth. measuring the back of the input shaft to the middle of the housing and take consideration for the little spacer stop between the input shaft bearing it looks about 1mm or 2mm someone want to give me a exact number?

[89redranger]

The pinion bearing depth in a stock axle housing measures 18.25mm deep without a bearing, and 15.25mm with. I'd set the pinion bearing depth at 18.3 for printing through Shapeways.

[89redranger]

Better yet, set it at 17.8'ish and eliminate a little shimming. Any deviation from Losi's specs will require you to cut the little flange off the Losi pinion shafts though, which is not a big deal. That little lip causes the pinion bearings to get crush any time you attempt to shim the pinion in, which is REALLY the way these Losi gears need to be shimmed. Start with pinion depth to get max face contact in the teeth, then shim the ring in tight'ish.

[T_Tank]

17.8 from center of the axle housing to the back of input shaft bearing? (side of the bearing facing out of the housing)

[89redranger]

Exactly. You can start with the stock number and always change the depth later or shim to suit your needs/wishes. I just know the pinion depth in the stock configuration could be almost a full mm deeper. Instead we all shim the ring gear over, which does tighten the mesh, but does very little in gaining tooth contact.

[T_Tank]

Ok looking over the model the inner bearing seat is actually at 17.75mm is that about good number to go with its likely more like 17.8 with the tolerances figured in.

Heres a cross section of it in tinkercad giver or take .01mm in tinkercad



Also if wondering why the servo plate would have the savox servo so forward is... when I get two of these and a chassis there will be a 540 sitting very close to the upper link mount but with enough clearance for the suspension links. Buuuuut since it does work with normal mrc servo plates you can use your favorite 1/10th scale servo plate!

[T_Tank]

Quick set of question for all of you. Would you rather have shock mount distance on axles like on the stock housings or right above the lower link mount or would you want a option for either?

And another question what are some decent losi shocks that have around 16-17mm worth of travel that could work in a 1/18th platform and by chance anyone have a moc up cad file for a mrc trans with 380 motor and ... I know this is a long shot but a mini T trans with motor plate aswell? (i could figure out the big block motor plate for the mini T trans)

I got something i'm working on that the axles are original built for (something fast an solid axle front to back that loves to jump) and like to provide atleast 3 transmission mount options (mrc,miniT,merv 380 or 540mount) maaaaybe mini lst transmission for dual 380 setup, luckly all the losi trans can take the mrc center locker!

Battery size I'm looking at a maximum size of 68x45x24 with a few ways to mount within the chassis depending on trans being used.
tire size is around 84mm dia x 50mm wide wheelbase around 185mm long
need a bit of vertical travel atleast 17mm would love to get a full 20mm of vertical travel but want to avoid cantilevrs and raising the body up more to make room for longer shocks

In theory if these axles should handle the abuse of going 25-30mph an crashing they should be able to hand tons of torque going inches per minute!

[T_Tank]

Forgive the tripple post and poorly done free hand drawing I did with my tablet but this is something bouncing around my head while I'm working and thinking what other things I need to do to the axles before odering a second prototype.



Chassis has to be narrower in the front an rear halfs compared to the middle for shock clearance though plan will be to have enough room between the rails for a 540 motor

[SFC K]

I'm liking that! Hope to see this come to fruition.

[T_Tank]

Thanks I'm still working on the drawing phase of the chassis I could just make it work with the merv trans an call it a day to get a quick prototype put together would make figuring the tube work between the two main halfs easier.

think of the chassis being like the exo cage with two main halfs then all the middle tube work that holds it all together.

Still rattling thigns in my head on the axles trying to think what other things I may need to change or adjust in the model before printing the second prototype if anyone has a throught on the axle don't be shy to comment or shoot a opinion I encourage it since I'm a eyeball it an make it work kind of guy and not a engineer XD

[89redranger]

I like the chassis design!

Only change I would make before moving into the CAD program is to make the cab the full width of the outer side plates. That would give the cab the full width of a real cage, and give a little more proportion to the chassis. Depending on what material you use for the chassis/cab you may be able to use a little narrower spacers at the top of the cab to make it bow in like this / \ when looking at it from the front or rear. Just my $0.02...

[T_Tank]

Plan would be to have shapeways actually print out the whole chassis/cage and the narrower sections to the normal width sections will have a smooth transision. Agree with the cab that the topmost parts will be slightly narrower to add strength and to add in better fitment for bodies.

Goal would be for the cage/chassis assembly to be similiar to how axial made the wraith an exo though I'm thinking between 4.5-5mm thick solid tube work made in cad with wherever a screw can go in making it about 6-7mm wide around that screw section for more strength.

Now I wonder... how many people crash test their rc designs to see if they can take a beating? >_>

[89redranger]

Originally Posted by T_Tank

Now I wonder... how many people crash test their rc designs to see if they can take a beating? >_>

I have some beef tubes I designed and printed through Shapeways for my SCX10 axles that I have purposely broken, and can post pics if you're interested in the destruction. It's not as exciting as it may sound. While I did manage to break them, I can tell you now that the nylon Shapeways uses is both stronger AND more resilient than either Losi or Axial's ABS products. These parts in particular took more punishment than anything else on the rig ever would or could be expected to live through.

How else you gonna trust what you're putting your name on?