Scrapheap Junior

[Johanp]

Here we go again.
I got a lot of extra parts when I purshased my Jrx2 project.
There were shock towers, Junior chassis, gearbox, bulkheads, dampers, steering parts, uprights and suspension arms.
I cleaned and sorted all parts when I did the Jrx2 and ordered what was missing.

I had to start with a chassis repair.
Someone had cut out the side edges probably to fit ESC and reveiver.

I cut out small strips of carbon from my old Composite Craft sheet and filled the gaps.

I then epoxied them into place and was quite happy with the result.
Sure, you can still see the repair, but it´s not as obvious as it was with the missing sections.

One thing I could not find for a reasonable price was the motor plate.
So let´s try to make one:
Draw the outline and cut it out.

Gently hammer the rounded shape using a vice and a piece of rollcage tubing.

Drill, file and tap all the holes. Fold 90 degrees.

Sort of worked. Can be fine tuned and all edges need to be rounded.
I will get a genuine one when the right part at the right price shows up. But it will work for now.

Assembly of the car will start tonight.

[blast]

One thing I could not find for a reasonable price was the motor plate.
So let´s try to make one:
Draw the outline and cut it out.
20210123_180616.jpg

Gently hammer the rounded shape using a vice and a piece or rollcage tubing.
20210308_135515.jpg

Drill, file and tap all the holes. Fold 90 degrees.
20210121_173917_l.jpg

Sort of worked. Can be fine tuned and all edges need to be rounded.
I will get a genuine one when the right part at the right price shows up. But it will work for now.

Assembly of the car will start tonight.

Good job ! Did you tap the holes with imperial thread ?

[Dadio]

That motor plate looks really good !

[TRX-1-3]

Motor plates are a big deal. I would have more complete builds if it weren't for the dang-blasted motor plate scarcity!!!! Nice work. Thank you for showinh me it can be done!

[matt1ptkn]

I love these kind of build threads! Keep up the good work, and keep the photos coming!

[Johanp]

Good job ! Did you tap the holes with imperial thread ?

Yes I did. But I had to be creative since imperial taps are very rare on my side of the world.
I have a neighbor who has "every" tool invented. He had some imperial taps, but not the correct one. So I borrowed the closest one he had and sort of got the thread to start, the I just used a 4-40 screw to create the rest of the thread.

I find it quite relaxing to fix and make stuff. Maybe because there is nothing to loose if it's already broken.

I didn´t get very far regarding assembly yesterday.

[juicedcoupe]

Good job ! Did you tap the holes with imperial thread ?

Yes I did. But I had to be creative since imperial taps are very rare on my side of the world.

Since nothing is really rare over here, it just means that you need twice as many tools.

[Coelacanth]

I just used a 4-40 screw to create the rest of the thread.

I've made my own 3mm thread taps from 3mm screws. I carefully cut notches on opposite ends of the screw tip with a Dremel cut-off disk. Kinda hard to describe, but it ends up looking like a tap and works pretty well. I've used it to tap my own 3mm holes in plastic and aluminum parts. I'll take a picture of one and add it tonight.

EDIT: Here is one of my 3mm screw taps. I have another made from a long 3mm button-hex-head screw, I recommend going with that because it won't slip while tapping threads like this first one I made with a Philips-head screw. I can't seem to find it however. Anyway, I just used the thinnest Dremel cutting disk I had to gradually cut a groove on opposite sites of the machine screw, deepening as it got closer to the tip. This particular one I've been using for many years, including to tap aluminum, hence it's a bit scuffed up. It still works like a charm to make threads, though. If you don't have a tap & die set and you need to cut threads in a pinch, this will get the job done.

[jwscab]

Nice work on that motor plate!

Yep I can't imagine the difficulty in the rest of the world vs U.S. to find some of these things. It has to be frustrating.

[Johanp]

The build goes on.

Since I had Pro SE front and rear shock towers I decided to use them instead of the plastic Junior ones.

But I ran into a clearance issue.
The front shock springs rubs the shock tower when using original arms.

Had to 3D print Pro SE front arms. I found the files (including front bulkhead) on the web.
Added a quick layer of black paint.

I didn´t know, but the swept front arms actually mounts the lower shock attachment further forward than the original arms.
No more rubbing.

Will be very interesting to se how the 3D printed arms will hold when I take the car for a testrun.

[matt1ptkn]

I didn´t know, but the swept front arms actually mounts the lower shock attachment further forward than the original arms.
No more rubbing.

I never knew that either; I learned something new! Thank you.

[Johanp]

EDIT: Here is one of my 3mm screw taps. I have another made from a long 3mm button-hex-head screw, I recommend going with that because it won't slip while tapping threads like this first one I made with a Philips-head screw. I can't seem to find it however. Anyway, I just used the thinnest Dremel cutting disk I had to gradually cut a groove on opposite sites of the machine screw, deepening as it got closer to the tip. This particular one I've been using for many years, including to tap aluminum, hence it's a bit scuffed up. It still works like a charm to make threads, though. If you don't have a tap & die set and you need to cut threads in a pinch, this will get the job done.

That is a clever way to do it. Never came to my mind that you can actually make your own taps that way. Thanks!



Finished assembly of the chassis including 3D printed Pro SE geometry front arms. Doesn´t seen very easy to find genuine arms. Or does someone have a spare set?
Maybe I should stick to the 3D printed ones. They look kind of cool.

On to the body. There was a couple of bodies in the parts lot that I bought.
The least sad one was this black one:

It had pink window mask and was broken (and repaired with CA glue and white plastic strips) at the rear shock mount.

I used flexible glue (like shoe goo) and some leftover carbon fibre weave to patch the broken halves together.
Not very pretty, but functional and is seems strong enough.

Then I covered the worst cracks with flat black vinyl wrap

The body still has to trimmed and fitted to the car, so it is not the final result in the pictures.

//Johan

[Coelacanth]

Nice body repair, Johan...you did it right by using Shoe Goo. CA glue is not the right adhesive to repair Lexan as it's hard and brittle when dried. You need a flexible cement.

[aconsola]

looks great, what 3d printer did you print the arms and bulkhead with?

[Johanp]

looks great, what 3d printer did you print the arms and bulkhead with?

Thanks!
They are printed in a 3D Systems Projet 2500 Plus. It is unfortunately not mine, I have access to it via a friends workplace.

I decided to make this one into a runner. I got some modern electronics for it, but still using a brushed motor.
The Radiolink controller I had since before, but I had to visit the local hobbystore to get a Tritronic 1060 ESC, a Hackmoto 13T brushed motor and a SRT servo.
Batteries are NiMH. I actually got a shorty LiPo, but I preferred the look of the NiMH. Call me old fashioned if you like!
The front tires are new, but the rears are NIP Yokomo Hotlaps TR-39 that I had in my old racing stuff.

Put the mildly restored body on it. I decided to keep most of the original decals, including the French/Canadian (Les miniatures) in memory of where I got this car from.

And I took it for a short run in our gravel paddock. Way to bumpy for this car, but it was fun!

I never realized how much I missed these old Losi cars!