Racing tracked vehicle

[Kemenb]

UPDATE:
Poly-amid and Al 7075 plates are about meter apart from CNC mill and waiting their turn.
Rubber will go on laser cutting in few days.
And PA bars are waiting for lathe, not sure if I will buy the lathe or pay someone to do it...

[Kemenb]

I made two printed circuit boards and soldered ten 470uF 63V capacitors on each. This will help the batteries overcoming high current spikes.

[Kemenb]

PA6 is tough to mill, they are only half true. I hope I get the parts soon.
But the good news is I got a lathe Prvomajska TPN 160, its old but in a good condition. Now I'm making parts, today I made 408 brass bushings for the track. They are made from thin brass tube. It took some trial and error to figure out go to cut the most efficiently because this tube is very delicate and easy to bend.

Does anyone know of a glue that will bind Polyamid (NYLON) and rubber?

[Kemenb]

A long over due update:
I finally received all PA6 parts. Buggies are 1/8 and 1/18 and that little motor in the back is CC2028


Track and wheels. Tracks have 945 holes and they all have to be threaded. I used battery drill for cutting threads. It still it took few moves, 3 battery packs and some snacks. But now they are ALL done!


Inner edges of tank track have a radius of 10 mm. They had to be milled and lathe was the safest and quickest solution. I used power feed in one way, turned the track piece around and use manual feed for the other direction.


I had some problems with brass bushings and M4 screws. A lot of bushings were hard to put on the screws, they had a bit of an edge.

[ddd228]

A long over due update:
I finally received all PA6 parts. Buggies are 1/8 and 1/18 and that little motor in the back is CC2028


Track and wheels. Tracks have 945 holes and they all have to be threaded. I used battery drill for cutting threads. It still it took few moves, 3 battery packs and some snacks. But now they are ALL done!


Inner edges of tank track have a radius of 10 mm. They had to be milled and lathe was the safest and quickest solution. I used power feed in one way, turned the track piece around and use manual feed for the other direction.


I had some problems with brass bushings and M4 screws. A lot of bushings were hard to put on the screws, they had a bit of an edge.

If you wanted to use titanium screws that would have been CUBIC DOLLARS (or Euros).
Even shouldered screws would have been a lot more cash. Maybe you won't need Nylocks on the backs of the screws because the PA-6 would self lock,correct? Well,if a bushing seized up,the ones on the left side would come out.
REALLY nice machine work on the PA-6,Kemen. Will that material "take" to dying? Curious,that's all.
Some of the white R.P.M. parts will take RIT dye.

Dave in Seattle.

[Kemenb]

Welcome in the forum Dave!

I wanted titanium screws or at least inox but ended with plane old zinc covered PH screws. I didn't find shoulder screws of the correct size for my needs. I went a bit overboard with screws, there are 17 different screw sizes and around 1300 screws. There is always next time for pimping.

Yes PA6 will self lock, I purposely left some trad uncut so the screws will lock.

I didn't test dying yet, well I certainly hope it does take RIT dye. Big pieces will stay white, track is going to be gray or red, the rest will be black. I'm still open for suggestions for colors. Body will be made from fiber glass with carbon fibers on top.

[Kemenb]

The machine work on PA6 is CRAP! Looks god but the track parts are up to 0.25mm bellow the measurement, and 10% of them are even above! Tolerances on the parts would make even woodworkers shame of those parts! And this was made by Mechanical universality. I told them about this and they says that PA6 is very difficult to mill and its not their fault, we shell see when Al 7075 is done.

Almost forgot, they made 2 holes about 1,5mm too small, guess material just moved out of their way during milling and then went back

Good news, track parts are finished!

Here are few ideas for color scheme, I prefer the 3rd one.


My "recycled" battery drill. Got the drill in a bulky refuse and Li-ion battery is made from old laptop batteries. Usually only one cell in the pack is bad. In bigger packs, there are 2 or 3 cells in parallel that whole section is bad and the rest of the pack can be still used. But be VERY careful during soldering, Li-ion batteries din't like heat so work as fast as you can and use big and hot soldering iron.
My pack has around 1250 mAh, more then enough for casual use. Back up: 2s+ 2s Li-Po packs from 1/18 car and flying wing.

[Kemenb]

O.K. went to the store and bought some dye. It was two part: liquid dye + crystallized fixer . This dye was meant for 5-8l of water + 400g of salt.
I took few scrap pieces of 6mm 10mm and 40mm PA6 and broken tire (didn't clean it, it was just for comparison). Parts were in slow boiling water for proximity 45min and then left to cool down for another 45 min. Broken wheel and 6mm PA6 absorbed color very nicely. Color is dark red-violet, rest of the parts are almost pink. And I don't wont a Hello Kitty tank!

Next week the other store gets new colors and I will try my luck with dose. In worst case scenario black would still make grayish color.

[Kemenb]

Al parts are home! But there was a mixed up at laser cut they made me only 60 of 220 track links. I E-mailed water jet company, hope they have some spare time soon.

[Kemenb]

I started assembling my MadCat. Chassis is almost done. I also received 4 additional yellow straps for batteries. Thanks to Me-Plast.
120mm PC fan will be powered with DC-DC variable voltage regulator set at 12V. I will also add four 1W 10mm round LEDs in front and four high power red LEDs in the back. LEDs will be connected in series and plugged directly to 12V line. DC-DC modules are really cheap 1.5$. In HAM radio club we use them for powering access points on the roofs, 12V goes to the box on top of the roof and then this little circuit converts to 5V. They can handle up to 1,8A without additional cooling.
Dave thanks for spell check.