M4A4 Firefly (Vc)

[RiskyR]

Also spent some time on refining the details and making as much doors and hatches working as possible. Does seem to work quite well when using a paperclip as a hinge pin.

Overall starts to look very nice I'd say. The next (complicated) step is to design the tracks. I've yet to find the correct spacing of the track links so that they'll fit the sprocket correctly.

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[RiskyR]

So after some prototyping (is that a word?) I finally got a correct spacing so that the tracks fit the sprocket.

The track links themselves are printed in 2 pieces, then glued together and then connected to eachother using a paperclip as a hinge. The connecting links are designed in a way that the hinge pins have a tight fit, so there shouldn't be any need for glue, except for some holes which could be a bit bigger because of the deviations in printing.

I also understand why nobody likes to assemble tracks... what a crazy amount of work... and I need 84 links each side for the longer M4A4 variant...!

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[HERMAN BIX]

A top effort mate, and yeah, tracks are ideally a ready made thing rather than a 'got to bung them together for a week' thing

[tankme]

Great effort on the tracks, but you might want to consider getting some actually steel pins. I know I've had tracks "stretch" with use, but in most cases it's the pins that bend somewhat elongating the tracks. I'd hate to see you assemble all those links and then have to take them apart to do it all over again.

[Herr Dr. Professor]

I second tankme's advice to use steel track pins now before you do any finishing work. The double-pin links on the M4 tracks love to climb out of the drive sprocket, and if the paper-clip pins do bend, you will be putting on steel ones later.
Regardless, I sure do admire your handiwork and patience with the printing, modifying, and reprinting. Bravo

[Conor]

Also, another small suggestion/question

What are you printing the tracks in? Ideally, don't use materials that are very brittle (ABS/PLA) and rather use something with more ductile strenght like PETG or Nylon.

I've done some track test prints in PETG PLA and ABS and the PETG track outperforms the other two by a large margin.

[RiskyR]

I'm glad people are still reading my topic

A top effort mate, and yeah, tracks are ideally a ready made thing rather than a 'got to bung them together for a week' thing

Thanks! Yes tracks are something I'm now building for a prototype, but if they wear or break I might consider buying some tracks instead

Great effort on the tracks, but you might want to consider getting some actually steel pins. I know I've had tracks "stretch" with use, but in most cases it's the pins that bend somewhat elongating the tracks. I'd hate to see you assemble all those links and then have to take them apart to do it all over again.

I second tankme's advice to use steel track pins now before you do any finishing work. The double-pin links on the M4 tracks love to climb out of the drive sprocket, and if the paper-clip pins do bend, you will be putting on steel ones later.
Regardless, I sure do admire your handiwork and patience with the printing, modifying, and reprinting. Bravo

On the track pins - thank you both for your advice! I chose to use the paperclip because I have seen this before in other designs. I've also almost built an entire track oh well, maybe I'll try this method to see how it works. I do want to share/sell the design after it's finished, so I want to test this method as well

Also, another small suggestion/question

What are you printing the tracks in? Ideally, don't use materials that are very brittle (ABS/PLA) and rather use something with more ductile strenght like PETG or Nylon.

I've done some track test prints in PETG PLA and ABS and the PETG track outperforms the other two by a large margin.

For this particular prototype I'm printing everything in PLA, as this is easy to work with. I know it would be better to do everything in PETG. Maybe the 2nd prototype will be made out of PETG

[RiskyR]

Not an awful lot of progress lately. Spending quite some time on refining parts and reprinting them. The track had to be redone as well... I found out it was too narrow! Now redesinged using the original dimensions (in 1/16th scale obviously so should be fine now.

Return rollers now finished so the bogies are finally complete! Now working on printing and assembling the tracks and ordered some OpenPanzer Heclo Shield boards which my dad will assemble for controlling the Firefly.

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[c.rainford73]

Really nice progress. You've apparently mastered the art of 3-D printing! Following along

[RiskyR]

Really nice progress. You've apparently mastered the art of 3-D printing! Following along

Well it's lots of trial and error

Finally got one track finished. Takes way to much time I'm almost tempted to buy some Heng Long tracks and sprockets
Anyway it looks good and seems to work well. Some fine adjustment needed but overall quite happy with how they turned out!

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