restoration Yet Another RS Hot Machine Conversion

[ivxcvi 1]

Nikko85 inspired me to take a similar approach to restoring my own Hot Machine:

 

I received mine as a childhood gift & determined about a year ago that I would upgrade it to work with a modern MCU. I'm planning on installing an F405-WSE & using Ardupilot, or similar.

Nikko found that a standard metal servo made a great replacement for the stock micromotor which acted as a servo arm. I've received my replacement servo today.

The replacement came with a servo saver, but it's going to be too big. I have access to 3D printing hardware & plan to use the old arm with a new plate to adapt it to the replacement servo. The next challenge will be finding a solid way to secure the servo to the top gear housing. Not sure if I'll use tape or create a bracket to secure it.

[Nikko85 3454]

A servo saver is a good idea. I didn't use one, and snapped off a few servo horns with very light crashes. A few other trucks of mine don't use them, but this one really needs them.

To attach the servo to the plate I used a double sided foam adhesive square, and then wrapped electrical tape around both, it worked well.

 

 

[ivxcvi 1]

On 2/13/2022 at 4:54 AM, Nikko85 said:

A servo saver is a good idea. I didn't use one, and snapped off a few servo horns with very light crashes. A few other trucks of mine don't use them, but this one really needs them.

To attach the servo to the plate I used a double sided foam adhesive square, and then wrapped electrical tape around both, it worked well.

 

 

Thank you for input! I will start with the stock servo arm & once it breaks I'll probably design a servo saver out of resin with higher tensile strength.

My plate looks different from the one you worked with. I'll see whether I can design around it. The screw studs get in the way of using the tape method, unless I clip them off. I may just redesign the entire upper gear housing plate with a bracket for a modern standard servo unit.

Resin printer is down for the moment & I'm out of PETG filament. I'll be putting this on hold until I solve one of those two issues.

In the meantime, I've loosened the sprocket pinion gear on the old drive motor by prying with a screwdriver at first, then following up with a needle nose pliers to step it up off the shaft.

EDIT: As I've already purchased the Hobywing EZRUN, it appears there is a difference in shaft size (stock=2.3mm, EZRUN=2mm). I'll either source a new brass pinion gear for a 2mm shaft size, or drop a plastic one in until it burns up.

[Nikko85 3454]

2 hours ago, ivxcvi said:

Thank you for input! I will start with the stock servo arm & once it breaks I'll probably design a servo saver out of resin with higher tensile strength.

My plate looks different from the one you worked with. I'll see whether I can design around it. The screw studs get in the way of using the tape method, unless I clip them off. I may just redesign the entire upper gear housing plate with a bracket for a modern standard servo unit.

Resin printer is down for the moment & I'm out of PETG filament. I'll be putting this on hold until I solve one of those two issues.

In the meantime, I've loosened the sprocket pinion gear on the old drive motor by prying with a screwdriver at first, then following up with a needle nose pliers to step it up off the shaft.

EDIT: As I've already purchased the Hobywing EZRUN, it appears there is a difference in shaft size (stock=2.3mm, EZRUN=2mm). I'll either source a new brass pinion gear for a 2mm shaft size, or drop a plastic one in until it burns up.

Nice work, I used a pinion puller on mine. I did manage to get the pinon on mine onto an EZrun - perhaps I enlarged the diameter?

I believe I sawed off the screw studs flat, then added two pieces of double sided foam pads.

https://www.amazon.co.uk/Double-Sticky-Adhesive-Mounting-Squares/dp/B07C6F7G3W

I needed two to fill the gap between the plate and the servo. I then wrapped electrical tape around the whole thing and it was solid. A 3D printed solution would be even better however.