Odometer Gear Nirvana

[Tom]

The odometer gear on my bench-test cluster broke, so I bought a gear for $25. When I got it, I could help but wonder if my Formlabs printer could print the tiny detail and make a functional replica. After a short odyssey learning about gear modulus, pressure angles, and a bunch of other esoteric gear lingo, I was able to model a replica of the gear I bought, and printed it. Pretty excited that it seems to work like a charm! I have it running on the bench cluster now, and it's up to 50+ miles. This gear is printed in a general purpose resin, but I have a super hard resin for the 'production' versions. Assuming all goes as planned, we can say goodbye to the days of $25 odometer gears!

Grey one is mine; white one is from eBay....

odometergear.jpg (1.11 MiB) Viewed 1940 times

[painenneck]

They are available on Etsy for $15 and change. Just bought one; works well.
With all these parts you're making you'll have to start hiring employees and offering medical, dental and 401K!

[Tom]

They are available on Etsy for $15 and change. Just bought one; works well.
With all these parts you're making you'll have to start hiring employees and offering medical, dental and 401K!

Yeah, I did see after-the-fact that there were some cheaper ones out there. Was the Etsy one 3D printed?

As for employees, it's not entirely out of the question if i could find someone good at HTML/PHP, 3D-printing, SEO optimization, graphic design, advertising, hardcore Porsche mechanics, bookkeeping, shipping and receiving, and public relations.

[painenneck]

I don't know if it was.

[Larry C]

They are available on Etsy for $15 and change. Just bought one; works well.
With all these parts you're making you'll have to start hiring employees and offering medical, dental and 401K!

Yeah, I did see after-the-fact that there were some cheaper ones out there. Was the Etsy one 3D printed?

As for employees, it's not entirely out of the question if i could find someone good at HTML/PHP, 3D-printing, SEO optimization, graphic design, advertising, hardcore Porsche mechanics, bookkeeping, shipping and receiving, and public relations.

Buy a clone machine and you may have one applicant.

[Tom]

They are available on Etsy for $15 and change. Just bought one; works well.
With all these parts you're making you'll have to start hiring employees and offering medical, dental and 401K!

Yeah, I did see after-the-fact that there were some cheaper ones out there. Was the Etsy one 3D printed?

As for employees, it's not entirely out of the question if i could find someone good at HTML/PHP, 3D-printing, SEO optimization, graphic design, advertising, hardcore Porsche mechanics, bookkeeping, shipping and receiving, and public relations.

Buy a clone machine and you may have one applicant.

You're hired! They now make resin printers capable of extremely high resolution prints (under 50 microns) for less than 3 tanks of gas. My Form 3 is part of the Formlabs eco-system, which caters to dentists, jewelry makers, etc. so is just a foolproof workhorse for the most part, but at less than 1/10th the cost, some of these new printers claim to print faster with higher resolutions, etc. so are mighty tempting. Can't really say whether they are as reliable and hassle free, but for the price, seems hard to go too wrong. For example:

https://www.amazon.com/dp/B09QGW5J8T/re ... g_ana_1-20

In the meantime, I let my speedometer run all night at 60mph, and the gear is going strong for over 900 miles now.... I just cranked it up to 120 to see how that does for a while. If this more general purpose resin lasts thousands of miles, the high-strength resin I got for this should last a very long time.

[Zirconocene]

You are on fire lately with the cool printed parts. If these work out how you think I'd be in for a couple, for the 944 and 968. Both of those cars are going to eventually get the gauge cluster sanded and resprayed; that stippling has started. I figure I can do a proactive gear change with everything off and out.

Awesome stuff, thanks for sharing!

[Tom]

You are on fire lately with the cool printed parts. If these work out how you think I'd be in for a couple, for the 944 and 968. Both of those cars are going to eventually get the gauge cluster sanded and resprayed; that stippling has started. I figure I can do a proactive gear change with everything off and out.

Awesome stuff, thanks for sharing!

Yes, sitting at my desk designing parts and hitting 'print' is just soooo much easier than actually working on the car. I was under the car much of the day, and missing my office chair. Not sure what it says about my car, but all of my recent 3D print projects have been to fix issues with the car (or in the case of the odometer gear, my simulator/cluster). I let the gear run nearly 24 hours at various speeds and let it go for over 1200 miles. Took it apart this afternoon and the gear showed zero signs of wear, which makes me wonder if I really needed to get the uber-strong resin for the 'production' run. But my plan is to print it in that material (good to like 400F and about as strong as plastic gets) and do a big batch to serve as welcome/thank you gifts for active Carpokeans. Does the 968 use the same gear? I see lots of references to a 15-tooth gear?


Here's the gear after 1200+ 'miles' on the cluster -- no visible wear at all...

no-wear.jpg (303.17 KiB) Viewed 1883 times

[painenneck]

Has anybody heard of the reasoning behind Porsche using a different plastic for this one gear in the cluster? I mean, seriously?

[Tom]

Has anybody heard of the reasoning behind Porsche using a different plastic for this one gear in the cluster? I mean, seriously?

Yeah, not sure, but that one gear turns on a perpendicular worm gear, so the gear teeth essentially slide against each other to make a 90 degree angle. If I had to guess, the clever engineers at VDO wanted to use a material that was self-lubricating, so that the gear teeth wouldn't wear down. So instead of using a gear that would wear out in 100k miles, they used one that would turn into crusty pine resin after a decade or two.