View Full Version : Prototype Build

Weston Bye
01-02-2010, 09:38 AM
We needed a proof-of-concept model for an actuator mechanism at work, so I built this in my Home Shop (I fill out a weekly report of my activities at work and always emphasize my Home Shop efforts on behalf the company)




I used my Sherline lathe and mill to machine all the gears and the base, and the cutters for the gears. This is the kind of work where the Sherline works well. The worm was also machined on the Sherline with my Electronic Gearbox attachment. The Electronic Threading series will begin in the next issue of Digital Machinist.

John Stevenson
01-02-2010, 09:51 AM
Is your electronic threading similar to the ELS project that is on the Yahoo groups Weston ?


Tony Ennis
01-02-2010, 10:18 AM
That looks like it took a while to make.

Weston Bye
01-02-2010, 10:31 AM
John, my approach differs from the Yahoo method in that I made use of thumbwheels and individual TTL logic elements; counters and digital comparators. I discussed some of it in these threads:




Tony, I made it all in the downtime between Christmas and New Years. I also worked on some other projects as well as holiday leisure activities, so I probably have 20-25 hours in the prototype.

Peter N
01-02-2010, 11:01 AM
Nice work.

01-02-2010, 12:47 PM
Nice, is that deralin for the gears?
Do the shafts just ride on those metal 'cap plates' you screwed in? kinda seems like a wear point when more UHMW could of been used there (still screwed in) insted for a nice low friction pure plastic solution

My first thought would be hotglueing the motor in place on the sides... you kinda wanna leave it exposed unless this is only for very intermitant use due to overheating.

01-02-2010, 01:04 PM
It's just for show and tell to prove the concept. Nice work

Weston Bye
01-02-2010, 02:10 PM
Carld has it exactly right. Monday, back at work I will measure the torque output and do a few other tests. This assembly will never see a lot of use or wear. The proposed final product will have a cover that has projections that will hold the motor and all the shafts down in their pockets.

I will have to add the electronics next - position and torque monitoring, motor drive and LIN bus communications.

I provided the concept design and found it faster to build it myself than wait to have it jobbed out. Cheaper for the company, too. I trust that this sort of activity has preserved my job in the midst of layoffs.

Your Old Dog
01-02-2010, 06:29 PM
.............. I trust that this sort of activity has preserved my job in the midst of layoffs.

Paladin roamed the west with a sixgun and a good handle (name). With a handle like Weston you would be the Paladin of the machine/prototype business and I'd assume you'd be the last guy to get a pink slip ! Nice work Weston. If I could work out problems like that I'd come out of retirement.................... no, that's a bare faced lie. I'd rather sit here and chear guys like you on ! :D

01-05-2010, 06:58 PM
Been trying to get some heat into the wife's Taurus. This motor assembly raises/lowers a large flap to add heat or shut heat off to the cabin, as manual control allows. Same assembly/electrics as used on the auto heating/cooling system. Only problem is--------the electrics smoked.

Power train looks vaguely like the proof of concept model as fabbed by Weston ie. high torque with small motor input.



Weston Bye
01-05-2010, 08:13 PM
Yep, there are a multitude of such acturators out there, and I've seen many of them. Guidos looks similar to, and serves the same purpose as, one that I built a tester for - for Ford - 12 years ago. Small motors = low cost, the name of the game.

Testing on my proto has returned about a quarter of the torque that I expected. I know that there is some periodic loss due to the gear profiles, but that can't account for all that much. I would like to use a larger motor, but the application is space constrained.

I am considering a rework with a worm gear on the motor shaft like the one that Guido posted. It will be much quieter. The final drive worm needs to be a worm to prevent backdriving, and the spur gear on the wormshaft needs to be there for other reasons. I will post any updates.

01-05-2010, 08:27 PM
It's cool that you made all of that at home, but just FYI, you can get plastic gears pretty cheap from www.sdp-si.com. Might be able to talk work into buying you a small assortment of worms and spurs in one pitch so you can make prototyping stuff like that considerably faster. But then if you are like me, I imagine cutting the gears is half the fun of that project.

When I was in the engineering field, I was a lot like you. I did stuff at home and saved a lot of time and $$ making prototypes or testing fixtures. In time, I talked my boss into helping me improve my tools and supplies at home to better benefit work. I also ordered 2x (in case of mistakes) all material and kept drops. I'm not suggesting theft, just keep in mind that they've made no capital outlayment for your shop.