Power Steering

[Mechanicalbob]

I originally posted an idea over in General Scale Talk about a Scale Steering Box.

There Red_Jim posted:
"But remember folks,push pull steering is crap(in the real world)like the setup shown,but that shouldn't stop anyone from trying a crossover steering setup with these parts"

So that got me to thinking about the setup and how to take it beyond a scale rig. So I went down to the local music store and picked up a coulple of "String Tunners" from there repair guy.


The tunner on the bar is a 16:1, the silver one is a 12:1 and the black one is a 14:1 gearing.


The next step is to turn one of these into a Power Steering unit. To do this I needed to hack a servo for constant turning. After I picked out a donor servo for the hacking (It was a Hi-Tec brand.) the fun began.

Here you can see that I removed the potentiometer (Yellow, teal, and red wires) and replaced it with a few 2.2k resistors.



While I was hackin the servo I also drilled out the output of the servo to fit the input shaft of the tuner.



This is one way to connect the two together. Later I plan on using some small u-joint's and a shaft to do this. This was just an easy way to put this together.



Here is how it is all held togehter one little screw. where the POT use to be, I also need to clean it up a bit so it looks better.




So the next step is to make a connection on the otput shaft to the wheels for a cross over power steeing or on the axle steering setup. To mount this up is not that hard to do on the output shaft there is a barrel nut with a washer. I just have to finish one of my trucks to realy try it on.

With this setup you should get some good steering power out of your servo's. If I remember right to get torque output you multiply the torque by the gear ratio (in a truck: ratio of tranny and diffs) then devide by the number of wheels being used. I think this was a 110 In Oz servo, so by adding a 12:1 on it I now have 1320 In Oz of steering Or I could go with the 16:1 and get 1760 . Now if you have a Chiken Butt servo that puts out 207 oz/in of torque and use the 12:1,you would have 2484 oz/in os steering power

So what do you think?

Steve

[west virginia krawler]

thats a sweet idea! Nice thinkin

[DaViolentOne]

That is a cool idea... Extra points for innovation, too... I never would have thought to use machine heads from a guitar for steering let alone anything on a crawler... I think you'd be better off to use the one machine head you show on the servo over the other style... The sealed ones last longer than the other style by far, because ya can't get any dirt or anything in it...

I wouldn't be surprised to find I have a few kickin' around here still... I'll hafta take a look and see if I do...

[speedsport22]

I'm VERY interested in how this turns out. Nice work.

[ROSS]

great idea, post pics when ya do it

[shutupanddrive]

How's the speed on that? Still decent?

Also, how are you gona rig the pot to stop it at the right time (since the servo will actually have to turn 12 times as much as it did before)? Attach it directly to the steering arm or something?

[Mechanicalbob]

Originally Posted by shutupanddrive

How's the speed on that? Still decent?

Also, how are you gona rig the pot to stop it at the right time (since the servo will actually have to turn 12 times as much as it did before)? Attach it directly to the steering arm or something?

The speed is ok, it is not the fastest, but it will work. The (mini)pot will be mounted to the output shaft of the gearbox. The setup I did here was to see if it would work. On the next one I will not hack the servo, just remove the pot and place it down the line. The original servo output would have to turn 3-4 times to turn the wheels the right distance, and this can be done with the pot being moved insted of being replaced.

Steve

[Wingin' It]

Nice set up. I can't wait to see how it works when it's finished.