47 replies to this topic

[dalek]

How can I automate my tire truer?

 

I'd like to have a little motor that I could couple to the feed screw of my Hudy truer.

 

The speed of the motor would need to be adjustable down to something like one revolution in 10 minutes.

 

The voltage of the motor could be anything, AC or DC.

 

Does anyone know if this modification has already been done?

 

If not, does anyone have any thoughts as to what motor might be suitable?

 

 

[Phil Hackett]

A small gear motor with a cam will do the job. I'd check McMaster or Grainger for ideas but it's not going to be cheap. There used to be a company in New Jersey (Servo Systems) that sold surplus motors, controls and more. I just looked and the same named company is selling new systems... not inexpensive.

 

If you gear down (way down...something like 10,000:1) an RC motor with a crank and spring mechanism and a variable power supply that might be the ticket.

[Pappy]

How about something like this.

 

 https://www.ebay.com...:Bk9SR4ip_qvJZg

[Phil Hackett]

He's looking for a 10 minute cycle.... 20,000 rpm motor would be turning 200,000 revolutions in that time. Even the 10,000 to one ratio  I suggested would be 20 cycles in 10 minutes. Maybe an AC motor turning 1750 (good luck finding a fractional HP motor turning slower at a reasonable cost.... I can be wrong)  is what;s needed. That's 17500 revolutions in 10 minutes...

 

I just reread Dale's requirement to drive the lead screw. This complicates things because of the requirement to reverse the motor after the cutting is done. A small PLC control is where I'd go. It can also be done with relays (single-phase AC motors don't lend to reversing direction) but this requires relay logic and PLCs are cheap on the surplus market... the problem with them is the programming the PLC, something I've never done. Manually backing out the screw could also be a cheap alternative.

 

I just remembered, there is a mechanical reversing mechanism involving a rotating cone clutch with 2 ends. Again, this can get more involved than the original poster wants.

 

Here's an example...https://youtu.be/aOa...0_HY7xaV-wILvHY

[MrFlippant]

You're gonna need to go a bit more complicated using a stepper motor and some computer controls.

 

This guy has already done it.

 

[Wizard Of Iz]

Seems like I recall that Hudy makes an automatic tire truer for RC cars.   I wonder if it could be modified to work on Slot cars?

[dalek]

I don't think I need to reverse the motor.

 

At this point, what I envision is a bracket attached to the Hudy on the same piece that the feed screw goes through.

 

The feed motor would slide onto the bracket and couple to the feed screw at the same time, hopefully with no tools required.

 

To true a tire:  

-- Slide the feed motor off its bracket so it's out of the way

-- Set up the truer in the normal way so it's ready to start grinding

-- Slide the feed motor onto its bracket

-- Turn on the truer and turn on the feed motor

-- As you are free to do other things, listen to the truer to determine when it is no longer removing material from the tire

 

 

[dalek]

I checked out the links posted above and I saw the little motors that are geared way down.  

 

They might work even though the output shaft still spins too fast, if I could come up with say an electronic device that would allow power to the motor to be pulsed.

 

Example, power on to the motor for 5 milliseconds then off for 5 seconds.

 

If the weight of the feed motor were to cause the Hudy to not cut normally, maybe the motor could set on a spring in order to compensate for its weight.

 

 

[dalek]

Seems like I recall that Hudy makes an automatic tire truer for RC cars.   I wonder if it could be modified to work on Slot cars?

 

I found a picture of it and it's a big beast -- not usable for our little tires.

[Guillermo Suar]

I think a stepper motor can be used for this. You'll need to control it with an Arduino. I believe that is what is using the truer in the video.

[dalek]

I think a stepper motor can be used for this. You'll need to control it with an Arduino. I believe that is what is using the truer in the video.

 

Awesome!  I didn't even know what a stepper motor was.

 

I just did a quick search and saw that they come in a wide range of sizes, including very small and even some with reduction gearing so I should be able to find one that's a good fit.

[Wizard Of Iz]

 

I found a picture of it and it's a big beast -- not usable for our little tires.

 

I'm stunned that I even remembered that such a thing existed.

[Mark Onofri]

When I first started using my Hudy, it would self feed on its own. It could be really irritating at times. I wound up installing a lock nut which was a pia. At the instance of Bill Breck, I installed a MidAmerice adjuster. It will still self feed if the adjuster are unwound. Mabe it's possessed by democrats

[Bill Breck]

When I first started using my Hudy, it would self feed on its own. It could be really irritating at times. I wound up installing a lock nut which was a pia. At the instance of Bill Breck, I installed a MidAmerice adjuster. It will still self feed if the adjuster are unwound. Mabe it's possessed by democrats

 

I don't remember this at all. 

[Mark Onofri]

Sorry for the typo:
Mabe it's possessed by demons.

[Mark Onofri]

You recommend it before you left and I got it after that

[Mike Patterson]

How about an old electric clock motor? They output at 1 rpm, and run on AC.

[dalek]

How about an old electric clock motor? They output at 1 rpm, and run on AC.

Thanks for the suggestion but the Hudy needs one revolution of the feed screw about every 8 minutes.

Since yesterday, when I learned that stepper motors exist, I've been learning about them and have found that they are just the ticket for what I am trying to do and the prices for them and the microcontrollers that operate them, are what I consider to be reasonable.

[Mark Onofri]

You might want to consider changing the bearings for the axel from metric. You'd have to resize the drive pully too.
From what I've read about step motors,they rotate to certain position(s) opposed to continuously rotating.

[Mark Onofri]

I found the reason it self- feed. The threads were over-cut. The original screw (left) would back out from the vibration. Cheaper and easier than a motor.

[Phil Hackett]

You might want to consider changing the bearings for the axel from metric. You'd have to resize the drive pully too.
From what I've read about step motors,they rotate to certain position(s) opposed to continuously rotating.

Step motors spin just like regular induction motors (or DC motors). They just need the electric pulses to be in the correct orientation and pulse speed. Very few but still a small number of CNC machines use steppers.

[Dave Crevie]

Step motors spin just like regular induction motors (or DC motors). They just need the electric pulses to be in the correct orientation and pulse speed. Very few but still a small number of CNC machines use steppers.

Exactly. Modern CNC machines use linear positioning scales to measure the length of cut. The rotations of the motor have nothing to do with it. Setting that system up on a small bench top tire truer would be next to impossible. Better would be an adjustable stop, with a low voltage motor that would stall when the stop is reached.

[Mark Onofri]

I'm surprised that no one questioned if I might have a screw or two loose .
Looking at my machine as I type, seems possible to add a pully,a very, very
small pully and a spur gear,a very,very large spur gear to turn the depth screw. Like the old saying:
" anything is possible given enough time and money "

[dalek]

This is what I put together to do the job.

 

I was glad to find that it works as well as I had hoped.

 

 

 

 

 

 

 

 

 

 

 

 

 

[dalek]

I think a stepper motor can be used for this. You'll need to control it with an Arduino.

 

How right you were!

 

===================

 

I still have a little more programming to do -- I want to create a safeguard to deal with the possibility of someone using a power supply that isn't capable of delivering enough amperage for the Budy to get up to the amperage setpoint (that the user has set using the feed rate pot).

 

When I've finished with the programming, I'll make a video of using the Budy.

 

Also I want to say that even though I've named my creation "Budy Auto True", that doesn't mean I intend to manufacture and sell it (I don't need the money or a lot of work to do).  I just felt like it's helpful to have something to call it during discussion.

 

However, I do intend to do what I reasonably can to make it feasible for other people to make their own, including offering the Arduino program I've written and maybe offering the Budy as a kit in some form, but not for profit.  If anyone wants to make and sell the Budy, it's OK with me.

 

BTW, in post #7, I said that part of my vision was to listen for the sound of the Hudy to know when it's finished cutting the tire.  But that isn't necessary because I put a relay in the Budy which shuts the Hudy off when the tire is done.