Electronic gearing for gear hobber

[Zahnrad Kopf]

That Overtons I've seen were pretty good machines. They were built like brick shitehouses and decently featured.

 

[Garwood]

That Overtons I've seen were pretty good machines. They were built like brick shitehouses and decently featured.

Thanks for the insight! To the slightly clueless me it looks to have the beef and the whistles and the bells.

So the place I got it from was pretty non-technical and I do not believe the Overton was used hardly at all. They mentioned they really struggled with it because it fed the hob from the bottom and didn't seem the features worked correctly on it.

I have a sneaking suspicion this machine is designed to climb cut and they didn't know that so they were trying to use it backwards.

 

[Milling man]

Green does not seem to be very old, most likely it has a backlash sampling system.

 

[Garwood]

Green does not seem to be very old, most likely it has a backlash sampling system.

Well, it's 1979, 4 years older than me. I try to limit my backlash, but sometimes I can't help it.

 

[Garwood]

Very Pfauter-ish. If you want to do conventional you just put an idler in the feed train. It might have the 'minch' feature as well but I think Pfauter made it so you could turn that on or leave it off. You might want to leave that off at first but latrer on, if you do any production, it's very nice

btw, next thing you need is a hob sharpener. Properly sharpened hobs are very important and getting it done outside is more than iffy. For a while you can send them to your friendly neighborhood competitor (gear shops tend to be unusually cooperative) but in the end you'll want your own.

And then a redin. You do not want to be deburring teeth manually for very long.

I'm sure we'll think of more stuff to buy

I read the Overton's manual today. My mind's blown. The damn thing does it all and then some. Axial feed, radial feed, tangential feed and diagonal feed. Climb or conventional hobbing. Incremental hob shift. One, two or three pass hobbing.

Neat stuff!

 

[EmGo]

I read the Overton's manual today.

Oh, that's too bad I was thinking you could apply for an H1B visa for a nice Rumanian girl to come read you Overton bedtime stories

 

[EmGo]

Bye Gar, and good luck. Ignorant stupid moderator here is up to his old tricks, so fuck this place. Have fun with the Overton

jaguar36 can go suck a dead donkey dick. Stupid, abusive, antagonistic, disrespectful bullshit posts by some parties are fine but reply to them and oh-oh, you're a bad person.

Eat shit and die, jaguar. Fuck you, the horse you rode in on and fuck this place that keeps you as well.

 

[newcomer]

Wait what happened? I was hoping this electronic gearing would come to fruition...

 

[Milling man]

Well, it's 1979, 4 years older than me.

Oh, by my standards, this is almost a new machine)))))) Yes, most likely this machine has backlash compensation, probably with the help of a hydraulic cylinder.

 

[Mike Gre]

//Arduino code for controlling stepper motor from encoder
//video at

//reconstructed code from 5+ years ago
//untested in current form
// include the library code:
#include <LiquidCrystal.h>

// initialize the library by associating any needed LCD interface pin
// with the arduino pin number it is connected to
const int rs = 12, en = 11, d4 = 9, d5 = 8, d6 = 7, d7 = 6;
LiquidCrystal lcd(rs, en, d4, d5, d6, d7);



#define encoder_a 2 //encoder a = arduino pin 2
#define encoder_b 3 //encoder b = arduino pin 3
#define motor_step 4 //motor step = arduino pin 4
#define motor_direction 5 //motor direction = arduino pin 5

// variables will change:

volatile long motor_position;

const int buttonup = 15;
const int buttondown = 16;
int buttonstateup = 0;
int buttonstatedown = 0;
int teeth = 14;
int steps = 0;
int variable = 9*teeth;
int lastbuttonstateup = LOW;
int lastbuttonestatedown = LOW;
long lastDebounceTime = 0; // the last time the output pin was toggled
long debounceDelay = 50; // the debounce time; increase if the output flickers


// 1.111111 / number of teeth = decimal to be converted
// this number wil be converted to an integer
// for 4 decimal place precision convert to 1/1000
// for example if the number of teeth is 14 then the number is .7936
// 7936/10000
// then each step of the encoder = 7936 and when step becomes more than 10000 the stepper steps and subtracts 10000 leaving a remainder


void setup ()
{
Serial.begin(2000000);
pinMode(motor_step, OUTPUT);
pinMode(motor_direction, OUTPUT);
// then the encoder inputs
pinMode(encoder_a, INPUT);
pinMode(encoder_b, INPUT);
digitalWrite(encoder_a, HIGH);
digitalWrite(encoder_b, HIGH);
// encoder pin on interrupt 0 (pin 2)
attachInterrupt(0, encoderPinChangeA, CHANGE);
// encoder pin on interrupt 1 (pin 3)
// set the cursor to column 0, line 1
// (note: line 1 is the second row, since counting begins with 0):
lcd.setCursor(0, 1);
// print the number of seconds since reset:
lcd.print(teeth);
pinMode (buttonup, INPUT);
pinMode (buttondown, INPUT);
lcd.begin(16, 2);
lcd.print("Number of Teeth");


}

void encoderPinChangeA()
{
if (digitalRead(encoder_a) == digitalRead(encoder_b))
{
steps+= 200;
}
else
{
steps-= 200;
}
}

void loop()
{
cli(); // Critical section for using steps.
if (steps >= variable)
{
steps= steps-variable; // Move this up here to make the critical section as short as possible. This equals 9x the number of teeth
sei();
digitalWrite(motor_direction, HIGH);
digitalWrite(motor_step, HIGH);
digitalWrite(motor_step, LOW);
motor_position++;
}
else if (steps <= -variable)
{
steps= steps+variable;
sei();
digitalWrite(motor_direction, LOW);
digitalWrite(motor_step, HIGH);
digitalWrite(motor_step, LOW);
motor_position--;
}
else
sei();
int buttonstateup = digitalRead(buttonup);
int buttonstatedown = digitalRead(buttondown);
if (buttonstateup == HIGH){
delay(100);
teeth+= 1;
variable = 9*teeth;
lcd.setCursor(0, 1);
lcd.print(teeth);
}
if (buttonstatedown == HIGH){
delay (100);
teeth-= 1;
variable = 9*teeth;
lcd.setCursor(0, 1);
lcd.print(teeth);
}



}

 

[Mike Gre]

Sorry should have explained that first.

Basically what I did was take a normal dividing head that already had a bevel drive gear on it. I produced an "acceptable" bevel gear to drive it with a stepper motor on my 3K K&T. I made the program above for an Arduino (with much help from the Arduino forum) for driving the stepper motor from the optical encoder in the pictures below mounted to the top of my drawbar. This makes excellent spur gears and I am now working my way to helical gears. The two buttons and the LCD select the number of teeth. My dividing head ratio is 40:1 and obviously account for the steps per rev on your stepper motor in your modification of the above program.

Got an error on uploading images. What's the best way?

 

[Zahnrad Kopf]

This makes excellent spur gears...

Can you quantify that statement, please?

 

[implmex]

Hi Zahnrad Kopf:
You know, I was thinking EXACTLY the same thing as soon as I saw Mike Gre's post.

But of course, "Excellent" means many different things to many different people.
We can celebrate Mike Gre's ingenuity...kudos to him and his work.
These may truly be brilliant gears for what he intends them for, and you've got to admit, there's nothing to criticize in his creativity and his persistence.

But I doubt you or any other professional gear maker would sell all your equipment and copy what he is doing in the expectation you could make better gears than you can now.

Cheers

Marcus
www.implant-mechanix.com
www.vancouverwireedm.com

 

[Mike Gre]

Can you quantify that statement, please?

Since I am making these gears on a retrofitted 75 year old machine with an (at the time) $6 Arduino I would assume you can tell that I am just happy they have teeth.

That said; the gears end up straight and mesh together well with very minimal noise and a good (to me) surface finish. The only thing I will say is that because it is driven by a stepper you can see an extremely small jerk if you are moving the dividing head too slowly. Adjusting the spindle speed slightly higher gets rid of this and makes for a smoother motion of the dividing head. I also forgot to mention that the stepper I used is a closed loop. This offers feedback and keeps the stepper accurate throughout the cut.

Overall I am very happy with the end result for my needs. Not making swiss watches here, just moving power from point A to B.

 

[CarbideBob]

Can you quantify that statement, please?

Is there some sort of rating or class?
Aren't gears just poopy, medium, good enough and excellent?
Bob

 

[Zahnrad Kopf]

Is there some sort of rating or class?
Aren't gears just poopy, medium, good enough and excellent?
Bob

You forgot "super poopy" and "totally bitchin'."

 

[Zahnrad Kopf]

Since I am making these gears on a retrofitted 75 year old machine with an (at the time) $6 Arduino I would assume you can tell that I am just happy they have teeth.

I had no idea. That's why I asked. It seemed a bit optimistic in my experience, but I'm completely willing to be wrong.

 

[David_M]

Is there some sort of rating or class?
Aren't gears just poopy, medium, good enough and excellent?
Bob

You forgot "super poopy" and "totally bitchin'."

And I thought they graded them the same way Russell grades motor oil.