Member postings for Kealan O'Carroll

Hi chaps,

As Les has said, the wiring is in the comments of the code, but Ive put a diagram below.
As per Dave's comment you might be better off with an arduino mega or something with 4x interrupt pins if you want it to run faster

Code here:

/*
Code by Kealan O'Carroll, April 2019
Encoder.h library by PaulStoffregen
http://www.pjrc.com/teensy/td_libs_Encoder.html

Code intended for an arduino nano with the following wiring:
Pins 2, 4 : Scale 1 inputs
Pins 3, 5 : Scale 2 inputs
Arduino Pins 7, 8 : Outputs to DRO A and B pins. (Pins 6 and 8 on a DSUB9 type plug)

*/

#define ENCODER_OPTIMIZE_INTERRUPTS
#include
Encoder scale1(4,2); //Wire first scale A & B quadrature lines to arduino Pins 2 and 4
Encoder scale2(5,3); //Wire second scale A & B quadrature lines to arduino Pins 3 and 5
//If either of the scales reads in the wrong direction, reverse the pin numbers above (e.g. (4,2) changes to (2,4)

long pos2 = 0;
long pos1 = 0;
long delt = 0;
long oldpos1 = 0;
long oldpos2 = 0;
long delt1 = 0;
long delt2 = 0;
bool outA = LOW;
bool outB = LOW;

void setup() {
DDRD = DDRD | B11000000;
DDRB = DDRB | B000001;
PORTD = B00000000; // sets digital pins all Low
PORTB = B00000000; // sets digital pins all Low
}

void loop() {

pos1 = scale1.read();
pos2 = scale2.read();

delt2 = pos2 - oldpos2;
delt1 = pos1 - oldpos1;
delt = delt2 - delt1;

while (delt > 0) {
if (outA == LOW && outB == LOW) { //if 8 is low and 7 is low
PORTD = B10000000; //push 7 high
PORTB = B000000; //leave 8 low
outB = HIGH;
delt--;
}
else if (outA == LOW && outB == HIGH) { //if 8 is low and 7 is high
PORTD = B10000000; //leave 7 high
PORTB = B000001; //Push 8 high
outA = HIGH;
delt--;
}
else if (outA == HIGH && outB == HIGH) { //if 8 is high and 7 is high
PORTD = B00000000; //push 7 low
PORTB = B000001; //Leave 8 high
outB = LOW;
delt--;
}
else if (outA == HIGH && outB == LOW) { //if 8 is HIGH and 7 is LOW;
PORTD = B00000000; //leave 7 LOW;
PORTB = B000000; //push 8 low
outA = LOW;
delt--;
}
}

while (delt < 0) {
if (outA == LOW && outB == LOW) { //if both are low,
PORTD = B00000000; //leave 7 low;
PORTB = B000001; //Push 8 high
outA = HIGH;
delt++;
}
else if (outA == LOW && outB == HIGH) { //if 8 is low and 7 is high;
PORTD = B00000000; //push 7 low
PORTB = B000000; //Leave 8 LOW
outB = LOW;
delt++;
}
else if (outA == HIGH && outB == LOW) { //if 8 is high and 7 is low;
PORTD = B10000000; //push 7 high
PORTB = B000001; //Leave 8 HIGH
outB = HIGH;
delt++;

}
else if (outA == HIGH && outB == HIGH) { //if 8 is high and 7 is high;
PORTD = B10000000; //leave 7 high;
PORTB = B000000; //Push 8 LOW
outA = LOW;
delt++;
}
}
oldpos1 = pos1;
oldpos2 = pos2;
}

Edited By Kealan O'Carroll on 26/04/2019 17:44:17

Hi all,

I've recently added a Ali-Express DRO to my Archdale 18" Mill. I was facing the problem of only having one Z-Axis and not knowing whether to attach it to the knee or the quill, so I bought a 4th glass scale from the seller and added a scale to both axes.

The DRO display only has one input for each axis, so I got an arduino nano via ebay along with a small enclosure and some RS232 cables. The two input cables attach to the scales and the output goes to the DRO display. The arduino calculates which scale is moving in which direction, sums them for an absolute position and then outputs that to the display so both the knee and quill can move in opposite directions at the same time and the DRO Z-position will remain correct.

Component parts came to about a tenner + labour time of assembling it and figuring out the code. It's possible to move the scales fast enough to out-pace the arduino and 'lose' steps, but my scales are 1 micron rather than the usual 5 micron so that's effectively limiting the maximum speed by 1/5th and even at that it's still capable of keeping the position correct up to about 100mm/sec so as long as I keep the quill retract speeds sensible I think it'll be okay.

The arduino gets its power from the 5V output pin on the DRO which supplies the glass scales, so no batteries / plug is required.

I'm an absolute amateur when it comes to the arduino stuff so it may be possible for someone to make the code much more elegant / run much faster but this does me for now.

I'm planning on using it to make a straight edge, and then using the plate & straight edge to scrape in my compound & cross slides as they're both tight at the extremes of travel & loose in the middle. I'll probably scrape in the base & top of my rotary table & angle plate too but there's no rush on them; I'll see how I find the process first.

I don't have any flat surface for marking out at the moment so I'll likely use it for marking out too; is this considered bad practice with a cast plate? I can imagine a cast plate wearing more than a granite plate when marking out?

I did consider the three plate method but I don't think it makes sense right now in terms of cost of all the plates and the time needed to get the job done. I saw the thread about the scraping class last year, I've watched Stefan & John Saunders' videos on the Richard King classes & they look excellent. I'm amazed to hear of the granite plate sagging!

Hi all,

I've recently won, but not collected, a 12" x 18" cast surface plate from the 'bay. I don't know how flat it is, & I'd like to hand scrape it in.

What's the done thing in terms of a reference plate? Do people borrow a master off a mate / go to a different workshop and scrape it in there?

Has anyone had a cast plate calibrated by a professional & can you give an indication of the ball park cost? Maybe I could farm out the plate scraping and then just scrape in some parts myself off the professionally done plate.

I'm based in the east mids

Hi all,

I'm not sure if this is the right place to post this question or not; feel free to move the thread

I'm planning on making an adjustable carriage stop with a dial indicator, similar to the one shown here;

Except for the hard stop at the bottom, I'd like to make it adjustable and use a captive nut like as per the below. I'll probably knurl it but leave the engraving off as the DTI can handle the measurement side of it.

My question is about the detail of the captive nut; I'd like to get a nice feel on the nut as you can imagine. I think a micrometer type feel would probably be too light, but a normal 6H/6h fit of a nut on a bolt would be too sloppy; does anyone have any tips on achieving a nice feel here? I thought about using an O-ring but I'm afraid that might feel rubbery (!!) and have too much stiction.

Any steer in the right direction would be appreciated

Hi all,

I got it put together today (eventually). I broke a timber lifting frame and ended up putting up part of a scaffold tower inside the garage and incrementally ratchet strapping it up to it's normal height and then bolting the legs on to the bottom of it. An engine crane would have been ideal!

I've got around 8 changewheels for it, but haven't checked the numbers yet (I did see a 127) so I'm not sure what pitches I can cut yet.

The carriage does get tight when the tailstock is off and it's moved right down to the end of the ways, so they're probably worn but if I'm spending most of my time within 6 inches of the chuck then I'm thinking it may not be an issue?

I ran it and made some chips from a scrap bolt I had laying about...at least it runs! I have a load of HSS blanks I got with it, but some of the smaller ones are lost in the toolpost and the larger bits that do actually fit the toolpost are ground miles above centreline. It's dead quiet with just the spindle running, but the tumbler is horrendously noisy when engaged in either direction, as is the powerfeed speed selector gearbox. The 3 - jaw also took both hands on the key to budge, so I took the jaws out and the spiral & the jaws are all gummed up in what looks like old dried up grease so that will need stripping and cleaning.

The half nut and, handwheel, and slides all have a lot of backlash too; I don't know if this will actually be an issue or if I can just go beyond my start point and take up the backlash to work around it?

Link to the assembled picture below; I don't know how to embed it. I'll post some pictures of the lifting arrangement later if anyone wants a laugh...

http://www.model-engineer.co.uk/albums/member_photo.asp?a=47788&p=792983

Bear with me!

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https://i.imgur.com/KmgSYzv.jpg?1

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Hello chaps,

I've just picked up an old lathe and would like to find some docmentation / info on it. Can anyone help me identify it please?
I've put a post up to the same effect on practical machinist but haven't had any joy yet.
I'm told it's German, and a search for "Germany" through the archives of Tony's site brought up a beling & lubke which looks quite similar but the handles on the apron are slightly different.

[img]https://i.imgur.com/0cmKwYR.jpg[/img]

[img]https://i.imgur.com/yT0r2ZX.jpg[/img]

[img]https://i.imgur.com/GF0Xl66.jpg[/img]

[img]https://i.imgur.com/UqwlcQ9.jpg[/img]

[img]https://i.imgur.com/Pe1ZxLl.jpg[/img]

[img]https://i.imgur.com/kBmXe9D.jpg[/img]

[img]https://i.imgur.com/1DmQ1Ji.jpg[/img]

[img]https://i.imgur.com/SYHh49D.jpg[/img]

[img]https://i.imgur.com/R5AGs3h.jpg[/img]

[img]https://i.imgur.com/KmgSYzv.jpg?1[/img]

[img]https://i.imgur.com/R5AGs3h.jpg[/img]

[img]https://i.imgur.com/YpWNK3g.jpg[/img]

Edited By JasonB on 01/03/2018 13:11:23