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tricklidz
12-01-2013, 09:41 AM
Anyone add a DRO to a small mill like Harbor Freight? Which one? Best price? Where to buy? Is it worth the effort/cost?
TIA

hoffman
12-01-2013, 10:57 AM
Not much of a DRO but these are becoming popular:

http://www.amazon.com/iGaging-Magnetic-Remote-Digital-Readout/dp/B003JUII2A

May want to check this out as well:

http://www.yuriystoys.com/p/android-dro.html

Works with the igaging scales.

Timewarp
12-01-2013, 12:16 PM
I have always wondered if certain dro heads might be interchangable with different scales, Say if you found a cheap head on ebay could you mix and match with scales of different brands or even scales of different models. I have an oscilloscope, but don't really know how to use it!
Paul

ycroosh
12-01-2013, 04:51 PM
I have always wondered if certain dro heads might be interchangable with different scales, Say if you found a cheap head on eBay could you mix and match with scales of different brands or even scales of different models. I have an oscilloscope, but don't really know how to use it!
Paul

Paul,
You might be able to, but you might have to change the connector or at least the pinout. I bought three scales from the same manufacturer and their pinouts were different.
Now my shameless plug: my DRO app works with most of the scales on the market at this point (using different controllers), so you can replace the "cheap head" with a "cheap tablet and an hour of soldering" and you'll get a pretty capable DRO...

Regards
Yuriy

lwalker
12-01-2013, 05:56 PM
I put the the iGaging scales on my mini-mill's X&Y axes. I have a Mitutoyo digital DI for those rare occasions when I need careful Z motion.

The iGaging scales update slowly, so you need to watch how fast you crank the handles when you get close to your stopping point. Also they are only 0.001" resolution but since my main use for them is cutting slots in electronic enclosures that's plenty good enough for my needs.

Lyndon

hoffman
12-01-2013, 06:26 PM
Paul,
You might be able to, but you might have to change the connector or at least the pinout. I bought three scales from the same manufacturer and their pinouts were different.
Now my shameless plug: my DRO app works with most of the scales on the market at this point (using different controllers), so you can replace the "cheap head" with a "cheap tablet and an hour of soldering" and you'll get a pretty capable DRO...

Regards
Yuriy

Nice to see you here and thanks for the good work!

I'm planning on doing one of your units but haven't decided on a MSP 430 or Arduino. I have both lying about.

Any advice?

Thanks

macona
12-01-2013, 06:33 PM
Paul,
You might be able to, but you might have to change the connector or at least the pinout. I bought three scales from the same manufacturer and their pinouts were different.
Now my shameless plug: my DRO app works with most of the scales on the market at this point (using different controllers), so you can replace the "cheap head" with a "cheap tablet and an hour of soldering" and you'll get a pretty capable DRO...

Regards
Yuriy

Add quadrature input support and you got something. You could use Paul Paul Stoffregen's encoder library on a teensy 3.0 which has lots of interrupts so you get fast encoder updates.

I see you are in Portland, do you go to the Dorkbot get-togethers?

ycroosh
12-01-2013, 07:27 PM
Add quadrature input support and you got something. You could use Paul Paul Stoffregen's encoder library on a teensy 3.0 which has lots of interrupts so you get fast encoder updates.

I see you are in Portland, do you go to the Dorkbot get-togethers?

Done :) The DRO can really work "with most scales on the market". So far I've tested iGaging, "24 * 2" scales, Harbor Freight calipers, glass scales and rotary encoders. The only thing that's not done yet on the hardware side is a controller that can use all of them together; right now there are three different firmware versions...

Firmware available here: http://www.yuriystoys.com/p/downloads.html#quadrature
Build instructions for the adapter can be found here:
http://www.yuriystoys.com/search/label/Quadrature%20Encoder%20Controller

I don't know what the max read rate is but I moved the scales by had *very* fast and it kept up with the pulses.

No, I don't go to Dorkbot get-together, but I've been meaning for a while.

Thank you
Yuriy

ycroosh
12-01-2013, 07:29 PM
Nice to see you here and thanks for the good work!

I'm planning on doing one of your units but haven't decided on a MSP 430 or Arduino. I have both lying about.

Any advice?

Thanks
MSP430. I'm not adding new stuff to Arduino; MSP430 will get tachometer support pretty soon and "mixed scale" firmware (right now it can't mix glass scales and capacitive scales).

Thank you
Yuriy

ycroosh
12-02-2013, 12:29 AM
I put the the iGaging scales on my mini-mill's X&Y axes. I have a Mitutoyo digital DI for those rare occasions when I need careful Z motion.

The iGaging scales update slowly, so you need to watch how fast you crank the handles when you get close to your stopping point. Also they are only 0.001" resolution but since my main use for them is cutting slots in electronic enclosures that's plenty good enough for my needs.

Lyndon

Lyndon,
One trick that I've learned while using iGaging scales is to still use the dials. DRO saves you a lot of counting but for precise work you can still use the tick marks to get sub-0.001" resolution.

BTW, to answer the OP's question: it's definitely worth on a Harbor Freight mini mill, given the backlash that quickly develops (even it it's not there from the factory) and insane 16 TPI lead screws. One of the first things I did to my Mini Mill was replacing them with Little Machine Shop screws (that at least give you 0.050" per turn). Backlash and Z head slop were still a problem, though.

Regards
Yuriy

macona
12-02-2013, 01:32 AM
MSP430. I'm not adding new stuff to Arduino; MSP430 will get tachometer support pretty soon and "mixed scale" firmware (right now it can't mix glass scales and capacitive scales).

Thank you
Yuriy

Well then! I will add a couple more things to the wish list. On my lathe I have three scales, the two standard ones plus one on the compound. The DRO I have now allows me to set the cross slide to 29degrees and it will do the trig internally and display the movement in the x axis (cross slide) That would be a nice feature especially if you can pick your own angle.

Last thing is I would like to incorporate CS (Constant Surface Speed). It would use the X axis scale to adjust the speed of the spindle. You have a top speed you set. I am using a servo drive for my lathe which accepts either a 0-10v signal like a vfd or step/dir signals. I had been thinking about using an arduino to go in between my existing scale and DRO.

-Jerry

ikdor
12-02-2013, 03:05 AM
Hi Yuriy,

Good to see you here. I've used your app to add a big screen to my home-made DRO
http://bbs.homeshopmachinist.net/threads/52517-Micro-DRO

The LCD screen was a bit too small for comfort and I could still fit a small bluetooth module into the housing. I built a bluetooth module but could never find the time to learn programming java for the tablet, and the project was shelved. Until I found your app that is, so many thanks for making it available :-)

As a bonus feature I can now use the Y channel to show the battery voltage, so I can keep track of it during use.

Igor

Paul Alciatore
12-02-2013, 12:54 PM
Could you elaborate on the term "teensy 3.0"? What the heck is it? Some kind of pad? Or what???




Add quadrature input support and you got something. You could use Paul Paul Stoffregen's encoder library on a teensy 3.0 which has lots of interrupts so you get fast encoder updates.

I see you are in Portland, do you go to the Dorkbot get-togethers?

hoffman
12-02-2013, 12:56 PM
Could you elaborate on the term "teensy 3.0"? What the heck is it? Some kind of pad? Or what???

It's a small Arduino board.

http://www.pjrc.com/teensy/

ycroosh
12-02-2013, 01:41 PM
Well then! I will add a couple more things to the wish list. On my lathe I have three scales, the two standard ones plus one on the compound. The DRO I have now allows me to set the cross slide to 29degrees and it will do the trig internally and display the movement in the x axis (cross slide) That would be a nice feature especially if you can pick your own angle.

Last thing is I would like to incorporate CS (Constant Surface Speed). It would use the X axis scale to adjust the speed of the spindle. You have a top speed you set. I am using a servo drive for my lathe which accepts either a 0-10v signal like a vfd or step/dir signals. I had been thinking about using an arduino to go in between my existing scale and DRO.

-Jerry

Jerry,
The first item will be included in the upcoming release of the app. That is really the sole reason I'm adding "lathe" mode to the app :)
Constant Surface Speed is much more tricky: right now the app doesn't talk back to the controller, which would be required to make this work. I've been hesitant to let the tablet control any aspect of the machine operation since any bugs in the app can have pretty serious consequences (apart from ruining a part...).

Thank you
Yuriy

.RC.
12-02-2013, 04:37 PM
Does DRO Pro work with 1 micron scales such as this type (yes it says 5 micron, but they are available with 1 micron resolution) http://www.thedrostore.com/details-scaleE5.htm

ycroosh
12-02-2013, 05:46 PM
Does DRO Pro work with 1 micron scales such as this type (yes it says 5 micron, but they are available with 1 micron resolution) http://www.thedrostore.com/details-scaleE5.htm

RC
I have three Easson scales on my mill that look pretty much identical to these. Mine are 5 micron, but 1 micron is no different, except 5x the number of pulses per inch.
I tested the controller at 100,000 pulses per second. With 5 micron scales this is about 20 inches per second; for 1 micron version this will be 4 inches per second. I don' think I have a chance of hitting that speed on my mill, but your mileage might wary...

Thank you
Yuriy

.RC.
12-02-2013, 06:10 PM
OK thanks, I was thinking more for my grinder then a mill..... I think 1 micron scales on a mill a bit of overkill...

ycroosh
12-02-2013, 06:39 PM
OK thanks, I was thinking more for my grinder then a mill..... I think 1 micron scales on a mill a bit of overkill...

RC,
I haven't used a grinder, so I don't know what a practical feed rate would be. Does 240 IMP sound reasonable to do you expect it to feed faster than that?
I'll try to do some formal testing with simulated 1 micron scales and will get back to you on the maximum speed the controller can reliably handle...

Thank you
Yuriy

.RC.
12-02-2013, 07:01 PM
Yuriy, I have no power feed on the surface grinder down feed... It is graduated in one ten thousand of an inch, as fast as I can wind the up and down handle I probably only get about two inches a minute travel speed as it is geared down quite a lot to get that very fine down feed capability...

Of course it would be nice to know what sort of feed speeds it could handle with one micron scales, as other grinders do have auto feed and rapids...

.RC.
12-02-2013, 10:49 PM
Actually I have one idea, it may not be possible or too difficult to implement as it is a feature I only ever see on high end DRO's, but that is a feed rate indicator, so you know how fast your mill table or whatever is moving...

Reason being, there is usually an optimum feed/tooth for milling cutters... The usual sort of millin gmachine found in the home shop either feeds by hand or has a variable speed feed motor on it.. Therefore you have little idea of what speed you are feeding it at... A feed rate indicator would give you some idea of what feed you are actually doing.. Either in inches per minute or mm per minute...

macona
12-03-2013, 12:24 AM
Jerry,
The first item will be included in the upcoming release of the app. That is really the sole reason I'm adding "lathe" mode to the app :)
Constant Surface Speed is much more tricky: right now the app doesn't talk back to the controller, which would be required to make this work. I've been hesitant to let the tablet control any aspect of the machine operation since any bugs in the app can have pretty serious consequences (apart from ruining a part...).

Thank you
Yuriy

For the CSS I would leave the control completely to the uC and keep the tablet as a display. A rotary encoder on the uC would set the speed and mode. SurplusGizmos has some real nice panel mount quadrature encoders in 16 and 32 ppr with a button built in. I think they are $3 each. They are nice little units from grayhill and really expensive from the dealer.

ycroosh
12-03-2013, 01:10 AM
For the CSS I would leave the control completely to the uC and keep the tablet as a display. A rotary encoder on the uC would set the speed and mode. SurplusGizmos has some real nice panel mount quadrature encoders in 16 and 32 ppr with a button built in. I think they are $3 each. They are nice little units from grayhill and really expensive from the dealer.

Oh, come on... I don't need another reason to go to SurplusGizmos :) Last week I went there to get a few ICs and ended up walking out with $240 worth of linear rails. I work one exit away from them, so I'll step by tomorrow and get one to play with.

ycroosh
12-03-2013, 01:15 AM
Actually I have one idea, it may not be possible or too difficult to implement as it is a feature I only ever see on high end DRO's, but that is a feed rate indicator, so you know how fast your mill table or whatever is moving...

Reason being, there is usually an optimum feed/tooth for milling cutters... The usual sort of millin gmachine found in the home shop either feeds by hand or has a variable speed feed motor on it.. Therefore you have little idea of what speed you are feeding it at... A feed rate indicator would give you some idea of what feed you are actually doing.. Either in inches per minute or mm per minute...

RC
This isn't difficult at all. I've had a number people asking for feed rate display but haven't gotten around to implementing it. Plus, I wanted to get the tachometer done first, so the feed rate display can the cutting speed as well.
It is on the list, though...

Thank you
Yuriy

macona
12-03-2013, 03:11 AM
Oh, come on... I don't need another reason to go to SurplusGizmos :) Last week I went there to get a few ICs and ended up walking out with $240 worth of linear rails. I work one exit away from them, so I'll step by tomorrow and get one to play with.

I have a few around here if you want. I have known the owner for a heck of a long time now. I work off off Cornelius Pass on Evergreen.

Did you get the rails with the steppers and drivers?

ycroosh
12-03-2013, 11:49 AM
I have a few around here if you want. I have known the owner for a heck of a long time now. I work off off Cornelius Pass on Evergreen.

Did you get the rails with the steppers and drivers?

No, just the rails (three of them). What sizes do you have?
BTW, I work on Tanasborne across the street from the new Kaiser clinic, so we're probably within a walking distance :)

Regards
Yuriy

macona
12-03-2013, 01:08 PM
I have a couple of 16s and a couple 32s. He gave me a handful when they came in. They terminate in a small ribbon cable with a 3m connector on them.

http://www.surplusgizmos.com/Grayhill-32-Position-Optical-Encoder-62SY11079-62S11-H9-020C_p_2330.html

.RC.
12-07-2013, 07:14 AM
A few more questions...

Firstly...

The Ardiuno controller... I see I should be able to get one locally here but it is not an Arduino UNO but one that says 100% compatible http://www.jaycar.com.au/productView.asp?ID=XC4210

I am guessing it will still work...

Secondly, connecting glass scales..

It says here http://www.yuriystoys.com/2013/11/mixed-scale-controller-firmware-posted.html

"To connect these encoders to the controller you will need to use the datasheet to locate Vcc, Ground, A, and B pins. Vcc and Ground should be connected to the corresponding lines on the controller. Outputs from A and B need to be connected to the “Clock” and “Data” lines. It doesn’t matter which is connected to which line, since you can reverse the direction in the application."

Looking up various manufacturers..

Firstly Easson scales, there is a pin out diagram here http://web5.streamhoster.com/HVP/DROPROS/DSub9.jpg

I guess orange will be Pin2, 0V or ground, VCC will be Pin7, 5V or red, but there are three other wires... Pin6 A, Pin8 B and Pin9 R.

For Sino scales, I have the instruction book here and it shows the same pin out as the Easson, except instead of a R it has a Z..

So is the wire on pin 9 (r or z) disregarded when connecting it to the controller?

hoffman
12-07-2013, 11:55 AM
A few more questions...

Firstly...

The Ardiuno controller... I see I should be able to get one locally here but it is not an Arduino UNO but one that says 100% compatible http://www.jaycar.com.au/productView.asp?ID=XC4210



He says that there won't be any more Arduino support so I would probably go with an MSP 430:

http://www.ti.com/ww/en/launchpad/msp430_head.html

I would double check before ordering anything though.

macona
12-07-2013, 02:18 PM
R and Z are the same thing. R means reference and Z is Z channel which is the index/reference pulse. Usually you do not use it. On some of the better DROs they have an absolute mode where you can enter the location of that index mark and whenever you "home" that axis the dro will reset its absolute setting to the preset distance. This would be used after the DRO is powered off.

ycroosh
12-07-2013, 02:33 PM
A few more questions...

Firstly...

The Ardiuno controller... I see I should be able to get one locally here but it is not an Arduino UNO but one that says 100% compatible http://www.jaycar.com.au/productView.asp?ID=XC4210

I am guessing it will still work...

Secondly, connecting glass scales..

It says here http://www.yuriystoys.com/2013/11/mixed-scale-controller-firmware-posted.html

"To connect these encoders to the controller you will need to use the datasheet to locate Vcc, Ground, A, and B pins. Vcc and Ground should be connected to the corresponding lines on the controller. Outputs from A and B need to be connected to the “Clock” and “Data” lines. It doesn’t matter which is connected to which line, since you can reverse the direction in the application."

Looking up various manufacturers..

Firstly Easson scales, there is a pin out diagram here http://web5.streamhoster.com/HVP/DROPROS/DSub9.jpg

I guess orange will be Pin2, 0V or ground, VCC will be Pin7, 5V or red, but there are three other wires... Pin6 A, Pin8 B and Pin9 R.

For Sino scales, I have the instruction book here and it shows the same pin out as the Easson, except instead of a R it has a Z..

So is the wire on pin 9 (r or z) disregarded when connecting it to the controller?

R.C.
"Arduino" is a prototyping kit based on ATMega microcontroller. There are a few major variants, but all of the smaller boards use virtually identical circuit. The software side of Arduino abstracts the pins, so D1 pin is D1 on any Arduino, and so on.

With that said, Arduino is not capable of handling asynchronous scales (anything except iGaging/AccuRemote), especially the glass scales. It is possible to ignore the Arduino software layer and write code against raw ATMega chip but that is a bit pain in the ... neck and negates the ease of use of the kit.

On Easson scales (I have a set on my mill) the index line outputs a pulse that is 1/2 the frequency of A and B. I don't think it could be used for absolute position. Don't have experience with any other glass scales [yet]...

Hope this makes sense.
Yuriy

ycroosh
12-07-2013, 02:46 PM
He says that there won't be any more Arduino support so I would probably go with an MSP 430:

http://www.ti.com/ww/en/launchpad/msp430_head.html

I would double check before ordering anything though.

Hoffman,
Minor correction: there won't be any new features for the Arduino, but I will keep it up to date. I.e. it will not become obsolete, but will be limited to iGaging/AccuRemote scales. No promises, but I might add tachometer to it if the time permits...

The link to the MSP430 you posted is correct. In addition to the MSP430, R.C. will need the adapter board that will translate 5V to the 3.3V level that is safe for MSP430 chip.

Here is a link to the relevant posts. http://www.yuriystoys.com/search/label/Quadrature%20Encoder%20Controller

Regards
Yuriy

hoffman
12-07-2013, 07:48 PM
ycroosh,

Sorry to muddy the waters. Some folks aren't familiar with microcontrollers but your site does an EXCELLENT job of explaining things!

I make toner transfer boards and was thinking about doing a single side board for this project. I do homebrew AT 328 boards for projects and am planning on doing something like that for this project using an MSP430 chip although I haven't worked with it yet other than LED blinking and simple things. If you have any PCB CAD files I'd be happy to etch a few boards and drop them in the mail.

I was going to breadboard it before doing a PCB but I'm waiting on parts.

Take care,
Jon

damengineer
12-22-2013, 03:53 PM
I don't mean to hijack this thread, but you all appear to be knowledgeable about the various dro's out there. I have an old glass scale Mitutoyo DRO on my bridgeport. I have had problems with the readout powering up for some time. It has now quit for the last time. Is there a readout box that would be compatible with my old glass scales. I had 0.0005 accuracy on them , and they are already mounted....
Any references would be appreciated.

ycroosh
12-24-2013, 07:54 PM
I don't mean to hijack this thread, but you all appear to be knowledgeable about the various dro's out there. I have an old glass scale Mitutoyo DRO on my bridgeport. I have had problems with the readout powering up for some time. It has now quit for the last time. Is there a readout box that would be compatible with my old glass scales. I had 0.0005 accuracy on them , and they are already mounted....
Any references would be appreciated.

Do you have a model number for the scales?