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DRO Project for Taig Lathe

vtcnc

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#1
I've wanted DRO for my Taig micro lathe for a few years now. I decided to roll the dice with iGaging scales and remote digital readouts. I've read mixed reviews, but the price is pretty low risk at about $85 for three 6" scales of eBay.

I snapped a few pics of the build and a final pic of the cross slide.

First, I needed to make a bracket to mount the scale to the carriage and the cross slide:

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Where I wanted to mount the bracket is tricky. There are four things to account for: the cross slide gib set screws, the carriage gib set screw locknut, the carriage gib itself and the carriage casting.

The draft angle on the back of casting was tricky, so I just filed that angle in by hand.

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Also, watch your depth on the hole depth when you drill into the carriage, you don't want to drill into the carriage gib.

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Here is a photo of the tight squeeze:

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Once the bracket is on the carriage, you can mount the scale. I cut my scale down a few inches since it wouldn't fit between the lathe and back of my bench. The last thing to do is connect the cross slide to the scale. I used some 3/8 rod that sits in the right t-slot for perfect alignment. A coupled of holes later and the rod is connected to the scale:

4b896aded98d82b16402d34c9b86a8f5.jpg

Works great! I haven't tested it for accuracy yet, if all goes well, I'll move onto the next axis.
 

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terrywerm

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#2
Nice job! You found a novel way to get around the problem of required room for the DRO read head, a real problem on those small machines. Thanks for sharing your solution, it will be inspiration for others I am sure.
 

vtcnc

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#3
Thanks. The only potential problem is fitting my top compound slide with that rod in the way. I will most likely make a bracket to mount off the back of the cross slide next.
 

vtcnc

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#4
Dang...I'm getting inconsistent measurements after testing the DRO setup today.

Backed the slide into the dial and zeroed the scale. Turned the dial until the readout said .500...measured with my Mitutoyo calipers...., and I get .525-.530. Tried it again and counted rotations, I definitely over rotated but the readout still claimed .500.

Went to iGaging website to see if there are any calibration routines for these readouts...nothing found. Does anybody have any advice here?
 

Jim Nunn

Steel
Registered Member
#5
Could be electrical noise try grounding the lathe to the 110 ground wire. Also ground the motor frame to the power outlet if it is not already grounded. if you are using a VFD they generate quite a bit of electrical noise and VFD noise suppression gets a little more complicated.

Jim
 

vtcnc

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#6
Grounded the lathe tonight. That seemed to knock some noise out of the area. It seemed to cut the inaccuracy in half. I had a "duh" moment and realized that there felt like a bit too much backlash. Tightening things up took the inaccuracy from about .010" off to no more than .002". I can live with this. Thanks for the advice Jim!
 

vtcnc

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#9
I couldn't leave well enough alone. During my research on scale calibration for this project, I ran across this website: http://www.yuriystoys.com

I ran to Radio Shack and grabbed the needed components. About 4-5 hrs later, I'm pleased to say that I now have not only DRO on my Taig lathe, but wireless DRO using my Nexus 7 as the display!! Amazingly, my first Arduino project worked the first try, I fully expected soldering and pin problems. No problems! I need to calibrate next. The Android app is called TouchDRO and it switches from lathe to mill using the device's Bluetooth connection.

When people say "what a weird world we live in"...it is these small examples of technology that make me marvel at what a fantastic world we live in where anybody can do this!

In the pic below you can see the extra enclosure containing the Arduino and SeeedProtoshield. My Android Nexus 7 is up on the board with full touchscreen controls. Even let's you add tool library!

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Next photo is a bench test of the board connected to a scale. Worked first time...still can't believe it

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And a shot of Arduino before it gets sealed up...

47e2ab7ca11d2698c4a409855ea55fd0.jpg
 

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ogberi

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Active Member
#11
Excellent work! I have been really thinking about the arduino/bluetooth route, but don't have a spare tablet or phone to use as the display.

I'm a bit envious, as the digital calipers I have mounted on my lathe work well, but can be a bit of a pain to read at times. They don't really appreciate being spattered in cutting fluids, either. But, they're inexpensive enough that I don't have to worry too much about them.

Do you have/use the milling attachment for the lathe? I used to use mine frequently, but it was relegated to very occasional use once I got a horizontal mill. I never bothered mounting a caliper to it, I just use a DI.

Aren't microcontrollers fun? :))
 

vtcnc

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#12
Ogberi, yes! Lots of fun!

I do have the milling attachment, but once I bought a mill, I found that it served me better in some other capacity. So I converted it to a compound slide.

Already having the tablet made this a no brainer project...I'm not sure if I would have gone this far with it if I didn't own one. The remote readouts that come with the iGaging scales are about twice the size of what you will find on a digital caliper, and they can be set away from the chip/splash zone. If the chips pile up too much on the cross slide reader, I may make a guard for it. I don't anticipate any issues with the carriage reader since it is tucked nicely under the bed. Also, I will probably run some of the steel brackets through our nickel plating line to dress it up and prevent any corrosion issues.