04 February 2015

TouchDRO setup completed

Well it took way way longer than I planned, but I finally completed the setup of Yuriy's awesome TouchDRO software and hardware on my non-milling machine..
Yes, it's a drill press and I know "you can't use a drill press as a mill". I already covered that here.

I used iGaging scales for X, Y and Z axes. The mounting worked out good and solid but it does look like junk somewhat :).

Y Axis

On the Y axis I ended up flipping the scale sensor track and sensor head over (vs what's shown in picture below) so the sensor head screws pointed out away from X-Y table. I made a new bracket that extended out and over the sensor head, coming down on the outside. This worked alot better since you could now attach the sensor head to bracket after the sensor track was all mounted and trued up.

Plus, you can now remove the sensor head now without removing the top section of the X-Y table.
Y Axis mock up using slightly trimmed  19" to 23" rack adapters

X Axis

For the X axis I assumed I'd have to eventually build some custom end brackets to replace the rack mount ears shown above, but the thing worked out so solid that I dont see any need to, as long as I can live with the the looks.
X axis test fit with rack mount ears as end brackets

Z Axis

 For the Z axis I drilled and tapped holes into the side of the drill press (it's cast iron) to mount the scale. I managed to nicely bend some 1/8"x3/4" flat stock around the quill and slip a short piece of angle iron between the ends.
Z axis mock up while building quill bracket

Z axis scale mounting complete
I'ts hard to see but there is a third 10-32 screw through the flat stock close to the quill where there is no angle iron between. Tightening that down clamps the assembly onto the quill really well.

Finished X-Y Table Scale Mounting

Final scale mounting
X axis is leaning to match sensor head bracket mounted to tapered cast surface
The completed assembly above shows the X axis with some obvious lean, this is due to the cast surface that the 90-deg bracket mounting the sensor heads is bolted to. I could either bend the bracket to 85-deg or whatever it took, but going with single hole mounting of the end brackets lets the sensor track and mount lean to match the sensor head.

Like I said, it's way more solid than it looks. At least I can't get any flex out of the stuff during usage that affects measurement.

TouchDRO Controller Hardware

I used an Arduino Uno and custom shield I described here.  At some point near the end, I decided I wanted to get the tachometer working. Even though a tach is not really useful now, I'd like to one day get a VFD or some type of variable speed setup. I eventually remembered that I had brought an extra Arduino pin out to the Bluetooth header row I put in the PCB layout.

I checked the latest tach enabled Arduino firmware v5.9 at Ryszard Malinowski's site and found that it used Pin D7 for tach input. I looked back at my PCB layout and I had written in that pin D7 was brought out for Bluetooth reset... very convenient, I could just use it for the tach input.

I had to make up a Y jumper to split the power and ground pins on the Bluetooth header row so I could power both the tach sensor and the Bluetooth module. Adding double power and ground pins to the PCB layout would be nicer.

Anyway, I picked up this reflective IR sensor for $10. It has sensors that plug into a "motherboard" that then plugs into Arduino.
Reflective IR sensor "motherboard" top left
Custom Arduino shield center.
Bluetooth module dropped down inside hollowed
out antenna mounted to outside of box.
I had some nice high priced Belden shielded cable I used to remote the sensor to the drill press and mounted the motherboard inside my Arduino box.
IR Sensor with headers removed, cable to be soldered in
IR Sensor with cable soldered in place of header pins

The drill press has a top cover that I could mount the sensor to so that it would be lowered into position up against a tall hub on the spindle pulley.
Spindle pulley with black and white electrical tape
Sensor mounted to lid so it is lowered right next to pulley hub

I used three of the unused iGaging scale mounting brackets to mount the IR sensor in an adjustable manner. You can't see really it in this picture below, but there is a hole cut in the middle of the bracket that lets the IR send/receive LED bulbs poke through. The sensor is mounted to the bracket with nylon screw and chopped up standoffs as spacer/nut. I know, bad picture.

I used white and black electrical tape around the hub of the spindle pulley on top of the drill press. Here is the lid just about closed, sensor almost in final position.

In the end it worked great once I adjusted the sensitivity pot on the IR sensor motherboard. It was a pretty broad adjustment, at the top and bottom end of the adjustment it didn't work at all (0 RPM reading).


It took me way too long, but in the end I'm happy with how it turned out. Along the way I bought quite a few machining tools etc. for use with the first couple projects I plan to use this for. I'm alot more familiar with what I want out of a milling/CNC machine in the future which was one of my main goals. I wanted to learn enough that I know what I want and not just pay $$$ for something I may not really need or want in the long run.

I spent quite a bit of time working on the "higher quality" Chinese X-Y table. It's been disassembled and reassembled several times. I'll skip all the details here and maybe do a full post on it, especially since I'm not "done" with it to my satisfaction. Right now I have .004" backlash in X and .007" in Y. The Z axis gets locked by the quill lock.

I've always had a goal of putting steppers on this creation. It's now built up to the point where I can use it to mill out the brackets/parts I'll need to mount steppers to it. I have another Arduino for use with some stepper drivers/motors I have yet to buy.

I would like to mount a network camera and create a camera zeroing system. Here's two links that got me hooked on the idea:

The first link has a nice Z homing/zeroing idea too. If I can learn enough about Android programming it would be nice to incorporate that into TouchDRO. The protocol to the controller could be modified to send a Z touchdown indication, or maybe just send some special Z axis value. You could provide a arming button in TouchDRO GUI, then when it sees the "z:-1.32566:HOME" or "z:3.14159265" come in it would know to zero the Z axis at what it just read (or the previous point).

I'll quit here and just say thanks to Yuriy for TouchDRO and Ryszard for the improvements to the Arduino firmware.

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