Arduino based rotary controller project

arlo said:
I regularly see threads about sharpening drill bits. I sometimes try to sharpen bits by hand but I agree 100% with the davidh's comment that "I don't have enough Saturdays left in my life".
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I guess I have to agree with davidh, especially on the smaller bits. Larger ones are sometimes worth sharpening though.

arlo said:
Could the indexer be set at the proper angle on the mill table and then rotated to the proper orientation. With a grinding stone in the mill, advance the table to grind. Retract, rotate exactly 180 degrees (using the digindexer's accuracy) and repeat? Maybe a similar process would work for mills with the rotation a function of the number of flutes. Or is the initial angular/rotational alignment too difficult to get accurate enough?
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Offhand I could could think of some simple jigs to do a 180 alignment of a rotating collar or chuck that doesn't need steppers, etc. but the step indexer would surely turn it accurately enough. I would be concerned that, depending on the angle presented to the wheel, that the stepper has enough holding torque to keep the bit locked in place - you might need a brake on it.
 
Arduino is such a nice platform to work from. The plethora of different shields and available open source code makes project development a real breeze. Usually you can go from proto to working hardware in one or two sittings as long as what you require is fairly common. The available code is astounding and all you have to do is a quick search and you can usually get a snip or enough code to get going pretty quickly. The beauty of that is most of the bugs have been found and worked out already so it becomes an exercise in cut and paste and logical progression. I also work with the much slower Picaxe platform and I have been experimenting with PIC Microcontrollers using C and C++. But I really prefer the Arduino and picaxe platforms for ease of use and easy prototyping.

Bob
 
Thanks for providing the code. I got it to compile the first time and the quantity of comments is great.
 
There is an update to Step Index available, version 2.2. You can download it from the Digital Machinist website, and there is more info about it and an update video on the website given in the last post.
 
I already have the steppers, driver & power supply, Benny is ordering the rest of the needed components this week so him & I are building one at the same time. I may have to build 2 as I have 2 RT's or make it so I swap the drive mechanism between the 2.

Thanks for this thread & links.
 
Charley Davidson said:
To clarify I plan on using this to turn my rotary tables
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That should work - I presume that both of the tables have the same gear ratio (usually 90:1 or so) but if not the recent version allows you to specify different ones you can select from at run time.

However, you may want to eliminate using micro stepping. With 16 microstepping, you have 16*200*90 steps per revolution, or 288,000 steps to move the table around. The Uno is fast, but it still takes time to generate that many pulses, and the stepper needs a finite pulse width. With no microstepping, you have 18,000 steps, which still provides plenty of resolution, but the table will position much more quickly.
 
There is a new version available from the DM magazine website, version 2.3. One reader reported that his fixture had a ratio of 4.5:1. Oops. I simplistically assumed that all gear ratios had a denominator of 1. In the new version you can declare at compile time the denominator of ratios as well as the numerators, so he could enter 9:2 to match his machine. Also, he was from Sweden, and wasn't friendly with Fahrenheit, so I added the compile time ability to display Celsius in the temp mode as well.
 
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