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Setting "steps per inch" - simplified

Setting "steps per inch" - simplified

Postby Awesomeness » Sun Jan 04, 2015 8:01 pm

I got asked in a private message about how to calculate "steps per inch". Even though it's sometimes presented in an overly complicated manner, the calculation is actually pretty easy.

The person who messaged told me they were using a "book machine", with 1/2"-13TPI threaded rod, and motor drivers set to 1/4 microstepping.

Things you know...
1. Motor has 200 steps per revolution.
2. Screw has 13 threads (revolutions) per inch.
3. 1/4 microstepping means each step is further divided into 4.

Things you can calculate from this...
1. Multiply the steps in a normal revolution by how many microsteps each full step becomes: 200 * 4 = 800 microsteps per revolution
2. Multiply the number of revolutions in an inch from your screw, by the number of microsteps in each revolution: 13 * 800 = 10400 microsteps per inch

Now, Mach3 doesn't care if they are microsteps, or full steps - it just calls them all steps. So you set the "steps per inch" to 10400.

Keep in mind that this will get you very close, but your machine may have slight mechanical variations, that will cause this to produce slightly inaccurate results. Once you've got this far, you can run Mach 3's calibration tool, over as long a distance as you can, to try to tune it in.
If you don’t have time to do it right, when will you have time to do it over?
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Awesomeness
 
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