Inches Per Minute

[aliva]

I have a thought of adding some sort of indicator to my mill that will show the travel speed of my mill table in inches per minute.
I've checked the speed of the table in various positions of the table power feed. It works but a pain in the butt. My thought is to some how adapt a tachometer or some indicator to a digital readout. I recently ordered a couple of graduated potentiometer dials to replace the dial on the power feed, maybe this would allow me to attach a number to a specific speed, time will tell.
Has anyone applied this concept to their mill?
All thoughts or opinions would be welcome

 

[RJSakowski]

With a reluctor mounted on the crank and a hall effect sensor, you should be able to use one of the cheap China tachs. If your lead screw advances at.1"/rev, a 10 ipm travel rate would be 100rpm. If you had a 10 tooth reluctor ring, this would give you a 1,000counts/min at 10 ipm. Depending on the tachometer, the number of teeth on the reluctor ring could be fixed to give you a direct readout in ipm.
This could be done optically as well with reflective tape and an optical pickup.

 

[aliva]

The optical or magnetic pickup was one of my first thoughts. I'll have to look into it deeper. may have to add several pickup points in order to get a useful reading from the tach.
Thanks for the suggestions.

 

[pontiac428]

Sounds like a fun data acquisition (DAQ) project. These days, you can bypass the expensive equipment and just use Arduino, a 3-line display, and a couple of eBay surplus linear transducers. You're only limited by what you are willing to learn. PM me if you want books to read...

 

[RJSakowski]

The optical or magnetic pickup was one of my first thoughts. I'll have to look into it deeper. may have to add several pickup points in order to get a useful reading from the tach.
Thanks for the suggestions.

Single pickup, multiple activation points. A slotted disk comes to mind. An optointeruptor ( e.g. https://www.ttelectronics.com/TTEle...Optoelectronics/Datasheets/OPB615-625-665.pdf) for the detector, some simple circuitry, and an off the shelf tach. A slotted disk can be made. The slots don't even have to be uniform. A disk with a hub to fit your mill's x axis shaft. A tachmometer: https://www.ebay.com/sch/i.html?_fr...sacat=0&_odkw=small+engine+digital+tachometer

If using a magnetic pickup suits you better, a visit to an auto salvage yard for an ABS reluctor and pickup, coupled with the off the shelf tach should do it.

For this application, I would use a rotary vs. a linear system. Direction doesn't matter so no need for a more sophisticated quadrature detector. Absolute position doesn't matter either so backlash is unimportant.

 

[aliva]

Thanks for the suggestions. Opted for a magnetic proximity switch with lcd counter. Should get it in a couple of weeks. Ill keep you posted on the results. If it doesn't work it was only $15.00.