Hi all mad modders.
I wanted to add a tachometer to my 7x12 lathe. After a bit of research I ordered a digital panel mount frequency meter of the bay.
As frequency is pulses per second I had to make a plan to get 60 pulses for every turn of the spindle so the meter will directly read RPM.
Decided to make a counter wheel with 60 holes mounted between the nuts on the spindle.
Made a quick indexer using one of the lathes change gears.
![](http://i519.photobucket.com/albums/u356/dozerd10/Workshop/Projects/LatheTacho/DSCN1764.jpg)
And used it to drill 60 1.2mm holes in a steel disc.
![](http://i519.photobucket.com/albums/u356/dozerd10/Workshop/Projects/LatheTacho/DSCN1765.jpg)
This was mounted on the spindle and an optical sensor was mounted on a bracket to the headstock.
![](http://i519.photobucket.com/albums/u356/dozerd10/Workshop/Projects/LatheTacho/DSCN1767.jpg)
![](http://i519.photobucket.com/albums/u356/dozerd10/Workshop/Projects/LatheTacho/DSCN1768.jpg)
I built a extension box that fit to the front of the lathe controls to house the meter and a supply that was salvaged from a mobile phone charger.
![](http://i519.photobucket.com/albums/u356/dozerd10/Workshop/Projects/LatheTacho/DSCN1769.jpg)
![](http://i519.photobucket.com/albums/u356/dozerd10/Workshop/Projects/LatheTacho/DSCN1771.jpg)
![](http://i519.photobucket.com/albums/u356/dozerd10/Workshop/Projects/LatheTacho/DSCN1770.jpg)
The meter works great and was tested with reference to a handheld tacho and reads within 1 or 2 RPM.
Cheers.
Abraham