@whydontu & @conbustableherbage - finally I now have my digital tachometer up and running although not without a bucket of problems, read on. Tools required, one brain, pencil soldering iron, volt meter and a life time of patience as I'm not into electronics other than the simple basics. My installation is semi wired across the inner top of the gear cabinet coming out at the upper rear where it connects to a 4 pole mini connector. System designed so I can quickly remove the power supply (120V -12VDC-500MA) and sensor wires from the RPM meter which sits nicely (using magnets) on top rear of the head stock. While machining I won't need to lift my old eyes far from the job at hand to catch the numbers.
Bugger it didn't work, what gives with that? Triple checked my soldered connections now covered with shrink tube with no issues there. Although the sensor and RPM display are lit up with a single digit far right there's no joy when running my lathe so I double check the position of the magnet.
Without going into my frustrations trying to resolve said issue(s) which all boiled down to a wonky digital display/card? Thankfully when I ordered this kit I actually bought two. Changed the RPM meter digital screen and we have lift off, perhaps not quite. When running my lathe the digital display was jumping all over the map so to speak so I added rather stacked another same type magnet on top of the first one sitting in the spindle nut wrench grove. That settled things down some although I believe I can fine tune the clearance between the magnet and sensor a blonde hair more and see if that helps.
Change speed chart on my Craftex B2227L lathe face plate shows the following speeds which I understand are incorrect from factory.
Upper row: 550 - 970 - 1620 RPM, on average the digital sensor reads 600 - 1060 - 1530 RPM
Bottom row: 115 - 210 - 350RPM, on average the digital sensor reads 380 - 460 - 760 RPM
Notes: RPM is more consistent at slower speeds than higher ones.
As for magnets I tried the one that came with the kit with poor results. Switched to a much bigger/stronger one where it simply migrated across the the two spindle lock nuts rubbing on the spindle housing at all speeds. Promptly gave that idea up.
Bottom line am I satisfied hell no, comparing the digital readout to the one on my hobby mill it wins hand down for being consistent.
Photo's:
1. sensor installation (single magnet in spindle nut)
2. upper left rear, gear cabinet wires.
3 & 4. Digital display box, quick disconnect wires through cabinet from sensor and power supply.
5. Digital display sitting idle. To the left, yes that's my head stock gear oil fill access modification.
6. sensor installation, stacked double magnets.
Suggestions welcome!!
