DIGITEN 4 Digital Red LED Tachometer RPM Speed Meter + Hall Proximity Switch Magnet Sensor NPN for Lathe Conveyor Belt

We have installed more than 10 of these on Fuel/Oil delivery trucks. These are mainly expensive new delivery trucks and we must stand behind them - so far no problems at all. We have supplied our own rectangular magnets to fit our purpose better: 1/8" x 1/4" x 1/2" that we install in an existing keyway, or we mill a 1/4" keyway into an accessible part, then epoxy in place. The sensor is installed in an existing part by drilling and tapping a 12mm x 1.0 thread (tap purchased from McMaster-Carr), or we fabricate a bracket and use the double nut method. The magnet must have North & South on the big flat side, and South must be out. We buy the magnets from K&J Magnetics (Part# B842), and they have a nice little iPhone and Android app available for identifying North and South. If the app gets confused, the magnet is probably not "pole"ed correctly. The wiring colors make it less than perfect for hooking it up, but the diagram included is correct. The tach reads 1 to 1: 1 magnet sensed = 1 full turn. No setup or programming required.

I wanted a direct readout of spindle speed on my metal lathe, and this little gauge/sensor fit the bill perfectly. It uses a magnetic sensor to detect a magnet attached to the shaft spinning past it. You need to tape, glue or otherwise affix the small disc magnet to the shaft you're monitoring, so make sure you attach it securely if your machine will be spinning at high RPMs. (It claims to measure speeds up to 9,999 rpm; I'd be a little nervous about the magnet flying off under those conditions. I don't know if you could use a stainless steel (non-magnetic) strap to attach it and still have the sensor "see" the magnet, but it wasn't a concern for my usage. Just a heads-up to others who might need to use it in a higher-rpm range. (Probably better to use a reflective vs magnetic sensor for high shaft speeds...)

I bought this for my Logan lathe. It works fine and everything was as advertised. The wiring diagram was correct and easy to follow. The unit requires 9-15 volts DC but it does not mention how much current the power supply has to supply. I first used a 9V battery with clip leads and it worked fine with the provided magnet. However with a 15V 200mA power supply, the magnet wasn't strong enough. So I ended up using a 9V 300mA power supply and it works fine. I just had to mount the magnet very close to the sensor. I used an ABS plastic sleeve with a counterbore and glued the magnet in. Then glued the sleeve to the spindle on my lathe. I was going to zip tie it on, but the zip tie interfered with the sensor.

I've been using this on my Smithy CB-1220 XL for about three months now, and am very pleased with it's performance. It certainly beats checking the belts to see how fast I'm going. The meter is designed to snap into a rectangular opening for an almost flush mount, but I didn't have enough clearance inside the gear box, so I whipped up a little case out of an old aluminum license plate. The circuit board is exposed from the back, anyway, and it probably would end up getting splattered with oil and chips if I had mounted it directly. I added a power switch on top, and used a surplus wall wart to supply it with 12 v. The magnet must pass very close to the sensor, and the only spot available was the face of the spindle pulley, so I mounted the sensor on a bracket that can easily be swung out of the way when I need to change a belt. I used epoxy to attach the magnet. The instructions were brief but to the point. I am considering getting another unit for my Shopsmith, if I can figure out where to put the sensor. A very good item!

I tried before installed this item. Worked fine. Installed on my drill press and stopped working after third time using press. I took it off and worked for an hour trying to diagnose and only got it to work intermittently on my bench. Ordered another. It did the same thing. Sent them both back.

I installed this tach inside the spindle gearbox of my lathe in 2017. It runs in oil, vibration, heat and general misery all the time. It was a simple install and very cost effective to try out, I didn't expect it to last very long. It is the end of April 2022 and this tach has never skipped a beat. Probably the best money I have ever spent for an electronic upgrade. I would recommend this product 100% of the time. It has been proven under the most severe conditions.

Used this for a one cylinder engine because it is difficult and expensive to find a good tach for a one cylinder. I have tried those inductive mini tachs that use a wire to wrap around the spark plug wire. They are not reliable and not worth installing. This works great. I installed on the end of the crank with a bolt and couple of washers. Grind a slot in the washers for the magnet and use a little epoxy extra security once you know you have the magnet installed with the correct side facing the pickup. I did have to fabricate a bracket to hold the pickup sensor ( not a big deal). It actually reads the rpm changes faster and more accurately than those little mini tachs. I am going to install another one on my other tractor this fall.

Installed this on my knee mill. I now can see the exact spindle speed. It was super easy to install and wire.