Ellectro - mechanical tachometer

Back in the days before cheaply available electronic tachometers I built this device to measure the speed of some of my model steam engines. Outdated now, it serves as a nice demonstration piece for teaching young people how rotary speed can be measured.

The turned disk has sixty 1/16" holes drilled in the rim so when the electronics are hooked up, one Hertz on the counter corresponds to one RPM on the tach. The holes interrupt an infrared beam impinging on a photo transistor to generate the pulses that are counted by an external counter.

https://s3-us-west-1.amazonaws.com/f...he/44899-1.jpg

Thanks mklotz! We've added your Electro Mechanical Tachometer to our Measuring and Marking category, as well as to your builder page: mklotz's Homemade Tools. Your receipt:

<div id="blocks"> <div class="block b1 pngfix"> <div class="bimg"> <div> <a href="http://www.homemadetools.net/electro-mechanical-tachometer"><img src="http://www.homemadetools.net/uploads/137530/electro-mechanical-tachometer.jpeg" /></a></div> </div> <div class="head pngfix"></div> <div class="left pngfix"></div> <div class="right pngfix"></div> <div class="blockover b1 pngfix"> <div class="title"> <a href="http://www.homemadetools.net/electro-mechanical-tachometer">Electro Mechanical Tachometer</a> <span> by <a href="/builder/mklotz_3">mklotz</a></span> </div> <div class="tags">tags: <a href="http://www.homemadetools.net/tag/tach">tach</a></div> </div> </div> </div>

Marv,

This would still be a great addition to any small lathe and the disk could have a double duty for mechanical indexing with addition of a locking detent pin (e.g., the HRSP model from J.W. Winco, Inc. Website and Online Catalog).

I looked at your other tools you posted on PhotoBucket and a very impressive collection (many not posted here at HMT).

Thanks for the ideas.

Paul

Quote:

---

Originally Posted by Paul Jones

Marv,

This would still be a great addition to any small lathe and the disk could have a double duty for mechanical indexing with addition of a locking detent pin (e.g., the HRSP model from J.W. Winco, Inc. Website and Online Catalog).


I looked at your other tools you posted on PhotoBucket and a very impressive collection (many not posted here at HMT).

Thanks for the ideas.

Paul

---

Thanks for the kind words, Paul. I thought I had posted here most of the tools on Photobucket. Tell me which I missed and I'll put them up here.

Thanks for the link to Winco Paul! Great site for hardware and then some. ~PJ

Marv,

I will look though your photos again and let you know if I find some not yet posted at HMT. You have so many special tools at HMT I probably missed a few.


Hi PJs,
Thanks. I used the Winco part 3TLR1 1/4-20 steel lock-out plunger for the detent mechanism to the indexing plates on my Unimat SL (see Homemade Indexing Plate for Unimat SL Lathe ). I used the Winco part because it was only $7 and would have taken me much longer to make my own (I even drew up the plans before spotting the one from Winco).
Paul

Thanks again Paul. Was really impressed with selection and pricing. Lots of stuff I have looked for over the years and McMaster has some but not all and dedicated to this type of hardware. Was looking for an M7 x 20mm nylon tip set screw a while back and there it was...and pretty cheap too, considering you can purchase individuals instead of a box for >$100! Admired your indexing setup from before...really versatile and well thought out! ~PJ