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Non-contact digital photo-tachometer... Useful?

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  • Non-contact digital photo-tachometer... Useful?

    I was gifted one for services rendered, new in box... still sealed.

    How's it work? Can I use it to (for example) scan my grinding wheels as they turn? How accurate are these things? Are they like those digital laser-thermometer guns where the accuracy is affected by a bizzlion environmental conditions?

    Hey price was right, it'll make a nifty toy if nothing else... plus I can also use the phrase Photo-Tachometer now! It's like a Star Trek technobabble.
    "The Administration does not support blowing up planets." --- Finally some SENSIBLE policy from the Gov!

  • #2
    I have 2, a bigger one from H-F about $25. Also a small one from Ebay $12 & use it all the time. It comes woth strips of reflective tape. cut about 1/4" pc stick it on a lathe chuck, compressor pulley, airplane prop, etc. Put the lazer on & it works great!
    Last edited by flylo; 06-01-2012, 09:23 PM.
    "Let me recommend the best medicine in the
    world: a long journey, at a mild season, through a pleasant
    country, in easy stages."
    ~ James Madison

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    • #3
      Ok thanks for the info Flylo!
      "The Administration does not support blowing up planets." --- Finally some SENSIBLE policy from the Gov!

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      • #4
        Before these I used a mechanical one with the rubber tips & still have it. Wasn't bad on the sawmill but I remember verifying my planes tach by having someone in the cockpit going to full throttle, holding the brakes while chocked & me trying to hold the tach on the spinner center, trying to read it all while praying the thing doesn't turn me into lunchmeat.
        "Let me recommend the best medicine in the
        world: a long journey, at a mild season, through a pleasant
        country, in easy stages."
        ~ James Madison

        Comment


        • #5
          Originally posted by flylo
          Before these I used a mechanical one with the rubber tips & still have it. Wasn't bad on the sawmill but I remember verifying my planes tach by having someone in the cockpit going to full throttle, holding the brakes while chocked & me trying to hold the tach on the spinner center, trying to read it all while praying the thing doesn't turn me into lunchmeat.
          I will never complain about my job again.
          "The Administration does not support blowing up planets." --- Finally some SENSIBLE policy from the Gov!

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          • #6
            Now that is just BIZZARRE!! -(or a bit on the Whacko side!!)

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            • #7
              I use mine frequently as well, it's nice having one around the shop.

              Can't beat this price either: http://www.amazon.com/Digital-Photo-...d=25SQ03LAZ8XQ

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              • #8
                Originally posted by flylo
                Before these I used a mechanical one with the rubber tips & still have it. Wasn't bad on the sawmill but I remember verifying my planes tach by having someone in the cockpit going to full throttle, holding the brakes while chocked & me trying to hold the tach on the spinner center, trying to read it all while praying the thing doesn't turn me into lunchmeat.
                Holy crap - some things are just not that important to know!

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                • #9
                  There's always a silver lining. "Damn it felt good when it was over"
                  "Let me recommend the best medicine in the
                  world: a long journey, at a mild season, through a pleasant
                  country, in easy stages."
                  ~ James Madison

                  Comment


                  • #10
                    They are extremely accurate.

                    There are digital, meaning they count the number of revolutions in a given time period, no impact from environmental conditions. They either give you the correct rpm or they give you nothing.

                    Phil

                    Originally posted by Grind Bastard
                    How accurate are these things? Are they like those digital laser-thermometer guns where the accuracy is affected by a bizzlion environmental conditions?

                    Comment


                    • #11
                      Originally posted by philbur
                      They are extremely accurate.

                      There are digital, meaning they count the number of revolutions in a given time period, no impact from environmental conditions. They either give you the correct rpm or they give you nothing.

                      Phil
                      Yes, and you can also test them by pointing at a florescent light. It should read 7200 RPM

                      Here's the math:
                      120 Hz = 120 cycles/sec
                      120 cycles/sec * 60 = 7200 cycles/min

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                      • #12
                        Originally posted by kennyd4110
                        I use mine frequently as well, it's nice having one around the shop.

                        Can't beat this price either: http://www.amazon.com/Digital-Photo-...d=25SQ03LAZ8XQ
                        Wow, how in the world can something like that be sold for $10.00 ???

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                        • #13
                          I have one and use it a lot. It helped me adjust the variable speed drive on my Bridgeport and it's nice to know that when I set the speed it is very close to what the dial indicates.

                          Brian
                          OPEN EYES, OPEN EARS, OPEN MIND

                          THINK HARDER

                          BETTER TO HAVE TOOLS YOU DON'T NEED THAN TO NEED TOOLS YOU DON'T HAVE

                          MY NAME IS BRIAN AND I AM A TOOLOHOLIC

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                          • #14
                            We put 4-digit voltmeters on the pair of knifemaker's belt grinders we built last year. Idea is to read out surface feet per minute on the belt in one setting, or RPM of an auxiliary spindle on another. One rotary switch routed the 0-10V output of the VFD to one of two resistive voltage dividers comprised of a resistor and a 10-turn linear trim pot.

                            Then we used one of those digital tachs to read the desired data and just tweaked the trim pots until the display read correctly. Worked absolutely perfectly. Little digital tachometer absolutely essential for the job.

                            Here are the grinders we built:

                            http://www.tinyisland.com/images/tem...indersDone.jpg

                            metalmagpie

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                            • #15
                              Those... are some sweet looking belt-grinders.

                              Put a vice and a slide-table under 'em and they would make excellent backers.

                              Dare I ask how much it would cost to build one of those? Or to at least aquire the plans?
                              "The Administration does not support blowing up planets." --- Finally some SENSIBLE policy from the Gov!

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