Thread: Probator

Hand Speed Counter

The info sheet doesn't really explain much.



So I have 3 questions:

What is it good for it the workshop?

Do I need one?

If I don't need one & should sell it what is it worth?

Originally Posted by DSEL74

What is it good for it the workshop?

Measuring the RPM of shafts
It relies on shafts having a centre drill hole to fit the end of the unit into.
We used to use these in first year mechanics labs in the 1970s

Do I need one?

They are very handy but the non-contact type laser tachos on eBay cost about $20 are safer and work on rotating parts that don't have centre hole in the ends of shafts.
The

Hi Dale,

I believe its all there in the instructions , wind the red knob in the direction of the arrow until the counter and stop watch are at 0
Press tip into the center of a rotating shaft, the stop watch should start. After any time that takes your fancy remove the tip from the shaft. divide the counter by the number of seconds on the stop watch, multiply by 60..... you have rpm.

Whats it good for? checking rpm

Do you need one? can be handy but laser rpm gauges are about $10 and you can check on side of the shaft which is normally easier(though they may struggle on the end of small shafts, which your's should be able to measure)

Whats it worth? I'd say not much unless you can tickle someones fancy or want to wait a long time. NO I don't want one I see someone is trying to sell a rougher one for $65.

Stuart

Yep I've got my head around it now & think it will be worth sticking in a draw for future use. First application I can see is used unmarked motors. I can at least figure out the speed.

Thanks

Stu did I mention it says on the box it is a special optical measuring one very rare!! ))

My dad had one of them. He was (still is at 84 ) a diesel fitter.

This is a 1960 equivalent usually supplied with:
Male cone
Female cone
Surface speed wheel - Imperial or Metric
Extension
Gave direct rpm with male/Female cones and surface speed in FPM /MPM.by dividing indicated speed
by 2 for FPM or 10 for MPM.
I used it for many years as a Production Engineer and Tooling Engineer in the Automotive industry.
I still use it occasionally today in conjunction with the VFD.

Colin

You can use the surface speed wheel to measure bandsaw blade speed.


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With the wheel and cup I can see yours having much more use and versatility.