Mrpete222 has one

cross thread said:
I saw this on tubalcain's YouTube channel so I had to have one . It's a tachometer , put the rubber plug on a spindle and it tells you the RPM .
I was thinking I would rig this up on a bench mill stand . Those digital read outs offend me .
IMG_1101 by mark westi, on Flickr
IMG_1103 by mark westi, on Flick
Click to expand...

interesting,
i've always preferred SW gauges whenever I replace or ad.
This is calibrated how?
 
Calibrated ? At the factory , I'm sure . Or maybe match it up with one of those digi things . But then is the digi correct ? NIST could probably do it .
 
It is basically the same mechanisim as found in the old analog speedometers. And we know how accurate they were.
 
I know I can't operate machinery, drive or talk well or maybe even get on here once I've taken my meds...
I even missed the Blue Berry Hill joke completely the other night

:laughing:

so I'm comparing this gizmo to mechanical tachs and speedos that I've had on older vehicles think (50's and 60's)

The shaft at back of gauge was connected to flexible shaft that had to be connected to a drive gear that was specific to the application with number of teeth etc. Some connected to distributers, some to a cam gear, some to transmission but all were very much in need of being corellated to the rpm of what ever it was connected to get a reasonably accurate RPM. So I look at this and think okay the rubber tit rides on the shaft and spins and converts to needle movement on the dial. What size shaft is this thing accurate with ? What am I missing ? surely a 1/2inch shaft and a 2 inch shaft are going to have way different circumference input to the little rubber tit ?
I'll get back on tomorrow after some coffee and maybe it will make sense then, don't worry I'll be okay.
Thanks for letting me ramble...
Jim
 
Look closely at the drive end.

If it pushes into a "center" on a shaft it is direct reading.

They also have a disk that can read against a wheel.

We have a couple of similar, very accurate.

Sent from my SM-G781V using Tapatalk
 
I have one of these that I use on my sailboat. Push the rubber tip against the middle of a shaft and it gives you the rpm. Just enough pressure to make contact. Not hard. I used it to calibrate an electrical tachometer which happened to be way off. I bought mine off Ebay and it came with a calibration certificate. Fun gadget.
 
cross thread said:
I saw this on tubalcain's YouTube channel so I had to have one . It's a tachometer , put the rubber plug on a spindle and it tells you the RPM .
I was thinking I would rig this up on a bench mill stand . Those digital read outs offend me .
IMG_1101 by mark westi, on Flickr
IMG_1103 by mark westi, on Flickr
Click to expand...
I think they are not meant to run continuosly . I have a mechanical unit, it has multiple ranges
 
Tools like this are the reason we can't wear gloves at the lathe. See, this is why we can't have nice things. Someone has to go and ruin it for everybody.
 
Running one of those on a machine at a full speed would surely wear it out in short order, they were made for short term readings, I have one just like it and use it as was intended by the manufacturers. Too many folks depent on this sort of input instead of focusing on the dials on the machines and consequent tool life, as the creator intended.
 
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