shaft tachometer

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ian.mcdougall
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shaft tachometer

Postby ian.mcdougall » Sat Jan 15, 2011 8:54 pm

Hi all
I am looking for a cheap solution to make a tachometer to give me the rotational speed of my woodturning lathe spindle
something that an electronics idiot can make :roll:


pfgiz
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Re: shaft tachometer

Postby pfgiz » Sat Jan 15, 2011 10:58 pm

Hi Ian,

What about a mechanical one from a mk3 / early mk4 spitfire? you'd need to fix the cable so you can drive it from the lathe but would be easier than an electrical option....
Peter Gisby.


irmscher
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Re: shaft tachometer

Postby irmscher » Sun Jan 16, 2011 1:36 am

bicycle electronic speedo :) or a digital motorcycle one which are not very expensive

Alec
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Re: shaft tachometer

Postby Alec » Sun Jan 16, 2011 8:03 am

Hello Ian,

"something that an electronics idiot can make"

I take it a variable strobe light wiould be too expensive to make?

A neat solution would be the sender and Tachometer from a MK 2 Jaguar\ S Type\ MK 10 etc if you can find them at a reasonavble rate, as the connection is by wire. Another solution is to simply work out the gearing and with the motor speed make a table of all the speeds?
Another :- http://business.shop.ebay.co.uk/?_from= ... acat=12576

Alec

ian.mcdougall
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Re: shaft tachometer

Postby ian.mcdougall » Sun Jan 16, 2011 9:32 am

Hi all
Thanks for the replies .A bit more information on the set up I have, I have put variable speed inverter on the lathe but also lathe had five speeds originally via different sized pulleys, normally the digital read out from the inverter would give you a speed, if you only had the one pulley , so thats why i thought if I could find something to attach to the shaft , it would not matter what pulley you had the belt on it would always read the speed.After posting this I found on the internet the idea of the bicycle speedo but I was not sure of how to set up the thing to give a reading of the speed of the shaft. If any one has done something similar could they let me know how they set up the unit as all they say is how it would apply to different sized wheels


Alec
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Re: shaft tachometer

Postby Alec » Sun Jan 16, 2011 10:29 am

Hello Ian,

as you only have five speeds then, surely, it's a simple matter to draw up a graph for each one to give speed for a given frequency. Once you get used to what speeds you practically need for whichever diameter\material combination you are using it will become second nature to select frequency and pulley?

Alec

silloyd
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Re: shaft tachometer

Postby silloyd » Sun Jan 16, 2011 10:40 am

Never used one on something like a lathe but bike speedos that I have set up usually require you to enter the road wheel diameter, which has limits of about 20"-30", so may not work for you.

Another suggestion is to use some form of digital multimeter, such as this http://www.maplin.co.uk/automotive-digi ... kup-222059 or this http://www.maplin.co.uk/digital-multime ... -test-4404. To generate a signal you could attach a strong magnet to the shaft and then place an inductive pickup nearby which is attached to the multimeter. You could even use the pickup from an old bicycle to achieve this.
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Matt
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Re: shaft tachometer

Postby Matt » Tue Jan 18, 2011 8:31 pm

frogeye sprites also had a shaft driven revcounter 8)

or

http://cgi.ebay.co.uk/DIGITAL-PHOTO-TAC ... 256089490c

RogerRust
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Re: shaft tachometer

Postby RogerRust » Thu Jan 20, 2011 6:13 am

there are hand held tachometers on ebay.

I have an on teleprinter hand held tacho an uncle gave me years ago that I use on my lathe to check speeds (it comes from an age when tools were made to last forever)
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irmscher
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Re: shaft tachometer

Postby irmscher » Thu Jan 20, 2011 7:36 am

and probably made in England :D

ian.mcdougall
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Re: shaft tachometer

Postby ian.mcdougall » Thu Jan 20, 2011 9:10 pm

Hi all
Thanks for the interest
Ithink all is solved with the push bike speedometer you have to input 166mm as wheel dia if it reads in kpm and 268mm if it reads mph. So Iwill try this solution when I am ready to fit

Regards Ian



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