MadModder
Gallery, Projects and General => How do I?? => Topic started by: MadNick on January 06, 2012, 05:23:04 AM
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Morning,
I have a belt/pulley setup on my lathe.
At the moment, based on the diameter of the pulley in use I have slow, fast and medium - I'd like better accuracy.
How would I be able to work out the spindle speed on any of the pulleys please?
Nick
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Take the motor speed and multiply it by the pulley ratio. If you have picador type pulleys they are usually in inches so let's say for instance it had a 2" pulley on the motor 8" on the countershaft that's a 1:4 primary reduction then it had a 2-3-4 and 4-3-2 step-pulley set between the countershaft and spindle would give you 1:2, 1:1 and 2:1 ratios there.
So, with a 4-pole 1450rpm motor, that would give you a 362rpm countershaft speed. Then you would have three spindle speeds from the step pulleys of 181, 362 and 724rpm
Or buy a cheap tachometer and measure it directly.
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A Barker lathe had 14 speeds!
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Thanks Pete.
@Fergus O'Doodle Doo, a good answer but not the right one ;)
Nick
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There are not a lot of Barker lathes around but that is what my records show.
Regards
N
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Mornin' Nick.
I've had one of these for several years now.......
http://www.ebay.co.uk/itm/Digital-Laser-Photo-Tachometer-Non-Contact-RPM-Tach-/200696522606?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item2eba71e76e
Works a treat!
(http://i110.photobucket.com/albums/n95/Dayjo/P9300021.jpg)
David D
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Check this out. http://www.sendec-products.com/products/5/Products+by+Type/rotating-shaft-tachometer-hour-meter
Cheers,
Chazz
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This page from Tony Jeffree (he of the book "The Taig Lathe" and very much more) should be of interest to anyone investigating spindle and surface speeds
http://www.jeffree.co.uk/pages/speedmeasurement.html
Good d-i-y approach.
Ray
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I've got a nice manual tachometer that I found laying in the dust under the road deck in the Mersey Tunnel of all places. Must have been sitting there for years all in it's box in perfect condition. No idea how it got there but I was glad to find it.
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Mornin' Nick.
I've had one of these for several years now.......
http://www.ebay.co.uk/itm/Digital-Laser-Photo-Tachometer-Non-Contact-RPM-Tach-/200696522606?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item2eba71e76e
Works a treat!
(http://i110.photobucket.com/albums/n95/Dayjo/P9300021.jpg)
David D
David,
How does it work?, do you have to "stick" something on the spindle. (To reflect the light)???
:beer:
DaveH
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Dave.
It comes with a couple of strips, of sticky backed white reflective tape.
A small offcut is stuck to the rotating spindle/ flywheel, and the laser counts the reflections...... :thumbup:
David D
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Thanks David,
For 10 squid can't go wrong :thumbup:
:beer:
DaveH
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Another cheapo solution:
If there's somewhere on the spindle or its pulleys where you can attach a little magnet , buy a "bicycle computer" or "cycle speedometer" for 7 or 8 quid (I'm avoiding the pound sign problem) and set it to read in kph rather than mph. You can also program in the circumference (not diameter) of your fictional bike wheel. If you go for 1667mm, the display reading will indicate 1/10 x the rpm. The reading shows to one decimal place, so 99.9 kph equates to 999rpm. Many won't go above 99.9kph, but Halfords sell a model (ASIIG, I think) which will go up to the improbable pushbike speed of 200kph.
I only mention this because the sensor (intended to clamp on the front fork of a bike) and the read head can be left permanently attached to a lathe. The actuating magnet is meant to go on a wheel spoke, but if you can't find a place for it on the lathe spindle or spindle pulley, embed it in a cork which can be stuffed into the outboard end of the spindle when required.
Andy
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Watch out if you go for a wireless setup though, because the display has to be mounted close to, and in a particular alignment with, the sensor. I found this out just this week when I wanted to put the sensor on the back wheel of a bike and found it wasn't picked up by the display.
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And then there are fluorescent tubes. We all know about them -don't we?
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And then there are fluorescent tubes. We all know about them -don't we?
Well I do, I spent a 20 years in the lamp manufacturing industry. So what do you want to know then?
:beer:
DaveH
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And then there are fluorescent tubes. We all know about them -don't we?
Well I do, I spent a 20 years in the lamp manufacturing industry. So what do you want to know then?
:beer:
DaveH
Not me! I'm still with it but I had 1.3 Million punters who used them. Others might be less acquainted with the mysteries of fluorescent tubes- so carry on.
Regards
F O'M
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And then there are fluorescent tubes. We all know about them -don't we?
Well I do, I spent a 20 years in the lamp manufacturing industry. So what do you want to know then?
:beer:
DaveH
Not me! I'm still with it but I had 1.3 Million punters who used them. Others might be less acquainted with the mysteries of fluorescent tubes- so carry on.
Regards
F O'M
Pulley rpm? :scratch:
I'm starting to get confused, again...... :(
Dvd D
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Fluorescent tubes can act as stroboscopes!
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Thanks Fellas,
All good solutions, that little handheld tacho looks very interesting indeed.
Of course this could all be a precursor to more work on making the Barker a bit more flexible in terms of speeds on offer...
Nick
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There are not a lot of Barker lathes around but that is what my records show.
There's been four on ebay since October last year. As an owner I keep a look out for them to download the photos to build up my archive. Only 1 of them had the thread dial indicator though and one of them was a right basket case!
John
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I saw one on there a few months back and someone else on this very forum also owns one.
I keep thinking of getting something more compact and not quite as abused as mine is but it is still possible to turn out items that are accurate enough for my needs - I certainly cant bear the thought of mine going down the scrapyard.
Nick