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Re: #MISC Pulleys?
#MISC
¿ªÔÆÌåÓýThat¡¯s the test that I did John. I left it running for an hour and alignment was still good. ?Overall I think the accuracy is better than when running with a many stage gear train. ?It¡¯s a lot quieter too.
This doesn¡¯t account for any per revolution noise. For instance an ovalized pulley could have the same circumference and match after days of running, but would create bad threads. ?I did see this when I first made my belt and it
had bump where the belt was welded. ?
I¡¯m open for ideas on how to do a timing belt on my lathe. I thought through a lot of options, but didn¡¯t come up with anything that wasn¡¯t a lot of work (like a two piece pulley or shimmed pulley).
alex
alex
From: [email protected] <[email protected]> on behalf of John Dammeyer via groups.io <johnd@...>
Sent: Monday, April 20, 2020 9:04:12 AM To: [email protected] <[email protected]> Subject: Re: [digitalhobbyist] #MISC Pulleys? ?
Perhaps do an experiment for all of us. Here's the premise. ? As long as the two pulley V grooves are identical in shape and depth and the same diameter of course and the belt is the same diameter over its entire length the encoder and the spindle should stay in sync. ? So with the lathe stopped place a ruler along both pulleys aligned with the center of each pulley axis and draw a line on each pulley from the center in the direction of the other pulley. ? Now if you were using toothed belts months/years later when you turn the spindle by hand until the lines point to each other a ruler will show they still line up. ? The question is, over a few minutes, hours, days will the lines on the non-toothed belt pulleys still line up?? ? If they do you won't have slippage. If they don't and it's in the minutes or hours then you can't trust their position accuracy. ? John Dammeyer ? ? From: [email protected] [mailto:[email protected]]
On Behalf Of alexphredorg ? How does a toothed belt provide higher accuracy than a round belt between the encoder and spindle? ?Assume high quality bearings and essentially zero friction at the encoder side. ? A timing belt is ideal, but in my case it wasn¡¯t a good option and the round belt has been working well including with thread cutting. ?A timing belt for me either would have added the lash and noise of a gear train or would require making a custom two part pulley that clamped around the narrow part of my spindle ¡ª that would potentially also add inaccuracies. ? ? ? alex From:
[email protected] <[email protected]> on behalf of Richard via groups.io <edelec@...> ? There is no way I would ever use a flat or round belt to drive an |