Best way to make a pulley for round belt

Inspired by Nick, I'm going to make a tramp oil skimmer for my mill. I've
scrounged a length of 7mm dia. PU belt that I'm going to use but I don't
have any pulleys, so I plan to turn up a pair. I'm going to use Delrin and
need to cut the correct profile which is a shallow flat sided V groove 7.2mm
wide at the top with a 3.4mm rad at the bottom; obviously I won't need to be
too accurate as the power transmitted is negligable. I was thinking of
cutting this in 1 hit by grinding a form tool for the correct profile but
I'm not sure if that's the best way; I seem to remember reading up on
cutting V belt pulleys somewhere but can't find the article any more. Any
hints as to the best approach?
Martin
--
martin<dot here>whybrow<at here>ntlworld<dot here>com

On Thu, 02 Aug 2007 21:59:06 GMT, "Martin Whybrow"
<aholeintheground@ntlworld.com> wrote:

>Inspired by Nick, I'm going to make a tramp oil skimmer for my mill. I've
>scrounged a length of 7mm dia. PU belt that I'm going to use but I don't
>have any pulleys, so I plan to turn up a pair. I'm going to use Delrin and
>need to cut the correct profile which is a shallow flat sided V groove 7.2mm
>wide at the top with a 3.4mm rad at the bottom; obviously I won't need to be
>too accurate as the power transmitted is negligable. I was thinking of
>cutting this in 1 hit by grinding a form tool for the correct profile but
>I'm not sure if that's the best way; I seem to remember reading up on
>cutting V belt pulleys somewhere but can't find the article any more. Any
>hints as to the best approach?
>Martin

Naw, just plow in, it's only Delrin.
10,000 rpm, 10 ft / im feed, back of a garden rake for a tool -
priceless

..
Regards,

John Stevenson
L Stevenson [ Engineers ]

Martin Whybrow wrote:

> but I don't
> have any pulleys, so I plan to turn up a pair. I'm going to use Delrin and
> need to cut the correct profile which is a shallow flat sided V groove
> 7.2mm wide at the top with a 3.4mm rad at the bottom; obviously I won't
> need to be too accurate as the power transmitted is negligable.

I just used a V-shaped lathe bit. The angle was 60Â°.
But I found out that you will need to transmit *some* force. When you let
sit the PU-belt for a while under tension, it will get deformed and then
will slip. So you need a bit rough surface. I made mine out of aluminium
and will see wether sand blasting them cures the problem. Some radial
scratches with a scriber solved the problem for now. :-)

Nick

On Fri, 03 Aug 2007 00:40:11 +0200, Nick Mueller <muellernick@gmx.de> wrote:

>Martin Whybrow wrote:
>
>> but I don't
>> have any pulleys, so I plan to turn up a pair. I'm going to use Delrin and
>> need to cut the correct profile which is a shallow flat sided V groove
>> 7.2mm wide at the top with a 3.4mm rad at the bottom; obviously I won't
>> need to be too accurate as the power transmitted is negligable.
>
>I just used a V-shaped lathe bit. The angle was 60°.
>But I found out that you will need to transmit *some* force. When you let
>sit the PU-belt for a while under tension, it will get deformed and then
>will slip. So you need a bit rough surface. I made mine out of aluminium
>and will see wether sand blasting them cures the problem. Some radial
>scratches with a scriber solved the problem for now. :-)
>
>Nick

Professor Chaddock recommended a 30° included angle for the round belt pulleys
on the Quorn. I used this angle for the pulleys on my cobbled together
toolpost grinder and it seems to work. You may need a bit more tension if the
belt is slipping after deforming when stationary.

Mark Rand
RTFM

Mark Rand wrote:

> Professor Chaddock recommended a 30° included angle for the round belt
> pulleys on the Quorn.

Oh sorry! It was 30°. It slips with all the oil on the belt. If I would
tension the belt more, it only would be deformed more and I'm fearing a too
big radial load on the tiny gearbox of the motor.
So it's best not to use a too slippery material for the pulleys. Maybe CI
would be better or an even sharper angle than the 30°

Nick

"John Stevenson" <john@stevenson-engineers.co.uk> wrote in message
news:3sl4b39s7fnvn4e9l7h1orc5dma3ovuo04@4ax.com...
> On Thu, 02 Aug 2007 21:59:06 GMT, "Martin Whybrow"
> <aholeintheground@ntlworld.com> wrote:
>
>>Inspired by Nick, I'm going to make a tramp oil skimmer for my mill. I've
>>scrounged a length of 7mm dia. PU belt that I'm going to use but I don't
>>have any pulleys, so I plan to turn up a pair. I'm going to use Delrin and
>>need to cut the correct profile which is a shallow flat sided V groove
>>7.2mm
>>wide at the top with a 3.4mm rad at the bottom; obviously I won't need to
>>be
>>too accurate as the power transmitted is negligable. I was thinking of
>>cutting this in 1 hit by grinding a form tool for the correct profile but
>>I'm not sure if that's the best way; I seem to remember reading up on
>>cutting V belt pulleys somewhere but can't find the article any more. Any
>>hints as to the best approach?
>>Martin
>
> Naw, just plow in, it's only Delrin.
> 10,000 rpm, 10 ft / im feed, back of a garden rake for a tool -
> priceless
>
> .

That explains the rake embedded in my shed roof then...
> Regards,
>
> John Stevenson
> L Stevenson [ Engineers ]

	#1
Martin Whybrow	Best way to make a pulley for round belt Inspired by Nick, I'm going to make a tramp oil skimmer for my mill. I've scrounged a length of 7mm dia. PU belt that I'm going to use but I don't have any pulleys, so I plan to turn up a pair. I'm going to use Delrin and need to cut the correct profile which is a shallow flat sided V groove 7.2mm wide at the top with a 3.4mm rad at the bottom; obviously I won't need to be too accurate as the power transmitted is negligable. I was thinking of cutting this in 1 hit by grinding a form tool for the correct profile but I'm not sure if that's the best way; I seem to remember reading up on cutting V belt pulleys somewhere but can't find the article any more. Any hints as to the best approach? Martin -- martin<dot here>whybrow<at here>ntlworld<dot here>com

	#2
John Stevenson	Re: Best way to make a pulley for round belt On Thu, 02 Aug 2007 21:59:06 GMT, "Martin Whybrow" <aholeintheground@ntlworld.com> wrote: >Inspired by Nick, I'm going to make a tramp oil skimmer for my mill. I've >scrounged a length of 7mm dia. PU belt that I'm going to use but I don't >have any pulleys, so I plan to turn up a pair. I'm going to use Delrin and >need to cut the correct profile which is a shallow flat sided V groove 7.2mm >wide at the top with a 3.4mm rad at the bottom; obviously I won't need to be >too accurate as the power transmitted is negligable. I was thinking of >cutting this in 1 hit by grinding a form tool for the correct profile but >I'm not sure if that's the best way; I seem to remember reading up on >cutting V belt pulleys somewhere but can't find the article any more. Any >hints as to the best approach? >Martin Naw, just plow in, it's only Delrin. 10,000 rpm, 10 ft / im feed, back of a garden rake for a tool - priceless .. Regards, John Stevenson L Stevenson [ Engineers ]

	#3
Nick Mueller	Re: Best way to make a pulley for round belt Martin Whybrow wrote: > but I don't > have any pulleys, so I plan to turn up a pair. I'm going to use Delrin and > need to cut the correct profile which is a shallow flat sided V groove > 7.2mm wide at the top with a 3.4mm rad at the bottom; obviously I won't > need to be too accurate as the power transmitted is negligable. I just used a V-shaped lathe bit. The angle was 60Â°. But I found out that you will need to transmit some force. When you let sit the PU-belt for a while under tension, it will get deformed and then will slip. So you need a bit rough surface. I made mine out of aluminium and will see wether sand blasting them cures the problem. Some radial scratches with a scriber solved the problem for now. :-) Nick

	#4
Mark Rand	Re: Best way to make a pulley for round belt On Fri, 03 Aug 2007 00:40:11 +0200, Nick Mueller <muellernick@gmx.de> wrote: >Martin Whybrow wrote: > >> but I don't >> have any pulleys, so I plan to turn up a pair. I'm going to use Delrin and >> need to cut the correct profile which is a shallow flat sided V groove >> 7.2mm wide at the top with a 3.4mm rad at the bottom; obviously I won't >> need to be too accurate as the power transmitted is negligable. > >I just used a V-shaped lathe bit. The angle was 60°. >But I found out that you will need to transmit some force. When you let >sit the PU-belt for a while under tension, it will get deformed and then >will slip. So you need a bit rough surface. I made mine out of aluminium >and will see wether sand blasting them cures the problem. Some radial >scratches with a scriber solved the problem for now. :-) > >Nick Professor Chaddock recommended a 30° included angle for the round belt pulleys on the Quorn. I used this angle for the pulleys on my cobbled together toolpost grinder and it seems to work. You may need a bit more tension if the belt is slipping after deforming when stationary. Mark Rand RTFM

	#6
Steve W	Re: Best way to make a pulley for round belt "John Stevenson" <john@stevenson-engineers.co.uk> wrote in message news:3sl4b39s7fnvn4e9l7h1orc5dma3ovuo04@4ax.com... > On Thu, 02 Aug 2007 21:59:06 GMT, "Martin Whybrow" > <aholeintheground@ntlworld.com> wrote: > >>Inspired by Nick, I'm going to make a tramp oil skimmer for my mill. I've >>scrounged a length of 7mm dia. PU belt that I'm going to use but I don't >>have any pulleys, so I plan to turn up a pair. I'm going to use Delrin and >>need to cut the correct profile which is a shallow flat sided V groove >>7.2mm >>wide at the top with a 3.4mm rad at the bottom; obviously I won't need to >>be >>too accurate as the power transmitted is negligable. I was thinking of >>cutting this in 1 hit by grinding a form tool for the correct profile but >>I'm not sure if that's the best way; I seem to remember reading up on >>cutting V belt pulleys somewhere but can't find the article any more. Any >>hints as to the best approach? >>Martin > > Naw, just plow in, it's only Delrin. > 10,000 rpm, 10 ft / im feed, back of a garden rake for a tool - > priceless > > . That explains the rake embedded in my shed roof then... > Regards, > > John Stevenson > L Stevenson [ Engineers ]