Pullys and their design

[GeorgeD]

Here's a pic of what mine looks like,its the one in the top row middle of the five.http://www.econobelt.com/e-store/Pulleys.jpg

Look at the bottom row,this is how it will start out in the milling process,now if we put this on a lathe(with shaft to hold before parting) we can then turn the sides and at the same time reducing the teeth pitch to the desired depth and then we end up with something on the top row pullys.

If I had a lathe it would be simpler to show rather than explain.

[John S]

The one in the top middle row has side plates pressed on. Also it's not the same as the one you linked to originally.
the one you linked to is a M3 HTD series, the one in the top middle is a trapezoid form like a XL or L series.
Two different animals.

[GeorgeD]

I know its not the same as the one I linked to at the begining,RCNC asked did I have a pic of mine and found one on the net rather than photograph mine.

[John S]

Whatever.
The answer still applies they are hobbed from bar stock irrespective of the tooth form.

http://www.youtube.com/watch?v=EXvBeQMKIEI

Look about 1:28 into the video, shows the hobbing of a batch followed by the fitting of the side plate.

This video gives a better explanation of the system.

http://www.youtube.com/watch?v=ZhICrb0Tbn4

It is a gear but all that differs is the cutter shape.

.

[Scott]

try here http://www.youtube.com/watch?v=Mm5MzBUmL2Q

[GeorgeD]

Thats exactly how I said it might be done in an earlier post,though why he did not do two sides I don't know?



Cheers Scott.

[John S]

Because he's going to have radii at both ends of the cut and if the belt tracks across into them it will wear the belt.

this is why they are hobbed thru and then sides are pressed on, so there is always parallel tooth form under the belt.

.