Pullys and their design

[GeorgeD]

How are these pullys made? can't find a vid on youtube of them being made?

http://www.bearingboys.co.uk/10-3M-0...Pulley-21167-p

[Smiler]

How are these pullys made? can't find a vid on youtube of them being made?

http://www.bearingboys.co.uk/10-3M-0...Pulley-21167-p

I imagine just like any pulley. Machine the blank to shape then an indexer to machine the flutes at the required pitch (Machining centre would I imagine do all these operations in a single run) then two sidewalls pressed on to keep the belt tracked.

But I could be wrong :-)

Jeff.

[GeorgeD]

Hi Smiler

I think they're made as one unit? as I've seen em in Aluminium,hence me asking how they're made.

I know how the spur geas are cut,but for the life of me just can't see how these are made.

[Ross77]

I think they're made as one unit? as I've seen em in Aluminium,hence me asking how they're made.

The ones I have are still made as separate pieces, theres no physical way it could be made in one piece. If you had semi circular belt tooth then maybe with a ball end mill but the edges would have to be over cut

[routercnc]

Hi Ross,

There is a way . At work we have a very expensive machine called a spark eroder. You make a male electrode from a graphite type of material using a cnc miller or std miller. In this case the shape of the tooth on the belt. This is then attached to the eroder, and lowered into the blank gear, and spark eroded to create the negative shape. You can cut square holes this way, or any shape you want.

I had a special hex bolt made this way once. Not really a production volume method though since it takes a while.

[Smiler]

Hi Smiler

I think they're made as one unit? as I've seen em in Aluminium,hence me asking how they're made.

I know how the spur geas are cut,but for the life of me just can't see how these are made.

The one you showed is almost identical to the one I bought from BB last week, it is definately a three piece unit, main pulley body and two sidewalls which are pressed on and I think peened in place.
As ross says, it would be difficult (not impossible, as you could cast it as one piece) to make any other way unless you had either the ends of your belt teeth rounded or overcut the tooth at both ends.


Jeff.

[GeorgeD]

Think I've sussed how its made?

They mill the blank with an over depth pitch and then turn its sides on the lathe and at the same time turn the pitch teeth so that at the requied depth the sides are evident and the pitch teeth are narrower?

[GeorgeD]

C'mon someone correct me if I'm wrong? :whistling:

Because I have one here in ally and its deffo a one piece unit.


Mill the blank,turn the sides and lower the pitch teeth. :dance:

[routercnc]

Hi George,

I can't quite picture what you mean. Do you have a sketch you could scan in, or give it another go at the description. Do you have a picture of the Ali one you have there?

Thanks

[John S]

Commercially they are hobbed and the sides are pressed on. Takes about 20 seconds to do the one you have linked to.