3D Printing Pulley Wheels

[IAmTheClayman]

I need miniature pulley wheels for a 2x2 block and tackle setup, and they have to fit inside of a tube with a 7/8" inner diameter. So if my math is right the wheels' outer diameters need to be ~ 10mm, which is obviously very small and causing problems trying to find suitable wheels online. I was thinking of 3d printing the wheels myself, but since I have no experience in that realm I was wondering how doable that would be. Any advice would be much appreciated!

 

[Mike J.]

Have you considered Lego or other toy parts as donors? I can't guarantee they'll be the exact size, but they should be very uniform and smooth, and relatively cheap.

 

[IAmTheClayman]

Have you considered Lego or other toy parts as donors? I can't guarantee they'll be the exact size, but they should be very uniform and smooth, and relatively cheap.

I actually did, but A) they seem to be V-groove, whereas I'd prefer U-groove, and B) this is for a kit I plan on selling so I'd prefer not to rely on "kitbashed" parts. Thank you though

 

[Teddyboy16]

Try stock drive products. They have a wide variety of pulleys for you too choose from either in inch or metric, plastic or metal. Timing pulleys, idler pulleys, grooved pulleys in just about every configuration possible. You'll prorabably want a idler pulley. Take a look at this one.

"A 6M 9-00604" it's a black acetal grooved idler pulley with a OD of .375, bore diameter of .128 +\-.005, .093 +/-.01 wide, .015 radius for the groove. The OD .375 is a little smaller then the 10mm OD you specified. It's light duty with no bearing. The belt will be a little more challenging to find as the smallest one is 1/16 cross section. A o-ring might work depending on the distance of the pulleys or you can roll your own even a rubber band might work if the material is sturdy enough. If you want off the shelf then you might consider changing the design to accommodate a slightly larger pulley if you can do that. Try digging a little deeper on stock drives website or call them to see if they have a belt you can buy. They do sell miniature parts. Hope this helps.

 

[zapwizard]

If you 3D print them, get it done using SLS Nylon (Shapeways strong-and-flexible). The parts will come with a sandstone like texture, but are solid all the way through. Make your mounting hole about 0.2mm smaller smaller than needed, and re-drill it after you get the part. Make the outside about 0.2mm thicker than needed, and sand it smooth.

Nylon is also self-lubricating, so the part will spin freely. It will last for a long time if you're putting it under constant use. It's not as good as Acetal, but far better than using ABS or PLA that FDM 3D printers put out.

Also, look at seeing if someone with a lathe can make the part for you. 3D printing is great, but better suited to parts you can't make using other methods.