pic: Harbor Freight 8 inch tire on 3d printed hub

[MrBasse]

loading photo ...

[SenorZ]

Have you tested the strength of the wheels yet? Our 3D printed parts usually hold up pretty well if there isn't much shearing force. If someone hits you from the side, you might get quite a lot of that.

[nxtmonkeys]

Did you design the hub or use a previously created file?

Also, could you post the CAD file?

[MrBasse]

So far it feels pretty strong, we'll test a bit more when the rest of our belts come in. My hope is that most of the load will be taken in the tire and soften the blow to the wheel itself.

I wasn't a huge fan of the look of the hubs from AndyMark so we designed our own but used some of their proven geometry to interface with pulleys and sprockets. There were probably more efficient designs, but these look good.

I'll post CAD soon, but I would want to make some changes first. The wheel is a tight squeeze in the tire and requires a bit of coaxing to get it together. All in all it turned out okay though.

[Lil' Lavery]

Are the tubes/tires from those actually 8", or are they 200x50mm?

[MrBasse]

Originally Posted by Lil' Lavery

Are the tubes/tires from those actually 8", or are they 200x50mm?

The are actually a little bigger than 8" when aired up. I think they were around 8.75 all said and done. The tire size is determined by the hub and measures 2.50-4 on these.

[pribusin]

Hey neighbor... How much for you to print us up some hubs? We're striking out getting 8" wheels - everything is sold out. We looked at the HFT wheels but they were so heavy with the steel hubs.

[SamM]

Nice!

It's important to note that the Harbor Freight tires will not work with the stock Andy Mark Hubs anyway, and it can be a bit dangerous to try.

[MrBasse]

Originally Posted by pribusin

Hey neighbor... How much for you to print us up some hubs? We're striking out getting 8" wheels - everything is sold out. We looked at the HFT wheels but they were so heavy with the steel hubs.

The cost isn't the big part... it's the time. 33 hours for each side of the robot. 66 hours is a loooooooooot of printing.

If you really want to we probably could do it, it's at least double the price of Andymark. Wouldnt you know it, once i hit print on the second set, AM hubs came back in stock. I'd have to do math to figure the numbers out for you and I'm nowhere near ready to be in a BOM mood yet...

I'll put a kid on it tomorrow and run the numbers for you though.

[pribusin]

Andy, will the AM hubs fit the HFT wheels close enough to use?? Did you try them?

[MrBasse]

Originally Posted by pribusin

Andy, will the AM hubs fit the HFT wheels close enough to use?? Did you try them?

They fit very very loose. The hubs spin inside the tire. You might be able to add material to the hubs, but I would have little faith in running the AM hubs with a non 200x50 tire. I think Airway Oxygen carries wheelchair tires though.

[SamM]

When inflated the HF tire bead will push past the wheel.

We sliced the HF hubs up to make adapter rings that fit over the AM hubs. They fit surprisingly well.

[Mechvet]

Originally Posted by MrBasse

The cost isn't the big part... it's the time. 33 hours for each side of the robot. 66 hours is a loooooooooot of printing.

If you really want to we probably could do it, it's at least double the price of Andymark. Wouldnt you know it, once i hit print on the second set, AM hubs came back in stock. I'd have to do math to figure the numbers out for you and I'm nowhere near ready to be in a BOM mood yet...

I'll put a kid on it tomorrow and run the numbers for you though.

Any update on the CAD of this wheel, and how they've been working for you?

We have some solid printing abilities, and if this saves weight we're definitely interested in trying a few out.

Also: How much filament is each wheel?

[andrew4130]

http://www.thingiverse.com/thing:1275569

Here you can download the .stl file of the hub!!!

[MrBasse]

If anyone is interested, I updated my file and will post a Thingiverse link tomorrow. They seem to hold up okay, but we haven't aggressively tested yet. That won't be done until next week, unfortunately.