Bearings Question

**Mega Masher** · 29th September 2013, 12:30

Hello, I am currently designing/looking for parts for the gearboxes on my FW Pizza Cutter, and I'm not sure about which type of bearings I should use. They will need to be tough, spin very fast and fit around an 8mm silver steel shaft.
also, how would I mount said bearing securely into 10mm HDPE.
thanks

**Max** · 29th September 2013, 13:24

You probably want deep groove ball bearings found in technobots. Or you could use roller bearings if you want a smaller outside diamter.
You can't really use hdpe as the supports for your gearboxes (are they for drive?), you need either thick aluminium (about 10mm thick) or steel (around 6mm thick but then there is no way of securing bearings- most people use axels that don't move then put bearings inside the gears) or you could possibly use 15mm nylon but that is risky as it is still flexible.
If this is for drive I suggest you get someone else to make your gearboxes for you are they need to be made very precisely to make them work properly.

**Max** · 29th September 2013, 13:25

Oh and to mount them most people would press them into the material into a hole very slightly smaller than the outside diamter of the bearing.

**Mega Masher** · 29th September 2013, 14:29

Thanks Max,
Is there anywhere you would recommend for aluminium? By the way, I've already looked at Technobots, and they don't have many bearings that wouls fit. I have had a look at RS Components and they have loads. These gearboxes are for drive and weapon (translational drift).

**Max** · 29th September 2013, 14:40

What gear ratio do you need? Also I don't think an 8mm shaft will be enough to support you wheel unless maybe supported at both ends. I'd go for 12mm shaft.
For aluminium is recomend ebay or your local metal workers.
By the way, how do you plan on drill the holes for the shafts accurately enough?