Three Wheel Scooter

I made this scooter for my daughter, she likes to scoot. Actually my daughter really liked the neighbors' scooter so I busted out the welder and made one for her.

Design Considerations

As with most of anything I build it has to meet certain specific project design considerations. This project's constraints include: dirt cheap (surplus parts will be used where available), indestructable (I like to build things just once), extra-low profile (1 inch ground clearnace so a 2 year old can touch the ground easily) and good looking (just like me).

Steel Frame

The main frame is made of 0.75" rectangular steel tube with 0.125" wall thickness. It was galvanized surplus steel, so need to be careful not breathing in welding fumes. I bought 4 lengths of 39" of this steel tube for $5. Sounds good but the catch is that the steel is attached to a cargo net with about 30 rivets. So I had to drill out all those rivets but hey, that's all fun too. The frame was cut to size with horizontal metal cutting bandsaw and MIG welded together. Here are photos of the frame parts before and after welding together.

Here's the picture of the painted frame parts before and after assembly.

Steering Bearing Assembly

I wuz origninally planning on using a thrust bearing on the steering shaft to reduce friction. But then I thought it's a bit overkill. It's not like the steering shaft needs to rotate at 1000 RPM, so there is no bearing in there at all. What does help is that this scooter uses an extra-long shaft colar as the steering shaft 'feed-through' on the scooter frame. This helps keep the alignment true and has little play/wobble. The steering handle and the lower axel mount have standard shaft collars welded to them and lock onto the shaft after assembly.

Front Wheel Axle Assembly

I ended up going with 1/2" thread rod for the front axle. I did this because it then is pretty easy to tighten the wheels on the axle with just a nylon-insert nut. The axle is one piece that runs from one wheel to the other wheel. This ensures that the alignment between the two wheels is pretty reasonable instead of all crooked-like if I just welded some studs on each end.

Rear Wheel Axle Assembly

For the rear axle I went with the 1/2" keyed shafting. Could have just as easily used the 1/2" threaded rod but since this axle is more visible I didn't want it to look stupid thread rod. That's right.

Wheels

Wheels are my new favorite stinky (they stink) wheel from the ol' surplus center. They're $3 each, have ball bearings and come painted red.

Complete with 'Hoo-lies'

My daugter likes Hoo-lies so I put some Hoo-lies on there. She likes them.

Link to the initial design of the toy.
Design01
Design02
Design03
Design04
Design05
Design06