Sep 29

All-terrain Mobility Scooter, Part 2

I’m using some thick-walled steel pipe to make the bearing housings for the rear axles. My chop saw doesn’t cut perfectly squarely, and it tends to leave swarf behind on the cut.

Same housing, with the swarf filed off. The axle is only going to be 17mm diameter, so the housings will extend all the way out to the road wheel hubs to provide the maximum possible support.

Unfortunately I don’t have a conical insert for my live centre that’s big enough to fit this pipe, so I’ve made a plug to use instead.

The plug is inserted on the tailstock end of the pipe, supporting the whole tube while I machine a bearing surface for the steady rest jaws to run in.

Steady rest fitted, and tube faced off. I’ll start boring out the recess for the bearings tomorrow.
I would have preferred to use 25mm internal diameter bearings, but my steady rest won’t hold a piece of pipe that big.

…and that’s what they look like once the rebate has been machined and the bearing is inserted.

I’m going to use some sections of an old barbell bar for the axles. These start out at 25mm diameter, so I’ll machine off 1mm or so to clean up the rust and remove the knurling.

It’s one long cut between the chuck and the live centre, then reverse the workpiece to finish off the end that’s in the chuck.

Pretty much any old bit of steel will clean up nicely. The axles next need to have their ends machined down to the inner diameter of the bearings, but I’ll leave that for another night.

Here I’ve rough-machined the axles to within about 0.5mm of their finished diameter.

The next day, and the end rebates have been finished off to exactly fit the bearings.

Two axle housings with bearings fitted. These just need hubs on either end and mounting brackets welded on, and they’re done.

The road wheels need to have their wheel studs on a 90mm diameter circle, so I’m making a suitable flange for the hub. Here I’m drilling the centre out to 25mm.

Two wheel hub flanges ready for mounting on their hubs.

That’s the roughed-out axle hub. As you can see from the flange above it, I still need to take another 10mm off the diameter so that the flange will fit on.

…like this!

Now I’m clamping the hub and flange together, ready for welding.

If I could go back in time 4 hours or so, I’d advise myself not to weld this side. These welds just needed to be machined off again, and the weld metal is much harder than mild steel.

Completed hub blank, from the inside of the wheel.

View of the hub blank from the outside of the wheel. The wheel is centred by the hub spigot, the bolts are just there to hold it on (i.e. the bolts shouldn’t carry any load in the vertical plane).

The hubs need to be accurately bored to 17mm to fit precisely on the axles. I’ve used a 15mm drill bit to get this one close to final size, and I’ll finish it off using the boring bar tomorrow.

Axle housing assembled, now they just need keyways so that the hubs can be power-driven.

Drilling the wheel stud holes in the road-wheel hubs.

Practicing my milling technique using some scrap material. The drill press vice wasn’t rigid enough, so I’ll look at using a different method hold the workpiece.

These new toys arrived today. When you buy a machine tool (like a lathe or a mill), what you’re really doing is making your first down-payment on a lifetime of purchasing cutting bits and accessories.

About to start the first keyway cut on the Real Thing. I’ve mounted the axle in v-blocks for stability, but I really do need to invest in some better hold-down clamps at some point.

That’s a nice clean cut.

And the key steel fits perfectly! Huzzah!

Welding the sprocket blank (bottom) to its hub. I would have preferred to bolt it, but there just wasn’t enough “meat” left in the hub to do so.

Set up to scrape out the keyway slot in the hub. I’ll probably discover tomorrow that my lathe has a built-in spindle lock, and that the clamps were totally unnecessary.

Both axles are now fitted with keyways and keys at each end. Just a little more work and we’ll be ready for Billycart Testing!

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>