Monday, October 10, 2016

Stub Axles For Toy Vehicles

These little stub axles can be bought ready-made. Lee Valley carries a selection of them, along with some very nice wheels.

But if you need axles of dimensions that aren't available, you have to make your own, and that's not easy to do from solid stock. I currently need axles with a quarter-inch diameter, two-inch long shaft, not including the wheel-retaining hub end. Those would be  challenging things to turn as single pieces from hub-diameter stock.

Here's a method for constructing such axles from two different diameters of dowel stock:

For each axle, begin with a 2 1/2" length of 1/4" diameter dowel for the shaft, and a 1/2" length of 1/2" diameter dowel for the hub. The hub piece ought to be cut as squarely as possible -- i.e. on a table saw. If you're making multiple axles, as you likely would be for most any toy vehicle, you'll want to rig your saw to produce uniform lengths of dowel. Here's a view of my crude rig for doing that.

The green-painted plywood scrap is clamped to the saw's table. (The clamp is out of view of the photo.) That plywood scrap is my registration block -- it's positioned so as to get the dowel stock launched at the saw blade such that a 1/2" length of dowel will result from the cross-cut. Note that the registration block's front edge is positioned so that the dowel stock will have moved forward enough to clear the registration block before the cut completes. That's important -- the short, cut-off piece of dowel must not be able to get pinched between the saw blade and the registration block. A cut-off piece of dowel that got pinched that way would be ruined.

Use at least an 80-tooth finishing blade, and go slowly. No matter how careful you are, the small cut-off may get hurled at the end of the cut -- be ready for that, and hope that you can find where the thing lands.

So, here we have the makings of an axle.

Next up is to bore the 1/2" dowel hub piece through 1/4" diameter to accept the shaft. I'm fortunate in having a small metal lathe, which is the ideal machine for such an operation. Here's a view of that part of the axle's construction just done.

Now the two axle pieces get glued together, and left to cure for awhile.

That 1/2" dowel stock that I used was prone to splintering out when I was cutting it on the table saw. That's ok here because I'll be turning down the diameter to 7/16", and the splintering out will disappear.

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And here's the axle with its hub turned down, and ready for further shaping.

Now, if what I was after was just a clunky. cylindrical hub, I'd just about be there; square off the end to the desired length and that's that.

But what I want is a much lower profile hub with a somewhat rounded-off face. So, I'll saw off the excess hub length, and finish off the hub to its correct length with a parting tool.[1]

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And here we are.

That hub just needs a bit of sanding to remove the pencil mark and finish off the face a bit better, and it's done.

Here's a view of  finished axles, and the wheels that I'll be using them with.

Not bad at all.

The axles are a bit of work, but the cost is very low, and the method is very flexible -- the dimensions can be altered any which way for particular applications.

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[1] You may be wondering why I made the hubs so much longer than I meant them to be in the end.

The reason was simply to facilitate chucking the hubs for boring them through. Thin hub blanks would tend to be a bit difficult get chucked squarely. The 1/2" long hub blanks were readily chucked squarely, for a good outcome from the boring operation.

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