Wednesday, October 26, 2016

A Toy Dump Truck


I'm on a roll here with the toy making. 'Latest is a dump truck.




It's small -- only about seven inches in overall length; a proper sandbox toy ought to be at least twice that size. But it was an interesting, challenging project, and I'm quite pleased with the outcome. Two aspects of it are noteworthy:
  • I again used my method for making stub axles, and I expect to be using that method routinely on future toy vehicles.
  • The original plan for the truck that I had obtained from the internet had no provision for latching the truck's tailgate shut. That struck me as a flaw -- cargo would tend to push open the tailgate and spill while in transport. I came up with a latch using a plastic turn button and a notched cross-bar, like so.


I think that makes the toy more useable and engaging.

* * *

A Refinement -- TUESDAY, DECEMBER 6, 2016

Something I neglected to show in the above photos is the front bumper. Truth be told, I made a bit of a botch of that. Here's a front-on view of the bumper.


There's some nasty tear-out, and the vertical registration of the two headlights doesn't match up well.

So, I made a replacement bumper with better headlights, like so.


Now I have to chisel off the old bumper, and glue the replacement bumper on in its place.

- - -

That turned out reasonably well.



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Saturday, October 15, 2016

Princess Auto's Wood Burning Stove -- Cat. No. 8282303


I've long dreamt of having a wood stove in my workshop, both for auxiliary heat, and to usefully dispose of woodworking off-cuts. (If you do any amount of woodworking, you soon find yourself up to your ears in off-cuts.) So, when Princess Auto put their little wood stove on special, I went and got one. Here it is still in its box.


And here it is out of its box.


You have to attach the four feet with the screws and nuts provided.

Right on the label on the box it says, "This heater is not C.S.A. or U.L. approved and is not intended for residential installation. Using this heater in an insured structure will void the fire insurance coverage."

Hmmm.

Moving right along, here's the stove assembled and sitting where I'd like it to be.


The lid pivots on a single 1/4"-20 nut-and-bolt, and opens like so.


The flue opening at the back is 6" diameter. It's a sort of a socket affair.

The intake draft control is obvious down in front. On top, between the lid and the flue opening, there's a tiny draft control that I don't really understand the use of. A few more points about the stove:
  • The only way to clean out ash accumulation is via the lid.
  • The stove has no grate inside -- just the naked sheet metal bottom.
  • The instruction booklet advises you to add a 2 1/2" deep layer of sand or fine gravel to the bottom of the heater. The booklet goes on to say, "Sand can be installed between the corrugated liner and the heater body to lengthen heater life and hold heat." Hmmm. I really don't see how it would be possible to do that.
The way that I mean to have this thing installed, it will have to function with a 4" diameter flue pipe. I found a 6" to 4" HVAC reducer at the Home Depot. With that, and a length of aluminum dryer vent tubing to vent the thing out a window above, I built a small trial fire in the stove to see how it would work. That seems to have been a success -- the fire drew nicely out through the 4" diameter tubing.

- - -

Anyway, that's the story so far. I knew from the get-go that my plan here was fraught with difficulty, and this little project may end up getting filed under 'folly'. We'll see.

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Update -- FRIDAY, NOVEMBER 11, 2016

I've abandoned the project, and put the stove back in its box to await the day when I can put it to use somewhere more suitable. What I had in mind was just too complicated and dangerous to carry on with.

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Tuesday, October 11, 2016

A Toy Eighteen Wheeler


I have an old Ryobi project book that has quite a nice toy truck in it. The book is Vol. 3, No. 1, February 2001. Here's the cover.


And here's the truck.


I like that truck. I think it's a fine truck.

I'm going to depart from the text's instructions in several ways, though.
  • The text makes much of making your own wheels with a circle-cutter.[1] The prospect doesn't really interest me, especially not when Lee Valley has exquisite ready-made hardwood wheels for a reasonable price. (I'll be using the 1 1/2" x 1/2" version of item 'A' -- Cat. No. 41K01.66.) Here's a view of Lee Valley's wheels, along with axles that I've made for them.

  • The text would have you build the truck using maple stock throughout. That's a nice choice of material, but maple is costly. I'll be building this truck from whatever odds and ends I can scrounge up. I splurged a bit on the wheels, so I'll make up for that on the rest of the material.
  • The text appears to have the wheels fixed to the axles, with the axles rotating within oversize holes through the chassis. I'm going to do the opposite -- the axles will be glued into the chassis, with the wheels rotating on the axles.
The Trailer Bed And Trailer Front Wall

The trailer bed is 1/2" x 3" x 10". The trailer front wall is 1/2" x 1 1/4" x 3". That 1/2" thickness figure is a bit of a complication -- I don't have a thickness planer. I'll have to resaw and hand plane some 3/4" stock; not one of my favourite activities.

- - -

That turned out not too badly -- I only had to make two attempts on the trailer bed. Here's what I have so far.


Where I went wrong on the trailer bed the first time was in trying to use stock that had the outskirts of knots at the ends. When thickness planing it, the knot outskirts tore out, like so.


Not useable. It's ok to use knotty material, but avoid knots or knot outskirts at ends of pieces.

The hand thickness planing was a chore; I'm glad that I'm working with softwood here. Maple would be more difficult -- a lot of plane sharpening would be in order.

- - -

The Rear Axle Mount

I have that made from a scrap of softwood. Here it is.


It's 7/8" x 1 1/8" x 3", bored through in two places 1/4" diameter for wheel axles.

There was an error in the drawing for this part that fortunately I caught in time. Had I not caught the error, I'd have ended up with the two axle bores too close together. You can't trust how-to drawings to be error free -- it's wise to go over them and make sure that dimensions add up correctly.


Wheel Bores

Since I mean to have the wheels turn freely on the 1/4" diameter axles, I have to give some attention to wheel bore diameter here.

The wheels I bought have 1/4" diameter bores. If I just install those wheels on 1/4" diameter axles, I'll have binding wheels. This is where a set of letter size drills comes in handy. Letter size drill 'F' is 0.257" diameter -- 0.007" greater than 1/4". So, boring out all the wheels with a letter size 'F' drill gives me nice, free rolling wheels. It's an important consideration; any child with his wits about him would rightfully perceive binding wheels as a defect in his toy. It would diminish his enjoyment of it.

Wheel Spacing (Axial Clearance)

Another consideration for freely rotating wheels is axial clearance; wheels mustn't bind between a vehicle's chassis and an axle's hub -- some axial slop is called for. Some plastic shim stock is helpful for establishing axial clearance at wheel installation time. I have a plastic display card from a store gift certificate that's exactly 1/32" thick. I cut it and notched it to give me a pair of wheel installation shims, like so.


Insert the shims between a wheel and the vehicle's chassis while the axle glue-up is tacking, and you'll end up with about the right amount of axial clearance for a free rolling wheel.


Progress So Far

Here's a view of what I've got done so far.


The trailer's rear axle mount and front wall are glued in place, but they lack reinforcement. I'll be adding dowels for that. I want this truck to be able to take rough handling without anything breaking loose.

- - -

Here are the reinforcement dowels installed, awaiting flush-trimming with a chisel.




A toy like this one is liable to be in for some rough treatment, and needs to be able to take it without anything breaking.

- - -

Taking Shape

Progress so far.


- - -

All Done


The 'logs' are from apple tree branches.

That was a delightful and satisfying project. I must pursue more.

- - -

Note:

[1] In fairness to the text's author, I'll make a wheel per his instructions and see how it turns out, and how it compares to the Lee Valley wheels.

There's a slight difficulty right from the get-go; i.e. 1/2" thick stock is called for. 1/2" thick stock is not something that's readily available -- it has to be resawn and/or planed from thicker stock. The text makes no mention of that.

I come across this often in published plans -- authors blithely call for stock thicknesses that one will not find at a typical lumber outlet, with nary a word about how one is to obtain such thicknesses.

Anyway, I'll resaw and hand plane a bit of 3/4" stock; I only need enough for one wheel here.

- - -

And here's my resawn and hand planed wheel blank from a scrap of softwood that was destined for the stove.


Hand thickness planing is quite a skill, and I don't really have it. What you see in the photo is a variable thickness approximation of 1/2" that will suffice for this exercise. I'd love to have a thickness planer in my shop, but those things aren't cheap.

Next up is to bore a hub recess, 3/4" diameter x 1/8" deep, with a Forstner bit. Then, I can apply my circle cutter to get the basic wheel cut out of the blank.

- - -

And here we are with the circle cutting just done.


The text then has you bore out the circle cutter's pilot hole to 1/4" diameter, and mount the wheel on a simple 1/4" mandrel for sanding and chamfering in the drill press. Here we are with that operation just completed.


And here's my shop-made wheel next to a Lee Valley wheel.


If you don't mind the austere plainness of the shop-made item compared to the factory-made wheel, the shop-made wheel is quite acceptable for toy making. I can't fault the text's author at all for his approach to fabricating toy wheels.

- - -

A couple of closing notes:
  • Wheel material really should be hardwood, and the text's choice of maple is a good one. 
  •  In any shop with a wood lathe, it's obvious that the wood lathe is the preferable machine for the sanding and chamfering operation. I only used the drill press to adhere to the text's instruction. I've never much cared for the use of a drill press as a 'vertical lathe'.
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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.

- - -

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]

- - -

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.

- - -

Note:

[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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