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I'm always looking for cheap wheels of various kinds, and rarely find anything for under £1 a piece.

How can I make a nicely round disc out of metal (aluminium) or wood with a central hole, if I don't have a lathe?

The best idea I've had is to use a scroll saw or similar to cut out a near-circle from a piece of plywood, then drill a hole in the near-centre with a pillar drill arrangement, and some how attach it to a power drill, using a block of sand paper or similar to make the outside more circle-like, around the axle hole.

Can anyone recommend any alternatives? E.g. for 4cm diameter wheel, 10mm thickness, 5mm axle hole?

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A hole saw. Nice and round, complete with a center hole.

enter image description here

  • Lol good answer! – CL22 Jan 26 '15 at 16:26
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    Was going to recommend the same as well. Just need to round the edges on a sander and you are set. – diceless Jan 26 '15 at 16:37
  • I was going to ask how to vary the inner diameter, but just realised it could be done with two sizes of hole saw, first the larger then the smaller, assuming they have the same sized drill bit – CL22 Jan 26 '15 at 16:41
  • That's the usually outer diameter, but yes, they come in sets, and usually the set will use the same sized center bit over quite a wide range of outer diameters. As for the inner, you can just drill a larger hole using the original center hole as a pilot hole, unless you want one large enough that a small hole saw will cut it. I think I have now got from 3/4" to 4-1/4 inch (but not every size in between) due to various projects. The big ones are strictly buy as needed for a particular project, but the smaller ones often make sense to buy as a set. And I save the cutouts to use as wheels. – Ecnerwal Jan 26 '15 at 16:48
  • Good case of a picture being worth a thousand words. – Kik Jan 27 '15 at 14:55
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Why not buy a dowel the size you need and cut off to width. 4cm is around an inch and a half, so you should be able to find this size of dowel fairly easily. Then, plot a cross to obtain the center and stick it with a drill. While the center hole will be a little harder to locate the a hole saw, your outer edge will be a lot smoother with less work. Once you get used to finding the center, it should be no big deal. You can also get metal stock this way (round bar), but it might be a little bit more difficult to work with than a hole saw in metal.

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    I have tried this - the main problem is getting the axle's hole well centred - I have tried with different bits on a pillar drill and even then it's hit and miss, as my pillar drill has some give. Drilling a small hole and working up doesn't help either. And the problem with dowels also is the grain is not great, the wheels tend to split after little use - plywood has been best so far. – CL22 Jan 26 '15 at 20:15
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In classical geometry there are only two tools you can use to form a proof. These tools are a straightedge and compass. So let us look at three ways to use a compass to make wheels. Aside from comics wheels should be round, so a compas is an ideal tool.

The first method I am going to use is a string compass. If you have a good metal compass in your drawing tools, and it is big enough, you can just use it. but what if you don't have one or it is not big enough? To build a string compass you need a thumbtack or nail or dowel for your centerpin, a string that is longer than the radius of the circle you are going to draw, and a pencil or other writing implement. you place the center pin in the center of your intended circle, tie a loop at one end of the string, measure where you want the pencil to be, tie another loop and insert the pencil. Then keeping the pencil straight and the string taught, draw a circle. You then cut it out.

But what if you want something better looking? You mentioned having a scroll saw. ( this also works with a bandsaw ) Place a piece of plywood on top of the deck of your scroll saw and secure it as a sacrificial deck. ( I recommend gluing paper on top for splinter control and to allow for easier sliding of your work. measure out from the blade (left side if you are right handed) the radius of the desired circle, and drill a hole into the sacrificial deck for a dowel. drill a matching hole into your work, and place the dowel through your work and into the sacrificial deck. Turn your work until you have cut out a circle. Fast, easy, repeatable, and better looking than doing it by hand.

Now for my favorite, for great looking circles with less work, a router compass. This is easiest to do with a plunge router, but can be done with any handheld router. remove the bottom plate from the router and replace it with a piece of plywood. You want to place the router at one end of your wood, with a hole for your centering dowel placed the appropriate distance from your blade. put a centering hole in your work, place the dowel, and use the router to cut your circle. Simple, Easy, Done.

  • Good point about using a plunge router. I can't see that working with a scroll saw though, surely it would snap the blade, since it would want to veer off? – CL22 Jan 27 '15 at 10:16
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    I'd love to see you plunge route a 4cm diameter wheel. 40 works pretty well, but it's not a technique that translates well to small sizes. Interesting things happen when you finish the cut and have a 22,000 RPM bit spinning next to a cut-out part that's too small to hold. As for drawing it and cutting it, that's where @Jodes is starting from, and there's always a difference between what is drawn and what is cut. – Ecnerwal Jan 27 '15 at 15:13
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    @Jodes The position of the pivot in relation to the blade is important, but as long as the circle you are trying to cut is larger than the blade's minimum cut radius, it can be done. To find the ideal position for the pivot, draw a line that intersects the middle of the blade front and back. this is the center of cut line.find the point on this line equidistant from the front and back of the blade. Draw a line that intersects that point and is perpendicular to the center cut line. place the pivot point on this line. – hildred Jan 27 '15 at 18:50
  • @Ecnerwal, Yes cutting a circle with a radius smaller than the base of the router is tricky, but if you can get to Thornton with a video camera, I'll show you how. (It involves duct tape.) Of course it is easier on a router table. – hildred Jan 27 '15 at 18:53

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