I was trying to make wagon wheels. The ones used for cannons. But I find making smaller circles and cutting out an even smaller one inside the first one to be a disaster for me.

What do you people use to cut small circles. I found a compass knife. Is that any good?

RD,

I have had good luck with just a compass (divider) with "points" in both ends. Scribe the circle in the plastic and pop them out.

Not sure how small of a circle you are talking about, though...

Shaun

if it's small enough you'll have to use a Punch & die set

Here's a way I go about it. I draw a circle on the plastic sheet (fig.1), then I'll cut close to the circles line (fig.2)and (fig3). Then using a sanding stick, I'll sand following the line (fig.4). I get near perfect circles most of the time. Simply enough.

Olfa makes a compass-type cutter that can go down to about 1 cm Would this work?

http://www.misterart.com/store/view/001/group_id/8132/Olfa-Standard-duty-Circle-Cutter.htm

Richard

Pre,

Are you tring to build a cart wheel like the one below?


If, yes, then I could probably help you out...but the problem is that its not made from styrene...

Arvin,

Why don't you tell us how you did it ? I am very interested in your way to do such a cart wheel.
I am actually using a Wheel from a LEGO- Wildwest wagon do simulate an medieval light. (with candles on top of it).

Cheers
Claude

I'm trying to build a cartwheel for a cannon. So I have to make the spokes and stuff too. I know Tamiya has one but it's too large for my purpose. What I need is 12mm in diameter and an interior circle of 9mm. The external circle is easy. But the inner one is a challenge. I had a hard time cutting it clean.

Just a thought but have you tried looking for plastic pipe with those dimensions and just slice the required wheel thickness off?
Try drainage pipes. even if you find pipe of 12mm exterior diameter but only 10.5mm interior diameter just look for another pipe 10.5mm exterior diameter to 9mm interior diameter.
hope this makes sense.
Tom

A circle template can be very good also. They come in a variety of size groupings with around 20-30 graded opening per template.
I use a very sharp conical point and scribe continually till through the plastic. Then I center a larger hole (circle)(which is the outside diameter of the wheel) on top of the opening at the desired thickness and repeat the process. Sand down the burr edge caused by the scribing and presto...a wheel (spokes not included!)

Gary

i like to use the compass cutter for circles. if that doesnt go small enough use brass bullet casings over a hard plastic cutting board as like a die set. you have a huge range in sizes from 22 cal to 50 cal. just a thought :-d