A Circle Cutter is so very useful for paper modelling
Trying to make wheels for paper models is quite difficult. It needs a very good set of scissors, a steady hand and a good eye to cut out accurate circles. After a number of attempts with only poor results I went hunting for a circle cutter and found this one on eBay
The make is Hobbico, and here is the web-site http://www.hobbico.com/tools/hcar0230.html
The scales are in millimetres of radius and diameter, but I find I mostly just adjust till I get the right size disc. It cuts 200 gram / sq. metre card-stock with ease. Very precise and clean edges. There is no problem with distortion of the tool - the end of the circle always meets the beginning of the cut. The blades have been long-lasting too (it comes with 6, and replacements are available).
It will cut out circles up to 150mm diameter, and I've used it down to about 13mm with no problem. Here is one of the finished 13mm wheels for a Messerschmidtt KR200 3-wheeler.
Price for the cutter on eBay is about $AU25.
This page http://tardus.net/circleCutter.html published: 4 Apr 2009