I use the Olfa circle cutter for, well, cutting circles. Eveytime I use it I think "What a cheap piece of crap". And rightfully so, it really is a cheap piece of crap. I'd recommend throwing it away if I could find a replacement, but they seem to have cornered the market, just like Microsoft. There is just no way around this lousy mood-destroying excuse for a tool . Ok, so perhaps there is, but I don't know about it. So I destroyed my Olfa cutter into something beautiful, something that actually cuts circles without constantly changing the setting, or without the blade running amok. Don't say the Olfa circle cutter is a decent thing. I need to make at least 10 disks before I get one or two good circles, exact to within 0.1mm. "Perhaps the cutter needs skill to use?" No, it plain sucks. So here's a way to fix things:
First of all, carve away the black part as visible above, over the entire height of the tool. Glue the pin back into the black part. This way you can make smaller circles. I mean, why buy a circle tool that can give you a circle the size of the moon? We're building small models, right? This way you can almost get a circle as small as the largest setting on your punch and die set. Fortunately I haven't encountered a disk that fits "just in between" (Edit: damn, I have! What a disaster)
Second, add a strip of Evergreen 9009 0.13mm/0,005" strip as on the image. OF COURSE you cannot use normal glue, it refuses to stick to such a piece of junk, who can blame it? So use CA. CA doesn't care, CA always works.
This will remove most of the 'backlash' in the setting, making it much easier to use.