what do you scribe with?

I have had most luck with a scribing tool I picked up at a hobby shop, and have also had limited success with a broken end mill mounted in an old pen.

I have most of the different tools that are marketed as panel scribers but there are the tools I use most often.

Ares,

The link below is for the scriber I use and it is great. I put the tip in the groove and hold it the tool lightly way down at the other end. That way it will tend to follow the groove better and less likely to wander off in a different direction.

http://www.ares-server.com/Ares/Ares.asp?MerchantID=RET01229&Action=Catalog&Type=Product&ID=60728

For really small curves or circles I will use one of the tools below. I made these from a set of replacement point for a drafting dividers. These actually were one piece and I cut it in half, drilled out the end of a quarter inch wood dowel and CA’d them in place. A light buff with a Scotch Brite green scouring pad will get in the groove and clean it out a little. A little 600 grit sanding after that and your in business.