The marking wheel holder works like a pencil except that it scores the work piece giving a definite border line to cut to.
If you put masking tape over the scribed line the marking wheel will cut through the tape giving you a positive visual line to cut to (pencil lines especially along the grain can be difficult to see).
Because the marking wheel cuts a line in the work piece tear out is greatly reduced leaving a better finish.
If you can work accurately to the line with a jig saw or hand tools you should get a near perfect fit.
Ideal for cross grain work with the scored line stopping the wood from tearing out when jig sawing but it can mark most materials associated with furniture installation (mdf, ply etc).
The wheel is set at a 15 degree angle which enables it to sit parallel to the scriber base for very narrow scribes.
A Veritas marking wheel is used (one wheel is supplied with the holder) which can be replaced when worn out or damaged.
Replacement marking wheels can be purchased from Axminster power tools in the UK and many outlets in the US and Canada.
Testing out the marking wheel holder in a big boy scriber
Showing the results you can get when cutting to a scribed line.