Work with roller glass cutter will be much more accurate if the basis for such processing, as shown in the figure.
Recommend to read
CUTTER OF HOOP
Loves to embroider or cross stitch is used for the tensioning of the fabric an ingenious device — the Hoop: two wooden or plastic rings, one of which together with the tissue fits snugly...
THE PLANE ON THE RAILS …
For individual construction is often necessary to make processing of logs for construction of wood with different cross-sections (beams, plates, boards). Due to the large weight of logs...