if anyone wants a pen that's not to expensive and irons off the Frixion range by Pilot do just that. Test a scrap first before using in case it has an adverse effect on your fabric.
Also, instead of drawing on your machines for guidelines, use masking tape. Easily removed and doesn't make your machine look awful.
Tomorrow I'm practicing making rouleau strips, I tried it for my first year to make my own frog fastenings but was hopeless!
HaveALovelyDayTiggaxx