I've done 3x cordura (or 2x plus zip) without problems - 4 layers needed some assistance to get through (finger pressing down on the needle clamp) but I wouldn't fancy doing that if a motor was involved.
Having said that, I have a spare (and suitably vintage looking) universal motor and a foot switch for one of my lathes. It uses a Singer compatible belt as a primary drive - I might be able to lash something together...
I've done 3x cordura (or 2x plus zip) without problems - 4 layers needed some assistance to get through (finger pressing down on the needle clamp) but I wouldn't fancy doing that if a motor was involved.
Having said that, I have a spare (and suitably vintage looking) universal motor and a foot switch for one of my lathes. It uses a Singer compatible belt as a primary drive - I might be able to lash something together...