What's the best way of adding additional waxed linen when stitching and you find you dont have enough to finish? I haven't found a knot that will hold in the waxed linen. there has to be a standard way of dealing with this. any ideas?

Try a drop of super glue on the knot and pull it into one of the holes
TJ

Cut off the thread flush with the leather, and start again with new thread 3 or 4 holes back (so 3 or 4 holes will be double-stitched). Make sure you have enough the second time. ;)

Don is exactly correct on the splicing method.

Ya I was about to suggest the same as Don when I read his post....it is so tiresom to find out you need just a few more inches of tread isn´t...I have started to calculate just how much I need by checking the thickness of the sheath and then say the lenght of the stitchen * 3-5..ussually gives enough...if I have less than one foot left on each side I am happy...

Thanks all, I usually have some left over at the end but this sheath was extra thick and I was way off. I did over lap, doubled up through three holes, and it worked fine, made a little variation in the appearance but enough to really matter. I was surprised how secure it felt, that over lapping through must sort of wedge the thread in the holes.

In order to do a real neat job of double stitching so the double stitches do not look thicker or of more bulk,Try this----When you are nearing the end of the thread take your stitching gouge and run one more pass on your stitch line for the last three stitches. This will slightly lower the stitches (Bury them deeper) so that when you sew through and over these stitches it will not show where the splice has been made. If both sides are to show, gouge the other side also.