To make a shank shorter all you have to do is cut it, the hard part is getting close enough to perpendicular to the shank and getting the face smooth to give you a good seal. Complicating matters will be the threads, if you're using a flexible blade(eg hack saw) then your blade will sink between the non-perpendicular threads and you'll be getting a crooked cut. I did the following to get a perfect cut:
Tools/materials:
1) saw
2) file(s)
3) fine grit sandpaper
4) vice
1) With 4 (old) shank nuts, put two on either side of the cut with the gap set at blade with + a hair of extra space so the blade doesn't jam. Two nuts tightened together will prevent them from moving. Have the larger nut face toward the blade for greater surface/guiding area.
2) Make the cut with the vice gripping a pair of nuts. (did i just say that?)
3) File down the cut marks
4) Sand down file marks.
I used a bandsaw which made the cut very quick and minimized the damage to the nuts. They're still usable with just some cosmetic scratching, if you use a hack saw expect more and deeper scratches which may penetrate any corrosion protection (because you'll probably be sloppier than the bandsaw). I did this on a brass shank but there's no reason why you couldn't do this on stainless steel as well, it'll just take a bit more time and elbow grease.
In the pics from left to right:
1) shank ready to cut
2) visible saw marks
3) sanded and ready to go
Tools/materials:
1) saw
2) file(s)
3) fine grit sandpaper
4) vice
1) With 4 (old) shank nuts, put two on either side of the cut with the gap set at blade with + a hair of extra space so the blade doesn't jam. Two nuts tightened together will prevent them from moving. Have the larger nut face toward the blade for greater surface/guiding area.
2) Make the cut with the vice gripping a pair of nuts. (did i just say that?)
3) File down the cut marks
4) Sand down file marks.
I used a bandsaw which made the cut very quick and minimized the damage to the nuts. They're still usable with just some cosmetic scratching, if you use a hack saw expect more and deeper scratches which may penetrate any corrosion protection (because you'll probably be sloppier than the bandsaw). I did this on a brass shank but there's no reason why you couldn't do this on stainless steel as well, it'll just take a bit more time and elbow grease.
In the pics from left to right:
1) shank ready to cut
2) visible saw marks
3) sanded and ready to go