best design so far for a vac clamp

[woodman08]

This design is the best so far as with different o rings you get different hold down techiniques
with 4 of these hold downs ,you7 get a lot of vac power to hold a large surface area
Took about 40-45 minto make


http://youtu.be/rSQvrg2TKzE

included some tests too!