Replies

1. 
   user-206453 | Dec 27, 2006 03:37pm | #1

   There was a thread awhile back with pictures etc about this: 5952.26

   Do you have the end of the channel closed off? Bill Lindau

2. 
   JohnH | Dec 27, 2006 05:35pm | #2

   I've built one and it works like a charm. I think your holes may be too big. Try this:

   1. Test for suction: lay a board on the fence that covers all the holes. If it grabs firmly, you have enough suction. If not, you don't. The board must fit FLAT on the fence.

   2. Test for coverage: In operation, some of the holes are covered and clamping, while others are uncovered and venting. Lay a board on the fence that covers half the holes. If it grabs firmly, your holes are not too big. If not, start with a new extrusion. My holes are 1/8" diameter on 3" spacing and powered by a 1 1/4" shopvac.

   I started with small holes and then enlarged them in steps to get the right degree of grip -- too little and the stock falls off; too much and the friction along the fence makes it hard to control progress through the blade. If it sings like a flute, the holes are too small. Since its hard to make a hole smaller, I walked up by enlarging alternate holes -- step-by-step.

   Good luck! Once its done, you'll love it.

1. 
   DonC | Dec 27, 2006 06:23pm | #3

   Thanks John,

   How many holes have you drilled?

1. 
   JohnH | Dec 27, 2006 07:28pm | #4

   The fence is 48" long, so there are 15 holes along the length. Mine is two banks high, for 30 holes altogether.

   Hole size and number (and fence length versus stock length) is a tradeoff between gripping and venting. Trial and error is the only way I know to get the balance right.

2. 
   user-206453 | Dec 27, 2006 08:21pm | #5

   Don, click on this link 5952.52 and you will see some photos of my fence. The holes are 3/8" dia, spaced 1" on center, and there's 14 of them. It works great! You have to make sure that the opposite end of the channel, from where the vaccum is attached, is closed off. How far from the table saw surface (the bottom of the fence) are the holes? Your vac hp is plenty. Bill

1. 
   DonC | Dec 27, 2006 08:42pm | #6

   Thank you for all the replys.

   I have a closed off extrusion with 14 holes of 3/8" and their centers are 3/8" above the table surface. I'm pretty sure this is the way the original manufactured fence was as well as the photos on this forum.

   I also have experimented with 1/8" dia holes and have covered several holes with tape in an effort to find the best balancing of air flow,hole size,and spacing.

   I don't seem to get any gripping power. My extrusion is hollow with "T" slots on the outside. I drilled thru the T slots to the hollow center and am sucking air all along the length of the T slot. A board with 3/8" holes is attached to the T slotted extrusion. Fortunately, the T slot center is 3/8" above the table surface and it seems is should work fine.

   Perhaps I need to get a hollow extrusion that is like the posted photos. Maybe my system introduces to much loss of suction due to resistance of sucking air thru holes and T slot.

   Where can I buy extrusions similar to yours?

   Thanks again for all your help and Happy New Year to all you fine guys that have given advice.

1. 
   user-206453 | Dec 27, 2006 09:06pm | #7

   Don, go to this link 9556.2 , a fellow there named Malcom shows pictures of one he made. If you contacted him, he could tell you where he bought the extrusion. My MiniMax fence could be adapted or a Felder could as well. My vacuum fence was purchased back when the company was still in business. Bill Lindau

3. 
   JohnH | Dec 28, 2006 02:55am | #8

   Hello Don,

   If there continues to be a problem with getting the right extrusion, here's a link to my homemade version with photos.

   http://www.sawmillcreek.org/showthread.php?t=37748&highlight=vacuum+fence

   Best regards, John

4. 
   DonC | Jan 09, 2007 07:41am | #9

   Yea!!!! Thanks to all our good advice, I now have a vacuum fence that finally works PERFECT! Did I say PERFECT! Holy Cow! YES!!! This should be a "standard feature" on all table saw fences with extruded aluminum fences. I can even saw to 1/32" with perfection. Forrest blade also deserves mention, the cut finish looks like it was planed.

   It's soooooo SAFE.

   I made my fence based on an extruded piece of 8020 aluminum extrusion. Prolly overkill. I think a guy could do the same vacuum fence with 100% wood from the shop. The bottom line is....it works better than I ever expected. Anyone into laminations/canoe building should invest  in a vacuum fence.

   I also like mine cause I could use it on table saw,router,oscillating spindle sander,ect.

   Thank you again for helping me go thru the learning curve. I hope I can share with you in the future.

   By the way, if you are not familiar with 8020, just do a google on 8020 aluminum. You will see the web site for "adult erector sets". Your imagination and creativity will enjoy the site.

   Keep in mind that any vacuum fence can be built with only wood that you already have in our shop.

   Don