Replies

1. 
   Aubster | Apr 11, 2006 04:45pm | #1

   I'm new at this but I think it is a good idea. Plus, when you are cleaning up, you can just unplug it and sweep all the dust right over the hole.

2. 
   DougF | Apr 11, 2006 05:26pm | #2

   It is unclear from your question whether you have spec'ed out the entire ductwork or you are simply curious.  The answer really depends on the total layout and CFM capacity of your DC.  First, I would recommend at least a 5" line and dust port located at at the saw.  Second, if laying this one line underground requires that it is a dedicated run from the TS to the DC as opposed to branching off of a larger  main line, then you increase the overall DC CFM requirements by increasing the overall length of the ductwork and probably the use of some additional elbows.  The additional run of ductwork should be taken into consideration when sizing the DC capacity.  If you elect to lay the line as you suggest, the other alternative to burying the line is to create an exposed chase with an inset that is flush covered by a metal plate or plywood providing ease of access to your ductwork and power.          

3. 
   JohnWW | Apr 13, 2006 02:37am | #3

   Since it is likely to be at the end of a long run, I would second the recommendation that you use a larger pipe to cut down on friction losses. 

   Second don't put in any elbows, except at the ends where the pipe comes out of the floor, and these would ideally be 45 degrees instead of 90's, again for better air flow.   The pipe between the two ends should be a straight run to avoid having a clog form in an inaccessible location.  While you are at it ,run wiring for the saw under the floor also.

   John White, Shop Manager, Fine Woodworking Magazine

1. 
   h12721 | Apr 13, 2006 04:14am | #4

   HelloWhat about " PVC " ?Hilmar

1. 
   QCInspector | Apr 13, 2006 10:19pm | #5

   Since the plastic pipe is in the cement it's self grounding. If that's the point you were trying to make. Once it comes out of the floor you may resume your argument if you like. ;-)

1. 
   h12721 | Apr 14, 2006 01:38am | #6

   >Since the plastic pipe is in the cement it's self grounding. <
   That would be the anwswer. Thank You! >If that's the point you were trying to make. <
   Not making a point.I was just asking the question from his third sentence. >Once it comes out of the floor you may resume your argument if you like. ;-)<
   Where is the argument,that remark is over the top.Hilmar

1. 
   QCInspector | Apr 14, 2006 02:31am | #7

   No offence intended. Thought the direction was going to head into the classic "dust collector piping, plastic verses metal, static electric explosion" debate, and was unsuccessful of making light of it.

2. 
   h12721 | Apr 15, 2006 04:01am | #12

   >> No offence intended.Thought the direction was going to head into the classic "dust collector piping, plastic verses metal, static electric explosion" debate, and was unsuccessful of making light of it. <<No problem QC. - That must have be some discussion.-Hilmar

2. 
   JohnWW | Apr 14, 2006 05:19pm | #8

   PVC should work fine in the floor, and you won't have to worry about grounding the buried portion. PVC elsewhere in the system can have static problems. Dust explosions triggered by static reportedly aren't a serious risk, but static shocks from exposed and ungrounded plastic piping are unpleasant and potentially dangerous when working around woodworking machinery.John W.

1. 
   DanAlberta | Apr 14, 2006 06:20pm | #9

   Grounding won't be a problem. All of my tools will be well grounded.

   Is a 4" pvc a big enough or will I need to go up to 5" or even 6" to keep up the CFM for the dust collector? How much of a problem is the static build up? Or should I think about some other type of ducting? I would like to keep the walls free for shelving and cabinets for the small hand tools.

1. 
   JohnWW | Apr 14, 2006 11:28pm | #10

   Machines being grounded won't prevent static buildup in plastic ductwork.

   For a whole shop system with a central dust collector, 5 or 6 inch diameter pipe is a minimum size, and larger may be needed, depending on the length of the runs, bends in the system, and the size of the collector.

   There are a lot of options for ductwork, almost all of them have tradeoffs especially between price and ease of installation.  If you post a question here on what system to choose, you'll get a lot of opinions.

   John W.

4. 
   AntzyClancy | Apr 14, 2006 11:55pm | #11

   Pentz has done all of the research for you.  The answers are here:

   http://billpentz.com//woodworking/cyclone/Links.cfm

5. 
   jafre | Apr 15, 2006 01:46pm | #13

   With my piping background and the "Murphy Universal Rule", I would suggest that you put a clean-out at the end of the main. I would use a 45 there also as it is hard to get any type of snake around a 90. Even though it is poured in, build it to service it  (remember Murphy). For lay-out purposes on 45 offsets, measure the center to center of both pipes X 1.414. Subtract the distance on both ends from the center line of the fitting to the "make-in" point on the fitting to arrive at your end to end measurement for the pipe.

6. 
   cadiddlehopper | May 25, 2006 11:05pm | #14

   The answer is "Of course not." What may be wrong is that moving your saw elswhere should you wish is more difficult in which case you would probably drop a line from the ceiling anyway. It will certainly require some careful advanced planning, at any rate.

   I have a 2nd floor shop (wood floor) with collector below. I would have all my ducting below the floor if I didn't have to cut so many holes in it and if it didn't make my shop layout so permament. After all, the collection ports of over half my tools are near the floor as are most small dust collectors' intakes. My shop has support posts in it also. The table saw duct runs down one of them. It is in the way of saw operations. If I move the saw by using a longer hose, I create a trip hazard &/or motion impediment. We all have our problems! LOL!

   Cadiddlehopper