DC duct question

[John Miliunas]

I believe I read (probably here on SMC!) that one should install the blast gates as close to the main run as possible. Given that, can a guy come off the supply Wye straight into a blast gate and then continue with the run to the machine? Or, would it be more beneficial to have the gate closer to the machine, preferably just before any reduction in duct size? I have far too many machines with 4" ports, which don't lend themselves to easy modification to 6", so I figured go 6 until just before the 6>4 reducer. I plan on taking the big duct right down to the reducer and only then use short pieces of coiled hose. Am I thinking in the right direction? :cool:

[John Weber]

John,

I believe that is correct in an ideal world the blast gates would be just off the main line. But it more important that they be used, so if you have a hard to reach line, you might be inclined to leave it closed for a cut or two – thus negating the dust collection all together. Most all my gates are in the vicinity of the tools the belong to. Some right off the wye, some just before the tools. I’m sure it’s against he dust collection gods, but I would put the gates where they are easiest to use, all things being equal near the main line being better. As for the reducers, reducing as late as possible makes sense, but you have a heck of a system, so you have a little leeway.

John

[Terry Hatfield]

John,

I would/did place the blastgates close to the machines. They will be much handier to get to there than at the wyes. If you can place them close to the wye off the main branch, you could benifit from less "dead" duct, but I really don't think it's a very big deal.

I still vote for placing them where they are easy to get to. Definetly run 6" as far as you possibly can. There is a BIG difference in the 6" and you will gain the most from it by having as much of it as you can.

Which tools is it that you are not able to increase to 6" hoods? Maybe I can be of some help on this issue as I changed almost all my stuff to 6". It really is worth doing if there is any way you can.

Terry

[John Miliunas]

John,

I would/did place the blastgates close to the machines. They will be much handier to get to there than at the wyes. If you can place them close to the wye off the main branch, you could benifit from less "dead" duct, but I really don't think it's a very big deal.

I still vote for placing them where they are easy to get to. Definetly run 6" as far as you possibly can. There is a BIG difference in the 6" and you will gain the most from it by having as much of it as you can.

Which tools is it that you are not able to increase to 6" hoods? Maybe I can be of some help on this issue as I changed almost all my stuff to 6". It really is worth doing if there is any way you can.

Terry

Thanks for the input, guys! I'm going to make every effort to try and combine both, effectiveness AND convenience. I'm thinking of maybe even keeping all of them on the main wye's, up near the ceiling, but then putting extension rods to engage/disengage them for convenience. Guess I'll see when the fittings and gates get here.

As for the machines in question, there's the Dewalt planer, the Jet belt/disc sander and the Ryobi OSS. Both the planer and belt/disc sander don't appear to have enough flat area to modify either, plus the planer already has a blower-assisted chip extraction feature. The Ryobi only has (I think) a 2-1/2" port, which I have a 4" reducer going to it already. *No* room for anything else on that puppy! There are two items I'm contemplating mods for: 1) The Grizz 6" jointer, as I think I have enough sheetmetal to work with. 2) The Bridgewood table saw, though I hate the thought of hacking into a brand new cabinet! I'm thinking I may hold off and see how well it does with the 4" in conjunction with the Excalibur overhead guard. I'm planning on adding in a router table to the future outfeed table on the TS and figured I'd use a 6" starter flange under that puppy. BTW Terry, it was YOUR inspiration which has led me to the way I'm setting up my CMS collection. I still have some more sheetmetal shroud to add on, but I think it will work nicely. Thanks! :cool:

[Terry Hatfield]

John,

Sounds like you have it under control. I'm looking forward to some pics and hearing your opinion of the system.

Terry