DC ducts - 4" or 6"

[George E. Cawthon]

Been reading this newsgroup for a long time, but selectively. Don't remember Grandma's face. Cheers.

Unisaw A100 wrote:

[Mark Jerde]

Both! One of each! Two of each! Three saws that tilt both ways!

-- Mark

[Roy Smith]

I don't get it. I can understand wanting a left and a right, and it certainly makes sense to have two of each (set up for rip and crosscut), but I don't see what you're going to do with the third of each. Do you really cut that many dados?

[Mark Jerde]

It takes a lot longer to change blades than to cut a piece of wood. If I had the space (I don't) and the money (I don't -- yet) why not leave a TS set up to cut double-sided melamine?

BTW, the scar on my left hand from a kickback accident about 6 months ago is still visible. It wasn't really an "accident" -- I should have taken the time to put on the guard and splitter. But mounting the spiltter & guard on my Grizzly contractor table saw, and aligning them, is somewhat of a PITA. In my "dream shop" I'd have made that cut on the TS with the guard & splitter permanently installed & the accident would never have happened.

-- Mark

[Greg G.]

If I only had the room! I'm still trying to figure out where to put this new 14" bandsaw, and the DIY router table that will replace the plate I'm pulling out of the table saw extension.

But no matter how bad 1/2 (sometimes 3/4) of a two car garage seems, I could be in Silvan's shoes. That gets me all excited again.

Greg G.

[Mark Jerde]

Have you seen this shop?

-- Mark

[Greg G.]

Have you seen the clamp collection?

course , they're NOT Bessy Full-bodies...

Greg G.

[TMDU]

Well, a long, long time ago, back when Israel owned the Sinai Peninsula and Egypt wanted it back, an old granny was flying peace keeping missions in A4s along the Delta line when she switched to pure oxygen. Nowadays, aging pilots just don't wear makeup, hairspray or greasy lipstick when using pure oxygen, face-fires ain't a pretty sight.

[TMDU]

Well, there goes any credibility D&C had....

[Chris Merrill]

Heh heh...that's an easy one: When the "PVS DC grounding" proponents start doing serious research about dust ignition points, static discharge and grounding, one of two things happens:

1) They can't build a good argument, so they give up arguing - but still believe they are right. 2) They become "PVS DC grounding" opponents

;)

[Scrit]

My insurance seem to think that it is - as do the authorities in Europe after a number of injuries in recent years in factories. The scenario seems to run something like this - spark generated in the ductwork (e.g. from a sander, grit from timber, lost carbide tooth, etc.), spark arrives in collector and smoulders in waste, someone knocks out the dust sack (creating a stochiastically viable mixture of air and fine wood dust), air/dust mixture ignites and causes a small explosion which blows the bag off the extractor, the force of this explosion is not enough to harm anyone but dislodges all the dust trapped on beams, tops of machines, etc for many years past, this is turn generates a much larger volume of air/dust which in turn is ignited by the initial explosion..... This can happen in small shops, too, but is probably much more of a problem in commercial environments.

Personally, I'm not so sure any more about the static sparking theory (and if you follow one of the links of Bill Pentz's site you'll find a properly researched paper on the subject by an academic which says just that), but I've heard enough foreign objects striking the ductwork to believe that a fire or explosion in a collector is possible. Never had one myself, but last year we did have a dust sack which had been removed at the end of the working day catch fire.... (luckily outside of the shop)

I'd still tend to earth galv. steel trunking in the same way as I earth strapped our steel roof trusses, gives lightening or shorts and easier journey to earth.

Scrit