I use PVC Air Hose. From my friendly neighborhood hardware store.
Looks like these.
http://www.merlett-pvc-hose.co.uk/images/911010_1.jpg

I also use 4". The 6" price is just too expensive to swallow...

Sorry if this is long. I started with 4" (20 some foot) the whole way. Was not adequate. Then I started testing. With 6" trunk and necking down to 4" at the Y car, the velocity increased as well as the CFM. I preferred the higher velocity at the shoe to help with collecting the fines. I have the Pentz cyclone 20 ft from the machine. I used a 6" trunk line with a short piece of flex between the cyclone and the 6" sewer and drain pipe to reduce noise transfer. At the side and center of the machine I transition to 6" flexible duct. This duct runs to then Y car where I taper down to 4" pipe to the shoe. My shoe is independent of the Z. With 6" the status discharge is large so Spiral wrapping and grounding is a must.
In short. 6" as far as you can before going to 4" smooth pipe. If you goto flex 4", the CFM drops dramatically.

I will post a picture later.

Smooth as much as you can, and gentle curves. When you use flex hose, use it for a little distance as is practical. Movable solid joints are possible, but get uber-expensive. Somewhere I saw (in the archives or in another site) one guy that made/used solid with one movable joint that made effectively a swinging crane over the top of the CNCRouter, and only used about 4 to 6' of flex to go from the swing arm down to the router head. Pretty awesome but complex.

Not saying that is what you or anyone should do, it was just a great build. Personally, going a bit simpler makes sense to me.

See here: http://www.mechmate.com/forums/showt...&postcount=309 and then later on on post 509. Not as complex as it looks, the supporting gantry is just some angle iron and solid rod, a lasy susan bearing and a bit of creativity, the pipes are standard 110mm drain pipe - the rotating coupling is very simple with the rubber seal removed from one side of the lower elbow so the pipe fixed to the upper elbow can rotate - works very well and didn't cost much (I'm too cheap to pay big bucks :) )

That was the gantry mechanism I saw. Alan, thanks for finding it! I still think it is a great project!

I remember that. That was a nice design.

I would have liked to had the option for the hinge pipe but I have metal structure tie rods at the height of 75" from the floor. I had to opt for flex. I trimmed out all the extra junk so you can see only the desired result. The best thing is the flex right before the cyclone and the flex right after the blower into the sound deadened box (not shown) reduces the sound to a very manageable level.

Pete I'm interested in how you made your adjustable shoe adjustable. Do you have pics of that posted anywhere? I've made several shoe configurations and have not been satisfied by any of my approaches. The nice thing is I have a Mechmate to assist with fabrication, ha ha.

Hmm
Questions:

I am looking into that, if I can built me a boom on the machine. But here I see people using straight parts of PVC tube, elsewhere I read one should never use that in dust collection... cause of static ( fire hazard icm with lots of air and fine dust ) and also dangerous to explode on impact of debree ?

...due to my alternative Z and the grizzly alternative I use I might not be able to do this approach, what if I would start with 4" flex and do the reduction to 3" pipe is the higher flow due to the stepdown or is the 4" just too small ?

If you are a member of Fine Wood Working or have access to issue 153 - PVC pipes are discussed in respect of using them for dust extraction: http://www.finewoodworking.com/works...-debunked.aspx

There are some good writings on Bill Pentz's site ( billpentz.com ) on various kinds of pipes for dust collection. I would use that as close to a canonical source.

http://billpentz.com/woodworking/cyc...#pvc_confusion

From all I read, PVC seems safe. Some wrap a continuous piece of bare wire around it 'slowly' (think 1 wrap per joint of pipe) with a wood screw near each connector on the 'top' side (to keep wood chips from sticking as they go by, and it doesn't need to protrude much, a quarter to 1/8 inch - 3 to 5 mm? - but on the outside it should be attached to the ground wire. The PVC should have the wire attached to earth ground a one end (keeps from having ground loops - a bad thing).

But there are many thousands of feet of PVC being used today without incident without the anti-static protection.

All that said, I have seen NO documented instances of wood shaving or chips catching on fire due to PVC collection ducts.

The big thing is to run enough air to keep the dust and chips flowing - at least that is what I am told.

(Summary of BIll's site on using PVC: Use PVC pipe, not sewer/drain tile because the sewer/drain tile is not smooth inside. PVC pipe is. He still prefers spiral wound smooth metal, but PVC is a much more affordable alternative for those on a budget.)

Jack,
ASTM D-2729 (Sewer & Drain) is PVC, just not Sch 40 more in line with Sch 10. You can find S&D in Styrene but he recommends ASTM D-2729.

Fox,
Spiral wrap with aluminum tinsel (hard to find) or Aluminum Foil folded into 2" wide strips, make wraps less than a foot apart.

Reference Section 5 on http://billpentz.com/woodworking/cyclone/ducting.cfm

thnx guys. Parts ordered.

Forgot to post a picture of this.

https://farm4.staticflickr.com/3927/...aba31062_c.jpg
2.2kW spindle , on Flickr

Talk about an explosion, wow!!

That's the great thing about building your machines, you can take them apart for repairs as well. Nice example. And you have even built some custom tools to make it happen.

BTW, Since we started discussions tomorrow I contacted Bill Pentz about a broken link. Since then I found he is updating his site and many of the updates are online and more on the way.

All that said, if you read his site some time ago (like I did), it might be time for a re-read to see if he found something new.

The re-reading reminded me about the difference between chip collection (important) and fine dust collection (more important). Something we should all consider carefully for our own and family health.

Ok, off my soap box now!

Good point Jack. Bill is a great guy. I spoke with him a few times and corresponded through email also. He really does a great service to us that are uninformed.

Nothing fancy here. Started this a while ago. We needed a holder for the extra parts for the super spacer we have at work. So I got a 2" piece of delrin and cut in the appropriate shapes and holes.

Tomorrow I start on Halloween silhouettes

https://farm3.staticflickr.com/2950/...187876d57d.jpg
Super spacer accessory holder

What is a super spacer?

It is a combination of a rotary table and a indexing head. See Here http://www.mscdirect.com/product/details/09150558

They come with a 3 jaw chuck and a flat table. You can mount either one you wish at any time but the chuck is usually mounted and pictured. By disabling the worm gear that is for setting the degree of rotation manually you then can put in indexing plates the allow only a certain number of positions to be rotated to by releasing a locking dog and snaps in when you manually turn the chuck and it reaches the index location.

First try, gave to neighbor kids.

2 of them are from Dave Lowe

https://farm4.staticflickr.com/3953/...0964dd16_c.jpg
Silhouettes , on Flickr

Some after photos

https://farm4.staticflickr.com/3931/...8625843c_c.jpg
Candle , on Flickr

https://farm6.staticflickr.com/5598/...6603b98a_c.jpg
Window Shot, on Flickr

And the next batch

https://farm4.staticflickr.com/3949/...3df00bce_c.jpg
More Cutouts , on Flickr

They are awesome Pete, well done :)

Nicely done Pete, but....Mummmm....those cookies look even better.... :p

The cookies are! Halloween was always a big decorating holiday when I was kid. Somewhere along the way I forgot that. I am trying to make sure the kids get to have as much fun with it as I did. It is hard though to find the classic stuff though. Everything now it a one season use item.