Tubing question

[Phil Thien]

Hi.

My mini CNC router never really had any sort of dust/chip collection. I added something simple and it worked surprisingly well, but with the machine having moved to my basement, I decided I need something better.

So I have a concept for a dust shoe but the concept requires that a piece of polycarbonate tubing with a 1" O.D. slide easily inside another polycarbonate tube with a 1" I.D.

Think of a piston and cylinder and in my case both are pieces of polycarbonate tubing, I need the smaller 1" O.D. tube (piston) to move freely within the larger tube with 1" I.D. (cylinder).

I'm not sure if tubing is sized this? I suspect if I order the two pieces that the smaller piece won't fit inside the larger piece or if it does it will be quite tight.

Any ideas if the smaller tube will slide easily within the larger?

[John McClanahan]

Are you trying to make a floating dust shoe? I thought of doing that, but finding floating dust shoes on the internet was rare, so I figured the floating concept didn't work well.

John

[Phil Thien]

Are you trying to make a floating dust shoe? I thought of doing that, but finding floating dust shoes on the internet was rare, so I figured the floating concept didn't work well.

John

Yep, that is exactly what I'm attempting!

For my machine, a floating shoe will actually be quite a bit easier to implement than one that doesn't float, so I'm going to give it a shot.

[Jamie Buxton]

McMaster-Carr has rather detailed specs on their polycarbonate tubing. They'd sell you 1" ID tube, and 1" OD tube, but the tolerance on the dimensions is .05". That is, you could well get tubes that don't telescope freely, or maybe they do.

Could you buy the interior tubing, and make the exterior part to fit? You could bore a hole through something convenient -- like wood -- to make the exterior part. With care, two parts would telescope pretty well. There are wood drill bits which are adjustable -- for instance http://www.amazon.com/Irwin-45002-Lockhead-Adjustable-Wood/dp/B00004YO6Y

[Phil Thien]

McMaster-Carr has rather detailed specs on their polycarbonate tubing. They'd sell you 1" ID tube, and 1" OD tube, but the tolerance on the dimensions is .05". That is, you could well get tubes that don't telescope freely, or maybe they do.

Could you buy the interior tubing, and make the exterior part to fit? You could bore a hole through something convenient -- like wood -- to make the exterior part. With care, two parts would telescope pretty well. There are wood drill bits which are adjustable -- for instance http://www.amazon.com/Irwin-45002-Lockhead-Adjustable-Wood/dp/B00004YO6Y

Yeah, the first thing I checked was the McMaster specs. The question I have I guess is whether tubing is normally designed to telescope? That is, does one size typically telescope within the next larger size? I kind of doubt it but I figured maybe that would be something the manufacturers shoot for, and the tolerances for individual pieces don't reflect this attribute. Highly doubtful, but...

Due to the way this would attach to my Z, it would be best to use the round tube. But I may need to resort to another method.

Hmmm...

[Brian W Smith]

Does it have to be plastic?Just sayin.....exhaust tubing(automotive) is pretty easy to work with?

[Phil Thien]

Does it have to be plastic?Just sayin.....exhaust tubing(automotive) is pretty easy to work with?

It doesn't need to be, it just simplifies things for me.

So I did some checking and it appears that a tube with 1" O.D. will not simply slip into a tube with a 1" I.D.

If there is too much play I will add some bushings to the ends of the larger pipe to keep the smaller pipe more centered. It may not even be a problem. But I've ordered some materials and I guess we will see how it works out.

[Brian W Smith]

All I know is that plastic work hardens over time.....at least every bit of it we've used.Metal,when kept in the same environs as plastic........dosen't change.Go find a hot-rod shop that bends and fabricates custom exhausts.They'll usually have exactly what you need in anything 3" and under.......Heck,even in our shop,we have the ability to swage tubing,just sayin?

[Phil Thien]

All I know is that plastic work hardens over time.....at least every bit of it we've used.Metal,when kept in the same environs as plastic........dosen't change.Go find a hot-rod shop that bends and fabricates custom exhausts.They'll usually have exactly what you need in anything 3" and under.......Heck,even in our shop,we have the ability to swage tubing,just sayin?

I did a little googling and the smallest exhaust pipes I'm finding are 1.5". Do you guys work with anything smaller than that?

[Brian W Smith]

Yup,but what we use(headers)"may" be a touch out of your price range,haha.Google foo Burns Stainless Steel.....we normally use 304 SS,but for your application see what they can do with Aluminum....I think they have some small diam stuff.And for a price......they can run a flow program(but don't quote me on that,I know they do it for header engineering)?They are a premier supplier in header world......their "merge" collector is what we base our WW'n DC,system parts on BTW.

[Jerry Bruette]

Could you use a bellows? If you do a search for bellows on McMaster-Carr they have all sorts of round bellows.