Medical Tubing for Neumann vacuum

[opcode66]

I purchased some of the amber colored medical tubing for the vacuum on my lathe. It is perfect. However the minimum quantity was 50 feet. So, I have about 47 extra feet. If anyone would like a length of hose for their setup let me know. I'll let it go very cheap!

[EmAtChapterV]

What's the inner and outer diameter?

[opcode66]

Ah, yes, sorry, should have posted that.

Tubing, Translucent Amber Natural Latex Rubber, 3/4" ID x 1" OD, 1/8" Wall, 50 Ft. Long

I've tested it last night. Works great! The tubing Al put on my lathe for the carriage was not quite right. It worked. But, it was very heavy. It would actually keep the carriage from moving smoothly if it wasn't settled just right and held tight with zip ties. But, it would inevitably shift and then start affecting the smooth movement of the carriage. This was a problem since at the inner diameter the tube was trying to pull the carriage back to center. Every once in a while this would cause my halfnut to skip and therefore grooves to collide.

[EmAtChapterV]

Awesome. I was just about to special-order some - the stuff I'm using is over a decade old, and drying out and cracking at the ends. I'll take three feet worth. How much are you asking for it, mailed USPS ground to Canada?

[opcode66]

How is $3.50 per foot? $10.50 for 3 feet.

For shipping cost I would need at least a zip code. You can PM me an address if you like.

[concretecowboy71]

I sent you a PM.

[gold]

The tubing Al put on my lathe for the carriage was not quite right. .

The white tubing with the 1/8" wall was very close to the original that Neumann supplied. It is called gum rubber tubing and can be found here. http://www.mcmaster.com/#gum-rubber-tubing/=l1dk49

The tan latex stuff sort of works but collapses with much more than 60vac to the motor. I used the tan stuff but got rid of it when I found the right stuff.

[opcode66]

The pictures I've seen from Neumann have tubing that is not that thick as what I got. If memory serves, the manual even discusses how the tubing should fit inside the metal tubing at the top of the chip jar.

The tubing I recieived would only couple with the top of the chip jar via another piece of rigid plastic tubing between the two. My tube was way to thick to couple on its own.

The thickness caused it to be very heavy and too springy. Therefore, it was pulling on the carriage. The carriage always wanted to settle in about the center of the track. The tubing was literally fighting the pitch motor.

Normally not a problem but every here and there it would cause a skip in playback. While cutting, the halfnut wouldn't catch to the leadscrew temporarily around the inner diameters. This is because of the weight and elasticity of the tubing. The lateral force caused the carriage to resist the pitch motor by popping the halfnut up momentarily. The end result was grooves that would overlap. Always around the same place.

I got around the problem by very carefully positioning the tube. It seemed if I had the tube cable tied with enough twist to it, the force from the spring force/weight of the tube itself was countered, and the carriage moved smoothly. But, I would constantly have to mess with the coupling of the tubing to the metal tube on the back of the suspension box. That is where the cable ties were. If I rotated the tube and tied it down tight it would be fine for a while...

New tubing works great. I've not had it collapse. I turned my variac up to full throttle and let it run for a while.

[gold]

If memory serves, the manual even discusses how the tubing should fit inside the metal tubing at the top of the chip jar.

The original tube was customized by Neumann. They shaved off the wall so it would fit.

[mossboss]

We have used automotive vacuum silicon hose quite successfully
I am sure it is available all over the world
The 19 mm internal seems to fit the tube at the top
At the the other end we have machined a small adapter on the lathe oyt of some solid plastic turning bar
May be the hose can be gouged out but the little adapter took me about 15 minutes to turn on the lathe we have
Here is a link to the hose type and seller in Aus.
http://www.ebay.com.au/itm/Silicone-Silicon-Vacuum-Hose-Tubing-Blue-Red-Black-water-air-tube-hose-/251208061450?pt=AU_Clothing_Merchandise_Media&var=&hash=item3a7d2ad20a
Cheers

[opcode66]

Hey Paul, does your carriage settle where you leave it? Or, does it always want to creep toward the center of the track on its own?

That's that main reason why I wanted to replace the tube to begin with. This stuff seems to be light enough, and not as elastic. My carriage actually stops where I leave it when using the wheel with the halfnut disengaged. And, it is not collapsing. So, problem solved for me. I guess in the long run, everyone's mileage may and typically does vary.

I'm saving the original tubing that Al gave to me.

[gold]

Hey Paul, does your carriage settle where you leave it? Or, does it always want to creep toward the center of the track on its own?

It depends on where the carriage is and how much force I use to move it. If I go slow it pretty much stays put. There are some spots that aren't that smooth. Mostly it will pull in the opposite direction that I am moving the carriage. At the very outer diameter it wants to pull in. At the inner diameter it wants to pull towards the outer diameter.

One of these days I'd like to remove the carriage and give everything a good cleaning. Maybe replace the rubber in the jib.

I'm pretty sure the tube you got is from McMaster-Carr. There were a few original tubes laying around but most of them were cracked and unuseable.