Stainless Steel "needles" or tubing --

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Stainless Steel "needles" or tubing --

Joined: October 22nd, 2009, 11:44 pm

April 5th, 2018, 11:58 am #1

I would like to use tubing, etc smaller than 1/16 " brass tube and rod for pitot sensors, etc. Apparently these may be available from Micro Mark.

Do any of them fit inside another to simulate the two diameters seen in most units ?

How do we cut them ?

Thanks for any thoughts and experience, George
Last edited by blueangelmodeler on April 5th, 2018, 11:58 am, edited 1 time in total.
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Joined: July 8th, 2008, 10:57 am

April 5th, 2018, 12:36 pm #2

using hypodermic needles. They come in many sizes and are inexpensive, at least where I am. I sometimes use a needle with a length of brass wire inside it for the stepped effect. I cut them with a good pair of wire cutters; putting a wire inside while cutting prevents crushing.

Stuart
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Joined: October 19th, 2006, 11:28 am

April 5th, 2018, 12:37 pm #3

I would like to use tubing, etc smaller than 1/16 " brass tube and rod for pitot sensors, etc. Apparently these may be available from Micro Mark.

Do any of them fit inside another to simulate the two diameters seen in most units ?

How do we cut them ?

Thanks for any thoughts and experience, George
I have a large collection of hypodermic needles of various sizes that I have used for many modelling applications, including pitot tubes, as part of landing gear oleos and as gun barrels. I don't know how easy it is to obtain in all countries, but here in South Africa any of the large pharmacy chains will sell them in singles and you get them in a huge variety of sizes from tiny insulin needles all the way to needles with a diameter just below 1/16". A single needle only costs a few cents.

Their diameters are given in gauge, so here is a list of what you can typically find:

15G = 1.45 mm
18G = 1.02 mm
19G = 0.91 mm
20G = 0.81 mm
21G = 0.71 mm
22G = 0.64 mm
23G = 0.58 mm
26G = 0.404 mm
Insulin:
27G = 0.361 mm
29G = 0.287 mm
I believe you get even smaller.

Not all sizes fit perfectly into the next size but it is generally very close.

Of course, these are stainless steel and therefore pretty hard (which also means your chances of accidentally bending your pitot are very small). I cut them using a fine cutting disc on a Dremel tool - I really haven't found any alternatives that give me the same clean cut as a Dremel. You can do some clean-up with a needle file by hand if needed, but on the insulin needles in particular you can accidentally bend them if not careful when working them by hand, so I prefer doing everything with a machine tool and a very soft touch.

It goes without saying not to use second-hand hypodermic needles...
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Joined: February 27th, 2005, 12:19 am

April 5th, 2018, 2:12 pm #4

I would like to use tubing, etc smaller than 1/16 " brass tube and rod for pitot sensors, etc. Apparently these may be available from Micro Mark.

Do any of them fit inside another to simulate the two diameters seen in most units ?

How do we cut them ?

Thanks for any thoughts and experience, George
Try these, available in the USA from Sprue Brothers

http://store.spruebrothers.com/category_s/2053.htm

Micro brass and nickel tubing is well down the long list of their products.

Shane
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Joined: May 19th, 2013, 2:26 am

April 5th, 2018, 2:37 pm #5

I would like to use tubing, etc smaller than 1/16 " brass tube and rod for pitot sensors, etc. Apparently these may be available from Micro Mark.

Do any of them fit inside another to simulate the two diameters seen in most units ?

How do we cut them ?

Thanks for any thoughts and experience, George
I bought some hypodermic needles in various diameters from an outfit called Small Parts. They had a very comprehensive catalog of small parts (get it) and you could get tubing in graduated sizes that would fit inside another tube. Last I know they stop publishing a catalog a long time ago cuz I certainly haven't gotten any but I believe the outfit moved to selling on Amazon. I don't know if they're still there or not. I never had luck cutting tubing with side cutters or sprue cutters. I would always get the end crushed down, so I went to cutting it with a Dremel tool with a cut off wheel. It worked fine for me as long as I held one end of the tube with a pair of pliers, so I wouldn't cut my fingers up.

Cheers
Max Bryant
Last edited by takenname1 on April 5th, 2018, 2:40 pm, edited 1 time in total.
Cheers,
Max Bryant

"You'll Love My Wingnuts!"
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Joined: March 9th, 2012, 4:57 pm

April 5th, 2018, 2:53 pm #6

I would like to use tubing, etc smaller than 1/16 " brass tube and rod for pitot sensors, etc. Apparently these may be available from Micro Mark.

Do any of them fit inside another to simulate the two diameters seen in most units ?

How do we cut them ?

Thanks for any thoughts and experience, George
Information not shared is information lost.
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Joined: February 26th, 2005, 11:35 pm

April 5th, 2018, 3:02 pm #7

I bought some hypodermic needles in various diameters from an outfit called Small Parts. They had a very comprehensive catalog of small parts (get it) and you could get tubing in graduated sizes that would fit inside another tube. Last I know they stop publishing a catalog a long time ago cuz I certainly haven't gotten any but I believe the outfit moved to selling on Amazon. I don't know if they're still there or not. I never had luck cutting tubing with side cutters or sprue cutters. I would always get the end crushed down, so I went to cutting it with a Dremel tool with a cut off wheel. It worked fine for me as long as I held one end of the tube with a pair of pliers, so I wouldn't cut my fingers up.

Cheers
Max Bryant
http://www.smallparts2.com/Product-Categories.html

http://www.componentsupplycompany.com/h ... chart.html
Last edited by HubPlott on April 5th, 2018, 6:17 pm, edited 1 time in total.
If anything in the above post offends you, I suggest you grow a thicker skin!
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Joined: March 24th, 2005, 3:01 pm

April 5th, 2018, 4:40 pm #8

I bought some hypodermic needles in various diameters from an outfit called Small Parts. They had a very comprehensive catalog of small parts (get it) and you could get tubing in graduated sizes that would fit inside another tube. Last I know they stop publishing a catalog a long time ago cuz I certainly haven't gotten any but I believe the outfit moved to selling on Amazon. I don't know if they're still there or not. I never had luck cutting tubing with side cutters or sprue cutters. I would always get the end crushed down, so I went to cutting it with a Dremel tool with a cut off wheel. It worked fine for me as long as I held one end of the tube with a pair of pliers, so I wouldn't cut my fingers up.

Cheers
Max Bryant
It's just a little hard to get to. The following at least gets you to the Small Parts-branded products:

https://www.amazon.com/s/ref=sr_in_s_p_ ... mall+Parts

You can then search from there.

Cheers,

Tim
Last edited by timhcampbell on April 5th, 2018, 4:40 pm, edited 1 time in total.
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Joined: June 29th, 2005, 6:06 pm

April 5th, 2018, 6:09 pm #9

seems to be selling 'stuff', not the raw materials that Small Parts had.
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Joined: January 17th, 2008, 12:33 am

April 5th, 2018, 6:41 pm #10

I would like to use tubing, etc smaller than 1/16 " brass tube and rod for pitot sensors, etc. Apparently these may be available from Micro Mark.

Do any of them fit inside another to simulate the two diameters seen in most units ?

How do we cut them ?

Thanks for any thoughts and experience, George
I've ordered fine steel tube from McMaster-Carr:

https://www.mcmaster.com/#

I second using a rotary tool with a cutting disc, to cut the material. If you use a wire cutter or similar too, you will distort the shape of the tubing. However, when I've had that happen, I used a straight pin to restore the tube's circular shape.

As to using second-hand needles, I guess it depends. My mother had to give herself daily shots of a blood thinner, and she saved the spent hypos for me. I took them apart and just stored the needles in a test tube filled with isopropyl. Would I pick up a hypo I found on the street and salvage the needle? No, of course not.
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