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Drill holes in thing stainles steel hypodermic tubing

Chrisgr99

Plastic
Joined
Jun 14, 2019
For a product I'm prototyping I need to make some approx. 0.5" long pieces of thin wall stainless steel hypodermic tubing with a small hole drilled in the wall at one end.

Probably I will use .058" OD,.05" ID tubing. The hole needs to be about 0.04" in one wall (about 1 mm). The hole does not need to be extremely accurate as long as it has a large enough opening. The tubes are to carry static air pressure air to pressure sensors.

What would be be easiest and and fastest way to drill the holes? What type of drill? Drill speed? How to clamp the tubing?
 
How about EDM? I suppose you could plunge a small center-cutting endmill/engraver as well. With EDM there is no risk of collapsing the tube with down pressure. If you don't have access to a sinker EDM, you could probably get a tap-burner with a wire electrode to work too.
 
+1 For EDM. I used to work making machines for small, precise EDM holes. Last I knew, they were still in business, but ol' George has gotta be coming up on 70 now.

If you had an interesting project, he would work on existing parts. How many do you need?
 
You could think about a slot rather than a round hole.
A small radius slitting saw sort of cutting tool.
 
I'd use a crazydrill pilot from mikron... They excel at drilling into rounds without walking... A cheaper alternative would be a circuitboard drill from kyocera (or tons of other manufacturers, they're just the ones I'm most familiar with), or finally, MA Ford should have a 305 series drill in your size, they'll be the cheapest option for sure, but they may want a spot drill to keep from walking, where the other drills probably would be fine without a spot.
 
Buddy of mine just drilled some .020 holes through .048? stainless hypodermic tube. He got a .020 four flute center cutting end mill and it did great. He said the cutter came from harvey tool.
 
Might be nice to know what machinery & experience you have at your disposal.

Suggestions are a flyin' and you could be hoping to use a cordless dewalt and
hold the tubing in your fingers....
 
I dont know what machine my buddy has at his work. He did say it has a 4000 rpm max speed and the harvey guys sugested 16000 rpm for the .020 cutter. They gave info on how to make his rpm work. I will see him tomorrow and will ask what machine he used.
 
We used to edm lots of holes of about .005 diameter with a wire edm. Not the wire edm's that you see in many shops but one that feeds a wire through a ceramic guide and the end of the wire burns the hole. My dad was instrumental in developing the technology in the 60's. The holes were in diesel spray tips.
 
We used to edm lots of holes of about .005 diameter with a wire edm. Not the wire edm's that you see in many shops but one that feeds a wire through a ceramic guide and the end of the wire burns the hole. My dad was instrumental in developing the technology in the 60's. The holes were in diesel spray tips.


If you're referring to what I think you're referring to, those are EDM Drills, "hole poppers" in common parlance.
 
For a prototype and one or two parts I'd go to a EDM house with the above mentioned.
This process is very slow to say the least but a quick and easy setup.
The hole takes up a significant amount of the tube size.
Drilling is faster but you will have to build a part nest and that fixture is expensive in one offs.
EDM dills exert no pressure so part holding is simple.
The dia of the hole to the stock bothers me. If a .015 hole I'd be just drill it. Drilling also leaves a burr inside that I'm not sure you thought about.
Light pecking a ballnose endmill either full or as a finish size pass can reduce that burr but some will still be there.
Is it large enough or low speed enough that flow rate is not a problem?
Bob
 
It sounds like all you really need is an OPENING in the wall of the tube. How about getting one of those cheese cutters that cut with a wire. Use medium diamond lapping paste and you should be able to RUB a hole in the side of the tube in no time.Clamp the tube in a very small vise with part of tube sticking out of the side. Use the side of the vise as your saw wire guide. Edwin Dirnbeck
 








 
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