Micro Drills - What are the for?

Flow Restrictive Orifices | Lenox Laser Micro Drilling and Machining

Laser micro drilled gas and liquid flow restrictive orifices. Lenox Laser drills flow restrictive orifices using flow calibration or optical measurment.
lenoxlaser.com lenoxlaser.com

I worked with Joe for a couple years when I was at AAI . He did some small holes and built a company around it .
 
I used them for modifying carbs on racing kart engines.
 
Sparweb said:
Another use for very fine drills that's becoming rare but not forgotten are in the models used for wind tunnel tests. To measure pressure on the surface of a wing or a control you need a pressure "tap" hole. These orifices would be very small so that they don't disturb the flow too much - about 0.03" diameter.
On many tests, a grid of these holes were drilled into both the upper and lower surfaces of wings, adding up to dozens of holes to measure the distribution of pressure over the whole surface.

Here's a great example of what they could do with these tests:

Search - NASA Technical Reports Server (NTRS)

ntrs.nasa.gov ntrs.nasa.gov

...in 1931, I might add...
Click to expand...

I spent most of my career at a company that builds wind tunnel models. My first 25 years were as a model maker and I spent many days doing nothing but drilling pressure taps. Typical sizes were from .010 to .030 diameter and from .15 to .30 deep. Materials ranged from 6061 to 17-4, A286, and Vascomax to name a few. Most of the pressure taps were drilled with a Servo drill press, but the holes have to be normal to the surface, which sometimes resulted in some crazy set-ups. Drilling the orifice is just the beginning. It has to have a steel tube connected to it that runs to a device that reads the changes in pressure. Usually that was done by drilling an intersecting hole from a trough that been milled into the surface. That meant drilling a .020 to .060 diameter tunnel that is .01- .02 deep , by hand with a Foredom. BTW, breaking bits is frowned upon.
 
Albrecht makes a sensitive Chuck for these.

It has an arbor you hold in collet and the Chuck has a disk you hold to move Chuck into work.

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I make my own circuit boards - for hobby purposes. I have a tiny chuck that fits into the larger chuck on my bench drill press. The setup is crude but works ok. I go through a lot of tiny HSS drills. The glass-epoxy circuit board substrate eats HSS, and yes, they break very easily. A pack of 12 bits doesn't last long. I think a commercial PCB fabricator must use carbide or diamond?
 
JPMacG said:
I think a commercial PCB fabricator must use carbide or diamond?
Click to expand...

Carbide typically, and more are expanding to laser drilling.

The biggest problem I've seen with tiny drill bits is that the run-out of the chuck is usually a large percentage of the bit diameter.
Cascading chucks likely amplifies this problem.

-brino
 
JPMacG said:
I make my own circuit boards - for hobby purposes. I have a tiny chuck that fits into the larger chuck on my bench drill press. The setup is crude but works ok. I go through a lot of tiny HSS drills. The glass-epoxy circuit board substrate eats HSS, and yes, they break very easily. A pack of 12 bits doesn't last long. I think a commercial PCB fabricator must use carbide or diamond?
Click to expand...
I had an electronics manufacturing business for 22 years and drill a lot of holes in pc boards. HSS worked OK for phenolic boards but glass boards need carbide drills. I still have hundreds of them. They have standardized 1/8" shanks with a collar to ser the tool depth. The smallersizes have carbide drills brazed into steel shanks but some of the larger sizes have solid carbide shanks. I use the broken drills with carbide shanks for scribes. They're great for marking even hardened steel.
 
brino said:
Carbide typically, and more are expanding to laser drilling.

The biggest problem I've seen with tiny drill bits is that the run-out of the chuck is usually a large percentage of the bit diameter.
Cascading chucks likely amplifies this problem.

-brino
Click to expand...
I made a version of a Set Tru chuck for small drills. Actually, two of them. One for use on the mill and another for use in my lathe. In addition to adjusting for radial runout, I could adjust for angular runout. The keyed chuck is a Jacobs 1B and the keyless is a Phase II 220-870
Tru Set Chucks 3.JPG
 
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