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View Full Version : Best way to approach this job?



T.Hoffman
10-13-2011, 09:55 AM
Some people here at work are doing investigations on probes.
And now they came to me to "split one open", well actually what want is to section the probe length-wise to reveal the inside.

Problem is these probes are quite delicate, and small. Outer tip diameter is around .060", probe is stainless of some kind.

http://www.blackfrogmusic.com/pics/temp/probe.jpg

They want to section off the probe up to the main barrel area (that's where it is mounted). The probe is necked down in different diameters toward the tip.

I'm guessing a surface grinder would be the best approach?

Rustybolt
10-13-2011, 10:09 AM
Surface grinder would work. You might want to mount it on another piece of steel, There isn't much there to grab.
I would suggest epoxy and go slow and light to keep the heat down.

T.Hoffman
10-13-2011, 10:11 AM
I was thinking something similar, embedding it in something.

How do you release it from the epoxy once your done?

Rustybolt
10-13-2011, 10:24 AM
heat it up. Put the piece of steel on a hot plate until the epoxy releases. Most readily available epoxys aren't much good past 250 deg F.

Stuart Br
10-13-2011, 11:19 AM
Embedding is the way to go. When I was an apprentice in the aircraft industry, they used to do this for inspection of welders samples for approval. They used a clear two part plastic, which I guess would have been some form of epoxy. From memory these samples were pretty small, only section across a weld. They were sectioned and then polished before etching and subjected to microscopic inspection.

You will have a much bigger challenge in embedding the full length of the Probe and then setting up to ensure you have an accurate section across the full length.

Toolguy
10-13-2011, 11:52 AM
I would mill grooves in a piece of steel with a ball or square end mill that match the diameter of the different steps, one radius deep. Then Loctite or epoxy the part in place and surface grind down till you kiss the holding block.
Then you will be halfway down on all diameters. Each groove can go a little past the transition point of the part.

macona
10-13-2011, 12:02 PM
I would take it down to someone with a wire edm and have them split it down the middle.

Weston Bye
10-13-2011, 12:26 PM
If you were on the other side of the lake I could have x-rayed it for you. That would at least give you an idea what axis to split it.

Boucher
10-13-2011, 02:38 PM
Metalurgical samples are mounted in a clear epoxy then milled, ground and polished and etched. We had a vacuum chamber and would pull it down to get the entrapped air out before the epoxy started to harden. I did this to section bullets to examine jacket thickness. We used a good sharp carbide end mill. Don't remember the brand but they sure worked good for sectioning things like you are working on.