Author Topic: How Do I Plug A Hole  (Read 5805 times)

Offline 75Plus

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How Do I Plug A Hole
« on: March 09, 2012, 01:45:22 PM »
I have a shallow hole, apparently bored with a 7mm end mill, that is .056" on the edge of it and .052" in the center. It is in a polished stainless steel article so the plug must be fitted and polished on one side prior to insertion.

Any ideas?

Joe

Offline 75Plus

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Re: How Do I Plug A Hole
« Reply #1 on: March 09, 2012, 06:32:41 PM »
Perhaps I should phrase the question another way. I need a .275" (7mm) disk, .056 thick, with a thinned center on the bottom and a polished surface on the top side. How do I hold such a work piece? The work must be done without access to the article that it is intended for. The article is a thousand miles from my shop.

Joe

Offline pjf134

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Re: How Do I Plug A Hole
« Reply #2 on: March 09, 2012, 11:34:18 PM »
 The way I would do it is machine the O.D. in the lathe, then do the thin center while in the lathe while leaving a stem at the center of the thinned part, then part off to the thickness plus a little extra for finishing and polishing. The stem is for holding either in a hole or by hand until you get the required finish on the polished side. Cut off the stem with a dremmel or similar tool and clean off burr as needed. You could put the stem in the lathe chuck and finish that way also on the polished side. Take light cuts on a thin part is always a good idea. I hope I was clear. I have chucked thin washers like that and machined out center hole with good results many times. If you feel lucky you could face off the finished side in the lathe using a real thin spacer taped to the outside of the jaws and have it stick out enough so the cutter will not hit the jaws and take light cuts.
 Paul
To error is human, but doing it a second time takes a better excuse!

Offline 75Plus

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Re: How Do I Plug A Hole
« Reply #3 on: March 13, 2012, 10:23:05 AM »
Thanks for your reply Paul. Using some of your suggestions and some of my tooling I was able to do the job.

I need to repeat the task and will get pictures and and post it under the "How To" forum when I do.

Joe

Offline pjf134

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Re: How Do I Plug A Hole
« Reply #4 on: March 13, 2012, 10:50:42 PM »
 Joe,
  Which way did you do it, just wondering. Will look forward to the how to post.
 Paul
To error is human, but doing it a second time takes a better excuse!

Offline 75Plus

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Re: How Do I Plug A Hole
« Reply #5 on: March 14, 2012, 10:21:18 AM »
Paul,

After I turned the diameter I stuck a ball end mill in the tail stock and bumped the center for the depression. I then parted it off leaving it about .025" long. Next I bored a short piece of 1/2" aluminum  round stock to 7mm and split the length with a hack saw. This gave me a sacrificial holder. I inserted the part into the holder, placed both in a R-8 collet adapter that I had made previously.





Using a 1/2" collet I closed it tightly and placed the unit in the 3 jaw.

Then, using this depth gauge that I had adapted, I proceeded to reduce the length to the .056" needed.



I removed the adapter from the 3 jaw and moved to the buffer for final polishing.

Job Done!!!

More information on the R-8 adapter and the depth gauge re-purposing can be found here.

http://madmodder.net/index.php?topic=4474.msg49168#msg49168

http://madmodder.net/index.php?topic=5934.msg62600#msg62600

Joe
 

Offline pjf134

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Re: How Do I Plug A Hole
« Reply #6 on: March 14, 2012, 12:04:24 PM »
 Joe,
  I am a little confused on the actual shape of the finished part, and how does that ball cutter come into play. Maybe a pic of the finished part would help me get the idea. I think the bolt thru the parts got me wondering why the hole in the part, I thought there was no hole.
 Paul
To error is human, but doing it a second time takes a better excuse!

Offline 75Plus

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Re: How Do I Plug A Hole
« Reply #7 on: March 14, 2012, 01:42:17 PM »
Paul,

The finished part is 7mm in diameter by .056" thick with a mirror finish on one side. It is made to plug a hole that was bored with a 7mm end mill thus the center of the hole is only .052" deep. That is the reason I bumped the one end with a ball end mill.

Sorry I don't have one of the parts to show but I am jammed up on other work at the present. I will be making more but not sure when. I will post pictures when I have to photograph.

Joe

Offline pjf134

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Re: How Do I Plug A Hole
« Reply #8 on: March 14, 2012, 10:57:55 PM »
 Joe,
  Thanks, I think I get it now, the ball turner got me confused.
 Paul
To error is human, but doing it a second time takes a better excuse!