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I've been working on this for a few weeks now off and on and finished it today. This is for my Hornady L-n-Load Projector press but may be able to work on other screw type metering powder dumps.
I didn't look too much into detail about the powder micrometers you can buy, but I do know that there is one for a rifle, and one for a pistol. I didn't see a reason for this so I decided to make my own, it can dispense anywhere from 0 to 70 grains, depending on powder, with minute changes and repeatable measures.
Plus, I just have fun making things! (and getting paid for it at work...shhh)

First off I used the fallowing tools/machines in the process: lathe, drill press, grinder, drills, taps, dies etc. Without these items this wouldn't of turned out so well.

Second, I had a perfect micrometer to use as the donor mic for the project. The micrometer I sliced up was an old General brand 0-1" micrometer. It was perfect because it had a very simple way to zero out the mic, just loosen a set screw at the bottom, and move the mic reader till it is at the desired length, then tighten the set screw back against the standard. This will make zeroing the mic a breeze when it comes time to install it. It was also aluminum construction so machining was easy.

Also be advised, I am not a machinist!

Just a pic of how the micrometer breaks down, the Mitutoyo would not have worked for this
m1.jpg

Here we go. All my pics are finished pictures so bear with me.

1.
Cut off the big "C" part of the micrometer, making sure to leave enough material that the area will clean up to .500" when turned on the lathe. Unscrew the reader off the mic and chuck it up in the lathe so you can cut the top to around .495" . Next take a 1/2"-20 UNF die and thread the end of the mic so it will screw into the coupler of the powder dump. Don't thead it all the way, I stopped about 1/8th inch from the bottom so it would tighten into to coupler, not just keep screwing in.
m2.jpg
 

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Discussion Starter #2 (Edited)
2.
So now screw the micrometer into the coupler, make sure it seats (further than the picture..)

m3.jpg

Then I drilled and tapped a spot for a set screw on the top of the mic. When tightened this will lock the mic from screwing in or out during loading, that would be bad. I picked this spot for the set screw because it passes though the coupler and the top of the mic, then tightens onto the mic tang which stops it from turning. It also stops the mic body from turning in the coupler, also important for good readings.
m4.jpg
 

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Discussion Starter #3 (Edited)
3.
Next onto the plunger.
So this was the trickiest part. I cut the plunger off so it had about 1.5" of threads left. I then screwed it into the coupler (before the mic was screwed into it) and then used the round jam nut to jam the coupler on the screw. Now You can chuck this assembly up in the lathe and drill and 1/4" diameter hole in the screw, the size of the micrometer tang, making sure the .250" diameter is held tightly, if not the plunger will bind in the dump upon turning the micrometer.

In this picture you can see the hole drilled, but I ground the threads off already, thats coming.
m6.jpg

Next I will cut the plunger shorter, I cut mine so it had 1-1/8" of threads left. Then I ground the threads off by hand with a bench grinder so when you unscrew the mic it can be retracted back into the coupler without interference.

m5.jpg

Then, I drilled and tapped the plunger for a set screw, about 1/4" from the end. This will tighten on the tang of the mic, so when the reader is turned, the tang turns, which is connected now to the plunger by the set screw, so the plunger turns.

m7.jpg
 

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Discussion Starter #4
4.
Final assembley.
Screw the micrometer reader into the the mic body so the tang sticks out of the mic body.
Push the plunger onto the tang and seat it to desired length and tighten the set screw onto the tang.
plunger not seated here, just starting in
m8.jpg

A little red paint to match the press and done!
final.jpg

press.jpg

I set my zero at the point where I can't screw the plunger in anymore because it's bottoming out in the dump. So I can return to that point, recheck and recalibrate
I have 7/10ths of an inch of metering adjustment now, hence 0 to about 70 grains, I could get more but doubt I will be dumping more than 30 grains very often.
 

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Now that is innovation at it's best!
 

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Wow that is awesome! I will make this a stickey.
 

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That's a really well designed measure.
I'm still going to do it the old fashioned slow way.
I'm going to measure my powder by weight. My scale will get me down to 1/100th of a gram.
Most scales only go down to 1/10th and aren't accurate enough for me.
When you're building a load to 6.8 gr. How accurate, and how much error can you have if your scale only goes down to 1/10th of a gram? What's the error alloted in the scale design?
You could be as far off as .7 grams on either side if your scale is zeroed incorrectly, or within .4-.5gr. regularly, depending on how you read the tip of the scale needle. Plus figure in the error that's inherant in the scale. Powder throwers seem to be pretty accurate and consistant too.
At least your micrometer scale will be consistant, especially for somebody as accurate as you show yourself to be.

Regards,
Gregory
 

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Really nice job...just one more reason to miss my lathe...
 

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Seems pretty detailed. I have two questions...
1) Did you keep track of how many hours it took to make this?
2) Taking time & materials into consideration, how much would this thing cost if you were to market it?


Sent from my Commodore 64 running Windoze 95
 

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It's nice
 
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