Receiver Measurements

Mauser720 · 11-21-2009, 10:27 AM

Hi Postino -

You are definitely on the right track! I was hoping you would jump in on this topic since you are a machinist.

Now if I understand your measurements, of the five receivers you miked, the variation in the measurements from the thickest to the narrowest is only .084 of an inch. Right?

Now each one of these measurements is valuable, because it shows what was created at a certain time and for a certain purpose.

For example, suppose that someone shows up with a 1914 DWM LP08.

You have already shown that a typical Imperial Luger will have a measurement of .875 inch. (And you don't have to use inches, but for purposes of this discussion that's what we'll use.) Now if someone took a 1915, or 1916, or 1917 DWM and ground the date off somehow, it would have to remove some of the original metal and it would have to result in a reduced measurement too. Then the date 1914 would have to be stamped on it. In this example, regardless of how professionally the actual date was removed, and regardless of how professionally the new 1914 date was applied, you would still have a receiver measurement that was below what is "normal."

And this in combination with other factors, would be an aid to determining whether the gun had been boosted or was a fake, etc.

And the value of this technique might not be limited to just changed dates either. Any Luger which had a controversial crest applied to the receiver would be a candidate for this measurement, etc.

If someone is already using this measurement to evaluate Lugers, then I would be interested in hearing more about their experiences.

It would take someone like Postino who knows how to use a micrometer and has the patience to track down and record the measurements before we could begin to draw some conclusions. You would want to take a sufficient number of measurements so that you could have some confidence in the averages for a particular year, etc.

Unless someone is already doing this, then at this point it is just an idea that has yet to be developed.

Neil Young · 11-21-2009, 11:45 AM

Maybe this would be a good project to request data from others who are proficient with micrometers, or at least have micrometers--it's not that hard to do. You could then build a data base and perhaps key the measurements to particular variations. We all don't have the drawings, so if you can, post a drawing showing exactly where to measure. Interested?

sheepherder · 11-21-2009, 08:16 PM

Quote:

Originally Posted by lnstumpy@msn.com

We all don't have the drawings, so if you can, post a drawing showing exactly where to measure.

How 'bout a pic showing where I measured???

"A" is the measurements in post # 12 above...

"B" are these measurements, taken from the barrel hood to the bottom of the receiver lug...

comm, 86434: "A"--.872"; "B"--0.966"
1937, 3649: "A"--.885; "B"--.976" [S/42]
comm, 6782n: "A"--.878"; "B"--.972"
Finn?, 77z: "A"--.873"; "B"--.965"
1917, 8514: "A"--.874"; "B"--.970"

This is a better area of measurement; I believe the lug is held to higher tolerances than that area under the hood...

...And the "B" variance from least to most is only .011"...

sheepherder · 11-21-2009, 08:18 PM

I used a Starrett dial verniers for this little test...here's pic of my measuring...

sheepherder · 11-21-2009, 08:26 PM

I have several 1" micrometers (well, who doesn't?

) but I prefer the dial verniers...they're easier to use...

If anyone is going to make up a database for these measurements, I'll do a better job with my 5...Serial # link to measurements at least...and measure 5 times & take the average...

Now...Why would anyone grind anything off the chamber hood??? I thought the idea of faking was to *add* characters to the receiver...crossed rifle, skull & bones, any date to a commercial...

What would you grind off??? A year date??? Why???

I don't think whipping out a mic at a gun show and measuring a Luger is a good idea...It's sure to get ugly...and will draw a crowd like blood draws sharks...Even if the guy you're talking to is agreeable, the guy two tables over with a boosted Luger will complain about it...

Neil Young · 11-22-2009, 07:39 PM

Gentlemen:
My measurements are as follows:

"G" date, 7158a: "A"--0.875"; "B"--0.969".

BYF42, 3732f: "A"--0.871"; "B"--0.968".

Neil Young

sheepherder · 11-22-2009, 10:27 PM

OK: I went back and re-measured all five of mine...This time I made sure I was *not* measuring across a date, or a number on the lug, or across a dent or ding...and I got several different measurements...so the letters/numbers and any dings or dents will affect the accuracy of the measurements...

I also made sure I was as close as perpendicular to the horizontal plane as possible...I noticed that if I went just a bit off 90º that the measurement would change...

The receivers are "fatter" on the sides than on the top/bottom...So the least measurement will be 90º from horizontal...or straight up & down...That's the one we want...

sheepherder · 11-21-2009, 07:13 PM

Quote:

Originally Posted by Mauser720

Now if I understand your measurements, of the five receivers you miked, the variation in the measurements from the thickest to the narrowest is only .084 of an inch. Right?

Uh, no...(Hopefully, Ron will double-check me on this

)...It's only .013" of an inch variance from least to largest...

.885" [largest] minus .872" [smallest] equals .013"

11-21-2009, 10:27 AM	#1
Mauser720 User Join Date: Aug 2007 Location: Kansas Posts: 535 Thanks: 18 Thanked 49 Times in 33 Posts	Hi Postino - You are definitely on the right track! I was hoping you would jump in on this topic since you are a machinist. Now if I understand your measurements, of the five receivers you miked, the variation in the measurements from the thickest to the narrowest is only .084 of an inch. Right? Now each one of these measurements is valuable, because it shows what was created at a certain time and for a certain purpose. For example, suppose that someone shows up with a 1914 DWM LP08. You have already shown that a typical Imperial Luger will have a measurement of .875 inch. (And you don't have to use inches, but for purposes of this discussion that's what we'll use.) Now if someone took a 1915, or 1916, or 1917 DWM and ground the date off somehow, it would have to remove some of the original metal and it would have to result in a reduced measurement too. Then the date 1914 would have to be stamped on it. In this example, regardless of how professionally the actual date was removed, and regardless of how professionally the new 1914 date was applied, you would still have a receiver measurement that was below what is "normal." And this in combination with other factors, would be an aid to determining whether the gun had been boosted or was a fake, etc. And the value of this technique might not be limited to just changed dates either. Any Luger which had a controversial crest applied to the receiver would be a candidate for this measurement, etc. If someone is already using this measurement to evaluate Lugers, then I would be interested in hearing more about their experiences. It would take someone like Postino who knows how to use a micrometer and has the patience to track down and record the measurements before we could begin to draw some conclusions. You would want to take a sufficient number of measurements so that you could have some confidence in the averages for a particular year, etc. Unless someone is already doing this, then at this point it is just an idea that has yet to be developed. __________________ Mauser720 - Ron "Those who do not know history are doomed to repeat it."

11-21-2009, 11:45 AM	#2
Neil Young Lifer Lifetime Forum Patron Join Date: Jun 2008 Location: Scottsboro, Alabama Posts: 552 Thanks: 567 Thanked 449 Times in 170 Posts	Maybe this would be a good project to request data from others who are proficient with micrometers, or at least have micrometers--it's not that hard to do. You could then build a data base and perhaps key the measurements to particular variations. We all don't have the drawings, so if you can, post a drawing showing exactly where to measure. Interested? __________________ Neil The hurrier I go the behinder I get. Sometimes it takes me all day to get nothing done.

11-21-2009, 08:26 PM	#5
sheepherder Lifer Lifetime Forum Patron Join Date: Feb 2009 Location: ...on the 'ol Erie Canal... Posts: 8,208 Thanks: 1,425 Thanked 4,474 Times in 2,343 Posts	I have several 1" micrometers (well, who doesn't? ) but I prefer the dial verniers...they're easier to use... If anyone is going to make up a database for these measurements, I'll do a better job with my 5...Serial # link to measurements at least...and measure 5 times & take the average... Now...Why would anyone grind anything off the chamber hood??? I thought the idea of faking was to add characters to the receiver...crossed rifle, skull & bones, any date to a commercial... What would you grind off??? A year date??? Why??? I don't think whipping out a mic at a gun show and measuring a Luger is a good idea...It's sure to get ugly...and will draw a crowd like blood draws sharks...Even if the guy you're talking to is agreeable, the guy two tables over with a boosted Luger will complain about it... Last edited by sheepherder; 11-21-2009 at 08:31 PM. Reason: wrong icon

11-22-2009, 07:39 PM	#6
Neil Young Lifer Lifetime Forum Patron Join Date: Jun 2008 Location: Scottsboro, Alabama Posts: 552 Thanks: 567 Thanked 449 Times in 170 Posts	Gentlemen: My measurements are as follows: "G" date, 7158a: "A"--0.875"; "B"--0.969". BYF42, 3732f: "A"--0.871"; "B"--0.968". Neil Young __________________ Neil The hurrier I go the behinder I get. Sometimes it takes me all day to get nothing done.

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