Vern juenke machine

Shielding

Millbo said:
The machine uses ultrasound to measure the jacket thickness just as you would use ultrasound to measure the wall thickness of tubes or pipes.

A little googling turned up this site: http://www.bulletinspector.com/Basic Kit.htm

I guess you can buy the parts to one and build it yourself.

A friend of mine had one and I watched him use it and it does register deviations in jacket thicknesses. Being lead is denser than copper is how I guess it sees where the inner jacket is.

That's my best guess...

Mike
Click to expand...

When suspected interference is an issue in test instrumentation the term shielding comes up. This process can become complex and expensive which could and often does more than double the production costs. The only way you can really tell if the device needs it is to compare the results of two such units one shielded and one not. If the un-shielded version is producing larger deviations than the other then it probably does need it.
Andy
 
Misconception about this machine is that it uses ultrasound

Millbo said:
The machine uses ultrasound to measure the jacket thickness just as you would use ultrasound to measure the wall thickness of tubes or pipes.

A little googling turned up this site: http://www.bulletinspector.com/Basic Kit.htm

I guess you can buy the parts to one and build it yourself.

A friend of mine had one and I watched him use it and it does register deviations in jacket thicknesses. Being lead is denser than copper is how I guess it sees where the inner jacket is.

That's my best guess...

This machine does not use ultrasound to measure the jacket thickness. We are guessing that what Vern intended it to do what do look for jacket flaws and or jacket uniformity or issues within the core that would affect the jacket in some way that would change the jacket to show irregularities in the jacket. As far as we can tell the machine does not check the core of the bullet. For larger calibers like this article eludes to http://www.24hourcampfire.com/reloading.html : one reason the machine does not read as many errors in the bullet as it does in the smaller calibers is because the way the bullets rests on the balls of Verns machine makes the bullet sit higher and further away from the sensor which would not allow the sensor to show the errors in the jacket as clearly. In this diagram: http://www.bulletinspector.com/Manuals & diagrams.htm : This shows what the sensor is. If you understand what this means then you would understand why the larger jacketed bullets do not show as many errors in the jacket as they would in the smaller caliber jacketed bullets: Being further away from the sensor the larger caliber bullets will not read as well as the smaller caliber bullets. This link has a picture in it which has a bullet in the machine and you would be able to see that if the caliber of the bullet was much larger then it would site further away from the sensor and this would not allow the sensor to be as effective. http://www.bulletdoctor.com/Manual/Operating Manual.pdf Reading both of these sites may give you a better idea of how this machine would help you with accuracy. (the 50 cal version) Vern did make 1 larger caliber version of his machine that I know of However the owner of the machine will not let the machine out of his sight. ( After looking at the larger caliber version we feel that we could make it: however the version we saw was a prototype and was not meant for production yet) Understanding this diagram (electric diagram with the sensor) shows that Vern's machines did not use ultra sound to test for jacket irregularities. Being a member of team that now makes these machines again we have a unique knowledge that we wish to share with the community that would give those of you in the shooting sport some more information about your Vern machine and would also give you the ability to get your machine repaired or spare parts for your machine. We suggest checking out the www.bulletdoctor.com site for fully built machines which we may no longer be making any longer due to the immense number of hours it takes to make these machines Or for www.bulletinspector.com for the bulletinspector kits.

Another lost sole looking for the magic bullet. I bet you I can miss the target more then you!
Click to expand...
 
vern juenke machine

WOW such a deal only $1350 for the kit' Thats about $150 worth of radio shack parts
All assembly required.:rolleyes::rolleyes:
 
GerryM said:
WOW such a deal only $1350 for the kit' Thats about $150 worth of radio shack parts
All assembly required.:rolleyes::rolleyes:
Click to expand...

That's kind-of what I thought too Gerry. I used to build kits much more complicated that that when I was 10 years old. What were those kits called? Anyone remember?
 
alinwa said:
Heathkits and Estes, brands of my youth :)
Click to expand...

And that was with a soldering iron, big and bulky, not the modern soldering gun of today with its small tip and temperature control trigger.

When I built an FM receiver the entire region only had one FM station and that was used mostly for semi-pro baseball games. No TV stations at the time. (1948)
 
Juenke machine

In the February 1999 issue of Precision Shooting magazine, M.L. McPherson reviewed the Juenke Internal Concentricity Comparator (ICC).

"Function of the Internal Concentricity Comparator
An ultrasonic emitter is located directly under the working end of the Drive Shaft (the area between the two left-end sets of smaller balls on the Carbide Ball Plate). This device generates a stable ultrasonic field above the Carbide Ball Plate. The field energy feeds back to the emitter, which limits field strength. Any given input power level generates a specific field strength.
Any metallic test item placed in the proximity of the emitter (a bullet or case positioned on the Carbide Balls absorbs some of the ultrasonic energy. The amount of energy absorbed depends upon test item location, density, and thickness. Unless the test item is perfectly symmetrical and has perfectly concentric walls, this value varies as the test item turns on the Carbide Balls.
Any decrease in field strength results in the emitter producing more ultrasonic energy, which requires an increase in input energy. As the test item turns on the Carbide Balls the emitter continously works to maintain field strength. This results in fluctuations of emitter input energy. These variations are what the ICC ultimately measures. For the user, the ultimate result is obvious, Meter needle movement."

Hope this helps in clearing up what the ICC is actually measuring.
 
No ultra sound or ultra sonic emitter is in these metering devices

While it is wonderful that someone wrote something about the machine not everything you read nor hear is the truth. http://www.bulletinspector.com/Pictures/Vern Diagram.jpg this has the diagram of the sensor for the machine in it. No where in this diagram is an ultra sound or ultra sonic device. We have a few of the machines that Vern made and from what we see no design that he had used an ultra sound or ultra sonic device in it. Just because it is written somewhere on the internet or in print does not make it true. This means you would have to see and use the bullet doctor machine or build the bullet inspector kit to see this for your self. I asked Elvis and he told me it was not an ulta sonic machine, but I decided to look at the diagram myself and after recreating the machine I found that it is not an ultra sonic device. If you build the kit you would see that for yourself too. I will tell Elvis you said hello. I hope this clears this up.

Any kind of free is good except for on the internet, where it must be true cuz somebody said so on the internet and now even in a magazine.
 
misfire said:
While it is wonderful that someone wrote something about the machine not everything you read nor hear is the truth. http://www.bulletinspector.com/Pictures/Vern Diagram.jpg this has the diagram of the sensor for the machine in it. No where in this diagram is an ultra sound or ultra sonic device. We have a few of the machines that Vern made and from what we see no design that he had used an ultra sound or ultra sonic device in it. Just because it is written somewhere on the internet or in print does not make it true. This means you would have to see and use the bullet doctor machine or build the bullet inspector kit to see this for your self. I asked Elvis and he told me it was not an ulta sonic machine, but I decided to look at the diagram myself and after recreating the machine I found that it is not an ultra sonic device. If you build the kit you would see that for yourself too. I will tell Elvis you said hello. I hope this clears this up.

Any kind of free is good except for on the internet, where it must be true cuz somebody said so on the internet and now even in a magazine.
Click to expand...

DUDE!!! Are you questioning The Mic???

NOBODY questions THE MIC! He's the EF Hutton of Things Shooting Don'cha Know?

I mean, just because you BUILD them and own the rights to them, you're spittin' into the wind here!

LOL
al
 
misfire said:
While it is wonderful that someone wrote something about the machine not everything you read nor hear is the truth. http://www.bulletinspector.com/Pictures/Vern Diagram.jpg this has the diagram of the sensor for the machine in it. No where in this diagram is an ultra sound or ultra sonic device. We have a few of the machines that Vern made and from what we see no design that he had used an ultra sound or ultra sonic device in it. Just because it is written somewhere on the internet or in print does not make it true. This means you would have to see and use the bullet doctor machine or build the bullet inspector kit to see this for your self. I asked Elvis and he told me it was not an ulta sonic machine, but I decided to look at the diagram myself and after recreating the machine I found that it is not an ultra sonic device. If you build the kit you would see that for yourself too. I will tell Elvis you said hello. I hope this clears this up.

Any kind of free is good except for on the internet, where it must be true cuz somebody said so on the internet and now even in a magazine.
Click to expand...

Hmmmm. Whom does one believe here???? McPherson or Misfire????

While I make no claims, I was just providing information from a published article. Perhaps you should take up your beef with McPherson.
 
Looking at the schematic, and the pictures, I would have to GUESS that what was going on here was related to eddy currents that are produced when a conductor is moved through a magnetic field, producing a counter emf. The schematic shows two independent coils on the same core, and although I am a bit rusty on these things, I would guess that one is the source of the field and the other senses variation of the counter emf, and that the adjustment knob varies the strength of the dc to the magnet coil. In the case of measuring bullets, I think that what the machine is differences in the mass of the conductive metal that rolls through its field of view as well as any variations in distance from the coil caused by irregular shape of the outside of the bullet. No, I am not an engineer, but I did stay in a Holiday Inn once.
 
vern juenke machine

Ah Ha Holiday INN " i thought so"
Was that you making all of that noise in the next room?
actually a great post.
Easy to understand.
 
Lou Murdica said:
Now we will know everything about it soon.
Click to expand...
Lou
Actually I think you will know all about how it is built , what theory it operates under, and you may still not know if it can really pick bad bullets from good. Or more importantly can it find ALL the bad ones. I will grant you if it can segregate most of the bad ones it would be a great help.
Dick
 
Frequency

Boyd Allen said:
Looking at the schematic, and the pictures, I would have to GUESS that what was going on here was related to eddy currents that are produced when a conductor is moved through a magnetic field, producing a counter emf. The schematic shows two independent coils on the same core, and although I am a bit rusty on these things, I would guess that one is the source of the field and the other senses variation of the counter emf, and that the adjustment knob varies the strength of the dc to the magnet coil. In the case of measuring bullets, I think that what the machine is differences in the mass of the conductive metal that rolls through its field of view as well as any variations in distance from the coil caused by irregular shape of the outside of the bullet. No, I am not an engineer, but I did stay in a Holiday Inn once.
Click to expand...
What frequency range does it operate. I suppose someone could use Spice or figure by hand.
 
Boyd's right, even if he ain't an engineer!

And, I'm an Electronic Engineer of the analog persuasion. I have looked into the circuit of the Juenke device and it is in fact a VERY crude Eddy current system. I say crude as way better circuitry was available when Juenke built these things.
There is a audio frequency (5-20 kHz) oscillator whose L-C tuning circuit includes the inductor used as a transducer. When in close proximity of metal, the magnetic field around the inductor induces eddy currents in the metal which acts like a shorted turn of a transformer robbing energy from the oscillator dropping the amplitude of the oscillation. This reduction in amplitude is monitored by the meter and when there are no discontinuities in the external metal the meter reading is pretty stable. When there is a discontinuity either in thickness of cladding or bubble in lead core, the meter will wiggle at the rate the bullet is turned. In a perfect world, the thickness variation or bubble could be quantified be proper calibration. But just familiar non-wiggles vs unfamiliar wiggles are apparently adequate to determine reject bullets.

Anyway, I'm building my own design with more up to date circuitry. We'll see how it works.
 
You must log in or register to reply here.
Back
Top