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Steel bearings are made with much tighter tolerances than lead pellets since they have to roll true, if you guys are looking to normalize geometry. Maybe a more consistent alloy too since they are made from rolls of wire and there is less variance in stainless steel than there is in shotgun pellet alloys.

Kits like these are cheap. Of course the response to steel is different than to lead and gold, but it might not matter if the main goal is just to have a standard baseline object that anyone across the world can test and replicate. 

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Note that those ball bearing are made from non magnetic steel and would remove the ferrous effect on the coil.

Austenitic steels, which contain 16 to 26 percent chromium and up to 35 percent nickel, usually have the highest corrosion resistance. They are not hardenable by heat treatment and are nonmagnetic. The most common type is the 18/8, or 304, grade, which contains 18 percent… In steel: Stainless steels.

Steel-composition1.jpg.a900fd9fe0baa1d084a2cdf14554bda4.jpg

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I purchased one gram of nuggets awhile back. Seven pieces/gram, time constant varied between 1 and 2 us. Thinking .03g nugget has a time constant less than 1us. I liked #9 shot since size and time constant (about .7us) should be similar to nuggets less than .1g until I found they weren't consistent. A 10mm square piece of aluminum foil has a time constant of .7us but is easily detected because of size. Standard target needs a time constant between .5us and 1us and a size that gives a detection distance similar to a small nugget less than .1g. I like the wire but if anyone can find a consistent sphere target with a time constant around .7us with a size similar to a small nugget all the better.

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A while back while on a prospecting trip with a buddy I told him the 6K was finding gold the size of #9 bird shot easily. When I got home I found a #8 shot shell and opened it up to compare as I did not have any #9 shot shells. To my surprise the size varied  substantially of the pellets in the #8 shell. I've nothing new to add here but this 🙂 

 

444387729_thumbnail(16).thumb.jpeg.b01448d12c3aeacbfa037524956f4410.jpeg

 

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On 5/17/2022 at 5:38 PM, Jeff McClendon said:

Again, this topic should be in the Minelab or gold prospecting section, not the Metal Detector Advice and Comparison section. Just ask Steve or Chase to move it.

This forum also covers general deteot tech stuff. I fits here or the other locations. Will leave it here until it runs out of steam, then move it elsewhere to see if it gets more interest. All I'll add is my GPX 6000 is finding lots of tiny shot my GPZ 7000 never knew existed. That can be either a plus of a minus, depending what a person is actually doing. There is something to be said for going for the weight, and that chasing tiny stuff past a certain point can actually impede a prospector in that goal. In other spots, tiny stuff is all there is, and it's that, or go home with nothing.

I use my own standard - the Bic Pen Test

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The test of the sensitivity of the detectors ... for the N.9 shot is definitely a challenging topic, for the PI detectors, but it can definitely take a different look at the various Vlf detectors for this purpose ...

... since I use to test the sensitivity and reach of very small gold targets ... several different tests .... I decided to supplement my testing with this test on shot N.9

IMG_20220502_164036.thumb.jpg.92617aaf9df75bfcd59eae38351a734b.jpg

 Since this "test shot N.9" is really challenging ... in the first place I am interested in the extent to which this test will correspond to my previous tests on gold targets ..

IMG_20220502_172257.thumb.jpg.fa9e8d1d55aa4f83cfbbb2bde926f618.jpg

 During testing, I noticed that the bullet had a N.9 ..is definitely a more challenging target ... especially for my detector PI Garrett ATX ... on a standard 12x10" DD coil .. as a very small flatter gold targets / 0.027 gram / which this detector can detect..on 2-2.5 cm .!!!

...enlarge this picture ..!!!

IMG_20220502_183433.jpg

------------------------------------------

... Therefore, I decided to adjust 3 spherical shots of N.9 to different surface shapes and then test it ...IMG_20220509_182416.thumb.jpg.fe67f0702307e7f220ab5be6b8bab1f9.jpg

 

... the result has not changed ... all 3 ar of the shots N.9  remained invisible to the 12x10" DD standard ATX coil ... but small gold 0.027 grams of gold target was detected at a distance of 2 to 2.5 cm .... what I consider to be such a big coil.. really great result ..!!!

...................................................................

In the end I decided to test the PI Garrett ATX still on a small 3x7" power DD coil from Infinium LS ...This little coil... is completely new, because it came to me from the seller yesterday...:smile:

IMG_20220526_090634.jpg

....The test result of the small 3x7"DD infinium coil pleasantly surprised me ... because the ATX reach of small 0.027 gram gold targets increased from 2-2.5 cm up to 4-4.5 cm ... !!!:wink:👍

enlarge this picture .. and you will see better...!!!

.....and this small coil began to see two pieces of the flattest shots N.9 ... if it's only when the target almost touches the coil at the intersection of the TX and RX windings of the coil ..!!!

Now I can say .... that PI Garrett ATX ... these flat shots N.9 can really "technically" detect ... even if it's completely at the reel .. -I'm satisfied with the result .. even though I still failed to detect the round and also the least flattened shot N.9 ..

In fact, I am more pleased with the fact that on this small 3x 7 "DD coil..l, the reach has increased to my very small 0.027 gram gold to 2 times .. at 4.5cm compared to the standard ATX 12x10" DD coil ...!!!

So the "Magic" of using a Smaller coil "on this PI detector also works successfully ... and the smaller coil has been able to improve the sensitivity and reach of ATX for very small targets.

IMG_20220526_090711.jpg

 I'm glad that ATX on a small 3x7 "coil started to detect my 0.01 gram gold target -... even if only at a distance of 2-3mm from the coil.. ..👍

------------------------------------------------------

In the final picture.. you can see that the really flat form of lead shot N.9 is already detectable .., but only right next to the coil.. ... but also note the good range of 4cm .. small 3x7 "Power DD coil for  target "35 pieces fine gold" of very small gold with a total weight of 0.4 grams gold ..
 It is also a complicated target .. and standard 12x10"DD ATX coil... can only be seen at 1.5-2 cm ..!!!

I will also be happy ..to reach my favorite test target 0.1 gram of gold .. where the reach of a small coil is really nice 10 cm .!!!

IMG_20220526_091756.jpg

----------------------------------------------------

PS....At the end of this test, I asked myself one question .... do we really need a detector that will detect such small lead micro targets?

From a "Technical point of view", detecting a target like leadshot N.9 is a really cool thing .., But....

Isn't it better to use a detector that eliminates a substantial amount of such junk targets ... but still detects very small and sometimes much smaller gold ???...

And this applies not only to PI detectors but also to VLFs...

 I think it's a good question for further discussion ....:wink:👍

IMG_20220526_092731.jpg

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  • 3 weeks later...

.... Since my last tests of the standard 12x10 "DD Garrett ATX coil ...and the small 3X7" Power DD Infinium coil ...showed a clear advantage of the small 3X7" Power DD coil for very fine gold .... at PI Garrett ATX ... even though I didn't reach success in detection on round shot N.9 I decided to find out what results I will achieve with a medium-sized 5x10 "Infinium power DD coil in direct comparison with a small sensitive coil 3x7" Infinium Power DD ..
...
I can get better results with the 5x10 "DD power coil ,, than with the 3x7" DD Power coil on  PI  Garrett ATX? .. I am very curious about the final comparison ...

I also included in the test a lead round shot number N 7.5 / the diameter is 2.4 millimeters /..to know how both coils I will react to a slightly larger shoot like shot N.9 .... which has a diameter of only 2 millimeters ..

 PI Garrett ATX.. was set in the test for both coils to stable sensitivity 12 ....and threshold 11.5 .. without Ground balance ..

IMG_20220612_103317.jpg

...Test of 5x10 "Power DD coil confirmed one important thing ... with the winner in range and sensitivity to very small 0.027 gram gold is still small 3x7"Power DD .. infinium coil / range is 4.5cm !!! for 3x7"Power DD  coil..  vs  2cm range for  5x10" Power DD coil /.. 

 ..but at 0.1 gram gold and more gold begins you have a slight predominance of 5x10" DD infinium coil  /11cm vs 10cm range small coil/ ,.. which already has a significant predominance even at 0.5 gram 24K gold .. where the range is a good 20cm !!! .. for 5x10" DD infinium coil ... vs. range 16.5 cm - at small 3x7" DD infinium coil ../

 ..The sensitivity of the 5x10 "Infinium Power DD coil to gold targets of 0.1 grams and less is very similar to the 12x10" DD ATX standard coil.
... This is in full agreement from Steve Herschbach's review of this 5x10 "Infinum power DD coil on ATX .. which he wrote years ago ...👍

Test 5x10" Infinium Power DD coil at  PI Garrett  ATX....shot N 7.5 is on an unmarked ruler...IMG_20220612_104712 (2).jpg

------------------------------------------------     

..Test small 3x7"Infinium PowerDD coil at PI Garrett ATX..IMG_20220612_111231.jpg

....Now the most important ... about this topic .. tests of both coils showed that shot N.9 stands out from the detection capabilities of both coils ..
 but ... for me it's a plus ..👍

During the test on ... shot N 7.5 .. coil 5x10"DD Infinium .. proved the data signal completely at the coil ... and only in the area where the windings TX / RX ... / in the picture / cross.

 The small  3x7 " Infinium Power DD coil... at ATX sensitivity at 12 .. on the shot number 7.5 did not give a readable signal ... across the entire surface of the coil ... at ATX sensitivity 13 max....I already heard a very weak response at the coil ..

... This is probably another big plus of this small 3x7" Power DD "coil because the sensitivity of the 13 at ATX is a range of 0.027 grams of gold at a nice 4.5 cm .... !!!

...this test also pointed to another important thing ... and that a certain coil size can really help in the detection of a certain type of targets and the size we want to find in the detection and PI detector you use...

..I think the important criterion for a given coil will be here .. especially a good range of the coil on a certain size and weight of targets we want to detect .. ... but also how a given coil on the detector can handle the detection of these targets in mineralized or salty terrain .. 

This way you can also extract the maximum of its detection capabilities from your detector..

PS...exact weight of gold on the test ruler 0.02 gram 24k gold ..is 0.027 grams..and therefore I published this exact value in the test....
IMG_20220517_124221.jpg

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If that ATX is detecting 0.027 gram nuggets at all then color me surprised... I have to admit I never really gave the ATX a 2nd glance at all due to it's weight, but if it's hitting 0.027 grammers at 2cm then it probably has something going for it in the underappreciated performance category.

Makes me wonder why they never redesigned it into a lighter machine? The 6000 is generally hitting down to 0.03g for me in the field, might go smaller in a testing setup but no idea since I haven't done tests. But either way, Garrett could have had a 6000 years before the 6000 came out with a lighter weight ATX if your tests are accurate, El Nino?

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I can vouch for his scales being good accurate ones 🙂 I have the same.  Yes, I'm quite surprised by the ATX too, if this is the case I have renewed attention towards the ATX.  If it had some decent coils it'd probably be a weapon. 

It's a shame Garrett didn't take all of Steve's hints and remake the ATX as their lightweight modern PI in a new land housing while fixing all of the known flaws with it at the same time, it sounds like it has potential to be a very popular detector after a redesign or the housing and coils designed around light weight and a land scenario.

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My recall was it lacked outright depth on the bigger stuff, but I don't remember exactly.

If so, some of that could be coil related too. Garrett might still want to consider making it as light as the 6000 and then looking into proper concentrics - or having them be made for them. 

A lightweight PI for less than half the cost of a 6000, but with equal performance on small stuff and better performance on the bigger, deeper stuff would put a US manufacturer right back into the game again. I'm actually pretty surprised they never did, especially as you mention Simon, how much Steve posted about something similar very early on.

Almost makes me want to see if Garrett wants to sell the ATX patents/design cheap if they have no plans for it. Minelab is kinda setting themselves up for stray competition to enter the game lately IMO and someone with a decent sense of business saavy, customer interaction, and a hunger for competition could probably find a way to take some decent market share away now if there is seriously just a machine out there floating around that could be fairly easily modified to equal or outperform the 6000 for half the price.

Edit: or maybe it already has a concentric? Looking at a photo of the machine stock. Admittedly, I don't know much about this one.

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