Conductive Carbon Fiber Lower Rods

[Jeff McClendon]

3 minutes ago, Chase Goldman said:

The technical aspects of this issue are very complex as is typical when discussing all the variables that influence our ability to detect and recover targets with these machines.  A couple observations:

Is this really a micro target recovery issue vs. a micro target detection issue?  In other words, the issue appears to be that the CF shaft lying flat up against the coil interferes with people's ability to use the pass the hand/scoop over the coil method to narrow down the location of a recovered micro target that was successfully detected in the ground.  Is that the limiting case?

Second, it was mentioned that the coil cable might play some role in the issue.  To a certain extent that is true from a pure metal standpoint (in this case, the metal being the coil cable shield and connector), but there was also a discussion as to whether current passing through the coil cable was also creating an interfering EM field.  Regarding the latter statement, that would likely be "a no" for two reasons: First, the magnitude of the current flowing the coil is relatively small and second, and most importantly, the cable is shielded coax which suppresses the EM field surrounding the cable such that it is limited to existing with the dielectric between the cable wire and the shielding.  Therefore, the fact that current is flowing through the coil cable has no effect the magnetic field effects.

Anyway, very little will get settled here, and mostly people are going to have to convince themselves whether this issue matters to them to the point of needed the lower rod.  I am going to do some additional testing on my own to help me better understand the practical impacts of the CF rod.

One detector design expert I would be interested in hearing from is @Geotech to see if he has any perspective to shed on this issue.

For me, it's a sub gram target recovery issue when using the hand or scoop passing over the coil technique. I have no idea if it is an "in ground" sub gram target detection issue as long as one is not detecting with the coil flat against the shaft. I do that sometimes on excavation trench walls but it's rare.

What isn't rare as far as using the hand/scoop sweeping or scraping the coil is that I may use that recovery technique 50 to 100 times per day. Not fun when the coil and shaft are that finicky when they are close together.

[Chase Goldman]

2 minutes ago, Jeff McClendon said:

For me, it's a sub gram target recovery issue when using the hand or scoop passing over the coil technique. I have no idea if it is an "in ground" sub gram target detection issue as long as one is not detecting with the coil flat against the shaft. I do that sometimes on excavation trench walls but it's rare.

What isn't rare as far as using the hand/scoop sweeping or scraping the coil is that I may use that recovery technique 50 to 100 times per day. Not fun when the coil and shaft are that finicky when they are close together.

Agree.  Was not commenting on whether or not it was rare to use the scoop or shouldn't be considered important, I know it is something that is used constantly in nugget detecting.  Just wanted to bound the issue between detection vs. recovery as it relates to the proximity of the shaft to the coil.  Thanks.

[Steve Herschbach]

13 minutes ago, steveg said:

Steve,

My point is, this could open up a WHOLE CAN OF WORMS.  And again, if it was a LEGITIMATE can of worms, then it's simply my job to fix it.  Recently, I had a bad batch of injection-molded plastic parts, that I built some shafts with, and a few customers had a breakage.  In other words, I sold a couple dozen shafts that unknowingly had a legitimate problem.  SO, I had to get to the bottom of it, and in the end, found that it was a mistake made at the factory, during the molding process.  So, I ended up throwing away hundreds of parts, having them remade, AND sending free replacement shafts to the customers who had the breakage issue.  That is simply what I do; it's a no-brainer.  But, what about in this case?  This is NOT a case where I have sold something flawed, or faulty.  It if were, I'd fix/remedy the situation IMMEDIATELY.  Instead, this is, as far as I can scientifically determine, NOT a problem.  BUT -- offering a "fix" implies that it IS a problem.  So, it presents a major dilemma...what do you do when you are selling a quality, properly functioning product, but that someone has become convinced IS faulty (though not in any measurable way)?  

These are some of the concerns that I have.  

Steve

You think too hard for me. I would not worry about what your are currently selling and continue to sell it. I would just explain that for most people this is not an issue (you've already presented the evidence), but for those who think it is, here is this alternative product I sell. Take your pick. You have done nothing wrong, sold nothing defective, have nothing to apologize for. So don't.

[steveg]

12 minutes ago, Jeff McClendon said:

For me, it's a sub gram target recovery issue when using the hand or scoop passing over the coil technique. I have no idea if it is an "in ground" sub gram target detection issue as long as one is not detecting with the coil flat against the shaft. I do that sometimes on excavation trench walls but it's rare.

What isn't rare as far as using the hand/scoop sweeping or scraping the coil is that I may use that recovery technique 50 to 100 times per day. Not fun when the coil and shaft are that finicky when they are close together.

Jeff,

I believe I have misunderstood, in the way that Chase is alluding to (detection vs. recovery).  My ENTIRE discussion in all of my posts on this topic, have been about IN-GROUND DETECTION.  It now seems that you, and some others, are concerned about waving the handful of dirt OVER the coil, WHILE the coil is folded flat, and with the carbon tube "between" the coil, and the target.  I do not know if in that SPECIFIC situation, with a tiny flake of gold, there may be an issue detecting it.  I don't know.  BUT -- I can see where that specific scenario (running the handful of dirt OVER the coil) presents a different scenario than detecting the same target in the ground, UNDER the coil.  

I just wanted to make clear that everything I was discussing, and everything I spoke with Tom about, was about detecting IN-GROUND targets...

Steve

[steveg]

2 minutes ago, Steve Herschbach said:

You think too hard for me. I would not worry about what your are currently selling and continue to sell it. I would just explain that for most people this is not an issue, but for those who think it is, here is this alternative product I sell. Take your pick. You have done nothing wrong, sold nothing defective, have nothing to apologize for. So don't.

I understand!  LOL!  I "think too hard" in alot of cases, according to friends/family.  LOL!  I guess it's the way I'm wired...

But, you make some good points.

Thanks!

Steve

[Steve Herschbach]

On 6/5/2024 at 11:37 AM, steveg said:

Jeff,

I believe I have misunderstood.  My ENTIRE discussion in all of my posts on this topic, have been about IN-GROUND DETECTION.  It now seems that you, and some others, are concerned about waving the handful of dirt OVER the coil, WHILE the coil is folded flat, and with the carbon tube "between" the coil, and the target.  I do not know if in that SPECIFIC situation, with a tiny flake of gold, there may be an issue detecting it.  I don't know.  BUT -- I can see where that specific scenario (running the handful of dirt OVER the coil) presents a different scenario than detecting the same target in the ground, UNDER the coil.  

I just wanted to make clear that everything I was discussing, and everything I spoke with Tom about, was about detecting IN-GROUND targets...

Steve

Detecting in ground while nugget detecting involves constantly banging the coils on rocks causing micro movements in relation to the rod that cause false signals. It is a problem with ultra hot VLF setups. It is also a problem with large coils where coils are very prone to move in relation to the rod. It's all about in ground targets and false signals compounded by false signals simply putting the detector on the ground, flipping the coil, etc.

[Chase Goldman]

20 minutes ago, steveg said:

Instead, this is, as far as I can scientifically determine, NOT a problem.  BUT -- offering a "fix" implies that it IS a problem.  So, it presents a major dilemma...what do you do when you are selling a quality, properly functioning product, but that someone has become convinced IS faulty (though not in any measurable way)?  

This is a good point, Steve.  The way I would look at it from your perspective is to determine first whether there is a viable market for the non-CF shaft from a pure business perspective then I would think about the unintended consequence of offering that product from the standpoint of whether it would imply that your bread and butter product could be perceived as flawed.  If there is no viable market for the non-CF shaft, I see no reason for jeopardizing your base product by sowing seeds of doubt.  However, if this gets a life of its own, the market place may force your hand and you should be ready to give people what they want regardless of whether you personally think it has a legitimate technical purpose. FWIW.

[UT Dave]

15 minutes ago, Jeff McClendon said:

For me, it's a sub gram target recovery issue when using the hand or scoop passing over the coil technique. I have no idea if it is an "in ground" sub gram target detection issue as long as one is not detecting with the coil flat against the shaft. I do that sometimes on excavation trench walls but it's rare.

What isn't rare as far as using the hand/scoop sweeping or scraping the coil is that I may use that recovery technique 50 to 100 times per day. Not fun when the coil and shaft are that finicky when they are close together.

Same.  I don't have a lot of experience nugget detecting with the Manticore, but what little experience I have, this has been the case.

While attending Gerry's class at Rye Patch, I was leaving an air gap over the coil while passing my scoop over it and one of Gerry's staff advised me to scrape the scoop right against the coil.  I replied that doesn't work so good with this machine and showed him.  He agreed, don't do that with this machine...

- Dave

[steveg]

28 minutes ago, Chase Goldman said:

This is a good point, Steve.  The way I would look at it from your perspective is to determine first whether there is a viable market for the non-CF shaft from a pure business perspective then I would think about the unintended consequence of offering that product from the standpoint of whether it would imply that your bread and butter product could be perceived as flawed.  If there is no viable market for the non-CF shaft, I see no reason for jeopardizing your base product by sowing seeds of doubt.  However, is this gets a life of its own, the market place may force your hand and you should be ready to give people what they want regardless of whether you personally think it has a legitimate technical purpose. FWIW.

Chase,

Thanks for the thoughts.

One thing I am loosely pondering in my mind as a sort of "middle ground," and it kind of goes along with some of what Steve said, is to consider a special "gold prospector's" lower rod.  I wouldn't "market it broadly," per se, BUT, since this is probably THE forum where gold prospecting detectorists most congregate, it could perhaps kind of be a "Detector Prospector" special, that I'd offer to those folks here who are concerned about the issue.  What I'm imagining is some sort of "adapter," roughly 8" or so in length, that would be made of "plastic," and would attach to the "clevis."  That plasic piece, with "clevis" attached, would then install into a regular "lower-rod-diameter" carbon tube.  That would mean that the lowest 10" or so of this "prospector's" Manticore lower rod would be "plastic," and the rest would be carbon fiber.  I think that would ease the minds of those with the concerns.  The issue is, having that plastic "adapter piece" produced.  I may look into it, but I suspect it would be expensive, and thus would add to the cost of this "specialty" lower rod.  It would also add some to the weight of the lower rod, which is not ideal...

Anyone have any thoughts, in this regard?

Steve