Manticore lower rods coming soon (estimated mid-November availability)

Hey all!

I am in the final stage of testing the new Minelab Manticore lower rods. I anticipate availability starting in about 3 weeks (mid-November). I will have both lower rods available, AND two-piece lower-shaft assemblies (middle section AND lower rod, connected with one of my proprietary, premium-quality cam locks).

The lower rods will be available in black at first, with tubes having the same matte carbon-fiber finish, and red "warning line," as the stock lower rods. The "standard" length will be roughly 23 1/4", with a "tall-man" version also available at roughly 27 3/4". I will also have them available in the near future in three colors -- red/black, green/black, and blue/black.

Pricing will be $79 for the black lower rods ($89 colored), and $119 for the black two-piece lower-shaft assemblies
($129 colored), and the coil bolt WILL be included.

So, with the Minelab accessory coils apparently available soon, spare lower rods for these coils will now be available as well, at [www.stevesdetectorrods.com]

email: steve@stevesdetectorrods.com

Thanks!

Steve

That's a nice looking lower rod. But I do wonder if it may be less sturdy that it could've been. I'm thinking of the issues a few people had with the Fisher AQ, where the clevis part broke where it attached to the carbon rod:
[www.detectorprospector.com]
I'm sure those AQ failures were on machines that were submersed, so subject to heavy drag forces. But the Mandingo is also likely to be used by many surf / water hunters, so may get a similar rough treatment.

I know that Fisher were re-designing their lower rod as a result of these failures, but I don't think anyone has seen the resultant product to see what was new.



Edited 1 time(s). Last edit at 10/23/2023 02:37PM by Pimento.

Pimento,

Yes, I get what you are saying; I didn't deviate from Minelab's design, since after using the machine for awhile, I wansn't particularly concerned about the design being unusually prone to breakage. And with the fiberglass-reinforced plastic that I use being a pretty stout/sturdy mix, I think they will hold up quite well. But, if I end up having to adjust in some way, I certainly will...

Steve

Obviously I cannot see the engineering details from the photo, but the 'weak point' in that arrangement is the transition from large ( 22mm ? ) diameter to small ( 20mm? ) on the plastic part. If there's a sharp internal corner, that's where the break will occur. I would prefer to see an internal radius at that transition; and as a result have a heavy 45 degree chamfer on the rod's internal wall .. or even a matching radius.



Edited 1 time(s). Last edit at 10/23/2023 09:10PM by Pimento.

Pimento,

Thank you for the feedback, I appreciate it.

The first thing I'd like to say is, should any type of breakage issue arise, contrary to my expectations, I'll certainly have the mold adjusted to allow whatever reinforcement or design tweak may prove to be necessary. That said, I haven't heard of any breakages of Minelab lower rods which include a very similar clevis design, from current Manticore users, which boosts my confidence that the basic design is itself not egregiously flawed.

Meanwhile when I look at the First Texas design utilized by the AQ, that you alluded to, I see a couple of things that stand out to me, that would seem likely to contribute to weakness/potential breakage. One, from pictures I have seen (haven't had one "in hand"), the plastic looks to be of a stiff (and thus more "brittle" so to speak) type of formulation. If the "ears" are stout, but stiff and inflexible, then any lateral stresses placed on the clevis by the coil (due to hyrdodynamic drag, for instance) would be focused at that "transition" location to which you refer. Secondly, the "walls" of the hollow cylindrical part of the clevis that fits inside the carbon tube are much thinner than I would have expected, ESPECiALLY if the clevis material is indeed a "stiff/brittle" type of plastic, as it appears to be. As such, those aforementioned lateral stresses that would be focused at that "transition point" by very stiff/stout coil ears, would then have much better chance of resulting in a "breakage," as compared to a thicker-walled design of that cylindrical section of the clevis, that fits inside the tube.

With my lower rod, I will be surprised if breakage occurs at the location you mention (especially with any more frequency than a "one-off" type of situation). The "ears" of my clevis are stout but somewhat flexible, on account of the type of plastic I'm using, and thus my expectation is that this should help to "absorb" shock/stress, thus reducing the direct stress that would be placed on the larger-to-smaller-diameter transition point to which you refer. This, plus the overall strength of the glass-reinforced plastic I use, leads me to believe that breakages should not become an issue to any appreciable degree at all. If anything, I could envision a breakage of one of the "ears," in a high-stress situation, but again...I expect that the very strong but flexible characteristic of the plastic I am using should to a large degree mitigate such concerns. But -- if indeed your concerns end up being borne out over time, I will certainly take appropriate/necessary steps to adjust the design, and the mold.

One final point. The cylindrical portion of my Manticore clevis (i.e. the portions both external and internal to the carbon tube) is IDENTICAL in design to the cylindrical portions of the clevises that are used in all of my other lower rods. And out of thousands of lower rods I've produced/sold, I have never had a single breakage of the clevis occur. Some of my clevises are made of Delrin, and fabricated via CNC machining, and others are injection-molded fiberglass-reinforced nylon. And even with the more stiff/brittle characteristics of the Delrin clevises, I've had zero breakages. This also lends confidence to my conclusion that any breakage issue should remain unlikely at best.

I appreciate your input, as I work through this final testing/evaluation stage, as such scrutiny always helps in any new design being tested.

Thanks!

Steve



Edited 1 time(s). Last edit at 10/24/2023 09:14AM by steveg.

"When I look at the First Texas AQ design ...the "walls" of the hollow cylindrical part of the clevis that fits inside the carbon tube are much thinner than I would have expected"
I agree, it certainly contributes to the weakness, probably along with a plastic choice that's not ideal.

I wish you all the best.

Thanks, Pimento.

Steve