swapping shafts to swing an 18"

[align600]

just bought a NF18" mono. read u have to change the upper shaft to a fiberglass or composite.
why not the lower shaft seeing its closer to the coil? or is it both lower and upper?

 

[Syndyne]

Hi align600,

Nice choice of coil!

That's a fairly easy one. As far as the lower shafts on the Minelabs go (assuming that's what you're running) they are made of fibreglass. Just checked my ones, both the one that came with the 5000 and the spare I have on my 16" NF Mono.

Not so sure about changing the upper shaft though? I have fairly minimal experience on the Minelab with a big coil. Perhaps someone with good time on a large size coil like the 18" will offer the advice needed.

Kindest regards,
Shauno.

 

[loamer]

I run an 18" on a 4500. The lower shaft is as Shauno replied and they are no problems. Upper shaft? Never heard of needing to change it as they come as standard with all minelabs. the only issues using a bigger coil are make sure your pick is slung, no metal eyelets in your boots and avoid lots of metal in your pockets when you kneel down to do your halving after digging up the gold!!!! All good to go with the standard lower shaft.

 

[minersright]

Don't know about the 5000 but know from 4000 down the upper shaft's were aluminium.
The theory was that large coils were not as sensitive because the detector had to null out
the upper aluminium shaft and lost some depth.
I fitted one to my 4000 but I can't say for sure if it helped, they are quite pricey to.

Regards minersright.

 

[align600]

oops. sorry. forgot to mention, im running a gpx4000