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This has got to be a wind up!
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tyneoharrow wrote: ↑Sun Mar 17, 2019 5:12 amHello Ixoye, I agree with you about the glove, anything that restricts the hand whilst holding the machine as you swing can cause pain and discomfort in and around the wrist area that's why a relaxed open hand and not gripping the machine is best when detecting for long periods.
But it would ruin my manicure!
During half a century of swinging a detector I often wondered when my shoulders or elbows would eventually give out. So far so good. Mostly there is a bit of discomfort with each new detector then the muscles compensate and all is well again.
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So many fields, so few permissions
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I agree with that! I see people recommending builders gloves and tight fitting neoprene stuff, awful things, you need to fight the glove to move in the damned things, not a problem if you are clearing rubble or removing an old bath but hopeless when it comes to lightly hanging onto a detector, I just use woven polyester/wool gloves that are both warm and non restrictive, obviously not waterproof though.tyneoharrow wrote: ↑Sun Mar 17, 2019 5:12 amHello Ixoye, I agree with you about the glove, anything that restricts the hand whilst holding the machine as you swing can cause pain and discomfort in and around the wrist area that's why a relaxed open hand and not gripping the machine is best when detecting for long periods.
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"Re: Any physics or maths bods - coil weight
Post by liamnolan » Mon Jan 07, 2019 12:42 pm
An interesting topic, has been discussed in the past when the bigger coils became popular but had unintended consequences.
My business is all about rackets. Tennis, squash, racketball and badminton. I run the UK Racket stringers Association www.ukrsa.com and I teach people how to service the rackets for stringing but also how to change the specifications to suit individual needs.
A racket is like a detector in how it is used, in that it is swung to and fro.
How that feels to the user is called the Dynamic Weight, or usually Swingweight.
The 3 specs we are concerned with are
Overall Weight - a pro's racket will weigh in around 300 gms.
Balance - Where along the 27 ins length is the balance point? If its 13.5 ins, then we have Even Balance.
Swingweight - The combination of Balance and Weight along the longitudinal axis. The weight of the racket/detector is distributed unevenly along its length. If most of the weight is towards the racket head, then it will feel heavy and less manoeuvreable, harder to swing fast. It will have a HIGH swingweight. Most players want a LOW swingweight as its easier to swing fast in a hurry. That means moving the weight back towards the handle end.
So, you could have a heavy racket, but if a lot of that weight is around the handle, then it will feel lighter than what it actually weighs.
Metal detectors - The Deus is a light machine, easy to swing around all day, hence its very popular. We have Minelabs that are heavy, ok for a few hours and then your arm drops off unless you use a sling support.
Deus - users went up a coil size to gain more coverage but of course that added more weight at the wrong end (ouch!) In tennis we can end up with the painful condition called Tennis Elbow which is an inflammation of the outer epicondyle and it stops you dead, just too painful to play. Its usually caused by a player moving from a racket with a LOW swingweight, to a new racket that has a much higher swingweight.
Detecting is exactly the same. I have a GMP as a spare machine. If you allow the cable to be wrapped around the lower part of the stem you greatly increase the swingweight. This makes it good for moving through stubble but at a cost to arm comfort. GMP users also know that it causes "falsing" as the coil becomes ultra sensitive and bleeps when knocking against the stubble. So they move the cabling up towards the control box, problem solved and also a LOT of arm comfort.
Here is a video on what swingweight is all about in terms of tennis, you can get the gist and relate it to detecting -
If we were discussing a uniformly weighted rod of plastic then we could start to work with numbers to calculate the variances in swingweight by adding small amounts of weight along the longitudinal axis. Unfortunately, as in tennis rackets, that weight is not uniformly distributed. In tennis, I have software that allows me to make adjustments to precise amounts, once I feed in the weight, balance and present swingweight, choose the specs I want and the computer will then tell me where to place lead tape to get the job done.
A pros racket may weigh 300 gms and if the balance point is even, then the SW will be 300. But he will want a SW of around 260 or less for his style of play.
For detectorists, all the above means that we should be aware that adding weight to the coil end WILL make it feel much heavier and so it will be harder to swing all day.
Inertia - before anything moves we need to overcome inertia, the coil wants to stay where it is and we need to exert force to get it going, then when it travels all the way to the right we need to overcome that inertia again to take it back to the left and on and on, each time the arm is having to stop the movement from one side, then get the movement reversed. So the Deus with a 9 ins coil (me ) is not going to present too many problems.
If someone HAS to live with a big heavy coil and has arm problems, then they could experiment by adding weight to the opposite end. This will take the balance nearer the control box end and lower the swingweight. That added weight will be hardly felt, will make the machine easier to swing.
Tip - one way to reduce the "heavy" feel of the coil is to reduce the distance from the grip down to the coil. So a more compact swing may cover less ground in a smaller arc but it will feel much easier to swing the coil Easy to adjust the Deus stem length
When they bring out a new large coil, it would be very helpful to also add some info on what differences the user may experience in terms of swingweight. They can be costly items and a sad investment if you cannot use it for more than 30 mins.