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Cam locks

A

Anonymous

Guest
I have been looking for cam locks so I can build my own metal detector rods. These are the twisting hand locks on most detector rod sections. Also where does one find the pin locks that are used on the rods?
Does anyone out there know of sources of lead shielding besides Eric and is within the <IMG SRC="/forums/images/flag.jpg" BORDER=0 ALT="USA">?
Rick S
 
Rick, as far as I have been able to determine, after two decades of searching the same question, everybody makes their own cam locks-- an expensive proposition, since injection molds typically run several tens of thousands of dollars. This is an example of how the self-imposed isolation of metal detector companies prevents them from cooperating on matters of mutual interest.
I have found cam locks on other apparatus, such as telescoping extension poles for brooms, car washers, and painting poles. You'd think that tripods and canes would be good places to look, but I've never found anything suitable for metal detectors on such things.
I suspect that cam locks could be manufactured by open-mold urethane casting, which is much cheaper than two-piece mold liquid resin casting. The result would probably be affordable for a low-volume specialty product.
If anyone wants to get into the business of manufacturing OEM parts that are needed but unavailable, here's another one: A decent OEM battery box for 9-volt batteries. The stuff from Keystone, Memory Protection Devices, etc. is unnecessarily bulky, lacks a proper means of closing the compartment, is difficult to get the battery in and out, ..... in other words, designed by engineers who didn't care whether it was any good or not. There are huge numbers of consumer products which use 9-volt batteries, and almost every manufacturer home-brews their own battery compartment in part because nothing is available off-the-shelf that a self-respecting OEM would want in their product.
Another thing that is conspicuously absent is a decent 9-volt battery snap. The thinking among connector manufacturers seems to be that nothing that uses a 9-volt battery retails for more than a dollar, so a battery snap has to cost less than ten cents. But, you look in an industrial instrumentation catalog, and see instruments costing hundreds of dollars running on 9-volt batteries. .....Keystone makes a reliable fish-paper battery snap, but the thing is so ugly that most OEM's don't like it.
Here's another needed item: a decent 6-AA slide-in battery pack, for machines which are regulated at 5 volts. GOOD QUALITY, preferably splash-resistant, not cheapo junk like most battery stuff is. The battery systems in use nowadays are mostly relics from a bygone era when more than 5 volts was needed to get good performance from analog circuits of the kind used in metal detectors.
Metal detector manufacturers believe that their searchcoil appearance has to be a trademark. Because searchcoil tooling and development is expensive, most manufacturers are unable to offer the searchcoils they ought to. So aftermarket manufacturers fill the void, and instead of viewing them as resources, the metal detector companies usually view the aftermarket guys as competitors! even though the aftermarket guys are helping to sell the metal detectors!
There's a better way, and when a manufacturer starts taking that better way seriously, their competitors who don't follow suit will get left in the dust.
Refs: read=3292 and 3275 on this forum, and related posts.
--Dave J.
 
Found a new product...a rechargeable 9 Volt NiMH battery that delivers 170mAH. an 9.6 volts. Interesting...
http://www.thomasdistributing.com/9v-nimh-batteries-chargers.htm
 
Nobody that I am aware of, has produced a camlock that is reliable for surf and underwater use. All the types I have tried, invariably fill with silt and seize up. Not only the camlock of course, but the space between the telescopic inner and outer shafts too. I have seen shafts where no amount of force or WD40 will free them up and they have to be sawn apart. I recommend that after each use in the surf that the shaft be taken apart and washed down but I suspect that happens only rarely. I have tried designing jam free camlocks and shafts, but only with limited success. Anyone have a solution to this problem? Other than a one piece shaft, of course <IMG SRC="/forums/images/smile.gif" BORDER=0 ALT=":)">
Eric.
 
I have dealt with this company before and I have been very happy with them. I use their 1600maH NiMH AA cells which are really great little batteries, Dave. * * *
 
Hello Frank,
I noticed that each battery is rated over 9.5 volts for each battery. A unit using two batteries may be rated to use only 18 volts Max! Using two of those batteries that are 9.5 volts each may be too much for the unit "9.5 X 2 =19 volts" Make sure the unit can operate on this high current.
Also! Too much voltage may make the unit run more sensitive and may create chirps and pops or even more falsing?
I would rather stick with two batteries near the 9 volt level rated at 150 mAh. This is plenty for any high sensitive detector. I've tested different battery ratings. Sometimes, too much is not good <IMG SRC="/forums/images/smile.gif" BORDER=0 ALT=":)">
HH, Paul
HH, Paul
 
Eric
Thanks for the info and the email. Also thanks to all others that responded to my request.
Rick S
 
First to admit I am not up to date on electronics....But I have noticed I use a Olms meter to check my batteries as I sometimes get the new one and the used ones mixed up....When I do this checking the new batteries are always around 9.35 to 9.40 volts when new....Is this not real near the 9.5 that these advertise? And the 170 makes them just last longer at the 9.5 volts doesn't it? I own now 9 detectors and all of them use 9volt batteries...I am battery poor.... Frank
 
Hello Frank,
If the newer batteries are testing a little above 9 volts. Then, I would say that the designer factored this in to not overload the unit when new batteries are installed.
I would say that it may be safe to use those batteries that you posted. They will last a little longer.
Only two or three people can answer what the maximum voltage is for the Headhunter Pi. Eric Foster, Mr. Bill and Gary from detector Pro.
Thank you for sharing those neat batteries with the forum.
HH, Paul
 
Hi Frank and Paul,
As far as the Headhunter PI goes, the battery voltage goes straight to a voltage regulator, any voltage between 12V and 20V makes no difference to the performance of the unit.
Eric.
 
Frank:
When I last checked on these you had to buy a charger for each battery and then it took a long time to charge it so I kind of thought it was cost prohibitive to purchase them.Do they now make a charger that will charge more than one? I to would like to go to rechargable Nicads but haven't found a cost effective solution yet. I do know the CZ-20 only runs on 18 v even tho they have 4 9 v in series. I used regular rechargables and found them to go flat real fast where the alkies you can usually detect back to your vehicle to change them even when dead.If you found a good charger please let me know. I also think the Whites PI detectors have a voltage regulater in them if memory serves me right. Not sure of the others tho.
Steve
 
Hi,
The charger they sell for these is rated at 25ma. I checked my radio shack chargers specs and it reads 23ma so I asked my brother who is heavily into RC electrics if it would be sufficient to charge these batteries. He told me that the only diffierence would be in the charging time. It might take a few extra minutes charging to bring them to full capacity. If you have a decent charger already don't waste your money on theirs.
 
They advertise 8 to 10 hours to re-charge. I bought 4 batteries and two chargers. I will be using 2 batteries and have two in spare. When the two I am using go down I will charge them that night and then have them in spare. If I was to consider using them in the CZ20 (requires 4) I would keep Alk. in spare. With 170 amp hours per battery they should last a longtime. I understand it is the nature of a re-chargable battery to stay flat at a certain voltage and then fall off fast....that is normal...When they go, they go! Frank
 
Hello Eric,O
Once Frank mentioned that his new batteries tested a little above 9 volts. I knew then that the designer was aware of this and would factor this into the making of any detector.
You are correct about the Headhunter working even when the battery voltage is near the 12 volt level. My Headhunter Pi can go for long periods with the 8.4 volt 150mAh battery set. Making this 16.8 volts.
I don't worry about 9 volt batteries having a higher voltage rating above 9 volts. As long as the rechargeable batteries can maintain a steady supply of voltage for long periods, the unit will work fine even when the voltage is near the 12 volt level.
Thanks again,
Paul
 
Frank:
Now you see why I didn't go the Nicad route. It is just not cost effective for me to do it. I would need 8 batteries and 4 chargers to just keep an even pace with it. All this can buy me a lot of alkalines with better end performance. Thanks for the reply and was hoping you might have known about a charger that would charge more than 1 9v Nicad at a time.
Steve
 
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