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Magnetic Rake Mod Advice Sought


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My 'failure' in the category was to add rare earths to a shop sweeper like this:

https://www.amazon.com/Magnetic-Sweeper-Telescoping-Release-Extension/dp/B08MTHGVWG/ref=sr_1_11?crid=2PJNJUBLFSLUL&dchild=1&keywords=shop+magnet+sweeper&qid=1621834875&sprefix=shop+magnet%2Caps%2C975&sr=8-11

I wanted to use it in a known meteorite field on the edge of a dry lake.  It was a complete failure because the meteorites were sticking too hard to the surface.

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Update:  I made two mods to improve performance.  First is shown in the sketch.

magnetic-rake_mod.thumb.jpg.72b0f68b7b554ab125d0194cac349601.jpg

I replaced the supplied (weak) alnico magnets with neodymium N45's from Amazon.  In addition, I modified the mounting bracket to bring the magnets closer to the wall, adding pickup strength just due to the inverse cube falloff strength of typical magnetic fields.

The second mod is shown in the following photo.

magnetic-rake_locking-clamp.thumb.JPG.36f20d144f1098a106a6f1896a7a16b0.JPG

This clamp (with magnets shown aimed at the handle so in the 'off' position for transport) locks the internal frame and magnets in place so the internal frame/holder doesn't rotate unintentionally.  The clamp is reversible (right to left in the photo orientation) to keep the thumb screw heads distant from the ground, depending upon whether the fork tines are down (to contact the ground) or up (to allow the smooth edge to leave the ground smoothed).

The last mod (to be completed tomorrow) is to add an O-ring to the transition zone between hexagonal aluminum extruded tube and the black plastic endcap at one end.  That will take up the slack and most importantly (hopefully) make a seal to prevent magnetic dirt/sand from sneaking inside and jamming up the works.

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  • 1 month later...

Field Report:  I got to try this out at a NE Nevada ghost town.  As typical around old buildings (still standing or just the surviving foundation in this case) there are oodles of nails, etc., and many are simply on the surface in the desert environment.  I first used the rake side to clear the dead vegitation, then the magnet side to pick up the loose surface iron.  That led to more non-ferrous target hits than my detecting prior to the cleanup -- i.e. less masking.

The attachment clamp I made to keep the cylinder from unintentional rotation turned out to be a more time consuming step than planned (when I wanted to rotate the cylinder to easily clean off the iron+ferrous).  Also, the screw threads not surprisingly wanted to retain loose sand, etc. and risk damaging the connection.  Some kind of quick cam lock/release would solve both problems.

Is this the right tool for everyone and every situation?  Obviously not.  I emphasize its light weight which makes it easy to backpack or carry to a remote site.  If your vehicle (truck, trailer, 4-wheeler, etc.) can be parked nearby and accomodate a heavy rake+magnet that is more robust then that's likely a better solution.  If you like low weight, particularly if you're packing tools and detector for quite a distance, this will clear small loose surface trash nicely and not wear you out with extra weight to carry.

P.S.  I had hoped to do some desert gold detecting in NW Nevada around old miner's dwellings (where this rake also would have had usefulness) but by the time I got a chance the daytime highs were over 100F.  Even if I got up at dawn to hunt until it got hot, what was I going to do the rest of the day, and how long would I have to wait in the evening for my vehicle to cool down before I could sleep?  (No AC for this cheapskate, nor a shower for that matter....)  Instead I headed to 9000 ft. in the Colorado mountains just south of the Wyoming border.  Not much trash there other than the usual lead bullets and brass casings and occasional discarded barbed wire.

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I read your post on Monte's site and sounds like you and your sister had great time. Ghost towns are tough to hunt, sometimes it's the amount time you put in hunting a site and the layout of the town to get the good finds.

My wife and l would like to make one of the outings in the future.

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GB_Amateur ... thank you for sharing this information ..., because of course, just like you, I also consider the effective possibility of removing iron from the ground up to approximately 5 cm ...
As a gardener, I used a motor cultivator for years to prepare the terrain before planting the lawn .., and several times I had a similar opportunity to cultivate terain to depths of 5-7 cm and then subsequently remove the iron, for example with magnetic rakes ...

.....since every year I have 2-3 months as a combine driver...so I have ideas how to do it more than enough ..where moving 10cm thick soil takes a moment ,, just attach some magnetic device /separator/to remove iron from the soil ..and of course it needs to be miniaturized to the size of a lawn mower...

 

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5 hours ago, GB_Amateur said:

Field Report:  I got to try this out at a NE Nevada ghost town.  As typical around old buildings (still standing or just the surviving foundation in this case) there are oodles of nails, etc., and many are simply on the surface in the desert environment.  I first used the rake side to clear the dead vegitation, then the magnet side to pick up the loose surface iron.  That led to more non-ferrous target hits than my detecting prior to the cleanup -- i.e. less masking.

The attachment clamp I made to keep the cylinder from unintentional rotation turned out to be a more time consuming step than planned (when I wanted to rotate the cylinder to easily clean off the iron+ferrous).  Also, the screw threads not surprisingly wanted to retain loose sand, etc. and risk damaging the connection.  Some kind of quick cam lock/release would solve both problems.

Is this the right tool for everyone and every situation?  Obviously not.  I emphasize its light weight which makes it easy to backpack or carry to a remote site.  If your vehicle (truck, trailer, 4-wheeler, etc.) can be parked nearby and accomodate a heavy rake+magnet that is more robust then that's likely a better solution.  If you like low weight, particularly if you're packing tools and detector for quite a distance, this will clear small loose surface trash nicely and not wear you out with extra weight to carry.

P.S.  I had hoped to do some desert gold detecting in NW Nevada around old miner's dwellings (where this rake also would have had usefulness) but by the time I got a chance the daytime highs were over 100F.  Even if I got up at dawn to hunt until it got hot, what was I going to do the rest of the day, and how long would I have to wait in the evening for my vehicle to cool down before I could sleep?  (No AC for this cheapskate, nor a shower for that matter....)  Instead I headed to 9000 ft. in the Colorado mountains just south of the Wyoming border.  Not much trash there other than the usual lead bullets and brass casings and occasional discarded barbed wire.

Very cool concept. Wish the farmers here would drag for nails 😀

Are you going to post finds from this trip? Sorry to read that it was too hot to hit the mining camps.

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10 minutes ago, F350Platinum said:

Are you going to post finds from this trip?

The finds were pretty lean, especially for native gold, but I will make a post.  This turned out to be another 'learning experience' which is always welcome, but kind of a consolation prize, if you know what I mean.  🤔

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59 minutes ago, GB_Amateur said:

The finds were pretty lean, especially for native gold, but I will make a post.  This turned out to be another 'learning experience' which is always welcome, but kind of a consolation prize, if you know what I mean.  🤔

Had one of those days myself in the river. Unless I go deeper there isn't much going on. Tried beach 1 underwater today, the 10x5 sees things a bit differently.

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