Finding those elusive hammered coins:
by Roger |
So you’ve got permission to search a farm with your metal detector, your mind pictures all those ancient hammered coins just waiting to be found, you set out full of hope and expectation, only to end the day tired and disappointed, with a pouch full of coppers and non-ferrous junk, can’t be anything on that field you think, I’ll try another one next visit.
Yes that describes me perfectly 30 years ago, but things change, your experience grows, and after a year or two you think more about the methods you use, and the machines that better suite the mineralization and iron content of the sites you hunt.
Any metal detector will find coins etc, some are far better suited to some conditions than others, the frequency, recovery speed, sensitivity, discrimination etc, play a big part on whether you consistently find these elusive coins, or just find the odd one or two now and again.
An example of this is shown in an article published in TH magazine several months ago, where a dealer took out a very expensive machine to try on a badly iron contaminated site and found very little, next time he took the cheapest Tesoro he had in stock and found plenty, you would have thought it would have been the other way around, I took an interest in this article, because its exactly what I’d found when testing machines myself, so don’t think you’ll find more if you spend more, people who think like that are best left with their heads in the clouds, an expensive machine won’t make up for a bad technique, the fact is the mid range machines are the best value buy’s, they usually have the same circuitry as their expensive relations, but not as many bells and whistles, which tend to be mainly gimmicks anyway, with the money you save you can get some accessory coils, to enhance the versatility of your detector.
Right, where are we going to find these hammered coins then, well I’d say just about anywhere on farmland, due to the casual losses by farm workers many years ago. I cannot remember a site over the 39 years I’ve been detecting, that hasn’t produced at least a few hammered coins, and one of my sites that I call “Silver Field” has produced an amazing amount of hammered over the years. So where do we start on this new farm, don’t be tempted to flit from one field to another, pick one and draw a rough plan of the layout, then slap on the biggest coil you’ve got for your detector and do a union jack search of the field.
This entails going from corner to corner, side to side etc, you can move pretty quick when doing this, as all we’re looking for is where the iron is, or hotspots as they are known to many, make sure your sensitivity is turned up fairly high, so when the head is over iron the machine spits and cracks, you can use all metal to suss out the iron but I prefer to do it in discrim mode, make a note of where the patches of iron are on your plan of the field, as this is where the hammered and other goodies are waiting to be found, I know its hard to ignore positive signals when doing a reccy like this, but if you stop to dig every signal while sussing out the iron patches you’ll never get the job in hand done.
If you used a large coil to find the iron, now’s the time to switch to a more suitable coil, over the last year or so, first using the DFX and then the MXT, personally I start by using the 14 inch DD on my MXT, going over the iron patches very carefully, this is important as a tiny coin like a cut hammered quarter can sometimes only gives a blip of a signal when on edge which can very easily be missed, and usually is if your not concentrating and moving slowly, surprising what the 14 incher can pull out even with a fair amount of iron in the soil, after going over the area with the big coil getting the easier targets its time to change to a smaller coil, I found the 10×5 DD coil to be a top class coil for this type of detecting, with its narrow footprint you don’t get to much iron under the coil at one time to cause target masking, also the DD type coils handle mineralised ground better than concentric type, the small 5.3 eclipse is the one to go for if the iron is really heavy, it also gives good depth for a small coil, and obviously very good target seperation.
As far as machines go, any machine will find hammered on the cleaner sites, but from my experience machines that transmit on frequencies between 10 KHz and 20 KHz are the best at finding hammered coins consistently on contaminated sites. With the DFX capable of transmitting on a single 15 KHz frequency and the MXT on 14 KHz, both these machines fall into this category, and have so far proved deadly at picking tiny hammered coins from amongst the iron debris that litters most good sites in the uk, a couple of other machines worth a mention are the XP Goldmaxx, and Tesoro Tejon, all these machines have a lightning fast recovery speed which is vital when working amongst iron, some machines are just to slow for this type of hunting, and will only get the odd hammered that’s not to close to the iron.
The other important thing a machine must be capable of is finding the tiniest items, all the machines I use at the moment have found me Roman minims, the smallest coins ever made as far as I know, the last one I found a few weeks ago with my MXT had me on my knee’s trying to find it in the soil, a hammered coin on edge in the ground is a very small target, and cut halves and quarters even smaller, and a lot of machines just don’t see them when their in that position, with the right machine and coil to suit the amount of iron contamination, its amazing what you can pull out if you work very slowly and patiently.
A trick to make a machine more sensitive to smaller finds is to set the ground balance slightly positive, on manual ground balance machines this means the threshold rising slightly as the coil is lowered to the ground, on the whites XLT and DFX this means setting the Trac offset to at least +1, unfortunately on factory set ground balance machines and a few other auto-balance machines this is not adjustable, also with the XLT and DFX turn modulation off, to increase the audio on deep faint signals, when I say deep, 4 to 6 inches amongst heavy iron is a very good depth indeed on hammered, although you can’t manually set the trac positive on the MXT, the way it plucks the small stuff from the iron, suggests it may be factory set slightly positive, and it certainly has a very quick recovery speed, nothing between the DFX and MXT as hammy hunters in my opinion.
The one thing that stands out about these machines is, their not renowned for extreme depth capabilities, which is a lesson in itself, forget depth when looking for hammered amongst iron debris, the majority of coins are in the top 6 to 8 inches anyway, that is a fact as all experienced detectorists know, digging deep holes slows you down, which reduces your finds rate. And any deep ones will be nearer the surface the following year anyway, after the turn of the plough, best to concentrate on getting every thing out of the top 8 inches, than worrying about the odd deep find that may or may not be there.
Now we are set up and ready to go, sloooow is the word from now on, I usually move forward about a third of the coil width at a time, which believe me is slow, keep the coil very close to and level with the ground, and don’t try and swing to wide as this will cause the coil to lift at the end of each sweep, as we’re working on iron contaminated ground any iffy two way signals need to be checked out carefully, if working on ploughed land scraping a couple of inches off the surface with your foot and rechecking the signal usually does the trick, on firmer ground checking the signal from different angles can usually sort things out, another trick is to check an iffy signal in all metal, if its a faint and narrow response dig it, if wide and loud leave it, as its pretty sure to be deep iron, but if your ever in doubt always dig the target, I’ve found coins below fairly large pieces of iron by digging signals I’m not sure about, my finds increased when relying on my ears rather than meter readings to decide whether to dig or not.
Don’t forget when you’ve done an area say from north to south, to go back over it from east to west, its amazing what you find doing this, most coins found on the second sweep of an area at a different angle, are usually at an acute angle in the soil, showing more surface area to the coil on the second sweep, all this takes a lot of patience and willpower, but will show far more returns than someone who speeds around a site swinging the coil like a maniac, these people stand out at the end of the day when comparing finds, the smallest find they have to show is a plough shear, complete with plough lol.
If the finds are slow to come, don’t be tempted to try elsewhere, stick with it, keep concentrating and moving slowly, Its no coincidence that the best days are when you get a decent find early in the day, it makes you concentrate even more, and the finds usually start to flow nicely for the rest of the day, if you lose concentration or interest you may as well pack up and go home.
Well that’s the method that works for me, I’ve lost count of how many hammered I’ve found over the years since I started detecting, but if I’d kept them all, it would have been a hell of a collection by now.
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