# hydraulic press and rolling mill



## Grassbur (Mar 31, 2012)

I have a few questions on some equipment that I’m thinking of getting, but I’d like to know a little more about it. I have read that the only way to correctly make 1 ozt. And 10 ozt bars is done via rolling mill, punching blanks, and then pressing with a die. The answers I am seeking is do I need a hot rolling mill, or is cold rolling feasible. The 2nd question is will I be able to use the same hydraulic press for punching and pressing and what ton is needed. Some of my thoughts have been a jewelers rolling mill but I am thinking that will be a bit small. My other thought was a 120 ton H-frame press. My final question is if you were to do this would there be any suggestions on the equipment needed. The reason I want to do this is so that I can make bars for myself of high quality and family members, similar to the current NTR and Engelhard bars. Also if there is any reading that you might suggest for me that would be grateful also.


----------



## Dan Dement (Mar 31, 2012)

Grassbur,

I am a jeweler and have quite a lot of equipment. What you are talking about is serious, heavy duty equipment that a large metal foundry would use. Now, it's no problem to make a reasonable price gold bar by melting and putting it into an ingot mold. Now, NTR owns part of Roseco which is a good sized Jewelers material house and I don't believe they make the triangle bars anymore. To make a 10 oz ingot bar of low quality is not a problem but to make one of high quality like an Englehart or even a coin is a totally different issue. To roll a hot ingot in a ten oz bar is beyond the height capacity of most rollers. Understand that these rollers are designer to roll different thicknesses of wire and sheet and use a set of gears to move both rollers. The gears have tapered teeth and most larger bars are not going to work as that's not what a mill was designed to do. The inch plus thickness puts the gears out of their range of engagement. 

To take 10 oz of pure gold and pour into a 10 oz graphite ingot mold is fairly easy task. Almost no waste but certainly a low quality piece of metal with no edges or letters. To laser engrave this bar is agiian an easy thing to do if you have the $40,000 laser engraver. Now, to make a pretty , jewelry quality bar similar to a finished Englehart can be done without all the equipment you are interested in but it's like making a quality piece of jewelry. You will have waste and metal lost. Most caaasting equipment is not set up to cast 10oz pieces of jewelry but would certainly be cheaper than spending the many tens of thousands of dollars necessary to do it correctly. Just depends on your budget and how many you want to produce. It's like a car, the first cost millions to produce and 1,000,000 cost thousands to produce. 

It is possible to make a hardened steel die and die strike blanks. Just depends on budget.

Good Luck with your project.
Dan


----------



## butcher (Apr 1, 2012)

Dan, I am no jeweler so I will ask this question.

Could he make a simple lost wax cast of a coin or bar, or carve a fish cuttlebone, or even book end type graphite mold? pour in the gold, maybe make the sprue like a loop on a necklace trimming this sprue to get weight to desired weight, or just stamp poured weight and purity, basically like making a ring, except a bar or coin shape, or even solid pure gold marbles, I have a black powder bullet mold with two wood handles, maybe replace iron block in it with a graphite block, what do you think?


----------



## nickvc (Apr 1, 2012)

Butcher all possible but repeated use of the moulds will create less and less of an appealing product.
Lost wax castings need polishing at least to get a decent surface finish so getting an ounce or exact weight is not easy. As Dan pointed out the only way to get a perfect product is stamping and the costs are out of the reach of most members, with my background been the manufacturing base here in the Jewellery Quarter I have access to sheet and strip production and stampers but the costs mount rapidly and you can see why small bullion bars and coins carry a hefty premium.
By melting your fine metal into grain and weighing the exact amount needed and then remelting in a graphite mould you can create a reasonable product but the moulds suffer very quickly and unless you can mill your own not cheap, controlled atmosphere melting also helps with finish and the life span of the moulds but again beyond most members.
Simple truth is there is no cheap way to make quality bars or rounds like you can buy


----------



## Geo (Apr 1, 2012)

i saw a documentary about how the US mint makes gold coins and even after stamping the blank rounds they still have to be trimmed to exact weight. if the mint cant stamp a round with exact weight i doubt any one can. how ever, you can stamp a round and mark the exact weight. if the round is a tad overweight, then really, who is going to argue the point, if not you.back when coins were struck by hand, the aesthetic quality wasnt as important as the accuracy of the weight. but some argue that hand struck coins are more beautiful than machined coins because each coin has its own character. as a thought, you could weigh the exact amount of gold and then strike each by hand.pure gold is so malleable, that you could start with a round ball and with a decent die, strike a beautiful coin with a hammer. any reputable machine shop can make a simple die with a logo and weight engraved.


----------



## Dan Dement (Apr 1, 2012)

Butcher,

A lot depends on hat size coins or bars you are wanting to do. No problem to make smaller items but you got lots of labor to make smaller items. If you see the special on gold, Stuller is the largest caster of gold in the US. The average cost of a Stuller casting is 50% plus over the price of the gold. When you can buy a Mapleleaf for $50 bucks over gold, How are you going to bet that. Sure the US Mint can do it! NTR us to make the one oz triangle bars but I don't think they make them anymore. The real question is: Can you do it for the same or less money? The answer to that is real simple: No and even Heck No! I have four full time people in the employment of making jewelry. All are well paid and are employees not 1099 paid. Can you buy the equipment necessary, pay the employees, rent, and everything else involved and do it for ANYWHERE near what you can buy a commercially made coin. Double heck NO

To makke a rubber mold, you got to first make a master. Now I got an $80,000 plus Rapid prototyping machine so it's no problem. My CAD operator has got to get paid. So, you got $100 bucks to make the model mininum. What to make a rubber mold or a good Steel model. $100 to $1,000. Now to got to shoot the model and make a tree to make 50 of them. One oz coins on a tree to make cast, you got several hours work plus 100 oz of metal. Plus now you need 100 oz of metal to cast 50- 1 oz coins. You got to have HUGH equipment to make the investment, burn it out, Hugh casting machine for 100 oz, cst it, devest it, cut it off the tree. Now you got to cut of csting spruea nd make all the metal shinny without pits. Not so easy to do. Lots of time, money, waste! And, you want to do it cheap!

Does not pay. Can it be done? Sure it can. I do harder stuff all day long and in more difficult metals than gold. Now can it be done and will a customer pay the price?? NO WAY. Happy to have come and give it a try if you don't believe me. Just pay my employees time and you can use my stuff for free.

Dan


----------



## Grassbur (Apr 1, 2012)

Just to be clear this is what final product i was hoping to accomplish. Again thanks for all your input on the matter. I have found it very hard to find out all the needed equipment to do it on any scale, and was hoping to be able to do this on a small scale. But I also wanted to get the info out on the forum for any others that wanted to know how, even if its not economic. Mainly because through many post that I have read on the forum many members have thought that they can "reinvent the wheel" as Harold has put it so many times when people want exact weight ingots. If I were to do this, or wanted to do I really wanted to know the fact's on how, even if I cant. Maybe I just like being a know it all on the passions I have. So to be clear the only way to achieve a product of this quality, is to use a industrial hot rolling mill (which is very expensive), and a blank on a press, and then strike it with a die? the other question I have is what ton of press is needed (yes I would like to know even if for the know how). one of the reasons I ask is I have seen one member on this forum produce a very nice quality bar in gold is Elfixx. Thanks again for all the input you all have given.


----------



## Dan Dement (Apr 1, 2012)

Grassbar,

The cheapest way of doing it is to get Elfixx to make them for you! I have almost $500,000 worth of equipment and I can't make this. I can cast it but no way can you get a shiny flat surface with raised border and letters without die striking it. I got lots of toys and make complicated platinum jewerly but that does not work for what you are wanting do. I buy these all the time for $20 bucks over metal up to $50. over metal. How much money do you want to lose in trying to complete your idea? NTR is a Billion dollar company and they stopped selling the gold triangles for 2%-3% over. Does that tell you something? Let's say you do it and you just dropped a minimum of $500,000 and now you want to make a 1000 pieces! Who is going to buy yours when you can buy a name brand for 3% over. Now they are sold, who is going to trust them? 

Excuse me, I have dreams too and I don't want be mean and come off as an a**hole but In My Humble Opinion, no way will this work! Not trying to hurt your feelings, just trying to be realistic!

Good Luck,
Dan


----------



## nickvc (Apr 2, 2012)

I must admit I totally agree with Dan this isn't possible to do on the cheap.
I have said before I have all the necessary skills and equipment around me here in the jewellery quarter including a mint but none of the necessary steps to produce your own bars or coins are cheap and the only economy is in scale, if you produce tens of thousands it reduces the cost of each.


----------



## MysticColby (Apr 2, 2012)

Let's say you weren't shooting for perfection.
Could it be possible to pour a 10 oz ingot, put in a die, press to x number of tons, and get something with your specialized logo and approx weight stamped on it? No rolling, just a hydraulic press. It would look less perfect than that Engelhard, but that's what gives it character, and your family would no doubt prefer the hand-made look to industrial-look.
How much pressure might be necessary for that? for pure gold and silver, I would guess not an ungodly huge amount.


----------



## Geo (Apr 2, 2012)

with enough force, you can press gold into just about any shape. with gold already being soft, its not impossible to make a die to make a beautiful bar (with enough money). the general shape can be poured and then pressed to form the design.


----------



## Dan Dement (Apr 2, 2012)

Just depends on what quality bar you want to produce. I think the first thing you want to try is to figure your dimensions of the bar you are trying to produce. I would then make you a rough model out of an iron ingot mold. Get your 10 oz's of pure and get your weight correct. From this rough weight, you will need a three to four piece steel master die made. I say three to four pieces as the top and bottom are going to need to come off and perhaps you might need to take the center section apart to get a clean master die. This master die is going to be CNC'ed out of some high carbon steel and be heat treated to hold up. I would think that the rough model needs to slightly smaller and slightly taller than the finished piece. Get a Big A** Hydraulic press or better yet, try to find someone who might already have one and see if you can rent it. Put in your $16,000 worth of gold, heat it up to about 600F and press the crap out of it. Hopefully, you will succeed in your project. I sure you will need to coat the die's with some type of lub to help make sure it would come apart. I think the first thing I would try to find is someone with the press because I am sure it has some requirements on size and construction of the die's. If someone has the press, I would think they could send you a die maker that would work with the press. 

If you can't find a big press, try googling a press manufacturer and ask for a demo. I would think that you could find a used one as sure lots of heavy metal manufacturing places have gone out of business, I would check with any foundries or big machine shop to see what equipment is out there. You alsmost try some of the "giveaway" coin manufacturers but 10 oz of gold is not your regular giveaway size. Boils down to budget. I would suggest trying 1 oz's first. Going to be a lot easier to do .

Good Luck,
Dan


----------



## Lou (Apr 3, 2012)

I'd try sunshine mint.

Failing that, you can always just spend the beaucoup bucks on one of these:

http://goldmachinery.com/machinery/TunnelKilobar.htm


----------



## Dan Dement (Apr 3, 2012)

Grassbar,

I found you a 30 ton or so stamping press. I say 30 ton but I think I am on the conservative side because of the size of construction of this BIG BOY, I would not be surprised if it was a lot more than that. I have a picture of it on my iphone and if you PM your wmail or phone I will send it to you. Now, it used government surplus and your going to need a pretty good sized trailer to move it. Understand, it needs some TLC but appears to be in sound condition. If $3500. does not interest you then I have an even cheaper deal. How about a 5-6 inch hydraulic jack. I got a friend that has several that are use to lift a fully loaded B52 bomber. How he was some short ones and he has some that are 4 feet tall. I am sure that you could heat up 10 oz and compress it with these big boys. 

Or, send the $1 million plus, hey don't forget the refinery part plus the metal! Now, you might be able to get this thing to work rigging up either one of these Government surplus big boys. You stil have to get your dies made. Depending on condition, I think you can buy the smaller hy. jacks for around $300 and the big ones for $800. bucks. You might have to rebuild them and build you a frame but it nothing ventured, nothing gained. I made a liar out of myself and found a cheap way of doing it if you want to make the effort. 

Dan


----------



## Grassbur (Apr 3, 2012)

I can get a 100 ton bottle jack no problem, I have found several on the internet and have a buddy that owns a steel erection business and have talked to him about making a H-Frame out of small I-beams and mimic similar designs of equipment out there. I am not currently working with gold. I am working with silver and have refined around 300 ozt .999 Ag so far. I am not trying to do exactly what englehard has done with the bars, just the main concept. I currently have logo's and other designs ready. Another buddy of mine does CNC and EDM machining to make die's with. More then likely I wont be using raised letters, it would be recessed. I do understand that the more surface area of pressing that needs to be done would require more tonne's. However I am not experienced in the coining aspect. I guess what I really was looking for was a formula that I could use to determine if the tonnage I had in mind was correct. Or if I did not need that much. Other information that I was confused on was when I have read about rolling mills I have seen some that range from 50mm - 150 mm and if these were the maximum thickness of final sheets. It would not be a problem to anneal the metal in between passes if needed or does the metal have to be Hot during the time of rolling. I understand that a final product of the exact same of big guys my be out of my reach but if say I needed to a 1.5 cm thick bar is ok with me, it might just end up needing to be longer & wider. Which if i understand correctly would change the tonnage required. So these were some of the bigger questions I have. Before I go out and buy or start getting help in building a press, I wanted to be able to know exactly what was required, and I have found very little information or books on this, maybe I have not looked or asked the correct questions yet. When I do begin to press gold I do not believe I would want to press 10 ozt bars of it. because of the sheer cost in the PM's I would leave those in 1 or 5 ozt. But with silver being much cheaper 10 ozt. bar's is an ideal amount.


----------



## nickvc (Apr 4, 2012)

The big boys use continuous casting machines to produce the initial sheet or strip for the rolling mills although a well cast bar could be used but the runs would take longer, from the cast strips they then put the billets through a braking mill, this does exactly what it sounds like it reduces the metal fairly rapidly but the finish is likely to be poor so it then goes through the finishing rolls, high polished rolls to give a good surface finish. From there the now correct thickness sheet/ strip is put through the shearing mill which cuts the strip to the correct width and removes the edges which will be unusable and wouldn't fit into the presses normally automated for striking the blank / bars out and then the blanks are put into a final die and struck with the required design, this is all heavy duty kit for the size your thinking of, the good news is the metals won't need annealing as in pure form they should stay malleable. 
I remember going round the Royal Mint and stood amazed watching banks of presses bashing out £1 coins, 20,000 an hour ! As I walked round the mint there were coins everywhere, on the grass, paths floors in the mill but as you entered you were told to remove all coins from your pockets and as you left you went through a metal detector so if you left any in your pockets they weren't coming out :shock: 
Bottom line in my opinion your going to struggle to get the required finish and the cost of the mills and presses and the space required would be fairly large but if you changed direction slightly and say had rounds cast to the correct weight you could just them stamp a design with dies and one press and the act of stamping the design should improve the look of the finished product. A little hand finishing would be required as in removing the sprues and I would aim to have the blanks slightly overweight to allow trimming to get the correct weight, modern casting techniques should be able to produce pretty consistent castings but the weight of the coins would probably need reducing as large castings would be more prone to surface problems but the costs and the scrap ratio would much less,
not perfect but possible with some messing and much less upfront costs, this all allowing for the fact that you can find an outwork caster who would be willing to do the prototypes and then cast the products with your metals to a decent standard and at a reasonable cost.


----------



## Oz (Apr 4, 2012)

Look at this members equipment and posts. Perhaps you should contact him through his website.
http://goldrefiningforum.com/phpBB3/memberlist.php?mode=viewprofile&u=3686


----------



## Harold_V (Apr 6, 2012)

Grassbur said:


> I can get a 100 ton bottle jack no problem, I have found several on the internet


There's no way in hell you'll be able to produce a 5 ounce silver ingot with that little amount of tonnage. You'd do good to be able to produce a 1 oz bullion coin. As you implied, the surface area determines the tonnage required, and it's one hell of a lot, although I can't provide a formula. 

Nick implied that you may not have to anneal pure silver and gold after rolling, but my experience dictates that you will have to. I rolled a small ingot of gold (about 2½ ounces) to make an anode for plating. When it was down to about .035" thick, it was stiff and could support itself when held horizontal. After annealing it bent at my fingers, of its own weight. Most metals work harden when worked cold, so figure you're going to have to anneal if you roll. The resulting material will be far easier to strike if it starts annealed, too, so don't discount the importance. 
Rolling is accomplished cold, not heated. Some metals suffer with being hot short---meaning that when they're hot, they crumble. I can not speak for gold or silver, but I expect they may be. No matter, it would be extremely difficult for a small producer to roll material that was heated. 

Harold


----------



## Dan Dement (Apr 6, 2012)

Harold,

First he has to establish what size coin or bar is talking about. Lots of difference in a one bar and a 10 oz bar in trying to make an ingot. Unless you are going to send mega bucks which is not what we are talking about here, the Englehart bars are not obtainable at this price point. Lots of difference in doing Silver and gold is just metal so I really think we are talking about Silver. Going to take more heat to get the silver to move around. I can see melting and pouring into ingot mold thin pressing a die into it using a couple of big hydraulic press. I think at a 10 oz thickest, no way are you going to find a roller unless it comes out of the steel rolling industry. No jewelry size roller is going 2-3 inches or at least none that I have seen. Would it be the quality he is looking for, No IHMO. Would it have acccepted in the trade, No. Is it going to worth the time , effort, and expense, No. If he is trying to do it on the cheap, and wants to spend the $10,000 for the chance it might be acceptable for his purpose, we all got our dreams! 

I make my living manufucturing Platinum and Palladium Jewelry which is a heck of lot harder than doing this bar. It not that you can't do it, you just can not do it as cheap as you can buy one already done. It's just a matter if wants to spend the time, money , and effort to spend the $10,000 to make a low quality bar he can buy for a $.30 preminum over metal.

Not trying to be a critic, I just do this everyday. I wish him luck and look forward to seeing his results. I hope he proves me wrong!

Dan


----------



## grainsofgold (Apr 17, 2012)

Why re invent the wheel and spend all the time and money?

Many companies that already have the equipment and knowledge will make bars / ingots to your specs for a fee. 

Add the fees to what the metal cost you and you are off running. 

But as Dan pointed out, the end product will only still sell for what the market will bear which isn't much over spot.

Reminds me of the mellon seller that bought mellons for $1 each and sold a 1000 of them for $1000 , then decided he needed a larger truck to be able to sell more and make more.


Unless you can add value of some sort to the bars/ingots you sell you would be better off not investing in the expensive equipment unless it's for a hobby and enjoyment.

Just my humble opinion.


----------



## etack (Apr 17, 2012)

you could ask the member that does it elfixx.

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=61&t=11246&p=125757&hilit=+stamp#p125757

Eric


----------



## Harold_V (Apr 18, 2012)

Dan Dement said:


> Harold,
> 
> First he has to establish what size coin or bar is talking about. Lots of difference in a one bar and a 10 oz bar in trying to make an ingot.


Seems to me like that's exactly what I said--and that 100 tons isn't enough, especially for five ounces. He commented on anything from one ounce up to ten ounces. Bottom line is, 100 tons will do a job (not great) on a one ounce medallion, and won't be enough for anything larger. 



> Going to take more heat to get the silver to move around.


Not sure where you're going with this comment. Silver melts at a lower temperature than gold ---and it is not rolled hot. Can you please clarify?

Harold


----------



## buckdec (Apr 18, 2012)

So what if you have access to a laser printer graphite mills and Cnc machines what would be the best way of getting a silver bar still just melt and pour into a graphite mould?


----------



## Harold_V (Apr 18, 2012)

You will NEVER achieve a great bar by pouring, assuming you're trying to compare the bar to a die struck bar. That's not to say you can't pour nice looking bars. You can, but it's not easy., especially without expensive equipment. 

Pouring to a graphite mold, without atmospheric control, isn't a good idea. The mold burns away constantly, so life is limited. Again, that's not to suggest it doesn't work---it does. Just not a good idea. 

There's no real substitute for die struck ingots, although the differences are strictly cosmetic. Don't lose sight of the real purpose in pouring ingots---it's to store and sell metals in a compact and easy to handle form---nothing more. Die struck ingots are sold for profit---not convenience. 

Harold


----------



## nickvc (Apr 18, 2012)

You can produce an exact weight by having shot and filling the graphite mould and melting, the problem is the moulds life is short unless you use a controlled atmosphere, argon I believe.
The finish isn't brilliant but the weight is right.

I still think the best way to get personalised products is to produce a pattern and have them lost wax cast, bear in mind that large plain areas are harder to get a decent finish on so some patterning would make it easier. We had an era of ingots as jewellery so many patterns are still around, unused maybe, but still extant that could be the basis for a personalised product. These bars were anywhere from 1/10 th ounce to 1 ounce mini ingots, they would need finishing but that could be done in-house fairly easily and we all have the means to recover and refine the waste thanks to Hoke..
To make them acceptable worldwide maybe alloy them back down to a karat product or sterling silver and send batches to a UK assay office for hallmarking where you can even register your own mark, proof of the content and a lot cheaper than trying to get individual bars tested and provide certificates for each.
There is a limit to size as large castings tend to be hard to get a decent product but a lot more cost effective than many other methods available.


----------



## etack (Apr 18, 2012)

buckdec said:


> So what if you have access to a laser printer graphite mills and Cnc machines what would be the best way of getting a silver bar still just melt and pour into a graphite mould?



You could mill the bars like APMEX
http://www.apmex.com/Product/50645/100_oz_APMEX_Silver_Bar_999_Fine_IRA_Approved_.aspx

All and all unless you get your Ag cheap you will lose money.

whats funny is you will spend thousands of dollars on the equipment to do this when APMEX and NWTmint had their silver for under a dollar over 

$0.65 over spot- spot.http://bullion.nwtmint.com/silver_nwtmintbullion.php
$0.99 over spot- http://www.apmex.com/Product/55208/.aspx?utm_source=HomePage&utm_medium=FlashBanner&utm_campaign=041712SSM


Eric


----------



## jimdoc (Apr 18, 2012)

Just to let everyone know, Northwest Territorial Mint takes months to get your order. They seem to always be a few weeks past the already lengthy expected delivery date. The price is good if you can deal with the wait, but with the way silver prices are, who wants that?

I checked my receipt. I ordered on Sept 23, and was told 8 to 10 weeks. I received the order on Jan 17.
That is a very long time to wait and watch the prices swing up and down the whole time. Especially the down swings.

Jim


----------



## etack (Apr 18, 2012)

jimdoc said:


> Just to let everyone know, Northwest Territorial Mint takes months to get your order.



yeah I've never ordered from them,and I read that on reviews; however $0.65 over spot with free shipping is a good price if you will wait. 

Eric


----------



## jrmycooke (May 10, 2012)

If I may, just out of curiosity, how did the Romans and other eastern countries produce their currency in the middle ages. You can still get a coin from B.C times that still have raised letters. Weights and measures were very important that time.


----------



## etack (May 10, 2012)

With a hammer, stamp, and slave labor. 8) 

Eric


----------

