FMTM 1 1

[Hoghead515]

Im reading @RWBbook  From Mine To Mint again and Im on the section talking about striking pressures. For example the quarter eagle needed around 92 tons per square inch. How do they calculate the area of the die? Does that include all 3 dies or just the striking die when they are talking about square inch? Im guessing they are only talking about the face of the die also aint it? Or the entire die? I wish I could find a diagram somewhere that showed pictures that demonstrate  how they calculated it. I looked through the internet and couldnt find anything. I wondered also how they figured how many tons was being applied. What kind of equipment was used to measure that sort of thing in the 1800s and early 1900s. Im very facinated by how intelligent and innovative they were in those days.

[GoldFinger1969]

I'm sure The Man Himself will be around soon to answer your questions. 

 

[zadok]

On 1/30/2022 at 9:46 AM, Hoghead515 said:

Im reading @RWBbook  From Mine To Mint again and Im on the section talking about striking pressures. For example the quarter eagle needed around 92 tons per square inch. How do they calculate the area of the die? Does that include all 3 dies or just the striking die when they are talking about square inch? Im guessing they are only talking about the face of the die also aint it? Or the entire die? I wish I could find a diagram somewhere that showed pictures that demonstrate  how they calculated it. I looked through the internet and couldnt find anything. I wondered also how they figured how many tons was being applied. What kind of equipment was used to measure that sort of thing in the 1800s and early 1900s. Im very facinated by how intelligent and innovative they were in those days.

...surface area of the quarter eagle die be approx .394 sq in.......

[Hoghead515]

On 1/30/2022 at 12:41 PM, zadok said:

...surface area of the quarter eagle die be approx .394 sq in.......

Thank you my good friend. I was wondering where they was figuring the area. 

[zadok]

On 1/30/2022 at 12:46 PM, Hoghead515 said:

Thank you my good friend. I was wondering where they was figuring the area. 

...im not knowledgeable nor want to be bout striking pressures but assume they had the means of adjusting the pressure depending on the size n type of alloy of the coin being struck...

[zadok]

On 1/30/2022 at 12:46 PM, Hoghead515 said:

Thank you my good friend. I was wondering where they was figuring the area. 

...i also assume that the chocolate coins in gold foil took much less striking pressure but of course they would need to calculate in room temp too...

[Hoghead515]

On 1/30/2022 at 12:50 PM, zadok said:

...im not knowledgeable nor want to be bout striking pressures but assume they had the means of adjusting the pressure depending on the size n type of alloy of the coin being struck...

I love mechanic work and how machines and engines work. And anything else machine related. I never was any good at all the technical figurings. 

[RWB]

Hope this will help a little ---

How do they calculate the area of the die?

Does that include all 3 dies or just the striking die when they are talking about square inch?

I'm guessing they are only talking about the face of the die also ain't it? Or the entire die?

I wondered also how they figured how many tons was being applied.

What kind of equipment was used to measure that sort of thing in the 1800s and early 1900s.

 

Die area was calculated by the formula A=πr^2.

Measurements were made inches, Avoirdupois pounds, and English tons (2,000 lbs per ton). Metric was not used. Pressure referred only to the face dies.

There were no really accurate means of determining coin or medal striking pressure until the 20^th century. There were a lot of ways to estimate and at least get approximately the same pressure for each coin diameter and alloy.

Mint documents usually refer to pounds per square inch, but it is not always clear if this is an idealized number or calculated for the actual area of the dies. An example of confusion is between small cent and quarter eagle pressures. Both were made on small toggle presses and the actual force was nearly the same, yet some sources have very different pressures. This table, from the early 1930s indicates pressures based on die area, and is thus more nearly accurate than earlier ones. Notice that quarter eagle and dime pressures are the same, and cent pressure is just 5 tons greater. Coins of similar size used similar striking pressures.

  

A toggle press produced the same force with every blow. Force was proportional to the size of the press and length of lever. A press of a certain size could produce only a limited range of striking pressure due to this mechanical limitation.

Toggle presses had a wedge shaped spacer above the upper die. This controlled the amount of force (“pressure”) applied by the upper die to a planchet. (The lower dies was usually a passive part.) This wedge was moved in or out to change the working distance and thus the proportion of available pressure between die and planchet. (It’s a little like using a log splitting wedge – a small wedge will not split a large log, and a large wedge might rip apart a small log.)

After hydraulic railroad wheel-set presses came into use, companies developed tables of force in tons necessary to bind wheels to axels. These quickly evolved into more general purpose tables showing the measured hydraulic force necessary to press machine parts and eventually strike coins and medals. We see greater consistency in Mint information after this time, although they are still estimates until the Philadelphia Mint acquired an hydraulic medal press in 1892 and put it in service the next year. Lengthy tests were made of coinage dies and alloys in order to calibrate toggle press size and wedge settings. The goal was more consistent coinage and elimination of guesses/opinion by press foremen.

Edited January 30, 2022 by RWB

[GoldFinger1969]

On 1/30/2022 at 2:20 PM, RWB said:

Hope this will help a little --- How do they calculate the area of the die? Does that include all 3 dies or just the striking die when they are talking about square inch? I'm guessing they are only talking about the face of the die also ain't it? Or the entire die? I wondered also how they figured how many tons was being applied. What kind of equipment was used to measure that sort of thing in the 1800s and early 1900s. Die area was calculated by the formula A=πr^2. Measurements were made inches, Avoirdupois pounds, and English tons (2,000 lbs per ton). Metric was not used. Pressure referred only to the face dies. There were no really accurate means of determining coin or medal striking pressure until the 20^th century. There were a lot of ways to estimate and at least get  approximately the same pressure for each coin diameter and alloy. Mint documents usually refer to pounds per square inch, but it is not always clear if this is an idealized number or calculated for the actual area of the dies. An example of confusion is between small cent and quarter eagle pressures. Both were made on small toggle presses and the actual force was nearly the same, yet some sources have very different pressures. This table, from the early 1930s indicates pressures based on die area, and is thus more nearly accurate than earlier ones. Notice that quarter eagle and dime pressures are the same, and cent pressure is just 5 tons greater. Coins of similar size used similar striking pressures.

  

A toggle press produced the same force with every blow. Force was proportional to the size of the press and length of lever. A press of a certain size could produce only a limited range of striking pressure due to this mechanical limitation. Toggle presses had a wedge shaped spacer above the upper die. This controlled the amount of force (“pressure”) applied by the upper die to a planchet. (The lower dies was usually a passive part.) This wedge was moved in or out to change the working distance and thus the proportion of available pressure between die and planchet. (It’s a little like using a log splitting wedge – a small wedge will not split a large log, and a large wedge might rip apart a small log.) After hydraulic railroad wheel-set presses came into use, companies developed tables of force in tons necessary to bind wheels to axels. These quickly evolved into more general purpose tables showing the measured hydraulic force necessary to press machine parts and eventually strike coins and medals. We see greater consistency in Mint information after this time, although they are still estimates until the Philadelphia Mint acquired an hydraulic medal press in 1892 and put it in service the next year. Lengthy tests were made of coinage dies and alloys in order to calibrate toggle press size and wedge settings. The goal was more consistent coinage and elimination of guesses/opinion by press foremen.

How on Earth did you get all that information ?  Even if it was recorded on some obscure papers.....who bothered to write all that technical data down....who saved it....who preserved it.....how'd you find it ?

Wow....impressive....most impressive, as noted coin collector Darth Vader would say. 

[Hoghead515]

On 1/30/2022 at 2:20 PM, RWB said:

Hope this will help a little ---

How do they calculate the area of the die?

Does that include all 3 dies or just the striking die when they are talking about square inch?

I'm guessing they are only talking about the face of the die also ain't it? Or the entire die?

I wondered also how they figured how many tons was being applied.

What kind of equipment was used to measure that sort of thing in the 1800s and early 1900s.

 

Die area was calculated by the formula A=πr^2.

Measurements were made inches, Avoirdupois pounds, and English tons (2,000 lbs per ton). Metric was not used. Pressure referred only to the face dies.

There were no really accurate means of determining coin or medal striking pressure until the 20^th century. There were a lot of ways to estimate and at least get approximately the same pressure for each coin diameter and alloy.

Mint documents usually refer to pounds per square inch, but it is not always clear if this is an idealized number or calculated for the actual area of the dies. An example of confusion is between small cent and quarter eagle pressures. Both were made on small toggle presses and the actual force was nearly the same, yet some sources have very different pressures. This table, from the early 1930s indicates pressures based on die area, and is thus more nearly accurate than earlier ones. Notice that quarter eagle and dime pressures are the same, and cent pressure is just 5 tons greater. Coins of similar size used similar striking pressures.

  

A toggle press produced the same force with every blow. Force was proportional to the size of the press and length of lever. A press of a certain size could produce only a limited range of striking pressure due to this mechanical limitation.

Toggle presses had a wedge shaped spacer above the upper die. This controlled the amount of force (“pressure”) applied by the upper die to a planchet. (The lower dies was usually a passive part.) This wedge was moved in or out to change the working distance and thus the proportion of available pressure between die and planchet. (It’s a little like using a log splitting wedge – a small wedge will not split a large log, and a large wedge might rip apart a small log.)

After hydraulic railroad wheel-set presses came into use, companies developed tables of force in tons necessary to bind wheels to axels. These quickly evolved into more general purpose tables showing the measured hydraulic force necessary to press machine parts and eventually strike coins and medals. We see greater consistency in Mint information after this time, although they are still estimates until the Philadelphia Mint acquired an hydraulic medal press in 1892 and put it in service the next year. Lengthy tests were made of coinage dies and alloys in order to calibrate toggle press size and wedge settings. The goal was more consistent coinage and elimination of guesses/opinion by press foremen.

Thank you. Sounds like they could get fairly close but not exactly accurate when measuring force of the machine in those times. 

[zadok]

On 1/30/2022 at 7:19 PM, GoldFinger1969 said:

How on Earth did you get all that information ?  Even if it was recorded on some obscure papers.....who bothered to write all that technical data down....who saved it....who preserved it.....how'd you find it ?

Wow....impressive....most impressive, as noted coin collector Darth Vader would say. 

...would seem logical that the mint director, chief coiner, floor supervisor, shop foreman, press laborer, team cheerleader, possibly the pet cat would have this info readily available for every denomination being minted...probably posted on the walls, carried on a piece of paper or in their pocket notebooks...almost certainly found in correspondence between mint administrators/directors n other supervisors confirming n reconfirming the tolerances being used...most likely derived by trial n error over time to give guidance of the best results for the denominations n alloys used...the table presented just a simple extrapolation from planchet diameter to square inch area n then adjusted to tonnage pressure needed to produce the desired result within the tolerances used n ability to estimate the accuracy needed for each denomination....the figures given doesnt seem to be uniform in the tonnage used for each metal alloy, possibly they made additional adjustments for thickness or even design detail differences?...as mentioned above the sophistication was not an exact science during that time frame n most likely the desired goals were to try to stay within a certain tolerance of product achievement, hence the varying degrees of striking on coins from that period....overall id say they did a pretty good job with the science available n the degree of consistency achieved....after all the end result was to produce coins that were going to be circulated to facilitate commerce n not survivable works of art...im sure the biggest concern was to insure each coin met the desired weight required, the aesthetic beauty was icing on the cake....

[Hoghead515]

On 1/31/2022 at 7:58 AM, zadok said:

...would seem logical that the mint director, chief coiner, floor supervisor, shop foreman, press laborer, team cheerleader, possibly the pet cat would have this info readily available for every denomination being minted...probably posted on the walls, carried on a piece of paper or in their pocket notebooks...almost certainly found in correspondence between mint administrators/directors n other supervisors confirming n reconfirming the tolerances being used...most likely derived by trial n error over time to give guidance of the best results for the denominations n alloys used...the table presented just a simple extrapolation from planchet diameter to square inch area n then adjusted to tonnage pressure needed to produce the desired result within the tolerances used n ability to estimate the accuracy needed for each denomination....the figures given doesnt seem to be uniform in the tonnage used for each metal alloy, possibly they made additional adjustments for thickness or even design detail differences?...as mentioned above the sophistication was not an exact science during that time frame n most likely the desired goals were to try to stay within a certain tolerance of product achievement, hence the varying degrees of striking on coins from that period....overall id say they did a pretty good job with the science available n the degree of consistency achieved....after all the end result was to produce coins that were going to be circulated to facilitate commerce n not survivable works of art...im sure the biggest concern was to insure each coin met the desired weight required, the aesthetic beauty was icing on the cake....

Thats what I figured. Id say to took alot of trial and error. Probably took quite a few strikes at first to get the desired outcome.  When it was time to start striking coins they would know close to where to set it when they changed denominations. Thats probably why the die setter watched a few strikes after he set the dies. So he could make the adjustments. These are just my guesses. They sure struck alot of beautiful coins. They were very good to figure tonage and things like that with the lack of technology. They didnt have the computers and measuring instruments we had. Thats why I was wondering how they measured it as close as they did. I really enjoy things like that. I been trying to get a deeper understanding. Thank you all for the information. 

[Hoghead515]

Sorry if these questions are of no interest to everyone. If they are ill not post anymore of them. Just let me know. Dont wanna bore everyone.  Im just really facinated with the subject when gets into machinery. I know alot of basic things but, Im trying to imagine how they had to do things in those days without the technology we have today. 

[RWB]

It is likely that the foremen and others carried small packet notebooks with lists and tables of press settings, alloy charts, annealing times, etc. We have just a handfull of these from the 1890 and 1930s - they are packed with information not fond elsewhere. (See my book United States Proof Coins 1935-1942 for extensive data from one of the notebooks.)

We also know that tests were (and still are) made when dies are changed or new designs introduced, and that the old branch mints were sent sample coin sets for guidance.

[RWB]

On 1/31/2022 at 9:58 AM, Hoghead515 said:

I'm trying to imagine how they had to do things in those days without the technology we have today. 

Everything was mechanical, but that does not mean primitive. Water wheel and steam power allowed a large investment in metal forming and cutting tools. Standard precision was 1/1000th inch and 1/10,000th was attainable. Abrasion and wear were hard to control, and maintenance was often short-changed by packing with stiff lubricants. If you examine the Franklin Peale press drawings, you can quickly understand how the machine worked, and possibly where improvements could be made. Over time, equipment builders often added changes in layers rather than redesigning equipment. One of the most fascinating areas of equipment technology (in my view) was in weaving and cloth manufacture - early combination of machines and "programming."

Your questions are very interesting and as you can see, there are differences in how results were measured and expressed. The internet has lots of back issues of The American Machinist and similar publications that might be of interest.

Edited February 1, 2022 by RWB

[GoldFinger1969]

On 1/31/2022 at 10:39 AM, RWB said:

Standard precision was 1/1000th inch and 1/10,000th was attainable.

So about 1/50th of a millimeter...today, probably 1/100,000 of a millimeter. 

Nanometers and angstroms ! 

[RWB]

Accuracy was determined not only by the stepping of gears/worms, but by the ability of alloys to remain homogeneous when finely machined. An analogous situation was assay fineness at the Mint. Routine reports were to the 1/1000th (0.001) but 1/10,000th (0.0001) was possible -- unfortunately neither was consistently repeatable in practice until the 1890s, or later. There's a mint discussion in 1908 of dividing a new DE into 8 parts and assaying each part -- they were almost all different when reported to the 1/1000th.

Edited February 1, 2022 by RWB

[zadok]

On 1/31/2022 at 2:01 PM, GoldFinger1969 said:

So about 1/50th of a millimeter...today, probably 1/100,000 of a millimeter. 

Nanometers and angstroms ! 

...is that like a fancy nanny with bad headaches?.....

[Oldhoopster]

On 1/31/2022 at 9:58 AM, Hoghead515 said:

Sorry if these questions are of no interest to everyone. If they are ill not post anymore of them. Just let me know. Dont wanna bore everyone.  Im just really facinated with the subject when gets into machinery. I know alot of basic things but, Im trying to imagine how they had to do things in those days without the technology we have today. 

You're asking great questions. Many are learning from the answers

IMO, even if 1 person learns something, it's a good question

[zadok]

On 1/31/2022 at 9:58 AM, Hoghead515 said:

Sorry if these questions are of no interest to everyone. If they are ill not post anymore of them. Just let me know. Dont wanna bore everyone.  Im just really facinated with the subject when gets into machinery. I know alot of basic things but, Im trying to imagine how they had to do things in those days without the technology we have today. 

ur questions r just fine.....serious n sincere, thats what it is all bout here...if u get too uppity for us hillbillies we just send u a paddle n a map....

[Hoghead515]

On 2/1/2022 at 12:06 AM, zadok said:

ur questions r just fine.....serious n sincere, thats what it is all bout here...if u get too uppity for us hillbillies we just send u a paddle n a map....

Thank you. I try to research some things but I dont have a whole lot of luck. I like to talk to you all also. Try to strike up a conversation and do some learning also. Dont see very many people around the house to talk to. 

 

[GoldFinger1969]

On 2/1/2022 at 5:00 AM, Hoghead515 said:

Thank you. I try to research some things but I dont have a whole lot of luck. I like to talk to you all also. Try to strike up a conversation and do some learning also. Dont see very many people around the house to talk to. 

The NEWBIE section here seems very active.  Hopefully, they'll also post and inquire in ours here.

Need more threads to have longer, wider, more voluminous back-and-forths like the RWB Saints thread. 

[zadok]

On 2/1/2022 at 11:11 AM, GoldFinger1969 said:

The NEWBIE section here seems very active.  Hopefully, they'll also post and inquire in ours here.

Need more threads to have longer, wider, more voluminous back-and-forths like the RWB Saints thread. 

...yea but 1.9955K of those were from some guy named goldfinger.....

[RWB]

On 1/30/2022 at 9:46 AM, Hoghead515 said:

Im reading @RWBbook  From Mine To Mint again and Im on the section talking about striking pressures. For example the quarter eagle needed around 92 tons per square inch. How do they calculate the area of the die? Does that include all 3 dies or just the striking die when they are talking about square inch? Im guessing they are only talking about the face of the die also aint it? Or the entire die? I wish I could find a diagram somewhere that showed pictures that demonstrate  how they calculated it. I looked through the internet and couldnt find anything. I wondered also how they figured how many tons was being applied. What kind of equipment was used to measure that sort of thing in the 1800s and early 1900s. Im very facinated by how intelligent and innovative they were in those days.

A die is really a very short circular cone. The formula is: