Mark's Monitor Build

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The Centennial Exhibition was about the accomplishments of the USA in the first hundred years ( thus 1776-1876) and was a massive display of technological developments . They painted a portrait
of about 56 (!) Inventors -living and dead- who made America great and they did not include john Ericsson and he got mad and wrote a book about his accomplishments , which is the one noted in my last post. Well the Exhibition commission realized they had made a mistake and added John to the painting. but this was just some of the negative feelings about John and they were embarrassed by his call-out. If you read the book, you will be amazed at his talent.
Besides building the Monitor which is said to have 40 inventions alone , he built the first steam powered Fire Engine, He invented the Screw Propeller used on every ship and boat today, he invented powered torpedo's and he started the Solar Energy capture by building a Solar powered motor that took sunlight and turned it directly into mechanical rotary motion and this was in 1870 ! His calculations of Solar power can still be used today. Don't forget, the Monitor was the first modern warship- all iron- engine power below waterline -rotating Turret- and stealth design .
More later
Rich
 
FWIW, I do recall reading that to speed up the build, many items were subcontracted. Not the norm where in a single shop or facility, a knowledgeable person would be available to give a hole dimension. Without giving a factual reason, the author reported serious troubles when a component would arrive and a hole was the wrong size. I figured without a good dimension, the subcontractor simply used what made sense to them.
Ron
 
Many of the original Monitor drawings I have seen were dimensioned, but it must be kept in mind that some of the Monitor drawings that exist today were created as the Monitor was being built, or even after the Monitor was built (according to one of the books Rich mentions above).

Back in the day, when I started school, there were no personal computers, no CAD; we had punch cards and FORTRAN on an IBM mainframe (don't underestimate FORTRAN, it took us to the moon). We hand drew everything using either ink, or more often pencil, and vellum. Vellum is a cotton-based paper that is very durable (like the material that money is printed on).

We used engineering and architectural scales, originally made of wood, and later of plastic.
Even if our drawings were not dimensioned, typically they were drawn to some scale, and I suspect the same holds for the Monitor drawings.
The folks building the Monitor and using a drawing that was not dimensioned would still be able to use a scale to read the dimensions of the various parts, as long as the scale of the drawing was known.

You can generally figure out the scale of a drawing pretty quickly if you don't know what it is, but not always.
One of the most costly mistakes you can make is to issue a sheet with the wrong scale on it.
When I print my sheets these days, I still lay a physical scale on some known dimension, just to be sure the drawing was plotted at the right scale factor.

If you ever had to produce manual drawings for a living, you really appreciate excellent draftsmanship when you see it.
The original multi-color Monitor drawings are just plain artwork, as well as some very creative engineering.
The only other color drawings I recall were for the Brooklyn Bridge project, and those too are works of art.

Rich's drawings are first rate too, with some stunning 3D color isometric views, and I am very glad I did not have to make those drawings, given how complex they are, and the enormous quantity of drawings involved.

Edit:
One thing to remember with old drawings is that the lines are generally first laid out with dividers, and the sharp points of the dividers actually punch holes in the vellum. If you ever seen the faint outline of pinholes in drawings, those are the reference points you should use for things like the centerpoint of circles, etc.

I think it was said that a good draftsman could control a drawing down to about 1/64", but check me on that.
When I am creating CAD drawings or 3D models of engines using photos only, I round the dimensions for each part to something usable; otherwise you end up with a lot of odd measurements such as 1.2157385". (round it to 1.2", or perhaps 1.22", but you get the idea).
I also have a standard bolt/screw chart, and select the bolt or screw that is closest to what I am seeing/measuring.

I read a Scientific American article about the ancient Greek/Roman temples, and it noted that no drawings had ever been found for those structures. Then a guy noticed some faint lines on the stonework of a temple that was destroyed by an earthquake before it was completed, and he discovered that the plans were etched lightly into the temple walls and floor. When the temples were completed, the walls were polished, removing all evidence of the drawings. The ancients did have exact drawings for temples, and they are illustrated in the Scientific American article. The columns were drawing foreshortened, perhaps 6 feet tall, and the compressed vertical scale makes them look like a beer barrel.
The builder took off the column width dimensions with dividers at the appropriate vertically scaled increments, and transferred that to the actual very tall column. This is a very clever way to avoid having a 50 foot tall (or more) drawing.

.
 
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FWIW, I do recall reading that to speed up the build, many items were subcontracted. Not the norm where in a single shop or facility, a knowledgeable person would be available to give a hole dimension. Without giving a factual reason, the author reported serious troubles when a component would arrive and a hole was the wrong size. I figured without a good dimension, the subcontractor simply used what made sense to them.
Ron
And I don't think there were standard fastener/thread sizes when the Monitor was built, but I could be wrong.
It makes me wonder if the Monitor fasteners were interchangeable, or if each one was custom-cut/filed, such that a nut would only screw onto its mated bolt.

.
 
And I don't think there were standard fastener/thread sizes when the Monitor was built, but I could be wrong.
It makes me wonder if the Monitor fasteners were interchangeable, or if each one was custom-cut/filed, such that a nut would only screw onto its mated bolt.

.
Ah. I've wondered about when they started making standard nuts and bolts too. We take them for granted but at the beginning of the technological (industrial) revolution, nuts and bolts were made one by one and matched as you all know already, but when did the standardization begin? It seems that someone clever would have made a fortune making standardized nuts and bolts and absolutely NOTHING else! They could have had two dedicated lathes and kept the machines running day and night just making nuts and bolts. How many nuts and bolts are made today in a year? Billions.
 
Charles Porter talks about the period of time when the standard twist drill bit was not common, in his book "Engineering Reminiscences" talks about when he first discovered some manufacturers using twist drills. (Charles Porter created the first high speed stationary steam engine).

https://archive.org/details/engineeringremin00port/page/n7/mode/2up
From page 30 and 31:

In preparing for the establishment of the governor manufacture I visited the works of Geo. S. Lincoln & Co., in Hartford, and saw twist -drills in use, cutting chips instead of scraping. They attracted my attention and I inquired about them, and was told that they made them themselves. They kindly took me into the smith-shop and had one made for me to witness the operation. The smith heated a round bar of steel and swaged channels in it on opposite sides. They had quite a set of top and bottom swages for different-sized channels. He then took another heat on the bar and twisted it by hand, giving a gradually increasing twist, which at the end was quite rapid.

An increasing twist was obtained in this way. The drill was held in a vise, so that only the projecting end of it could receive the amount of twist then being imparted. The drill had to be moved in the vise of course a number of times. The channels were smoothed out with files, and when the drill was turned in the lathe sharp cutting edges were developed, which needed only to be backed off by grinding.
I took one of these drills home with me to serve as a pattern and equipped my shop with them. They were of the highest use to me. The small ones drilled the holes for the governor joints, and the large ones drilled the counterpoise and the column for the governor spindle. I suppose the twist-drill had its origin in these Hartford works.


I never saw any twist-drills in England except at Mr. Whitworth's, and these I thought were the funniest things I ever did see. They were twisted by the blacksmith out of square bars and with a uniform quick twist, were left rough, and did not fill the hole, and the ends were flattened out in the form of the common drill to scrape, and not to cut.
When I returned from England in 1868 twist-drills were coming into general use in this country. After 1876 the firm of Smith & Coventry introduced them in England.


At that time almost everything in machine-shops was done in the old-fashioned way, and accuracy depended entirely on the skill of the workman. The tool work left much to be done by the fitter.
Interchangeability was unknown, even in screw-threads. For example, when nuts were removed from a cylinder head, pains had always to be taken that each nut was replaced on its own bolt, as no two were exactly of a size. This condition developed a class of very skillful all-round workmen; but my earliest observation showed me that in manufacturing it was important that so far as possible the personal factor should be eliminated.

I adopted the rule that in mechanical work there was only one way to insure that anything should always be done right, and that was to make it impossible that it should be done wrong. For example, in my governor gears their true running required that the bore should be absolutely correct, both in position and in direction. I had seen many gears bored. They were held in the jaws of a chuck and trued by marking their projecting side when running with a piece of chalk. It was evident that absolute truth could hardly ever be reached in this way, and the approximation to it depended wholly on the skill and pains of the workman.

.
 
And I don't think there were standard fastener/thread sizes when the Monitor was built, but I could be wrong.
It makes me wonder if the Monitor fasteners were interchangeable, or if each one was custom-cut/filed, such that a nut would only screw onto its mated bolt.

.
The Brits were the first with Whitworth 1841. US had some, a document was published in 1864. Civil War rifles had interchangeable parts, as did standard Quartermaster mule wagons. But IIRC it wasn't until 1916, WWII and the introduction of Johansson Blocks that standardization really hit the US. The now standard reference Machinery Handbook was first published in 1914 with several standards, but SAE wasn't there yet. Wikipedia, and an interesting book "One Good Turn: A Natural History of the Screwdriver and the Screw"
 
I have done a study of bolts in connection with my Monitor research. Unfortunately the real
expert I found ( Mel Kirsner) has passed on and his Museum burned down years ago.
Standard Nut Donates Items to Museum | Global Fastener News. He called it "Mell's Nut house"
You have to be careful when you talk about threads !
Whitworth started the standard with THREAD FORM (55 degrees)in England and the Franklin Institute ( Philadelphia) in 1864 set the USA form at 60 degrees, but the threads per inch and bolt size were not standardized (in the USA) until about 1906 (ANSI) and have progressed from there .
Mel told me that Maudsley invented the Hex Nut Milling Machine in 1829 which allowed nuts to be made and the first commercial Nuts sold in a US Catalog was from a new England source in 1854.
The impetus for standardization was driven by the Carriage/Wagon trade as manufacturers of tooling or in the case on Monitor, made there own nuts and bolts to their own standards . For example, I have a 1890 B & S Dividing head and it has 1/4-22 screws . WW 1 brought great demand for standards, but it seems that the Automobile Industry was the real driver after that.

A little trip back in time !
Don't forget that many shops made their own tools.
You had "machinists" working in machine shops but the best machinist , or I should say the most skilled man worked in the ........Tool Room . There, he was known as "the Tool Maker" or a
"Tool and Die Maker" as he made tools for the shop to use. He made drills,taps,cutters and Dies and special tools. He was special , but the world has changed as most of the stuff is now commercially available
It is sort of funny to me to hear about lathes being described as "Tool Room Lathes" and folks have a mis-under-standing what a Tool Room Lathe is ?
In the old days , A (real) Tool Room lathe was very precision for making tools and had a unique threading ability and arrangement where the feed would drop out ( Single dog clutch-No threading indicator needed ) and then re-engage in perfect timing and at high speeds needed for quickly making threads.- remember, these guys made taps and dies ! I believe only Hardinge makes such a lathe today

In my Drawing book for the Monitor, I only specified diameters of bolts, except where a few threads were called out on those early drawings
Rich
 
Another boring bit from me...?
On history of toolmaking: I am descended from a family called "Filer" - because he made files.
Imagine a blacksmith who made seriously good wrought steel, before manufacturing mass production of steel was developed. The steel was used for swords, knives, tools for woodworking, and for graving metal (Not just engraving, but for using hand tools to machine softer metals in simple lathes, based on wood working expertise). In flintlock strikers you needed a small piece of hard, rough, sharp, abrasive steel to make the flint "spark".
https://www.bing.com/images/search?...k+steel&form=IGRE&first=1&tsc=ImageHoverTitleThe first files being the abrasive plate installed in a flintlock (never seen one - just what I was told) had to be very fine. The modern equivalent is the abrasive steel wheel of a sparking lighter that uses a flint. A piece of grind-stone in a flint-lock mechanism was prone to falling out, but the "new steel" files were fixed in place and didn't fall out when the metal was hot from use and expanded.
- I was taught the flintlock promoted the original design of files - single cut, not like modern cross-cut files. The teeth were cut by a cold chisel, very hard and sharp, held at an angle to create the sharp edge of the teeth. A single strike per tooth. Try it, quite a difficult skill! The skill was in making the uniform spacing and close alignment of the teeth so the file action was smooth and it cut soft iron cleanly.
Hand-held grind-stone tools were used to hand shape knife blades etc. But the guy who made good steel started making files, by cutting annealed steel bar with a chisel, then hardening and tempering the file - and was called "Filer". Instead of "Smith".
A "steel" was the name given to a very fine file used for sharpening knives (and swords) - like a chef uses. (Or did before H n S changed the design!). sharpening steel for knives - Search
Carrying fine grind stones for sharpening the plough or sword was not so easy, as they broke when struck or dropped. A steel was a more durable sharpener... But you can still buy them for sickle and scyth sharpening.
https://www.bing.com/search?q=scyth...57j0l8.13702j0j1&pglt=515&FORM=ANNTA1&PC=U531
Many blacksmiths made wrought steel for tips for ploughs, etc. as they wore much less than the softer iron shoe that turned the soil. - Hence, when war developed (e.g. Charles Cromwell's mob etc.) they turned Ploughshares to swords" - and back again after they returned from war.
One reason that old battlefields rarely have deposits of swords, knives and other weapons, etc, is not just that they have rusted away, but were spirited away immediately afterwards by the camp followers as useful steel for everyone afterwards!
Move on to later tool and manufacturing processes: (MY distorted memories from tales told by the machinist when I was a lad in a workshop?). When they started making metal bicycles, they set the thread cutting lathes to 26threads per inch - to try to emulate a METRIC 1mm pitch that was developed as a common size in France...
Once set, they made all the bolts, of whatever diameter, in 26tpi. And Triumph motorcycles and others were doing this in the 1960s - until the "dammed infernal yanks" overwhelmed us with their machine tools in WW2 and we started using UNF, UNC, sizes in car manufacturing... displacing the historic quirks and idiosyncrasies we had held onto for so long in our beloved Great Britain. Of course, some threads in the transport industry, and in many other industries, they had used Whitworth and BSF for decades, and electrical people used BA... "because it suited them". Gas people used "pipe threads, brass component makers used their own brass threads, etc. But it was all the stuff from USA (that wasn't sunk by U-Boats) that changed the UK (to the 53rd state) to using UNC and UNF - until politics decided we should become "European", and thus converted us to "Metric" sizes.
I'll not rant about that one.
Enjoy! (And correct my errors for the record?)
K2
 
This particular topic was created by dnalot, but it is not a run of the mill model engine build, but rather a build of what is argueably the most historic marine engine every built, certain with respect to American history.

On top of that, Rich Carlsedt has spent many years documenting this historic engine, and he has uncovered a vast amount of technical information about it, and the methods used to build it, and dnalot is using those plans for this build.

There is no way to conveniently pigeonhole this build into a nice little simplistic model building thread.
This is a very significant engine, and it deserves significant discussion. This engine cannot be trivialized.

The fact that dnalot (Mark) has gone to so much trouble to build a very accurate Monitor engine makes the peripheral discussions all the more important, especially with regards to those who may follow and want to build their own accurate models of this engine.

.
 
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I have not heard Mark complain about this thread or its contents, and it is his thread as you say, so perhaps we should let him determine what information he wants to display here, and not try to tell him what his thread should look like or what comments it should or should not contain from other members.

I am hoping that he will post an update soon.

I am assuming that he is working like a beaver on his Monitor, and hope that all is going well.
This is such a complex undertaking, especially given the fact that he is making his own castings.

I have been following Mark's investment casting thread with great interest:

https://www.homemodelenginemachinist.com/threads/marks-first-investment-casting.33864/
and Mark's burnout kiln thread:

https://www.homemodelenginemachinist.com/threads/marks-kiln-build.33783/
This fellow has a lot going on, and the quality of his castings is most impressive.

.
 
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There is a discussion on another thread about a governor, and it does not seem the Monitor had a governor, so it makes me wonder exactly how the Monitor engine was controlled.

I notice the bypass valves in the upper steam chests, so that the cutoff valves can be bypassed.
So is it safe to assume the main Monitor valves were designed for a late cutoff?

And there is a throttle valve on the Monitor, in the main steam line.
So is that really a throttling valve, or just a cutoff valve?
I would assume it is really used for throttling, since it is a rather elaborate valve design.

I would really like to hear what Rich knows about how the Monitor engine was operated.

My guess is that the boat speed was controlled by the throttling valve, and the cutoff valves were simply used to produce the same amount of power and torque, but using a greatly reduced amount of steam (ie: use the expansive power of steam, and an early cutoff).

I would also guess that during fighting maneuvers, the bypass cocks were open, thus giving the engine maximum torque regardless of efficiency.
Who cares about efficiency when cannon balls are flying?

Edit:
I am going to have to look at Rich's drawings again.
The crank handle and gear mechanism was used to reverse the engine? but I was thinking this mechanism controlled the cutoff valves.
Now I am wondering how the cutoff valves were adjusted.
.
 
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No governor used on Monitor, the 9 foot propeller kept the RPM's down , really the engine room staff were the governors :)
The Grate Valve in the main steam line was the Throttle Valve for the engine. Coal was a very expensive fuel and conservation of fuel was paramount to marine operations, particularly if you operated in unfriendly waters. The engine ran on 30 PSI steam and when in cutoff mode made 60 RPM which produced 6 Knots on the 980 ton ship. Full speed, without cutoff ,was 80 RPM and resulted in 8 knots of speed. At that point , the boilers were maxed out as the ship had other steam engines running pumps and blowers ( Hull was pressurized to facilitate boiler draft and prevent asphyxiation ) Ericsson testified that the engine could run 100 RPM if the other steam engines were silenced , but of course that could only be for a very short time. The engine was rated at 350 to 425 HP depending on the information source .
Yes, in battle the Cutoff valves would be bypassed to give full power to the engine . By the way because of the close proximity of the boiler to the engine, engine room crew worked in 135 degree (F) temperatures and served only 1/2 hour at their post except during battle . Amazing !
if you look at the engine , there is three gauges , with the engine "register" on the left. It recorded
the "turns" ( revolutions) of the engine . The center gauge is steam pressure and the far right is a clock with a sweep second hand and the Captain would holler the number of turns he wanted in a tube to the engine room and the chief engineer would count the turns made in one minute as he adjusted the throttle. the grate valve was very effective as a steam control device
Rich
 
Another boring bit from me...?
On history of toolmaking: I am descended from a family called "Filer" - because he made files.
Imagine a blacksmith who made seriously good wrought steel, before manufacturing mass production of steel was developed. The steel was used for swords, knives, tools for woodworking, and for graving metal (Not just engraving, but for using hand tools to machine softer metals in simple lathes, based on wood working expertise). In flintlock strikers you needed a small piece of hard, rough, sharp, abrasive steel to make the flint "spark".
https://www.bing.com/images/search?...k+steel&form=IGRE&first=1&tsc=ImageHoverTitleThe first files being the abrasive plate installed in a flintlock (never seen one - just what I was told) had to be very fine. The modern equivalent is the abrasive steel wheel of a sparking lighter that uses a flint. A piece of grind-stone in a flint-lock mechanism was prone to falling out, but the "new steel" files were fixed in place and didn't fall out when the metal was hot from use and expanded.
- I was taught the flintlock promoted the original design of files - single cut, not like modern cross-cut files. The teeth were cut by a cold chisel, very hard and sharp, held at an angle to create the sharp edge of the teeth. A single strike per tooth. Try it, quite a difficult skill! The skill was in making the uniform spacing and close alignment of the teeth so the file action was smooth and it cut soft iron cleanly.
Hand-held grind-stone tools were used to hand shape knife blades etc. But the guy who made good steel started making files, by cutting annealed steel bar with a chisel, then hardening and tempering the file - and was called "Filer". Instead of "Smith".
A "steel" was the name given to a very fine file used for sharpening knives (and swords) - like a chef uses. (Or did before H n S changed the design!). sharpening steel for knives - Search
Carrying fine grind stones for sharpening the plough or sword was not so easy, as they broke when struck or dropped. A steel was a more durable sharpener... But you can still buy them for sickle and scyth sharpening.
https://www.bing.com/search?q=scyth...57j0l8.13702j0j1&pglt=515&FORM=ANNTA1&PC=U531
Many blacksmiths made wrought steel for tips for ploughs, etc. as they wore much less than the softer iron shoe that turned the soil. - Hence, when war developed (e.g. Charles Cromwell's mob etc.) they turned Ploughshares to swords" - and back again after they returned from war.
One reason that old battlefields rarely have deposits of swords, knives and other weapons, etc, is not just that they have rusted away, but were spirited away immediately afterwards by the camp followers as useful steel for everyone afterwards!
Move on to later tool and manufacturing processes: (MY distorted memories from tales told by the machinist when I was a lad in a workshop?). When they started making metal bicycles, they set the thread cutting lathes to 26threads per inch - to try to emulate a METRIC 1mm pitch that was developed as a common size in France...
Once set, they made all the bolts, of whatever diameter, in 26tpi. And Triumph motorcycles and others were doing this in the 1960s - until the "dammed infernal yanks" overwhelmed us with their machine tools in WW2 and we started using UNF, UNC, sizes in car manufacturing... displacing the historic quirks and idiosyncrasies we had held onto for so long in our beloved Great Britain. Of course, some threads in the transport industry, and in many other industries, they had used Whitworth and BSF for decades, and electrical people used BA... "because it suited them". Gas people used "pipe threads, brass component makers used their own brass threads, etc. But it was all the stuff from USA (that wasn't sunk by U-Boats) that changed the UK (to the 53rd state) to using UNC and UNF - until politics decided we should become "European", and thus converted us to "Metric" sizes.
I'll not rant about that one.
Enjoy! (And correct my errors for the record?)
K2
Charles Cromwell? You mean The Lord Protector? The one who cut off the head of king charles I? Oliver Cromwell?
 
Thanks Rich for the fascinating information.

I thank my lucky stars every day I did not have to work in that engine room.
I have worked as an operator of a large sawdust-fired boiler, but it was in a large well ventilated room, but still a bit hot.

I am studying your video now, and looking at what happens to the valve gear as you rotate the valvegear actuator.
Starting at 1:00.



What I am seeing is the eccentrics for the cutoff valves and the eccentrics for the main valves shifting as a unit, together.
And so what this tells me is that there is no adjustment for the cutoff valves, and no adjustment for the main valves either.
Is this true? There was no way to adjust the cutoff?

It would make sense that if you change the phase of the main valves, the phase of the cutoff valves would have to follow proportionally.

.
 
Yes, The Cutoff function was only used in forward motion.
when the engine was reversed, the cutoff bypass valve would be opened and
that effectively meant the cutoff eccentrics and cutoff valve were inoperative.
So at the 1 minute mark, the main eccentrics are being rotated 180 degrees for reverse and if you look at the cutoff valve rods right behind, you see no motion. The cutoff eccentrics are fastened (keyed) to the reversing shaft, while the main valve eccentrics are really "slip eccentrics".
You could adjust the main valves somewhat and give them "Lead" . The quadrant gears turned the main eccentric ( pinion) and stopped when the key was met/engaged with the pinion gear fastened to the main eccentrics. ( see 1.00 to 1.20) -

Now "if" the quadrant gears rotated the pinion , but stopped short of the key, the engine would reverse and run , but then had lead on the timing. Of course the penalty for doing that was the reversing shaft transmitted power to throwout bearing which then passed it to the quadrant gears ,which then transmitted it to the Pinion gear fastened to the eccentric . That does work but involving the whole mechanism means excessive wear of all those components. Normally, the pahse changing mechanism has no load on any component during running operation, only during the actual changing of direction do they see load
Hope this helps

Rich
 
I have done a study of bolts in connection with my Monitor research. Unfortunately the real
expert I found ( Mel Kirsner) has passed on and his Museum burned down years ago.
Standard Nut Donates Items to Museum | Global Fastener News. He called it "Mell's Nut house"
You have to be careful when you talk about threads !
Whitworth started the standard with THREAD FORM (55 degrees)in England and the Franklin Institute ( Philadelphia) in 1864 set the USA form at 60 degrees, but the threads per inch and bolt size were not standardized (in the USA) until about 1906 (ANSI) and have progressed from there .
Mel told me that Maudsley invented the Hex Nut Milling Machine in 1829 which allowed nuts to be made and the first commercial Nuts sold in a US Catalog was from a new England source in 1854.
The impetus for standardization was driven by the Carriage/Wagon trade as manufacturers of tooling or in the case on Monitor, made there own nuts and bolts to their own standards . For example, I have a 1890 B & S Dividing head and it has 1/4-22 screws . WW 1 brought great demand for standards, but it seems that the Automobile Industry was the real driver after that.

A little trip back in time !
Don't forget that many shops made their own tools.
You had "machinists" working in machine shops but the best machinist , or I should say the most skilled man worked in the ........Tool Room . There, he was known as "the Tool Maker" or a
"Tool and Die Maker" as he made tools for the shop to use. He made drills,taps,cutters and Dies and special tools. He was special , but the world has changed as most of the stuff is now commercially available
It is sort of funny to me to hear about lathes being described as "Tool Room Lathes" and folks have a mis-under-standing what a Tool Room Lathe is ?
In the old days , A (real) Tool Room lathe was very precision for making tools and had a unique threading ability and arrangement where the feed would drop out ( Single dog clutch-No threading indicator needed ) and then re-engage in perfect timing and at high speeds needed for quickly making threads.- remember, these guys made taps and dies ! I believe only Hardinge makes such a lathe today

In my Drawing book for the Monitor, I only specified diameters of bolts, except where a few threads were called out on those early drawings
Rich
Hi,
I don't know if you have identified your B & S dividing head screws but if not I would check the thread angle as that dia x pitch is a British Standard Fine (BSF) combination using a Whitworth thread form.

Regards
TerryD
 
................. But it was all the stuff from USA (that wasn't sunk by U-Boats) that changed the UK (to the 53rd state) to using UNC and UNF - until politics decided we should become "European", and thus converted us to "Metric" sizes.
I'll not rant about that one.
Enjoy! (And correct my errors for the record?)
K2
Hi K2,
It wasn't politics that decided to change to the SI metric system (defined by the ISO of which GB is a participating member) from the imperial, it was economics we didn't become 'European' we became 'International'. Most of the rest of the world had been metricated quite quickly and certainly by the mid 20th C. the SI units were standardised especially in the scientific community, after all there are now only 3 countries still using derivations of the 'English' system officially and the USA is in good company with such influential industrial countries as Myanmar (Burma for Imperial supporters) and Liberia. Although units based on the Imperial system (The US system is the 'customary' system and differs from the imperial in some units) are still in limited, vernacular use in many others, mostly ex Empire countries where British systems were imposed on the locals. It was realised that the UK would lose out on international trade if we stuck to an outmoded system so capitalism won, alongside science and technology.

The UK government first discussed the prospect of adopting the metric system in 1818 - most scientists and engineers agreed. The metric system, based on units of 10 was first proposed by several English scientists and engineers during the 18th C. (e.g. John Wilkins suggested it in 1790 and Gunter's chain, still used by some surveyors and cricket lovers, has 100 links as part of the move to decimalisation) but the idea was taken up by France as their measurements were in chaos, (as was most of the rest of the Worlds at that time), each region and sometimes towns had their own definitions of the so called 'Standards'.

The systems on which the 'Imperial' system was based was basically European developed from earlier units such as the 'cubit' and 'hand' by the Greeks and Romans essentially and used parts of the body as the basis for linear measures. Unfortunately not everyone has the same sized bodies and very different definitions of, for example, feet and inches existed, weights were based on the natural world on such things as the carob seed and barleycorn and multiples thereof and the sexagesimal system for time was defined by the Babylonians. It's interesting to note that the Imperial system of measures was not finally defined until 1824 while the French had defined the basic metric system in the 1790s (although Napoleon later reverted to the traditional names for measures) based on previous suggestions from among others British scientists and engineers. By the way the 'Standard' Kilogramme of 1790 was made of platinum cast by Johnson Matthey in England.

Familiarity with a particular system, be it Tte Imperial, the Winchester or the US customary doesn't make it any better it is standardisation that matters and the SI system with it's well defined basic units from which all others are derived won out.

Best regards

TerryD
 
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Many of the original Monitor drawings I have seen were dimensioned, but it must be kept in mind that some of the Monitor drawings that exist today were created as the Monitor was being built, or even after the Monitor was built (according to one of the books Rich mentions above).

Back in the day, when I started school, there were no personal computers, no CAD; we had punch cards and FORTRAN on an IBM mainframe (don't underestimate FORTRAN, it took us to the moon). We hand drew everything using either ink, or more often pencil, and vellum. Vellum is a cotton-based paper that is very durable (like the material that money is printed on)............

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Hi,

As a point of interest, vellum is actually made from animal skins aka 'parchment' but vellum was distinguished by being made from calf skin which made a superior product and has been in use since ancient times, I think it may have been the Babylonians in Mesopotamia (now iraq) where it was first used. They also made a writing medium from the local 'papyrus' reed leaves woven and then beaten into thin sheets hence the name 'paper'.

I started my drafting career in the early 60s in the UK engineering industry and generally we drew on paper using pencil, which made it easy to rectify mistakes, then the important ones (drawings not mistakes!), once okayed by the Chief Draftsman were transferred onto drafting film, which is similar to what you refer to as vellum, by tracing using ink pens by 'tracers' usually women. That film was made from cotton fabric stiffened with starch and was more or less transparent. (If you managed to get hold of a length the starch could be washed out and the cotton sheet was great for pressing the crease into formal trousers). Cotton based 'paper' is indeed very smooth and was referred to by manufacturers as 'vellum' to infer a higher quality product, smooth and consistent like the original material it superseded in everyday usage. These master traces, being transparent were used to make working copies of the drawings on the large printing machines for use on the shop floor.

Vellum (the animal skin) was used for important and permanent documents in ancient times and for books such as those beautiful illustrated Bibles in the medieval period among other uses, even now it is used for important ceremonial documents, at least here in the UK.

TerryD
 
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Charles Cromwell? You mean The Lord Protector? The one who cut off the head of king charles I? Oliver Cromwell?
Thanks Richard, Of course you are right. That is an example of how my brain jumps out of mesh sometimes... and why I don't trust my own writings...
Sorry if this discussion of the history of technology around the time leading up to the monitor has detracted from some peoples' enjoyment of the thread.
K2
 

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