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[tonyH]

Hi Daves,
Just thinking whether there would be need for weight in the piston to create enough inertia for full rotation, bearing in mind that the originals would have worked with very low pressure and relatively slow rotational speed.

 

[daves]

As I research and draw the engine and boiler for the steam ship Mississippi I came to the conclusion I will have to research and study the steam engine before I can draw and build one. It stands to reason the more input I have the more information I can collect so I contacted adminstrator on this forum as well as the moderator of another forum asking if I can link this topic on both forums.

 There is no reason to build and maintain two separate topics It makes more sense to link them.

I would like to invite you to take a walk about in a boiler graveyard over at the other site here is the link




https://www.shipsofscale.com/sosforums/index.php?threads/marine-steam-engines-and-boilers.2272/page-2#post-41960

[daves]

I finished the CAD work for the gothic style frame of the engine and posted more images at this link


https://www.shipsofscale.com/sosforums/index.php?threads/marine-steam-engines-and-boilers.2272/page-3#post-42771


now I am moving on to the CAD work for the condenser but it has me stumped right now as to how it goes together 
I will post my drawings as soon as they are done.

[derekwarner_decoy]

Dave...I see in the alternate WEB site you ask ......'what is a P Block?'....and the resulting comment of a Pillow Block


I believe an earlier definition or of a P Block terminology was a Plummer Block......further I suggest the bearing housings you have drawn were originally cast as Plummer blocks....and long before someone converted dimensions to the ISO Standard referenced


One of the main differences between the P Bolcks is that the Pillow variety are usually centered around the shaft axis, whereas Plummer had upper and lower elements that had little resemblance with matters of symmetry ...or exactly as the original Drawings depict


Remember these structures featured heavily of Gothic Design   


Derek

[daves]

Dave...I see in the alternate WEB site you ask ......'what is a P Block?'....and the resulting comment of a Pillow Block


I believe an earlier definition or of a P Block terminology was a Plummer Block......further I suggest the bearing housings you have drawn were originally cast as Plummer blocks....and long before someone converted dimensions to the ISO Standard referenced


One of the main differences between the P Bolcks is that the Pillow variety are usually centered around the shaft axis, whereas Plummer had upper and lower elements that had little resemblance with matters of symmetry ...or exactly as the original Drawings depict


Remember these structures featured heavily of Gothic Design   


Derek

on some of the drawings the blocks are referred to as just a P block

the original drawings are difficult to see but here is the original

on the plan the blocks are called pillow blocks but your right there is a big difference  between a pillow block and a plummer block.

I do not know if back in 1840s the term was interchangeable

I did post a few pictures of these type of blocks at this link

https://www.shipsofscale.com/sosforums/index.php?threads/marine-steam-engines-and-boilers.2272/page-3#post-42774

[grendel]

I am guessing but plummer blocks may have had a white metal or lead insert, which would have formed the bearing surface, and been hand scraped to get the correct seating of the shaft in the bearing - plummer as in lead?

[daves]

the drawings have 4 different blocks I have to figure out where they go

the first says P block the other one does not say anything

[daves]

I am guessing but plummer blocks may have had a white metal or lead insert, which would have formed the bearing surface, and been hand scraped to get the correct seating of the shaft in the bearing - plummer as in lead?

from what I photographed in the Ford collection there seems to have been a brass bearing surface but in the second photograph you can see a light colored insert at the top of the shaft

[daves]

on the two pictures there is a brass insert or bearing surface

this block and shaft is quite different it has this big split ring around the shaft

I wish I would have taken a picture of the back side to see if this ring goes all the way through the block and what stops it from spinning around with the shaft.

[derekwarner_decoy]

Do not be put off by the irregular octagional shaped bearing element blocks.....these were cast from the RED copper metal family.....down to Muntz Metal or a even softer from the White Metal variety


So,yes......after casting the blocks would have been lathe bored & then hand scraped....again we must remember that these new steam engine machines were to be melded with the accepted Gothic constructional[/size]  architectural design

[/size]Imagine today's costs .....this style of design must have created a very high demand for qualified Journeyman of the Pattern Making and Metal Casting Trades 

[/size]Derek

[daves]

I have been busy with CAD drawing this engine and finished the condenser drawings. NOW! the problem is how in the world does it go together
I do know it goes in the blue area

[daves]

here is the master drawing of the condenser and a series of closeups

[derekwarner_decoy]

Dave, forgive me...but do you not now have a series of layered tracings taken from an original hand drawing?....


If this is the case, does each sub component tracing on another layer confirm all dimensions of the sub component?


So as such...I wasn't aware  that CAD packages have an auto assembly tool from tracings


Derek

[daves]

I do not understand your post



Dave, forgive me...but do you not now have a series of layered tracings taken from an original hand drawing?....

no layered tracings but what you see are tracings from the original and are all scaled to one another

If this is the case, does each sub component tracing on another layer confirm all dimensions of the sub component?

each component on the original had dimensions drawn in so I used those dimensions to size each part so everything drawn is now the same scale.


So as such...I wasn't aware  that CAD packages have an auto assembly tool from tracings

I do not know what "auto assembly tool" is somehow all the parts fit together to make a condenser

the original look like this and I used the dimensions on the plans are redrew the pARTS




Derek

[grendel]

put the different drawings into a single drawing, on different layers (maybe think of saving each as a block) then you can adjust the relative positions quite easily by turning layers on and off and moving the parts on one layer relative to another)

Of course as a professional CAD draughtsman, I would probably have initially drawn up the parts using the drawings as a guide, but creating the CAD in 3d to start with, then with the individual components all saved as separate blocks, juggled the parts around until they fitted properly. (but that is me being a smartie pants)

[daves]

and the smartie pants are the people I hope to meet

I can send anyone who wants a copy of the CAD drawing a DWG or DXF file if you want to just fiddle with it and try to put it together or do a 3D file
 
I have the main frame and the condenser files done and working on the cylinder
it may take a village to build this engine I am not smart enough with steam engines to do it alone

[daves]

3D modeling is an art unto itself  I think I get what your saying that is to create the parts in 3D and try to fit it all together brilliant!

like the frame columns

[grendel]

yes, thats the idea

[grendel]

basically you create building blocks and then merge them together to form your finished object

[daves]

my problem is I am OK with cad drafting not a pro just at a hobby level.  I did have a pro who would take my CAD drawings and redo them as 3D models but lo and behold that person is no longer available. So at this time I am at a stand still until I can find someone willing to create a 3D model from the CAD drawings.

I will carry on with drawing the parts and hopeful someone with an interest in this old gothic engine will attempt the 3D model.

my skills with 3D modeling is with a simple program Google sketchup

[daves]

a progress report on the CAD drawing

so far I finished the main frame, the cylinder, the condenser and the air pump

I am wondering if these engines had just one lever or was there a lever on both sides of the frame?

[derekwarner_decoy]

Dave.......


1. the image you are working on [progress3] is an inverted beam engine.........these [usually] have a symmetric pair of 'outer' lower beams driving a top mounted crankshaft


2. the gloss white images from a restored engine with the beautiful exampled Gothic cast entablature and structure is of single 'central' upper beam engine driving a lower mounted crankshaft


So to answer your question, as far as I can see......yes....your design example will have a balanced symmetric pair of 'outer' lower beams driving a top mounted shaft

Derek

[ooyah/2]

a progress report on the CAD drawing

so far I finished the main frame, the cylinder, the condenser and the air pump

I am wondering if these engines had just one lever or was there a lever on both sides of the frame?

Daves,


Here is a link to side lever engines (  https://en.wikipedia.org/wiki/Marine_steam_engine ) which may be of some help to you.


 can't prove it but I am sure that the engine has only one beam per side, "Hence a side lever engine."


The engine shown at Dumbarton is only about 20 miles from me but not in a place that I visit often, it sits outside Denny's experimental tank, at one time the longest in Britain if not the world and can be visited anytime that one is in the area, this tank was used by Barnes Wallis to experiment with his design for the bouncing bomb used by the Dam Buster patrol during the WW 11 bombing raids.


I hope this is of help to you.


George.

[ooyah/2]

Dave,
(can't prove it but I am sure that the engine has only one beam per side, "Hence a side lever engine." )

OOPS wrongly worded,


I should have  said , Only one beam on the engines "  side.


George.

[Treble]

Dave , There is a side lever engine at Markham Grange Steam Museum , Doncaster , England . They have a web site , where you will find pictures and a description of its working . Hope this helps a little . Sorry , I am not computor literate , and so cant post a link . Trevor .