Chris's Slew-Crowd Engines

[crueby]

Lovely work, Chris.  I do like that idea for the threaded piston rods, and a good explanation for "why". 

Thanks!  Another reason why is that I have had troo many times where the die did not track quite straight when making the threads, where the tap will follow the hole better. As long as the drill was centered and tracked, anyway!  I like using sections of screws instead a lot!

[vtsteam]

I like your method there, too. Must remember....

[crueby]

The rest of the crossheads have been shaped just like the ones yesterday...

and have started milling the flat sides of them. A collet in a square block makes it easy to do one side of the bar,

then the other by flipping the block over in the vise

I'll drill the hole for the wrist pin before removing the bar from the collet to ensure that it is perpendicular to the flats, then flip the bar around in the collet to do the same on the other end, finally cutting the bar in half to separate the two crossheads for shaping the last end...

[cnr6400]

 

[crueby]

After lunch, drilled the wrt pin hole in the first end and got the other end of the Marion crosshead bar shaped down and drilled its hole...




So thats one pair down, three to go. Next up is the Thew, since its got the same OD crosshead as the Marion did so same collet...




Also, yesterday I had been doing some more exploring online about the Great Eastern ship/engines, and branched out to the Great Britain, one of Brunel's earlier ships. I was looking at the website for the museum where that ship is, and queried them about any plans of the main engine for it. Turns out they do have a set of drawings for the engine and boiler from back in the day, they are checking on cost to have them duplicated for me!      Not a super detailed set, but enough to work from. Is there anyone out there who has visited the SS Great Britain and has any pictures of the engine? There are some online, am searching for more, the more the better.
 
 




Edit: fixed ship name above..

[Fj45]

 Hi Chris,

 A little confusion there re Great Britain and Great Western. Great Western of 1838 was the  first of the 3. A 4 masted paddle wheeler and an immediate success on the Atlantic route the latter 2 seemed to fail at. Wooden hulled, she was scrapped in 1856.
 The Great Britain's (6 masts and screw drive, no paddles) planning began in 1838 and she entered service in 1845, 5 years late. Brunel kept "upgrading" and convincing the owners to go along, draining financial resources (sound familiar?). 2 years later she had been run aground, sat for a year and been refloated at a cost of 34,000 pounds. Owners went broke and sold her for salvage, 25,000 pounds.
 New owners refitted with 4 masts, smaller more modern engines and boilers, many more less luxurious cabins and put her to work carrying emigrants to Australia and expat holiday makers back to the UK, and of course cargo both ways.
 She must have been a success in this trade as she was kept at it for 30 years!
 Now the bad news, in 1882 she was "converted to a sailing ship". I believe the engines and boilers would have been removed to increase payload.
She is now a museum. As for the engines, sorry mate, you won't find photos, they've been gone 140 years.

[crueby]

Hi Chris,

 A little confusion there re Great Britain and Great Western. Great Western of 1838 was the  first of the 3. A 4 masted paddle wheeler and an immediate success on the Atlantic route the latter 2 seemed to fail at. Wooden hulled, she was scrapped in 1856.
 The Great Britain's (6 masts and screw drive, no paddles) planning began in 1838 and she entered service in 1845, 5 years late. Brunel kept "upgrading" and convincing the owners to go along, draining financial resources (sound familiar?). 2 years later she had been run aground, sat for a year and been refloated at a cost of 34,000 pounds. Owners went broke and sold her for salvage, 25,000 pounds.
 New owners refitted with 4 masts, smaller more modern engines and boilers, many more less luxurious cabins and put her to work carrying emigrants to Australia and expat holiday makers back to the UK, and of course cargo both ways.
 She must have been a success in this trade as she was kept at it for 30 years!
 Now the bad news, in 1882 she was "converted to a sailing ship". I believe the engines and boilers would have been removed to increase payload.
She is now a museum. As for the engines, sorry mate, you won't find photos, they've been gone 140 years.

I know about the engines, they were replaced in the ship by the museum with replica ones that can be turned for viewing. I'm  looking for pics of the replacement  ones. The museum is getting me copies of the original  drawings they have, but they don't  show all the details that photos of the replacement  ones would.


I see that in my post I  did give the wrong name in one spot, been doing searches on the Britain as well as the Western and Eastern, got the wrong one in my fingers!   

[Fj45]

  "I know about the engines, they were replaced in the ship by the museum with replica ones that can be turned for viewing"

 Sweet, that is good news.

[crueby]

  "I know about the engines, they were replaced in the ship by the museum with replica ones that can be turned for viewing"

 Sweet, that is good news.

Yes, its rare for a museum to go to such lengths!

[crueby]

The Thew crossheads have been milled flat/drilled just like the Marion ones were, though you can see the Thew ones have a thinner profile:



Swapped collets for the smaller OD Bucyrus crossheads, and have started shaping them...

[cnr6400]

  Looking great Chris!

[Kim]

There's a surprising amount of diversity in crossheads between the engines! 

Kim

[crueby]

Thanks guys!  Yeah, for engines doing the same job in the same space, each manufacturer had their own  style. Keeps it fun.

[crueby]

All of the crosshead bars have been flattened on the sides:

so they were sawn apart

then trimmed to length

giving a herd of partially completed crossheads:

Still remaining is to cut the hollow in the ends for the con-rods, and shape the bases to final profile. I was going to do the hollow ends first, but without cutting the profiles, the cuts would be too deep for small/narrow end mills. So, I'll at least have to rough in the profiles on the longer ones first. To that end, I sketeched on the shapes that need to be cut in for the profiles, different for every manufacturer:

The Erie ones, bottom/center, just need a shallow notch, the others get a more complex shape. They did this to save metal on the castings, and reduce the moving mass.

[PaulR]

Looks great and what a lot of work in that batch