A Project Without End

[carrdo]

Hi All,

Remember that what I am about to describe is just for ONE operation on this never ending project.

I will let the photos speak for themselves.

to be continued.

 

[carrdo]

Hi All,

I am hoping against hope that one day, if I live long enough, that the locomotive will look like this but I am still a long, long, long way from that.

to be continued.

 

[Mike R]

Looking good, soooo familiar with never ending projects. I keep adding more of them too! 5" gauge?

 

[carrdo]

Hi Mike,

It is 3/4" scale and 3.5" gauge. Much like the Martin Evans Columbia.

 

[djberta]

Cardio unreal work, these live steam trains are a huge commitment.

 

[carrdo]

Hi All,

25+ years of work on and off to date.

I did not make the boiler - it was custom made by one of the best boilermakers in the US. It is all steel welded with rolled in copper tubes.

All of the bits and pieces for the boiler mounting/clamping system had to be invented /made as the boiler was too wide to clamp the boiler directly to the mill's table tee slots.

 

[carrdo]

Hi All,

Boiler alignment which was critical for the one operation.

 

[carrdo]

Hi All,

Finally, the actual machining operation. One has to centre the boring head/boring bar and this was done by moving the knee cross slide and the knee height micrometer dials while employing cigarette paper and sweeping the inner circumference with the tip of the boring bar.

The smokebox connecting ring needs to be a very close fit to eliminate any and all outside air leaks as in operation the smokebox has to be under a slight negative pressure and maintained that way to aid in drawing the combustion gases through the boiler tubes. One also needs to apply an anti seize compound to the ring as with such a tight fit, the heating and cooling of the boiler will result in the ring becoming welded in so if ever disassembly is required in the future...

 

[Ishmael]

I really like this. I'm working on refurbishing a Baldwin-style 3.5" gauge locomotive built in around 1900 so I can appreciate the work involved here.

 

[Dan Dubeau]

Nice job on the machining. Looks like it stretched your work envelope, but you managed it well, with good creative work holding. Looking forward to seeing this progress. I have an arms length interest in live steam. Meaning that I love seeing others projects and threads on the internet, or in person, but have zero interest in getting involved personally. Too many other interests, and not enough time in a lifetime.

 

[carrdo]

Hi All,

Another rather unique setup.

I needed to machine two emergency grate dump bars on this boiler. I won't go into all of the details but what we are dealing with here are two pieces of hot rolled steel 7.5" long with a cross section of only 1/4" by 7/32". Initially, they were milled from a longer and slightly larger piece and then finish ground on the top surface.

Of all the machining setups I have faced over the years, this was one of the worst and this time I did it to myself as I wanted to have the grate keeper cross bars machined to a 60 degree triangle or as near as possible to that.

Rigidity problems, holding problems, alignment problems, clearance problems, vibration, overhang, deflection and warping all come into play here.

To start with I pre-indicated along the length of a bar with the bar sitting on an adjustable parallel held in the angle vise as seen in the photos. Both free ends of the bar were then indicated to an equal reading (less than 0.0005" difference) to set the angle vise dead "square". If you try and indicate straight along the length of the bar you will just end up chasing your tail as the bars were nearly straight but not absolutely so.

Rigidity/overhang/vibration/deflection were huge recurring issues. I probably changed the setup three times until I came up with what is shown in the photos while employing miniscule passes of only 0.002" DOC. It was wild but in the end it worked.

Both free ends of the bar should have been supported with the detail shown at the milling vise end but as I don't have two identical milling vises this was not an option. One could make a custom angle plate or block bolted to the table of the mill to replace the toolmakers jack but I got away with using the miniscule DOC, a very slow feed and a very sharp cutter.

 

[carrdo]

Hi All,

A couple of additional photos and a little explanation.

Why the strange keeper shape? Well, the answer is you don't want any of the coal ash or as little as possible to build up on or adhere to either the grate bars themselves or to the keeper bars. Coal ash is very corrosive (alkaline) and will rot out these items regardless of whether they are constructed from cast iron, mild steel or stainless steel.

The grate bars shown will also be tapered 2 degrees on each side to minimize any ash retention but this has yet to be done. This is another interesting setup due to all of the same issues as with the keeper bars but as I have done it before... stay tuned.

Another reason for tapering everything is the extreme temperature variation (which increases the corrosiveness of the coal ash) and the repeated heating and cooling of the boiler/firebox in an often humid/wet environment. I can't quite believe it but in the model engineering literature temperatures of up to 2000 degrees F have been reported directly above the glowing the coal bed.

Coal fires produce exceptional radiant heat from their combustion which is the most efficient form of heat transfer and is one reason why steam boilers, historically, have been coal fired (besides being a cheap and an abundant fuel source).

 

[6.5 Fan]

Coal fires produce exceptional radiant heat from their combustion which is the most efficient form of heat transfer and is one reason why steam boilers, historically, have been coal fired (besides being a cheap and an abundant fuel source).

Holy crap, don't let the envirofreeks see that post. They will be after you with pitch forks.

 

[Ironman]

They are after words first, and will boil him in oil for saying anything good about coal.
I had an enviro Marxist in the house raving about coal one day and I said, "I'll bet you have never even seen coal." He looked down and mumbled a bit, and I handed him a lump from the coal scuttle and said, "I was wrong, now you have seen it" He suddenly realized he was warming himself at a coal stove.
He asked if he could take the lump home

 

[JustaDB]

They will be after you with pitch forks.

Call me. I'll be there, standing opposed.

 

[JustaDB]

He suddenly realized he was warming himself at a coal stove.

Idiot...

 

[Tom O]

Holy crap, don't let the envirofreeks see that post. They will be after you with pitch forks.

It’s not always the case my Grandad told us that one time that the ship was low on coal they stopped off in Seattle I believe to buy cheap coal which they had to unload because of the low grade they couldn’t raise a good head of steam.

 

[Ironman]

It’s not always the case my Grandad told us that one time that the ship was low on coal they stopped off in Seattle I believe to buy cheap coal which they had to unload because of the low grade they couldn’t raise a good head of steam.

That must have been brown coal, not fully formed yet. Germany is mining that stuff now for power because the bird grinders and solar panels crapped out and the war with Russia means no natural gas. Brown coal burns dirty and is very poor heat. Chinese are burning it as well.

 

[carrdo]

Hi All,

By a mere mortal compared to PeterT's and thestelster's work .

I had to haul the boiler up onto the table of the mill again for this drilling and tapping operation.