Rebuilding the Central of Georgia #408

[John_S]

I gave up on the laser cutting place (I submitted the drawings to them in early or mid January ...) and had another shop do the boiler pieces with a waterjet machine instead. The results are fantastic!

Boiler parts!

All holes are undersized so I can do the final machining on them. Saves a bunch of time drilling (and drilling, and drilling!).


If anyone in the north Georgia area needs this type of cutting done, the company I used is a small shop called Atlanta Waterjet. They are located in Buford, Georgia. http://www.atlantawaterjet.com 678-714-8008.

Jim Porter is the owner and a super nice guy. He gave me a tour of their shop, their machines, and showed me a bunch of the work they do there. I was pretty stunned to find out their big waterjet machine can cut through EIGHT inch thick material. They did a job recently where they had to cut some white cast iron parts out of an 8" block. That's pretty impressive!

[John_S]

One more photo of looking down into the steam dome of the old boiler. I had a borrowed pressure washer here at the house about a week ago so I thought what the heck and blasted the tubes through the dome to knock off as much loose crap as I could.

Once the loose stuff flaked off you could really see how eaten up the steel tubes are.

[John_S]

Should be a good update this Sunday. Hauling the boiler pipe out to the CSPPRY to use the big milling machine we have there to finish drilling all the bushing holes and bore out the steam dome hole (my Grizzly mill isn't large enough).

I got a piece of 3.5" o.d. .375" wall pipe today to use for the steam dome itself. I had a heck of a time finding a piece of material locally -- most suppliers only carry up to schedule 80, but I wanted something with much more wall material. Found a 21" long drop from Alro.

Rumor has it a certain boiler maker will be visiting the RR that day ... Probably a good time to pick his brain!

[Marty_Knox]

Should be a good update this Sunday.
Rumor has it a certain boiler maker will be visiting the RR that day ... Probably a good time to pick his brain!

Well, I'm certain I'm a boilermaker, and I'm pretty sure I'll be there - so the rumor must be true!

[John_S]

Set up the front and rear tube sheets in the mill this morning to bore them out to .865" (.010" undersize for reaming after assembly).

I had the waterjet place cut the holes to .800" to save me some time laying out and drilling them. I just had to get everything set up nice and square, center on one of the holes, and go to town with the boring head.

Setting up the tube sheets

Centering on one tube hole

[John_S]

After a few delays, I was able to get in the shop and finish up the tube sheets this morning.

The three other reference holes in the front sheet are for the steam supply to the cylinders (center) and longitudinal stays.

[John_S]

Got most of the holes done in the boiler tube yesterday at the railroad shop. Only ones we didn't get to (I ran out of time) were the holes for bushings for the water glass and the pressure gauge.

Using a centercutting .750 endmill to machine the holes for the safety valve bushings.

After starting with a 3.250" hole saw, bored out the opening for the steam dome to 3.500"

Almost all bushing holes done

Once the remaining holes are done I'll go back and chamfer all of them for welding and clean up the pipe so there's no cutting oil remaining.

Unfortunately I only got to say hello to Mr. Knox as he arrived about the time I was starting to finish up and head home.

[John_S]

Drilled the remaining bushing holes, cleaned up and chamfered everything.

The bushings will be TIG'd in from both sides.

Getting ready to drill out the longitudinal stay holes in the front tube sheet and backhead (stacked together on the mill).

[John_S]

Got more boiler part work done. Lots of beveling and whatnot for all the upcoming welding. Drilling out the remaining holes for bushings for things such as the blowdowns, sight glass, washout plugs, throttle gland (which will also serve as a 1" inspection port in the backhead), etc.

Next I'll make the steam supply pipe gland for the front tube sheet. Then it won't be too long before things start getting welded together!

[John_S]

Nearly done with the supply pipe packing gland.

Starting with a largish hunk of round stock:

The OD and internal bore done. The bore is 0.008 larger than the od of the stainless steel 3/8 NPT supply pipe.

The two halves of the gland, done with lathe work:

Halves fit together:

I've got the rotary table set up on the milling machine and will drill and tap four 10-32 holes in the base and #10 clearance holes in the "nut."

Once the boiler is put together the supply pipe will pass through the front tube sheet, and through the base of the gland. Packing material is wrapped around the pipe and stuffed into the base of the gland. Then the "nut" half is bolted to the base, tightening the packing around the pipe.

This is exactly the same arrangement on my mogul, seen here: http://whatthehal.com/mogul85.jpg

Out of time for today, hope to finish this up tomorrow!

[John_S]

Finished up the supply packing gland this morning.

A bit more grinding on various boiler parts then I'll start sticking 'em together.

[John_S]

Getting a new TIG/stick machine setup the past couple days so progress has slowed a tad. Did get some time to work on the steam dome.

Turned to length and drilled and tapped ten 10-32 holes for high strength allen head cap screws for the lid.

Turning the steam dome

Drilling and tapping the bolt pattern for the lid

It's parts such as this that make me long for a DRO on the mill! Someday I'll break down and finally buy one, hah! Counting turns for all the X,Y offsets on a hole pattern is one of those "Please dont interrupt me right now!" moments.