Steam drum

A special section just for steam engines and boilers, as without these you may as well fit a sail.
Post Reply
User avatar
marinesteam
Full Steam Ahead
Full Steam Ahead
Posts: 300
Joined: Thu Nov 19, 2009 2:51 am
Boat Name: TBD
Location: Colorado USA

Steam drum

Post by marinesteam » Wed Jun 22, 2022 3:49 pm

Just a quick pic to get the board traffic up, it's been a bit quiet lately.

Center drill, drill, ream, repeat 206 times. Each series of holes required moving to clear the end of the tube so as to be able to change between center drill & drill and also to change the drill chuck for collet & reamer. Used every bit of the vertical, even with the 4" riser" for the reamer to clear the tube. Was only able to do about 2/3 of the holes in a row due to length of the X axis travel. Once all of the reachable holes on one end were done, flipped end for end then picked up the last hole to complete the remaining holes in the row.

Now on the the mud drums, which should be easier since I should have enough room in the Z to use the longer keyless chuck for all of the operations.

Cheers

Ken

Steam drum.jpg
Steam drum.jpg (96.49 KiB) Viewed 298 times
User avatar
barts
Full Steam Ahead
Full Steam Ahead
Posts: 1011
Joined: Wed Nov 18, 2009 6:08 am
Boat Name: Otter, Rainbow
Location: Lopez Island, WA and sometimes Menlo Park, CA
Contact:

Re: Steam drum

Post by barts » Wed Jun 22, 2022 5:12 pm

Ouch - that takes some patience; at least you have a power traverse :). I remember doing the same for Otter's boiler (well, it was only 110 holes iirc ) 27 years ago on a mill-drill. I had a very stubby 5/8" drill Latrobe drill bit that saved the day wrt clearance; putting the drum directly on the table and nestling it into a slot helped as well. W/o a DRO, I center-drilled, pilot hole and then the 5/8" hole in one position, so my fingers and the chuck key got a work out.

Nice work! I look forward to seeing your boiler take shape.

- Bart
-------
Bart Smaalders http://smaalders.net/barts Lopez Island, WA
User avatar
marinesteam
Full Steam Ahead
Full Steam Ahead
Posts: 300
Joined: Thu Nov 19, 2009 2:51 am
Boat Name: TBD
Location: Colorado USA

Re: Steam drum

Post by marinesteam » Wed Jun 22, 2022 6:43 pm

Bart,

Thanks

Your a much more patient person than I. Can't imagine having a mill without a DRO.

Since the tube is offset along the X and the end is beyond the slots of my table I needed to use the extension plate that you can see in the photo. To reduce the need to indicate for each row of holes I made a set of "V blocks" and the V-blocks also gave the clearance needed to fit the extension under the tube end. I was expecting I would probably needed to trim the shank of the reamer, but there was just enough clearance for the reamer to clear the tube but couldn't swap tools without going to the end.

Cheers

Ken
S. Weaver
Full Steam Ahead
Full Steam Ahead
Posts: 336
Joined: Mon Sep 26, 2011 4:23 pm
Boat Name: SL Iona

Re: Steam drum

Post by S. Weaver » Wed Jun 22, 2022 10:31 pm

Beautiful, Ken.
Steve
User avatar
TahoeSteam
Full Steam Ahead
Full Steam Ahead
Posts: 757
Joined: Fri Mar 07, 2014 5:38 am
Boat Name: Wayward Belle
Location: South Lake Tahoe, CA, USA
Contact:

Re: Steam drum

Post by TahoeSteam » Thu Jun 23, 2022 10:17 pm

Hi Ken,

That's a lot of drilling and reaming. All tubes will be rolled in I assume.

Is your boiler following your own plans? How many square feet of heating surface are you looking to achieve? Any drawings we may peruse?
~Wesley Harcourt~
Check out the steamboat and steamSHIP videos on my YouTube page: https://www.youtube.com/c/wesleyharcourtsteamandmore
User avatar
marinesteam
Full Steam Ahead
Full Steam Ahead
Posts: 300
Joined: Thu Nov 19, 2009 2:51 am
Boat Name: TBD
Location: Colorado USA

Re: Steam drum

Post by marinesteam » Fri Jun 24, 2022 5:07 pm

Wesley,

Yes, Tube will be rolled in. Purchased a tube expander from Wicksteed in the UK as they were the only ones that offer an expander for 1/2" tubes and not too long to fit into the 4" mud drum. (Still may have to trim a mandrel to fit)

Using John King's boiler as a guide but have changed from Cunifer tubes to steels tubes and worked the math to ASME code. Copper alloys are problematic with ASME code and the grade needed aren't available in the states. Several suppliers list them, but they are not available in quantity less than a mill run, or in the grade or size needed. Since the Cunifer tubes wouldn't have met code and were unavailable anyway, the decision was made to go with steel tube. The steel tubes were difficult to get as well and while they don't meet ASME code they are a hydraulic tube grade that is materially the same as A-179 boiler tube. It's the same tube that some of the Stanley guys are using to tube their boilers. Otherwise, the remaining materials are all code listed but the boiler won't be to code due to the tubes.

The heating area is 39.9sq ft based on tubes only, but I expect the steam drum doesn't add more than another square foot to the total as not much is exposed to the firebox radiant energy.

I have been working directly from the CAD model so don't have a set of drawings per se. Working on the sheet metal for the casing so don't have the spare time to make drawings at this point but I'll contact you in private.
Last edited by marinesteam on Sun Jun 26, 2022 3:27 am, edited 1 time in total.
User avatar
TahoeSteam
Full Steam Ahead
Full Steam Ahead
Posts: 757
Joined: Fri Mar 07, 2014 5:38 am
Boat Name: Wayward Belle
Location: South Lake Tahoe, CA, USA
Contact:

Re: Steam drum

Post by TahoeSteam » Sun Jun 26, 2022 2:36 am

Thank you for the explanation and info Ken. It sounds like a viable option to have a code boiler (save for the tube issue) without paying for an expensive code welder. I wonder what the 'code shop' requirements and inspection regimen during construction would be for manufacturing a boiler to that design and it be code.

Good affordable option for the steamboating community.
~Wesley Harcourt~
Check out the steamboat and steamSHIP videos on my YouTube page: https://www.youtube.com/c/wesleyharcourtsteamandmore
User avatar
fredrosse
Full Steam Ahead
Full Steam Ahead
Posts: 1872
Joined: Fri Nov 20, 2009 5:34 am
Boat Name: Margaret S.
Location: Phila PA USA

Re: Steam drum

Post by fredrosse » Mon Jun 27, 2022 9:48 pm

To be a Code Boiler, welded or not, requires material certifications, and if the boiler drums are not seamless tubes/pipe, then radiography is required. That is plenty expensive by itself.
User avatar
barts
Full Steam Ahead
Full Steam Ahead
Posts: 1011
Joined: Wed Nov 18, 2009 6:08 am
Boat Name: Otter, Rainbow
Location: Lopez Island, WA and sometimes Menlo Park, CA
Contact:

Re: Steam drum

Post by barts » Tue Jun 28, 2022 12:35 am

Caution: Some opinions follow. This is of course US practice; other countries have their own regulations, which are often much stricter.

Something is either a Code boiler, or not a Code boiler. Code boilers are required in some areas/services, and not in others. If you want to put a boiler in a place of employment, most (all?) states require only Code boilers to be used. If your boat is over about 40', the Coast Guard requires a Code boiler. Some states require a Code boiler under a lot more conditions. If you need a Code boiler, you buy one. Full stop.

If you don't need a Code boiler, you can build a serviceable small boiler yourself given sufficient skills at welding and machining.

Opinion: well designed small hobby steel boilers fabricated from commercial pipe (either seamless or welded) have much higher factors of safety than are normally employed in large scale boiler design, and are quite safe in practice. Small steel water tube boilers in particular are very robust and quite resistant to catastrophic damage. Tube failures due to corrosion (usually pin-holes in tubes) or low water levels (typically w/ copper tubes) can and does occur, but these events have an inherently limited release rate of energy, and over-pressure events basically don't happen because the pipe thicknesses used (and safety valves!).

If I were designing/building another boiler, I'd focus on following good engineering practice as documented in the code for custom sections (say end plates w/ stays in drums) and wherever possible use pipe and thread/weld-o-lets and forged drum end caps. I'd also avoid copper tubes; in my experience they just don't have the tolerance for abuse displayed by steel tubes. This is particularly true for designs in which the tube joints are directly exposed to the radiant heat of the fire and are easily uncovered when the water gets a bit low - such as a Yarrow or express boiler.

- Bart
-------
Bart Smaalders http://smaalders.net/barts Lopez Island, WA
User avatar
marinesteam
Full Steam Ahead
Full Steam Ahead
Posts: 300
Joined: Thu Nov 19, 2009 2:51 am
Boat Name: TBD
Location: Colorado USA

Re: Steam drum

Post by marinesteam » Thu Jun 30, 2022 3:19 am

fredrosse wrote:
Mon Jun 27, 2022 9:48 pm
To be a Code Boiler, welded or not, requires material certifications, and if the boiler drums are not seamless tubes/pipe, then radiography is required. That is plenty expensive by itself.
Steam & mud drums are SA-106 gr B seamless carbon tube, End caps are SA-516 grade 70, all definitely code material & have certs.

Cheers
Post Reply