Cast iron Allen smoke box vs Aluminum smoke box

This forum is dedicated to the Live Steam Hobbyist Community.

Moderators: cbrew, Harold_V

trackfrog
Posts: 8
Joined: Sun Jan 15, 2012 9:50 am

Cast iron Allen smoke box vs Aluminum smoke box

Post by trackfrog »

Hi I am Tony

I am building an Allen models Consolidation.
I was Machining the throat on the smoke box saddle to 4 3/4" radius.
It seems that the smoke box in the cast iron version has a diameter of 9.125.

I was wondering Is the outside diameter of the smoke box supposed to be turned down?
or does the saddle have to be machined with a radius of 5 1/16"?

Was the aluminum smoke box casting smaller in diameter or did it have to be turned down ?

Would appreciate any info , ideas or opinions.

Thanks
tetramachine
Posts: 236
Joined: Sun Mar 19, 2006 6:27 pm
Location: NJ
Contact:

Re: Cast iron Allen smoke box vs Aluminum smoke box

Post by tetramachine »

Best use a calculator, 4-9/16 radius for a 9.125 OD. A 4-3/4 radius would be a diameter od 9-1/2.

But no help in answering your question.
My wheels don't slow me down
trackfrog
Posts: 8
Joined: Sun Jan 15, 2012 9:50 am

Re: Cast iron Allen smoke box vs Aluminum smoke box

Post by trackfrog »

Thanks for pointing that out.

Mistakes due to trying to multi task and not concentrate all on typing.

Plans call for 4 3/8" radius for 8 3/4". Diameter.

Thanks again
User avatar
Bill Shields
Posts: 10459
Joined: Fri Dec 21, 2007 4:57 am
Location: 39.367, -75.765
Contact:

Re: Cast iron Allen smoke box vs Aluminum smoke box

Post by Bill Shields »

saddle ID must match the smokebox OD

Bore of the hot end of the smokebox ID must fit the boiler...whatever OD that is (it can vary).

Suggest you not cut the ID of the smokebox socket until you know the actual OD of the boiler...
Too many things going on to bother listing them.
10 Wheeler Rob
Posts: 1546
Joined: Tue Mar 21, 2006 2:44 pm
Location: East Hartford, CT

Re: Cast iron Allen smoke box vs Aluminum smoke box

Post by 10 Wheeler Rob »

Yes, I had to machine down the OD of my Allen Ten Wheeler aluminum smoke box.
trackfrog
Posts: 8
Joined: Sun Jan 15, 2012 9:50 am

Re: Cast iron Allen smoke box vs Aluminum smoke box

Post by trackfrog »

Thanks for letting me know the casting had to be machined down.
The thing is that the cast iron casting for the smoke box is quite hefty.
Seems that turning the two joined cast halfs could be quite difficult.

Would machining on the mill with a rotory table be a better method?

I'm not sure how I would keep the two halves of the heavy casting lined up .
User avatar
Gary Armitstead
Posts: 279
Joined: Sat Mar 02, 2013 12:35 am
Location: Burbank, CA

Re: Cast iron Allen smoke box vs Aluminum smoke box

Post by Gary Armitstead »

I also had to turn the OD of the aluminum smokebox casting when I built my Allen ten-wheeler almost forty years ago.

Depending on your experience and machining capability, this is how I did the job. Go ahead and machine the flats on the INSIDE of the smoke box halves and fasten these together. Then proceed with the OD turning and the machining to attach the smoke box to your boiler. All of this is custom to YOUR boiler, because not all boilers are finished the same way or to exact dimensions. I turned my smoke box entire in my 12X36 Atlas Commercial lathe. I was also a machinist by trade for almost forty-five years (Die Sinker).
Gary Armitstead
Burbank, CA
Member LALS since 1980
Member Goleta Valley Railroad Club 1980-1993
lrdg2150
Posts: 61
Joined: Thu Jul 07, 2011 9:17 pm
Location: Flagstaff AZ

Re: Cast iron Allen smoke box vs Aluminum smoke box

Post by lrdg2150 »

I turned the smoke box on both of my Allen's. The method was close to how it was described earlier. I bolted the halves together as described on the prints but threading the smoke box shell and bolting from the inside. I'm only a hobbiest and not a Machinist so I worked slowly and taking small cuts.
Attachments
15-11-14_JTSRR-8701~2.jpg
trackfrog
Posts: 8
Joined: Sun Jan 15, 2012 9:50 am

Re: Cast iron Allen smoke box vs Aluminum smoke box

Post by trackfrog »

Thank you for the information.
My concern is now that the cast iron smoke box halves are extremely heavy.
I feel the aluminum is much lighter and easier to keep bolted together and lined up on the lathe.
I guess a sturdy 1/8" steel plate at each joint might be enough.

How did you deal with the extruding rivet or bolt heads while turning?

The picture is great!
Don't see a lot of Allen Consolidation pics.

Thank you on both replies
trackfrog
Posts: 8
Joined: Sun Jan 15, 2012 9:50 am

Re: Cast iron Allen smoke box vs Aluminum smoke box

Post by trackfrog »

Sorry just reread and see the internal threading part.

Just worry about the weight issue with the cast iron.
trackfrog
Posts: 8
Joined: Sun Jan 15, 2012 9:50 am

Re: Cast iron Allen smoke box vs Aluminum smoke box

Post by trackfrog »

The top half of the smoke box weighs 15lbs. And the bottom half is 18lbs.
trackfrog
Posts: 8
Joined: Sun Jan 15, 2012 9:50 am

Re: Cast iron Allen smoke box vs Aluminum smoke box

Post by trackfrog »

Possibly bolting a steel plate to to the rear lip as well.
Post Reply