Building the 2.5" Scale Shay

[Fender]

Marty Knox had a great idea for attaching a separate smokebox to the boiler. You machine matching 45 degree bevels on the rear of the smokebox and on the front end of the boiler barrel. Then, weld four square nuts set on edge into the inside of the boiler barrel and in a corresponding place on the rear of the smokebox. The nuts on the smokebox are drilled out to clearance size for the bolts that will hold everything together. When the bolts are tightened, pulling the nuts together, the bevels keep everything aligned. A small amount of high-temperature sealant between the bevels will form a good seal.
You may have to use socket-head cap screws (which have smaller heads than hex bolts). Goop up the threads with a generous amount of anti-seize.

[Soot n' Cinders]

Marty Knox had a great idea for attaching a separate smokebox to the boiler. You machine matching 45 degree bevels on the rear of the smokebox and on the front end of the boiler barrel. Then, weld four square nuts set on edge into the inside of the boiler barrel and in a corresponding place on the rear of the smokebox. The nuts on the smokebox are drilled out to clearance size for the bolts that will hold everything together. When the bolts are tightened, pulling the nuts together, the bevels keep everything aligned. A small amount of high-temperature sealant between the bevels will form a good seal.
You may have to use socket-head cap screws (which have smaller heads than hex bolts). Goop up the threads with a generous amount of anti-seize.

That's a good idea! That would definitely pull tight and make everything square and air tight.

Another thought me and my dad have had is machining shoulders on the smokebox and boiler barrel and then either screwing or hot riveting the smokebox back into the barrel.

[PeterCraymer]

Tristan,

I just formed a ring out of 1/8" x 1" HRS that was a good snug fit into the boiler side. I set the flue sheet back from the end of the boiler pipe about an inch or so (don't remember exactly) so I could weld everything and then the ring was tack welded in a bunch of places around the OD of the ring. Small recessed welds so they wouldn t interfere with the smokebox. My smokebox is made from the same pipe so the ID was a perfect match and can be adjusted with a grinder. There are screws that are in the line of rivets around the back of the smokebox that hold boiler and smokebox together. The ring is drilled and tapped and the smokebox has clearance holes. Just another option.

Peter

[tomc]

Hi Tristan, I think your rode in #9 as 12 is parked and not run anymore.

Tom C.

[Soot n' Cinders]

Time for another update. Not a whole lot of progress to report but its something. Got both trucks complete and also got the frame painted. Brushed the paint on the frame because of all the corners and the finish didnt come out as good as the trucks, but once it gets a coat of grease and oil on it, nobody will be able to tell the difference.

Also decided to throw the decking boards and boiler barrel on the frame just for grins and chuckles. Makes it start to look more like a locomotive!

[Soot n' Cinders]

Work on the shay continues! Albeit slowly since school is now back in session for the semester.
Got the support bracket for the johnson bar welded to the frame.

The tumbling shaft arm made and brazed on to the shaft.

The johnson bar shaft and johnson bar made and connected to the the tumbling shaft through some nice ball end from McMaster-Carr.

And just started on machining the quadrant, the notches should be interesting to machine.

[Jawn]

Looks like good progress.

[John_S]

And just started on machining the quadrant, the notches should be interesting to machine.

IMG_0242.JPG

If you've still got it in the rotary table, cut the notches. Use a file to square out the bottoms after you pull the part off the mill. This will allow you to have perfectly machined notches to match the radius you've cut.

[kvom]

Or mount rotab vertically to index. Notches will be milled square.

[Pontiacguy1]

Or put the rotary table vertically and mill them out using a slot cutter or slitting saw. You could also use your fixture that you have and clamp that in the vise and use a slot cutter/slitting saw to make those.

[Soot n' Cinders]

My rotary table will go vertical and the plans call for the slots to be 1/8" wide so I was just going to use an 1/8" end mill to mill the slots out. That's this afternoons project so should be interesting.
Then it's on to the latch hardware.

[Harold_V]

My rotary table will go vertical and the plans call for the slots to be 1/8" wide so I was just going to use an 1/8" end mill to mill the slots out. That's this afternoons project so should be interesting.
Then it's on to the latch hardware.

Not a good plan unless you happen to have a very short end mill, as opening the slots will be somewhat troublesome. Deflection, even breakage, will be the enemy.

If you must use an end mill, you'd be best served to use a 3/32" to open the slots, then go back to take them to size and to achieve proper location. The first pass will have deflected and not leave a great finish, nor will it be on location. By using an undersized end mill, when you take finish cuts you'll be able to take a climb cut on both faces, yielding a uniform finish. The roughing and then finishing operations provide the added benefit of permitting locating the slots in the proper location.

Assuming you have clearance, using a slotting saw for this operation would be in your best interest. You might also consider the use of a Woodruff cutter, which would be a great choice.

Harold