"Catherine", a USA "Sweet Pea" engine build

[Benjamin Maggi]

In place of riveting, I used red Loctite 271 on the bolts that were supposed to be rivets and that should help strengthen the joint between the soft bolts and the nuts. For areas where strength will be critical, I will use socket-head cap screws sticking out from the rear and square nuts on the outside for appearance. I purchased smaller sized square nuts, which I can always drill larger and thread if I want hardware that is more in scale.

[Benjamin Maggi]

The end buffer beams proved to be a little challenging to acquire. Though they are simply rectangles with the corners cut off, the overall height of the beams is 6.625" and this precludes using 6" stock. It also means that using 8" stock will result in a lot of mindless machining. So, I took the easy way out and inquired locally about having them water or laser cut. Surprising, one quote for waterjet work came back so low including the metal that I couldn't refuse. They even cut the corners for free. Though I had to drive to their store in an unfamiliar part of the city at night in the dark (and got lost, to boot!) when all was said and done I am really happy with them. The plans called for ¼" steel but I upgraded to 3/8" for extra strength. The edge finish is super smooth, and though I was told it was going to be hot-rolled the surface is flat as glass. When it comes time for the motion plates, they are getting the job.

[Benjamin Maggi]

I laid them out per the plans but ran into one of my first divergences from the book- I wanted dual sprung buffers on the front. Though it is a model of a narrow-gauge engine, my wife and I both think that they look great on an engine. I don’t care if they work, but I don't want just a link-and-pin coupler on the front. I want it to look like a British engine. As stated previously, the Talyllyn Railway is one of my favorites and they use dual buffers. In due process I ordered a set of castings but unfortunately they didn't come with prints to machine them too. Making some educated guesses as to bolt mounting holes, I realized that by just slighting adjusting my plans I could re-use some of the bolt holes currently drilled for the angles that mount to the sides of the frames and support the end buffer beams.

[Benjamin Maggi]

The next natural step was to mount the 8 angle iron pieces at the ends of the sideframes which allow the buffer beam to be bolted on. My first attempt was a disaster, and involved clamping one to one of the side frames and getting it perfectly perpendicular with a machinist's square stretched across the ends of both main frames. Then, I marked the holes and drilled one. This was paired back to back with another and through-drilled, leaving the pair inversely identical. This process was repeated for all four per end, and then they were all bolted up. All seemed well, sort of. However, when I put the end buffer beams in place they rocked a bit, meaning all four angles weren't truly in line. Even worse, one of the end stretchers extended too far out from the sideframes and I hadn't noticed this!

Faced with these facts, I put the project aside for a while to think it over. Then, I came to see that if I could somehow temporarily hold the buffer beam against the end frames, I could butt the angles up against it, clamp them in position, and drill out. I didn't want to cut new angles, so I reused the old ones.

Once they were clamped in position, I used a corded hand-drill and went through the angle, sideframe, and other angle. One hole at a time was done, with each being bolted securely after. This took a bit of time and several drill bits, but worked well. I elevated my project on my new "workbench" which was just the half-wall between our kitchen and dining room.

[Benjamin Maggi]

I felt just like the machinists of old, reading Curly Lawrence's "words and music" and making do as best I could.

The other end with the improperly bolted end frame stretcher was more problematic. The easy solution would have been to unbolt the stretcher, clamp it in proper position with it flush to the ends, and then re-drill the holes. Not having a clamp large enough to do so (I had borrowed my friend's clamp for the first operation), and not wanting to drive to the store for one, I thought about an alternate plan.

I tried running a bolt through the sideframe, clamping the end buffer beam to that, and then drilling the holes with the stretcher clamped to the end buffer beam. This was a tremendous flop. After trying every other option except duct tape to hold the stretcher in position, I finally opened up the bolt holes in the sides of it with a larger drill bit. This increase allowed me to bolt it back on and then "adjust" it with a hammer until it was flush with the ends. I tightened up the bolts again, clamped the end buffer beam to the newly installed stretcher, and was back in business.

[Benjamin Maggi]

Looking back, it would have been far better just to purchase a large clamp. Or, I could have milled the bolt holes in the stretcher into slots to allow it to shift back.

[Benjamin Maggi]

This process has also forced my hand for attaching the end buffer beams to the frame now. Originally, the end mounting angles were to be temporarily mounted to the sideframes, then marked for the end buffer by clamping it up and using a transfer punch, then each angle was to be removed and individually drilled out. Only after this was done were the end angles to be permanently riveted to the sideframes, with the buffer beams later attached by bolts.

Because I didn't want the angles to shift in alignment again, once I was satisfied that they were all in their proper position I substituted strong socket-head cap screws inserted from the inside. They were trimmed to length with a Dremel tool and then square nuts were installed on the outside with Loctite 271. I will later file them down to be perfectly flush, but I won't use the Dremel because the heat build-up could loosen the Loctite.

[Benjamin Maggi]

Because the angles are "on for keeps" to mark and drill them for the buffer beam holes will require bolting that onto the frame and using either a large pillar drill (with the table moved aside) or a hand drill. I am comfortable with the hand drill so I will use that, and the 3/8" thick buffer beam will help ensure the holes are drilled straight.

The original design relies entirely on steel angles and bolts to attach everything together. While not very elegant, and probably more work then just welding the thing up, it is accessible to the beginner and produces a robust frame.

[SilverSanJuan]

Hi Ben,

Greetings from a fellow Upstate NY'er. I live north of Schenectady.

Nice work on the William! I love all the detailed photos and explanations.

You either have a very understanding wife, or you live alone. My wife supports my hobby as long as I keep it all in the shop.

Todd

[Benjamin Maggi]

My wife is very understanding. At one time when I was taking machining classes over an hour away (and the classes proved to be very useless) she said "why don't you save your money and just buy a lathe. We can put it in the family room." She has since "forgotten" about that conversation!

Are you a member of ALS or any other local train club? Perhaps I know you.

[backyardrails]

Ben
you said the classes proved to be very useless. Was this in a technical school? I am familiar with vocational training. I am coordinator for the Machining Techniques program in my area. What area proved to be useless? By the way, I was a member of ALS and first started going there around 1988. I haven't been back to ALS for the last 3 years. We were always good friend with Hank and Don Buesing.
Bernie Grow
MLS

[SilverSanJuan]

hehe.. yeah they can have short memories concerning certain things huh?

No, not a member anywhere yet. I'm just starting on a Kozo A3 in 3/4" scale. My first project of this type.