Argent Lumber 3 spot

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rudd
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Re: Argent Lumber 3 spot Chapter the second.

Post by rudd »

So everything seemed to center on the cylinder saddle. Cylinders/steam chest, pilot truck running gear, etc.
Gents, I think I am past that hurdle!
I made the portion of the frame that holds all this a separate section. I'm thinking I may try to make some taper bolts - learned about those on the little Porter 0-4-0 at the museum. If I make them 1/4" per foot taper, I can use taper pin reamers for the holes. I'm concerned that regular bolts would "get to working" and fail.
Anything you see with weld on it was either a forging or casting on the prototype. The welds are a bit ugly, but if anyone besides me sees the underside of this thing, I think that will be the least of my worries.

Anyhoo, on with the show.
front section of the frame w/ the smokebox bottom/center of the universe.
front section of the frame w/ the smokebox bottom/center of the universe.
underside with equalizing bar - per prototype.  There are a couple of "ears" that the prongs of the "fork" bear on - original looked to be a forging, so I used a welded ass'y.
underside with equalizing bar - per prototype. There are a couple of "ears" that the prongs of the "fork" bear on - original looked to be a forging, so I used a welded ass'y.
pilot truck in place.  No, it is not a Bissel, it is modeled after the prototype.
pilot truck in place. No, it is not a Bissel, it is modeled after the prototype.
I am still wondering if Mr. Porter figured out a way to make this pilot self centering, but I see no evidence of that.
right side up again, pilot equalizer hooked to the yoke between the two front leaf springs.
right side up again, pilot equalizer hooked to the yoke between the two front leaf springs.
I made a little movie showing the equalization system working, but the file is huge.
OK, lets assemble steam chests and cylinders!
OK, lets assemble steam chests and cylinders!
The orange goop is loctite 510, I also used the recommended primer. This held at 110 PSI of air on my mock-up ass'y, which had a much looser fit.
mated up
mated up
The 510 cures in the *absence* of oxygen, so the exposed stuff will remain "goopy". I leaned this on my mock-up.
There are (4) 10-24 SHCS on each ass'y. I ran the numbers and (1) would handle the shear stresses of fully locked up and boiler pressure on the piston.

I've moved to semi-retirement at my work. Every weekend is a three day weekend now. Progress is being made.

One question - I got some rings from Otto Gas Engine. The end gap is about .0015. Two rings per piston or one? No way to pin them with that little gap, so the gaps would probably migrate to the same place.
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rudd
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valves

Post by rudd »

Cut down some Allen Mogul valves I had. Trying to stick a little closer to Porter practice with the gland and valve stem.
I learned something - the "valve packing" they sell at the big box store has rubber in it. Seals well, but when exposed to oil it turns into a black gummy mess. Going to pick up some teflon string at Ace Hdwre next time I am by there.
The glands are bronze silver brazed to the cast iron valve chests with some special solder I have for use on cast iron.
So far so good on holding 110 air pressure.
I lapped the valves and seats with timesaver lapping compound, what a difference in before and after lapping.
DSC04181.jpg
DSC04182.jpg
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Harold_V
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Re: Argent Lumber 3 spot

Post by Harold_V »

I just noticed you didn't receive a response to your question about rings and the gap.
I'm no expert, but a couple things come to mind.
One is that the spring pressure of rings intended for internal combustion tends to be quite high. Not suggesting that yours are wrong. Just thinking out loud.

The other is that the end gap may not be adequate to deal with expansion, although I suspect that in a steam engine the cylinder and ring will pretty much have an equal temperature. That may negate my concern about end gap. However, you suggested that with two rings, the end gaps may wander until in alignment. I don't think they will. There's no real reason for a ring to move unless the cylinder isn't straight. There should be enough pressure on the ring to make it stationary as far as rotation is concerned.

Love to hear more about your project, so keep us informed.

H
Wise people talk because they have something to say. Fools talk because they have to say something.
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Steamer Al
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Re: Argent Lumber 3 spot

Post by Steamer Al »

Tubal Cain's "Model Engineers Handbook" has some information on piston ring wall pressure and ring size calulations for steam engines. I am definatley no expert but its worth a read.
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Fender
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Re: Argent Lumber 3 spot

Post by Fender »

"I am still wondering if Mr. Porter figured out a way to make this pilot self centering, but I see no evidence of that."

Although I don't have any drawings to substantiate this, I suspect that Porter used conventional swing links to center their leading engine trucks. It's unlikely that they used a more modern design such as heart-shaped links.

" I'm thinking I may try to make some taper bolts "

An alternative to making these bolts from stock would be to shorten a taper pin and silver solder a hex head on the large end. Make the hex head from hex stock, and use the taper reamer on the hex head for a snug fit on the pin, cutting off the excess length. Center drill the small end so you can run it on a center in the tailstock to cut threads on that end. Ream the hole in the frame so the hex head barely touches the frame. This would be much easier than cutting an accurate taper to match the taper reamer.
Last edited by Fender on Wed Sep 29, 2021 4:09 pm, edited 3 times in total.
Dan Watson
Chattanooga, TN
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NP317
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Re: Argent Lumber 3 spot

Post by NP317 »

Alternatively, do not use taper bolts.
I have made and installed taper bolts on full sized locomotive smokebox-to-saddle mounting, per original design. Definitely non-trivial.
In my experience our model locomotives can use straight bolts in such joints. The forces are small enough for straight bolts.
And the difference is not visibly detectable on the models.
However, your particular area to be connected may be different. I do not understand the particulars.
RussN
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rudd
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Re: Argent Lumber 3 spot

Post by rudd »

Harold, Thanks. I have the info on how to make rings, I was trying to avoid building all the fixtures to just do two pistons, but it may come to that. I got the rings from Otto based on recommendations I found here, told the man I was going to use them for steam, he said something to the effect of "lots of people use my IC rings for steam." They seem hard, like maybe they would eat my cylinders.

Al, I think I will order that book. Thanks

Fender, I have spent time under the Argent Consol in Hardeeville SC and the Mogul in Waycross Ga. I have the drawings I made from my field measurements. There are links, but the top of the link is connected to a roller, not a fixed point. See photo below. It is not a Bissel truck.

NP, maybe the straight bolts would be OK, but I think I am going to try the taper bolt. I have hex stock, I got a sine bar to set my TA, and holding on to a taper pin to machine it doesn't sound like much fun, esp. a tiny one.
thanks all.
Rudd
argent7fronttruck1.JPG
argent7fronttruck2.JPG
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Bill Shields
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Re: Argent Lumber 3 spot

Post by Bill Shields »

I get rings from Otto...used them for years in steam and no problems.

If worried about pressure...get the rings from Otto ..put them in an od collet and thin them down a bit.

Trick is to get the collet bored slightly off center. I do it in a fixture in my vertical mill.
Too many things going on to bother listing them.
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Short Line Tom
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Re: Argent Lumber 3 spot

Post by Short Line Tom »

rudd wrote: Wed Sep 29, 2021 5:47 pm Fender, I have spent time under the Argent Consol in Hardeeville SC and the Mogul in Waycross Ga. I have the drawings I made from my field measurements. There are links, but the top of the link is connected to a roller, not a fixed point. See photo below. It is not a Bissel truck.
Some drawings of the PORTER engine truck design might be useful. :wink:
.
PORTER - FOUR WHEEL ENGINE TRUCKS - PART LIST.jpg
PORTER - FOUR WHEEL ENGINE TRUCKS.jpg
PORTER - TWO WHEEL ENGINE TRUCKS - PART LIST.jpg
PORTER - TWO WHEEL ENGINE TRUCKS.jpg
.
Cheers
Tom
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rudd
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Re: Argent Lumber 3 spot

Post by rudd »

My drawings are done for me to understand and get to a place where I can go out in the shop and build it once. So, no, they aren't beautiful. And I think I lost some data when I figured out I had two duplicate files and had to pick one. If someone wanted to dig into the archives in Quebec and find the drawings for this engine, hey, I am all for it.

The main point to understand is that the "swing link" truck, aka Bissel truck, has links that fasten into fixed points at the top, therefore they "swing" sideways as the truck takes curves, putting more weight on the outside wheel. (Note that the links are slightly further apart at the bottom than the top. To move sideways means one gets "taller" and one gets "shorter".) The links would like to be the same vertical length, so the truck tries to move away from the wheel with more weight, thus leading the engine into the curve.

The Porter design has links, but the tops of the links are not in fixed positions, they are on rollers, and are vertical. Therefore, unless I am missing some nuance, there will not be weight transfer as the axle/bearings/links assembly moves in relation to the large casting that is under the boss cast into the front deck of the engine. That large casting takes the downward force from the equalizer that transfers forces from the front diver pair. The pivot is cast integrally with center of the cylinder saddle. You can make out this boss at the top of this photo, which shows the rollers a little clearer. The sorta U shaped bar moves left-right with the links, springs, and rollers. How it works is shown pretty well in the model photo above with the "front end" assembled and turned upside down.

The only "known unknown" I have at this point is - why are the rollers tapered - i.e, sections of cones, smaller towards the fore-aft center and larger where the U shaped brackets attach? Is it wear? Were they made this way?
P8180327reduced.jpg
Attachments
porter lead.JPG
Last edited by rudd on Fri Oct 01, 2021 4:50 pm, edited 2 times in total.
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rudd
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Re: Argent Lumber 3 spot

Post by rudd »

Bill, Sorry, I wanted to ask - are you thinning the ID or the OD of the Otto rings? I think you mean ID, but want to be sure. Being a bit off center, you'd end up with the "elliptical" inner profile, which is better.

I just watched a video last night of a couple of British chaps "knocking up" Clupet rings - it looks like a fun challenge, not sure I want to spend the time on it though.

https://www.youtube.com/watch?v=80jzsNM6olE
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Bill Shields
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Re: Argent Lumber 3 spot

Post by Bill Shields »

Thinning the id...which is why I mentioned working off center
Too many things going on to bother listing them.
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