Overmod All that is likely to be no fun without a proper drill-press fixture and perhaps some jigs.
If it comes down to that, I have access to a pretty decent machine shop, and several machinists who have a lot of skills I don't, as well as a number of 3d printers that are better than the four I have, and 3D modelers who are faster and more skilled than I am.
But that's probably even further down the list than spending several hundred dollars on a functioning model and cannibalizing it.
Great info in the conversation though, I appreciate everybody's input.
-Eric
I don't think there is any practical way to use thin-end wheelsets for quartered counterweighted rods, especially not if the parts are 3D printed in brass.
If he uses the Precision Scale frames, I think he's going to have to drill out the cored holes in the sideframes and machine through axles anyway; he might as well fabricate lower-friction bearings or bushings to go in the drilled-out holes and make the axle ends a correct fit for the Shapeways counterweights.
Naturally if he wants to use the Shapeways rod he is going to have to very carefully drill his axle bores in the sideframes so they are spaced apart at precisely the length between eye centers -- there is very little room for play in those rod eyes where they would pin to the counterweights. That also implies that he take great pains to drill exactly square to the frames, and take similar care to fit the bolster correctly to put the truck in square. All that is likely to be no fun without a proper drill-press fixture and perhaps some jigs.
As with electrically-driven model reciprocating locomotives, it is very important that the two wheelsets be in exactly the same angle of quarter, but not that they be precisely 90-degree quartered.
The horizontal engine and steamline joints and piping for this truck is Precision Scale #3297, which was available as eBay #233311546797 ($10 plus $5.05 shipping)
The Shapeways parts are apparently for the 'original' tender booster prototype, the one described in Railway Mechanical Engineer vol. 73 p.145 (the full volume is available to download as PDF through Google Books) that was developed by J.A.McGrew and J.T.Loree. It turns out that there were a raft of interesting patents granted in 1925 for various aspects of this (which as I suspected was for use with locomotives with no trailing truck, here large 2-8-0s):
By McGrew alone: 1,580,838; 1,605,367; 1,605,366
By McGrew and Loree: 1,580,211; 1,580,837; 1,609,964
Some of these were assigned to Bethlehem, which identifies this as the genesis of the 'auxiliary locomotive' and not the Franklin design.
The improved version by McGrew, with a proper reversing engine to clear jams, is 1,742,610 (Jan 13 1930)
It should be easy to construct an appropriate truck (well, easier than without the reference) using the drawings and information in these patents.
Interestingly, there is a case concerning booster design that was appealed (and lost by McGrew/Loree and Bethlehem) at about the time of that last patent -- Ingersoll v. Delaware Hudson Co. -- over some details of the NYC version of the booster (see patent 1,383,633). In this decision is an interesting history of booster devices and their advantages and drawbacks that I have not seen in any railroad-related source or discussion, and the OP might find some of this information useful.
ekervinaFinding the parts is at best half the battle.
Lots of models are becoming available with "rotating end-cap bearings" and Rivarossi made the U-25-Cs with rotating end caps. There may be enough of a pin projecting the axle end you could fit the eccentric on to it.
Maybe you could figure out how to 3D print the eccentrics and side rod (at the exact centers) and go from there?
https://www.shapeways.com/product/QWZ56MZQ8/outside-cranks-for-1-5mm-axles?optionId=40954311&li=marketplace
Perhaps this? (I do not know the scale of this)
https://www.shapeways.com/product/26M9W7GW6/m-l-booster-truchk-counter-weights-and-side-rods?optionId=57188793&li=marketplace
Sometimes you can contact a designer and ask them to modify a part or dimension for you. If you convince them there is a market they might jump on the opportunity.
Just a thought.
Good Luck, Ed
ekervinaAny two-axle booster with side rods would work for me, really, I'm just not finding anything else at a reasonable price.
gmpullman (snip) Good Luck, Ed
(snip)
The siderods are really what I'm going for, and the Franklin has them, it just isn't evident in the 3-piece truck that PSC offers. They have a full kit (#3334) that includes the wheels and booster, and the (2017 list) price is not a problem. That's probably the way I will go, assuming I can get one. I was just thinking if there is a ready-assembled solution (a repair part or something) for not too much more, I'd go that way and avoid the hassle of building it.
Any two-axle booster with side rods would work for me, really, I'm just not finding anything else at a reasonable price. Plus, I wouldn't feel bad scavenging a truck off a scrap pile model, but I don't want to kill a perfectly good model if I can avoid it.
I'm rubbing my hands together over the prospect of what Ed provides for the Franklin tender booster.
"I see you shiver with antici..."
Bethlehem:
B_Booster_dwg1 by Edmund, on Flickr
Bethlehem_Booster_0008 by Edmund, on Flickr
Franklin booster applied to tender truck:
Franklin by Edmund, on Flickr
— and as applied to the trailing truck:
Franklin_trailing by Edmund, on Flickr
doctorwayneThe full kit, which includes the truck, booster engine, a pair of steam joints, and siderods for the truck seems a bit vague regarding the price - some of the parts are add-ons, and the siderods don't seem to have a price, other than that for the 3-piece truck kit.
I wouldn't be surprised to find a detail castings company making both types of truck, though. Or that Franklin did make a variant to "compete" with the supposed adhesion of the Bethlehem type.
I'm not really familiar with the Franklin truck, but from what I see in the PSC catalogue, it's designed for use with a booster.The kit for the truck-only is 3 pieces and, in my not-recent version of the catalogue, it's $12.50. I'd guess that it's for modellers who wish to add their own booster details.
The full kit, which includes the truck, booster engine, a pair of steam joints, and siderods for the truck seems a bit vague regarding the price - some of the parts are add-ons, and the siderods don't seem to have a price, other than that for the 3-piece truck kit.
I'm sure that the current prices are considerably higher, but if you need a four-wheel truck with a booster engine, it's not likely going to bankrupt you.
Wayne
I assume you mean this.
This was a somewhat more workable method of putting an auxiliary locomotive (it would be a 'booster' on a trailing truck) on power like a 2-8-0 or Decapod than a Bethlehem type (the one with the outside coupling rods to additional axles, which had augment issues at any particular road speed).
These were essentially near-drop-in replacements for tender trucks -- usually lead tender trucks, for dynamic reasons, but either could probably be used. In real life you'd have to arrange for steam and exhaust pipes, a couple of lube lines, and some air control, much of which might not be clearly visible with the locomotive on the track. The gear in the cab might be little more than that required for a nonreversible booster, which in simple form (as for the booster on Frisco 1351) is just a vertical air pipe with a push lever on top.
If this is a pure scratchbuild and the locomotive has no trailing truck, consider 'pushing' the Franklin truck forward into the space between the trailing driver axle and the rear of the locomotive chassis, then putting the radial buffer (also from Franklin) at an appropriate pivot to let the powered truck 'steer' the rear of the engine chassis as a partial replacement for what a Delta truck would do. That would give you much better riding as well as shorter piping.
For the price they're asking in the page I linked, it would be hard to imagine the time and effort involved in scratchbuilding a visual equivalent, even assuming that you knew why all the detail on the Franklin truck was made as it is. (And don't ask me, as I don't either, without doing quite a bit of additional research )
I probably shouldn't add this, but you might find more visual interest from a Bethlehem auxiliary locomotive, a model of which was provided with many of those IHB 0-8-0 models offered in HO and O scale over the years. This has the extended frame at one end for cylinders and gear, and the external counterweights and coupling rods that rotate for visual appeal. Think of it as the same thing that was on the Union 0-10-2s when they were built; parts of the Bethlehem truck frame survive on the preserved example if you want to use pictures as a basis for scratchbuilding.
There were also six-wheel versions (Southern, I believe, had engines in hump service with two such things under the tender!) but you would have to build them, and mama, you wouldn't use such a thing on road power and stay sane...
The only PSC trucks I have any experience with are their Buckeye tender trucks and while they look fantastic they don’t track very well at all. After putting in hours and hours trying to get them to run without derailing I finally gave up on them. Replaced all of them with Bowser Buckeye trucks and sold the PSC trucks on eBay. Mel My Model Railroad http://melvineperry.blogspot.com/ Bakersfield, California I'm beginning to realize that aging is not for wimps.
I'm looking for a franklin tender truck in HO for a "what if" scratch-build. Wheel and wheelbase dimensions aren't set, I'm going for the look. Level of detail also isn't a huge issue, I can add detail if necessary. I'm hoping for something that will give me the look and will roll without constant tweaking. I'd like to keep costs down, so I'm not looking to spend hundreds of dollars on a perfectly good model to scavenge one part from.
I found that PSC has a kit, but I'm just wondering what my other options might be.
I appreciate any advice or suggestions.