Rollwagen no. 28 of the Plettenberger Kleinbahn in 1/22.5 scale

[Ray Dunakin]

Absolutely stunning!

[Hydrostat]

Thanks, Ray.

Meanwhile the axles and steel tyres arrived from a turnery.







The printed master form waits to be casted in brass. One can see some 'pimpels' at the rear side of the circumference which are remains of the printing process (support material) which don't need to be removed because the tyre hast to be lathed later on.



Cheers,
Volker

[finescalerr]

Adequate. -- Russ

[1-32]

hi volker
i cant wait to see the finished item lovely skilled work.
regards kim

[turtle]

Beautiful work shown here Volker, the axle bearing just leave me speechless.
Just out of curiosity, approximately how much time is spent doing CAD work as opposed to the actual machining ?.
Really enjoying seeing the progression.
Thanks.

[Hydrostat]

Beautiful work shown here Volker, the axle bearing just leave me speechless.
Just out of curiosity, approximately how much time is spent doing CAD work as opposed to the actual machining ?.
Really enjoying seeing the progression.
Thanks.

Thanks, Roger. It's difficult to put a number on this because on the one hand I'm an autodidact with CAD and this was my first large project with a lot of components having to interact and on the other hand my friend Frithjof mills the parts for me. I think I spent some 200 or 250 hours with research and construction. CAM for sure is faster than handcrafting, but it's the way if you want to create more than one item (this is going to be a lot of 10 Rollwagen). Maybe Frithjof can write something about the time it takes to mill one special part for example. I've been modeling 'by hand' before and I can't say, that CAD and CAM makes things 'faster' if there's only one item, but it surely makes things a lot easier, especially if working condition is the aim.

Thanks for looking in!

Volker

[marc_reusser]

Beautiful work, as usual. really glad to see the progress on this.

[Hydrostat]

Beautiful work, as usual. really glad to see the progress on this.

Thanks, Marc. Glad to see you back posting!

Meanwhile the remaining brass castings arrived. There's the upper supporting bolt for the binder pendulums ...



... and the wheel disks,



which have to be lathed at circumference, center and front and then are going to be pressed in the steel tyres and with plastic bushes to the axles. I'll have this done for I don't have the tools for that. That's a project for next year.

Unfortunately the bearings have to be mounted before that. I found some inexpensive custom floating reamers at Ebay with 3,02 mm H7 and managed to have one first axle test mounted:



The axle sits nearly backlash free between the bearings. I'm quite sure that there won't be problems with the low distance of 0.5 mm between steel tyre and bogie frame.



Cheers,
Volker

[Hauk]

The axle sits nearly backlash free between the bearings. I'm quite sure that there won't be problems with the low distance of 0.5 mm between steel tyre and bogie frame.

Nice! I follow your progress with great interest.
But how freerolling are those bearings/axles?

[Design-HSB]

Hello Volker,

nice that it continues, even better, of course you attend your quality stay.
Now there is still the challenge to the wheels also isolate.

[1-32]

 but volker is it going to work.
kind regards kim

[finescalerr]

I think we can be confident the wheels and axles will be perfect. -- Russ

[Hydrostat]

Hi all!

Nice! I follow your progress with great interest.
But how freerolling are those bearings/axles?

Hauk,

I think they'll be sufficiently freerolling. I had to put some work into 88 bearings before answering your question. Now I've got a state of axles which are turning when moving a fingertip over them without pressure. This will improve with a bit of silicone lubrication. For my gauge this is good. I've heard of a lot of modelers who aren't too happy with their ball bearings because the wagons tend to run away after a slight shove.


My bearings aren't split like the prototype parts and so they have to be included when mounting the wheelsets. I'll have this done by Holger Gräler, a guy who's company is very famous in Germany for his H0 scale prototypical wheelsets (he's called "Räderpapst" [wheel pope]). The bearings had to be reamed far enough not only to have them running free on the axle but also after mounting them to the bogies ... This is a real challenge according to the cast parts which never come out identically. At the first lot of bearings I removed the cast-on section succinctly and then sanded the seating. The result can't be neither level nor always absolutely accurate to size. At the second lot I've chosen another way. First I used a 3.02H7 mm reamer to ream the bearings manually. This makes them freerolling on the axle, but I wanted more backlash because of the described inaccuracies of the cast parts. So I chucked the reamer to the slowly running drill and reamed the parts with oscillating movements by hand again. After that I clamped 4 bearings into the edge of an aluminum angle and reamed them all in one to avoid any offset.



Then I cut the cast-on section off ...



... and sanded a minimal channeling into the seating.



Sanding the bearings' seatings until they start to be shiny provides at least a level seating. Maybe it's more precise, too.



Cast parts almost never can be used without some treatment. At the bearing was a small mold mistake, resulting in a knob at one edge.



This had to be removed with a sanding disk. Frithjof afterwards uses a jig to drill the four holes which have to fit precisely to the milled bogy parts.



Doesn't matter for one wageon, but with 44 axles or 88 bearings this starts to dwindle into real work  .



Frithjof provided the next milled frame parts for me  . The Rollwagen meanwhile received the base plate with the brakeman's workplace. The tear plate is an etched part, but shape and drillholes are made via cnc by Frithjof. The U-sections have little keys fitting to slots in the frame. I should have provided those slots for the tear plates, but it works without them, too.



The brakeman's seat is a folded etched part with screw imitations. Trunnion diameter is 0.4 mm. RSU makes mounting the part quite easy. I used some soldering fluid and tinning paste. At the tear plate it takes some more solder.



The base plate then is soldered to the U-sections, using the frame as a jig. Then the U-sections are soldered to the steel frame. There's some wear on the steel surface from the carbon electrode, which has to be sanded and hopefully should not be visible anymore after sand blasting.



Last step is soldering the plate to the frame. I tried to create a solder fillet on the back side. It's a bit difficult to avoid solder building up on the front side which then has to be removed with desoldering braid, but it will work after some exercise. The dark spots aren't mistakes in the fillet. i didn't manage to take a better picture.



Next parts are the weighbeams, connecting the frame to the bogies via the binder pendulums.



For that the cast parts needed a complex treatment. The closed side was a bit too thin for casting and so the caster put some putty there. This had to be removed to level at all parts. Frithjof milled this. I sanded the contact areas to dimensions and removed some brass pearls from the cavity which result from air bubbles in the investment compound. All the square holes have to be filed and the holes have to be reamed to fit to the bolts' dimensions.



I think the construction is clearly visible here:



Everything seems to fit insofar.



Thanks for looking in!

Cheers,
Volker

[finescalerr]

With slightly more material and no more effort you could have built 1:1 scale components and then earned money by using them to transport goods on a nearby railroad! The modeling is most satisfactory. -- Russ

[Ray Dunakin]

Great stuff, Volker!

Although this kind of work is beyond me, seeing it always helps my understanding of working with brass, and gives me courage to achieve as much as I can with my limited tools and abilities.