Another Pennsylvania A3 Switcher

[Roger B]

That's a splendid looking tender   

[JCvdW]

Thanks Kim, Per and Rodger for the kind comments! Yes Per, it is indeed a lot of work, but I am enjoying it immensely. Each new component is a mini project in itself.

To keep Kozo's beautiful book nice and clean, I usually work off photocopies in the workshop. Recently I discovered a neat way of making photocopies, without having to put the book on top of the copier. The 'Notes' app on the iPhone allows one to 'scan' a document using the camera. It also provides filters to enhance the scanned image, which can then be printed out. Android phones most likely have similar functionality.

Next up was the relatively straightforward coal stopper.



To make the Tender manhole, I first formed the manhole tube. I could not find small copper rivets to tie everything together for silver soldering. Since the rivet heads are filed away after soldering, I decided to make my own rivets from one of the 1.8 mm diameter strands of copper wire used in heavy duty electrical cable. This worked really well, and I ended up with a nicely formed circular tube. 

All the other brass sheet metal parts were 3D modelled in Fusion 360 and then cut out with the CNC router.



At this point I decided to deviate from the sequence in the book, and to locate and attach the manhole flange only after fitting the manhole cover and hinge. This way, it is much easier to clamp the manhole tube while working on the hinge. Fitting the flange after the hinge, also ensure that enough space for the hinge is left above the flange.

  When making the hinge, I removed all the material before drilling the pin hole, to reduce the chance of the 2mm drill bit going skew.



Aligning and fitting the hinge and manhole cover to the tube:



And finally, manhole and headlight base fitted to the tank. The CNC'd manhole plate fits snugly into the hole in the top, which was also CNC'd a while ago.



Next up was the steps. As is customary, I first reviewed how Kim and Blondihacks did it. Blondihacks pointed out that the dimensions of Kozo's bending jig must be adapted to the width of the vice yaws being used, otherwise the yaws will interfere. This certainly spared me some heartache!

 I used the sheet metal functionality of Fusion 360 to draw the steps and determine the exact location of each bend. Without a vernier calliper that is long enough to mark the locations of the bends on the strip of brass, I used the DRO on the milling machine instead.



This all worked out really well. The resulting bend radius matches the bend radius in Fusion 360 very closely.



And finally a shot of the manhole, headlight base and steps all mounted on the tank.



Paging through the book, I think I am done with sheet metal work for a while. Next challenge is to drill 1mm holes through 2.5mm stainless steel rods for the handrail. But first I am off to the UK to visit my first grandchild. And to buy some 303 stainless steel rods for the handholds, and small screws of all shapes and sizes, which is difficult to find locally...

[Kim]

Wonderful progress!  The manhole and stairs really add a lot of detail to the tender.  Yours looks lovely!  Well done! 

You're going to finish up the tender here soon!  That is very exciting

Kim

[crueby]

Stunning results on the tender!   

[JCvdW]

Thanks Kim and Chris for the kind comments!

I returned from the UK with an assortment of small screws (some imported from Knupfer in Germany) and 303 stainless steel rods for the handrails and handholds. The thinnest available rod for the handrails is 3mm, while Kozo asks for 2.5 mm.

I decided to first try some 2.5mm rod from some Maritime antennas that were scrapped at work. These are probably 316 stainless steel.

To drill the 1mm holes for the pins at the T joints, I first made a cross drill jig similar to the one Blondihacsks made.



This turned out to be unnecessary though, as all the 1mm drills at my disposal only made a dimple in the 316. No such problem with the 303 rod though, but the 3mm diameter just looks too thick.  I thought of reducing the rod diameter bit by bit in the lathe, but decided to first try to silver solder the 316 without a pin to strengthen the T junctions. I made a jig for silver soldering, and this worked really well.



The silver soldered T junctions turned out more than strong enough, without any pins.



To bend the handholds I made the bending jig suggested by Kozo, which really simplified things.



And after an unexpectedly long time, the handholds and handrail were finally done, and I also had the first parts for the loco!



For the four upright handholds for the tender and loco, I also used 303 stainless steel. To make the small bead, I followed Kim's example and made a form tool from heat treated drill rod.

Only the hand pump, light and pipe work now remain to complete the tender.

[Kim]

That's looking really nice!  The handrails add a lot of detail to the tender! 

Yeah, I think the pins on the railing are mainly to hold it in place while you solder it.  So your method of making a good holding jig seems just as good.  Nicely done!

Kim

[JCvdW]

Thanks Kim for checking in. It keeps me motivated!

The hand pump is finally complete. It took longer than expected as I had to make a few parts twice.

Living in a metric world, Kozo's plans are converted to metric before machining. So when seeing a 1/4 - 32 UNEF thread, I immediately look for the closest metric thread. Given the required inside diameter of the pump column, this resulted in M6 x 0.5. This seems to be too fine for brass, so I had to drill out the column from the pump body and remake it. I then used 1/4 - 32 thread which worked fine. No reason not to use imperial threads when making both sides of the thread!

The lug for the handle also ended up in the wrong place, so it had be milled off and a new slot machined. A new lug was then silver soldered after the rest of the pump was complete. Fortunately no harm done in the end.



Silver soldering the fine brass screen to the bottom of the suction valve seat, seems problematic. So I made a retaining ring that can be silver soldered to hold the screen. I am still waiting for the screen to arrive, and hope this will result in an easier silver soldering operation.



I have not tested the pump yet to see how much pressure it can generate, but it at least moves water!

<a href="https://www.youtube.com/watch?v=7Tw6oB9lq5Y" target="_blank">http://www.youtube.com/watch?v=7Tw6oB9lq5Y</a>

[Kim]

Nice looking hand pump! 

I had the same problem with the screen. Couldn't get the silversolder to work with it at all.  I ended up making a cap like yours and securing it with a small screw.  I wonder what is so different about the screen we can get now vs the screen Kozo used for his model?

Nice progress, regardless!  You're getting close to finishing the tender.
Kim

[PaulR]

Very tidy and a nice compact mechanism. What's the little screw on top at the handle end doing, securing the bearing/bush? Also, how did you keep the little brass triangle on top in the right place for soldering - is it maybe in a shallow slot?

[JCvdW]

Thanks Paul. The design is straight from Kozo's book. The little screw on top is to prevent the bronze bush from sliding out. The bush has a small dimple for the screw.

The little brass triange sits in a 3mm slot, which nicely keeps it in place for soldering (provided the slot is in the right place, which was not the case the first time round).

[JCvdW]

The screen for the suction strainer and suction valve seat has arrived. I ordered both brass and stainless steel. I soft soldered the retaining ring to the suction strainer using the brass screen. The result was less than satisfactory, with a lot of black burned flux stuck on the inside behind the screen. I managed to get rid of the flux by pickling the strainer while it was still sizzling hot, but the brass screen looked very flimsy. I was also not convinced that the soft solder flowed properly. Somehow soft soldering now seems more difficult than silver soldering.

The stainless steel screen is much more sturdy compared to the brass screen. So I decided to use this, and fix the retaining ring to the strainer using JB Weld epoxy glue. The results are much better.



Next up was the tender piping. I first tried bending the pipe clamps by hand in the machine vice, with limited success. Using a simple bending jig in the mill vice while holding the correct thickness drill bit as mandrel in the chuck, produced much better results.



The tender piping is nearly complete. Using Kozo's simple bending jig to bend the copper tube worked really well.

I am now just waiting for the protective jacket for the rubber tubes to arrive, before sizing and making the heavy duty tube clamps.





It is finally time to paint the tender, and to start thinking about material for the engine main frame!

[crueby]

About to wrap up the tender, thats a major milestone!   

[Kim]

That's looking very nice!  And I like how you did your screens. I don't know how Kozo soldered his.  Must have different screen material in Japan!

I like your bending jig for the pipe clamps. That's pretty nice!

You are getting so close to being done with the tender!

Kim