Another Pennsylvania A3 Switcher

[JCvdW]

After paging through Kozo's excellent book for more than a year now, and inspired by Kim https://www.modelenginemaker.com/index.php/topic,8552.0.html and Blondihacks on Youtube https://www.youtube.com/playlist?list=PLY67-4BrEae-xhrvZX33gPk4Q87S1ttae, I finally decided to take the plunge. Who knows, if I can get past the boiler, I may just finish this project one day.

I will try to follow the build sequence suggested by Kozo, and will buy materials as needed along the way. Specific materials and sizes are not always readily available, so I will have to adapt and improvise as I go along. For instance, brass will be replaced by mild steel where possible.

I do not intend to post every step of the way, but will try to make notes where I think it may perhaps benefit others (and/or myself) in future.

Every journey begins with the fist step - in this case cutting the first mild steel disk for a tender wheel:



A few days later - eight tender wheels ready to be painted:



Notes:

1. The 30 deg pointed cutting tool used to machine the wheel plate, must have sufficient side rake to clear the rim of the wheel.

2. Turn the mandrel in the sequence suggested by Kozo. First cut the thread before turning it to final size.

[crueby]

Great  start!  Will be watching along...   

[Kim]

Eight beautiful tender wheels!  What better start to the A3 Switcher project could you ask for? 

Good luck on this extended project.  I wish you all the enjoyment that I have had in tackling this project.  Have fun! 

Looking forward to reading as many updates as you care to post!
Kim

[JCvdW]

Chris and Kim, thanks for the encouragement! I may be finished before the switcher! Let's see.

Axles, bearings and journal boxes complete.





I found the use of a go/no-go plug gauge for the holes in the journal boxes, as suggested by Kozo, very helpful. Also the use of a mandrel to turn the outside of the bearing, as suggested by Blondihacks.

The journal boxes saw my first use of a 10mm carbide end-mill on mild steel on my RF-45 clone. So far I have only used HSS cutters. The higher feeds and speeds of carbide resulted in much less vibration, and hence better surface finish, compared to HSS. Not to mention the much faster progress, and hopefully significantly longer tool life. Very happy with the result.

Next in line the truck columns. This will be my first venture into the world of silver soldering...

[Admiral_dk]

Those look ready for assembly on the chassis     

Per           

[crueby]

Great start!!  And the silver soldering is a very useful skill, comes in handy on so many parts, worth doing some practice pieces to get the process down at first.   

[Kim]

Sorry to be late to the party here, I've been out of town for a while.

You've made good progress here. Those journal boxes look great!

I agree - the carbide end mills work great on steel.  I've mostly switched to carbide on my mill, at least for all the standard sizes. Though I still have a lot of HSS end mills and they work fine. But the carbide is much faster and better, especially on steel!

Which brings me to my next thought - looks like you're using steel instead of brass for a lot of the parts?  That's what I did, and I'm not sorry.  It has worked quite well for me.

Kim

[JCvdW]

Thanks for the comments Kim. I decided to use steel where possible, as brass in small quantities and with more or less the right dimensions are very hard to come by (and expensive!) around here. It is assuring to hear that steel worked for you.

Chris I followed your advice and practised quite a bit of silver soldering until I could get more or less repeatable results using Kozo's guidelines. After settling on a process, silver soldering the truck columns was straight forward and quite satisfying!

The process (for future reference):

1. Heat the drilled and tapped parts to remove any residual cutting fluid trapped inside the holes that will form part of the joint.
2. Clean the surfaces to be soldered with sanding paper.
3. Add punch marks to one side of the joint to ensure a sufficient (50 micron) gap.
3. Pickle the cleaned surfaces.
4. Apply flux. If the flux does not readily adhere to the metal surface, it is not clean, so pickle again. Apply flux to the screws as well.
5. Screw the parts together. Use screws of the same material as the parts to be joined. Harder screws will complicate subsequent drilling operations...
6. Do not wipe off excess flux where the silver solder will be placed. Push a piece of solder into the flux next to the joint.
7. Apply heat to the bulkier side of the joint, opposite to the solder. Keep applying heat until solder flows and fills the joint. Heat must be sufficient to complete operation within 5 minutes, to prevent flux from disappearing.
6. Allow piece to cool completely before removing any other jig screws, to avoid breaking off screws that are stuck while hot.
7. Pickle to clean the soldered joint.

The completed truck columns:

[Admiral_dk]

Success is always a great feeling     

Per

[crueby]

Excellent!  Sounds like the practice was well worth it - its a fairly easy process once you go through it a few times. One big thing I learned the hard way was that larger mass parts, and especially large copper parts, need a bigger torch to get the pieces hot enough quick enough to not burn off the flux.

 

[JCvdW]

Thanks Per and Chris for checking in. Silver soldering the boiler still looms somewhere in the distant future...

The truck side bars were cut from mild steel sheet using an angle grinder, and then milled to size on the mill. The mill vice was too small to hold the pieces, so a temporary vice was devised using a few lengths of cold rolled flat bar that were on hand.



The bending jigs suggested by Kozo made bending the side bars straight forward. The sharp edges of the v-slot in the jig were rounded on the belt grinder to prevent marks on the side bars.



The jig to cut the sloped slots in the bolsters was made from mild steel. To mill the 3 degree slope on one side of the jig blocks, a wooden jig was first made on the table saw with the blade set at a 3 degree angle.



Stainless steel coil spring wire was sourced from a local spring manufacturer. The coil springs were then turned on a mandrel in the lathe as described by Kozo. It took longer to select the correct gearing for the required pitch, than it took to actually make the springs.

And finally the two trucks were assembled, with all parts numbered, as suggested by Kozo!





Next step is painting, before starting with the frame. I am unsure about this. The side bars fit tight in the bearing block slots and will most likely not fit if painted first. Inserting the bolsters will however require disassembly after painting, which may also be problematic. Any advice will be appreciated.

[Kim]

Sorry, I seemed to have missed one of your posts in August!  You've made a lot of great progress and have some fine looking trucks there!

As for painting, I masked off the notches in the journal boxes where the arch bars fit, and of course, all of the sliding portions of the columns and bolsters.  But I painted all of the arch bars.  I didn't seem to have any problem making things fit after painting, though I may have had to sand down a little on the edges of the bars to make them fit if the paint was too thick.  I don't remember for sure, but that is certainly something I've done on this build.  I am using powder coat rather than spray paint though, and powder coating adds a bit extra thickness. If you're spray painting, I can't think that it will add enough thickness to cause you too much issue.  If so, just sand a bit off so it will fit  :embarrassed:

Wonderful looking trucks for sure!
Kim

[Admiral_dk]

Another great step forward - looks good 

Per         

[JCvdW]

Thanks Kim for your painting suggestions, and Per for checking in. Two months later and the trucks are finally painted! During this time I also replaced the spindle and gearbox bearings of my RF-45 clone milling machine, but the main reason why painting took so long, is procrastination - I do not particularly like painting.

I first experimented with rattle can paint, hoping for a straightforward and simple process, but could not achieve satisfactory results. In the past, I had good results with 2K automative spray paint, but this is quite a tedious process, as curing time may be 24 hours or more.

To make things a bit more attractive for myself, I first made a counter top spray booth which takes care of over spray and noxious fumes. It consists of an extractor fan from a domestic oven, some filter material and a few pieces of styrofoam taped together.





I then made an oven that reduces curing time to around 30 minutes. The oven consists of a temperature controller, two 125 W lamps and a styrofoam box.





The spray booth and oven make life much easier, especially the short curing time. Progress can now be made quickly. Suddenly painting is not so bad!

The final result:



As suggested by Kim, the edges of the bars had to be sanded down to fit into the slots of the journal boxes. This was then re-sprayed after partial assembly. The sliding interfaces between the bolsters and columns were also sanded down, and is now covered with oil. This will hopefully prevent rust. The wheel rims were sprayed with 2K clear coat.

The screws will be replaced by scale bolts to be ordered from Knupfer in Germany.

[Kim]

The trucks are beautiful!  Great job on the painting.   

And the paint booth & drying oven are great additions.  Love the foam construction too! Very nice!

Kim

[Roger B]

Looking good     

I like your painting system 

[JCvdW]

Thanks Per, Kim and Roger for checking in!

The tender frame was completed today and is ready for painting!





The vertical slide was used on the lathe to drill and tap the holes in the ends of the sidle sills. This worked quite well, but in hindsight, the drilling jig used by Blondihacks is probably a better and safer idea.





The only part that had to be fabricated twice was the rear coupler pocket. The first silver solder attempt came out skew, due to too much heat on loose mounting screws.

With summer holidays around the corner, painting will have to wait for next year...

[Sanjay F]

That spray booth is seriously cool - I have a cardboard box 

I bought a rotating cake stand make things easier to turn, but need to get something rigged like yours

[crueby]

Frame and trucks are looking great!!

[Kim]

That looks great, JC! 

With the frame it starts to pop into 3D and you really start to get a feel of the size of the tender.  Very nice work!

Kim

[JCvdW]

Thanks Sanjay, Chris and Kim for checking in!

I finally had some time to paint and finish the tender frame. I am still pondering whether to paint all the screw heads.





Time to start with the tender tank proper!

[Roger B]

Nicely done  Do you have a length of test track you can try it on?

[Kim]

Your tender is looking great, JC!  Nice paint job! 

As for the screws, I don't know what to tell you.  I ended up just using a permanent Sharpie to cover the shiny screws, but I didn't paint them.  It's not perfect, but it made me happy! 

[JCvdW]

Nicely done  Do you have a length of test track you can try it on?

Hi Roger, Thanks for checking in. No test track yet. The local club track is about 30 km away. Will have to take it there soon to at least see if it fits!

[JCvdW]

Thanks Roger and Kim for checking in. The permanent sharpie is something to remember!

In the last two month time in the workshop was very intermittent, but some progress has been made.

Given the price of brass, I took Kim's lead and made the tank floor out of 304 stainless steel plate. This machined more easily than what I expected.

The wooden former and backing plate for the copper side plates were made with my home made CNC router.



I also used it to cut out the copper profile for the side plates and to separate the two halves after forming. I have never used the router to cut metal before, but it seems to handle brass and copper sheet quite well. It is going to be very handy for all the sheet metal work to follow.



The bottom horseshoe member was carefully mounted to the floor to ensure proper alignment with the side plates. The top horseshoe member was then formed to mirror the shape of the bottom member.



The vertical board was mounted to the bottom horseshoe member to provide a good reference for the rest of the parts of the coal bunker.
This required endless assembly/drilling/tapping/disassembly/drilling/assembly operations, adding one or two screws at a time, until everything was screwed together.





I used the sheet metal function of Fusion 360 to create the profiles for the verge board and top strip, and then cut those with the CNC router.



It is always very satisfying to see how well the parts then align after bending.



The coal bunker turned out to be quite complex, and I am very glad that I first studied how Kim and Blondyhacks approached it. This definitely allowed me to avoid quite a few pitfalls!

I decided to defer all soldering until all the sheet metal parts of the tank are made and screwed together.

[Kim]

Very nice looking!  You did a great job forming the copper sides AND the horseshoe bend parts.  Those cause me no end of grief! I had to do that upper horseshoe member a couple of times to get it right.  But I'm glad I did, because that cool shape of the tender is part of the charm of the A3!

Looking great! 

Kim

[matthew-s]

I missed this build. Great progress.

I’m building one too, I chip away where I can.
I very much enjoy the process. It looks like you are too!

Kim and BlondiHacks have been a great help to me. Although I suspect I’ve been working on mine longer, and I’m way behind them!

 

[JCvdW]

Thanks Kim and Matthew for checking in. Your interest and comments keep me motivated!

The sheet metal parts for the tender tank were cut out with the CNC router. As always sequence of operations are important, and the top plate had to be made twice. Trying to do the top bend after the man hole opening was cut, resulted in a warped top plate.

An embossing tool was made following Kozo's instructions and lots of fake rivets embossed. I followed Blondihacks method to first print the location of the rivets on paper, to ensure that rivets aligned on all edges.



Sourcing small screws locally to join the sheet metal turned out to be a problem. Luckily, a local optometrist turned out to be an excellent source of small screws. He had some small stainless steel M1.6 screws with heads exactly the same size as the embossed rivet heads.

I used my Dremel mounted on the milling machine (https://www.modelenginemaker.com/index.php/topic,12280.0.html) for drilling and tapping M1.6 holes to fasten the top plate to the side plates.



All the tender tank parts ready to be fluxed and screwed together for soft soldering:



And after soldering, pickling and a bit of Scotchbrite (this short sentence belies a marathon session of fluxing, assembly, soldering, pickling and re-soldering!):





Quite a few of the screws did not solder, even after pickling all the parts and screws before soldering. Pickling probably did not clean the screw holes well enough. An ultrasonic cleaner may be the answer. Rather than trying to get the screws soldered in, I decided to fill and seal the holes with JB Weld instead.

I also found (by luck) that reheating a soldered joint and then only applying some flux, will more often than not 'pull' the solder out from the joint to form a fully soldered joint.

And finally, with the dummy side plates attached, it now really is beginning to look like  a tender:





There are still some small dents here and there on the curved edges of the copper side plates which happened during forming, which I hope can be filled and levelled with etch primer when painting.

Now I only need to make the coal stopper, to finish the tender tank section before moving on to the man hole.

[Kim]

That is beautiful!  You're doing a bang-up job on the tender, it's coming along wonderfully! 

Kim

[Admiral_dk]

Looks good  and a LOT of work ....

Per     

[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