Pennsylvania A3 Switcher (Kozo)

[RReid]

Though for some places a ball peen hammer may be used (Kozo says this is OK in his book, as long as you don't dent the copper).

A lot of it can certainly be done with a ball peen hammer. The key is to remember to use lots and lots of light and closely spaced taps, no heavy wanging away.

[Kim]

Chapter 23.4 – Forming

Today we start with the copper!

I purchased a 12” x 36” sheet of 0.080” 110 Copper which is rather unwieldy to be slinging around trying to cut parts from.  So what I did was to figure out the smallest rectangle that would fit all five of the formed pieces and sliced that off the big sheet.  Turned out to be just a tich over 6”x12”.  I can't slice off a 6" chunk on my bandsaw - it just can't handle that width (the ubiquitous 4”x6” HF horizontal/vertical saw) and I didn’t really want to try it on my table saw (though copper might be OK, I didn't want to chance it).  So I went with the sawsall, which I’ve used before in this kind of situation.  However, this time, I clamped on a bar to it to use as a guide. This worked quite well and the cut came out nice and straight!


In my original plan for the Cu sheet, I overestimated the size for all the parts by 1/2" or so in all directions, just to make sure I had a little wiggle room.  But as copper is so stinking expensive, I wanted to be as frugal as possible.  So I made 1:1 patterns for each part and shuffled those around to figure out how to optimally position the parts.  This was my design:  (and yes, I actually did this BEFORE I cut the 6” chunk!)


Then I took each piece and, using Elmer’s spray sticky glue, glued my patterns to the sheet one at a time, and cut them out.  I used a combination of the bandsaw and the scroll saw.  The bandsaw for long straight cuts and the scroll saw for all the curvy cuts.  The reason I did them one at a time is then I didn’t have to estimate the kerf-width of the saw.  Once I got one piece cut out I knew exactly where the edge was and could cozy the next part up against the edge without worrying about the blade width.


Here’s all five parts cut out of the sheet.


Now, dumb me, I was thinking the copper came pre-annealed.  So I set up one of the parts and tried to get it to bend. Guess what?  It wasn’t pre-annealed!  Later I looked it up and the copper 110 comes ‘half hard’.  All I can tell you is ‘half’ is still pretty hard!

So, over to the torch where I annealed all five pieces:


Then I went to work forming!  You can see the hammer I’m using (Your basic plastic soft mallet - it has been used before! )


Here’s the throat sheet.  I had to make a smaller backing plate to bend the sides of the throat sheet.  The other former for this pair was way too wide to allow me to get to the copper.  You’ll recall I left it extra wide to make sure the tips wouldn’t break off.  Well, they didn’t break, but they sure wouldn’t let me get access to the copper!  So I just took a scrap of wood and cut it so it would fit.  The fact that it has an arc taken out of it is immaterial since I’m not bending that section of copper yet.  The scrap I had handy just happened to have that already done (remember when I broke the tip off my first throat sheet former? Happy serendipity!)


But now I am bending the throat!  This picture is after the second round of annealing.  The sides are pretty close, but the throat will need another round or two.  I did end up using the ball peen hammer for the throat.  The rubber mallet just didn't get in those corners very well.


After two rounds I was out of shop time.  I went ahead and annealed all the parts again for the third round of pounding.  But that won’t be till next week.  I’ve got family stuff to do this weekend!


And there you have it – the boiler has officially been started!

Thanks for looking in,
Kim

[crueby]

Great start on the forming, looks just like it should.   


 

[RReid]

the boiler has officially been started!

And a good start it is too. 

[vtsteam]

Looks great!   

[cnr6400]

 

[Kim]

Thanks for the kind comments Chris, Ron, stream, and Jeff!
Kim

[Roger B]

That's off to a good start     

[Admiral_dk]

Now you are Really off on the Boiler 

.... and the rest off Us are still enjoying this Build Thread imensly         

Per

[internal_fire]

Heatin' and beatin'. 

I found I had a tendency to try to minimize the heating and maximize the beating in order to save time. Not a good idea.

You may need 6 or more cycles for a complex shape like the throat sheet. Even the simple ones will need at least 4 cycles to get a good smooth shape.

If it does not move at all with a fairly light tap then more annealing is needed.

Gene

[Kim]

Thanks Roger, Per, and Gene!

Good advice Gene,  I know I've got more heatin' and beatin' cycles to go (I like that phrase ).  But that's a good thing to be aware of - don't be afraid of doing another anneal cycle.  No need to skimp on that!

Thanks for looking in on me and for the advice!
Kim

[learn2turn]

I just found your thread Kim after watching Blondihacks and spent some time binging to get caught up.  Your work to date is superb and I made it just in time for what I consider the most exciting part.  The boiler...I have only recently entered the model engineering world with the purchase of a lathe and hope to add a small mill in the future.  One day I want to build a locomotive as you are but for now I will learn from you.  Keep up the great work.

[Kim]

Hi Learn2Turn!
Welcome to the forum!  And wonderful to have you following along with my build 

Anything you can learn from me you're learning from the skilled and generous people who have helped me get this far, or from seeing the mistakes I've made and avoiding them!  That's what I can offer, and it is my goal in documenting my build. To get help and to offer that same help to others!  I love Blondihacks philosophy of doing things, making mistakes, and learning from them.  And I'm doing my best to emulate that philosophy in my humble way.

Enjoy your new lathe! You should post your current project here!  I'd love to see what you're working on. And I can tell you that you will get great advice and encouragement from the knowledgeable people who frequent this site!

Also, we have a tradition of people posting a short 'intro' of themselves in the "Introduce Yourself" section of the forum.  It gives everyone a chance to welcome you to the forum and get to know you're goals and what you're doing.

Thank you for your post! It is much appreciated.  Always nice to know that my mistakes are helping other people! 

Kim

[Kim]

Today I completed the forming step for the various plates of the boiler.  It ended up taking five anneal & pound cycles to complete this.  I considered another cycle but it just didn’t seem like there was much to be gained.  Five seemed to do it for me.

I did find that around the 3rd hammering cycle I started to have difficulty getting the copper off the form.  So I had to find a way to hold the form and gently tap on the part to get it to release.  Then I’d try to even out the places that had bitten into the form so that I could better fit it on for the next round.  Not a big deal, but it did add a bit of time to each cycle.


And here’s the family shot of all the boiler parts to date.  Don’t they look like a happy family? 


Next time I’ll begin machining the formed Front Tube Sheet.  This is getting exciting, isn’t it?! 

Kim

[crueby]

Awesome results!  If you haven't machined copper before, its well worth a practice piece, copper is very grabby and can leave a rough surface. Light cuts, experiment with speeds, and use a block between the piece and the tailstock to keep it from moving. The form blocks work great for holding for machining.