Steam Tractor 3/4" (Rudy K)

[Kim]

With last weekend being Easter, I didn’t get any shop time – all family time, which was a great thing!  But it makes progress even slower than normal

Today, I picked up where I left off with the Cylinder; drilling the steam passages.  I started with the exhaust passage. I drilled that, then drilled and tapped two 2-56 mounting holes for the exhaust flange.


And, since I’d now defined the bottom side of the cylinder (by drilling the exhaust hole) I could drill and tap 4-40 holes for the Condensate Release Valves.


Moving to the ends, I drilled a passage for the Condensate, and the incoming steam.


Then cut notches for them both.  Now that I look at it, I think I may have to make the notches a bit deeper or the registers for the end caps will cover it completely!


Next I moved on to the Steam Chest.  I cut a length of 1/4” x 5/8” Brass bar, Indicated it up in the 4 Jaw, and then cut the 1/4" spigot to the specified length.


Next I drilled and tapped it 10-32 for the Steam Chest Gland:


And finally, drilled and reamed a hole 3/32” for the valve rod to pass through.


Moving back to the mill, I squared up the brass bar to the right dimentions.


And here’s where we ended with the Cylinder today.  Next will be carving out the center of the Steam Chest and drilling the mounting holes.


After that – the Steam Chest cover and the Cylinder covers!

Thanks for checking in,
Kim

[Don1966]

Looking good Kim .....


Don

[crueby]

Nice work!


What will the condensate valves be like? I could use some on my current build, not sure how to make them.


 

[90LX_Notch]

Still following along Kim.  Everything looks awesome.

-Bob

[Kim]

Thanks Don, Chris, and Bob,

Chris, Here's a copy of the the Condensate Release Valve that is show in Rudy's plans. I think its OK for me to post it here since plans for the whole thing are freely available at various sites on the internet.  And in fact, this is from those downloads.  The plans in the book have been re-drawn and are much nicer. But its still the same thing regardless.



Not quite sure when I'll get around to this, but I'll get to it eventually!
Kim

[crueby]

Thanks Kim!

[Dave Otto]

Nice work on the cylinder assembly Kim!

Dave

[b.lindsey]

Nice progress Kim. Good to see an update as well. Are those thread forming taps you are using?

Bill

[Kim]

Thanks Don and Bill,

Are those thread forming taps you are using?

Yes, the are.  A few project back (maybe the 5-cylinder radial?) I broke several taps and was having quite a time with it and someone mentioned the roll-form taps.  I Amazoned a few of those in and from there on, they have been the only taps I buy.  I find that they work much better for me and I've broken far fewer taps using them.  You don't have the chip issue, they don't get dull (that I know of) and they are higher quality.  Undoubtedly, I could buy higher quality cutting taps too, or even spiral taps, but these have been a great investment for me. I've collected a half dozen sizes (the ones I used most; 2-56, 4-40, 6-32, 8-32, 10-32, 1/4-20, and maybe a few others).  I'm quite pleased with them!  The only trick with the forming taps is that you have to use a different drill size chart! But its been working for me.

Kim

[crueby]

Have not tried those before - do they work with just certain metals, or any? Any limitations on them other than the different drill chart?

[Kim]

Chris,The only thing I've heard is that they work well for softer metals, but might not work as well for harder steels.  I can tell you I've used them on aluminum, brass, bronze, 12L14 and 1018 all with good success.  I haven't tried any of the really small taps (2-56 or smaller) on steel.  I'd do a little more research before I used them there.  They have to squeeze the metal out of the way and into the shape of a thread.  But they've worked beautifully for me

But I'd love to hear the comments of others with more experience.

Kim

PS Oh yeah - I've also used them on that really hard DOM tube that I'm using for the Boiler Casing. Not exactly sure what it is, but it was busting HSS drill bits like nobody's business.  But I've been able to thread it to mount various items on it (like the smoke stack).

[Kim]

Today I got a few more hours of shop time and finished up the Steam Chest.

My next operation on the Steam Chest was to drill the clearance mounting holes:


Then I spent some time laying out the coordinates for the inside area to be removed.  Here’s the corners drilled at 1/16”.


And then I milled out the center with a 1/8” two flute mill.  Unfortunately, after all my careful math, I chose to cut ‘inside’ my lines by 20 thou, so that I could clean them up with a final pass (which is my standard procedure). The thing is… you have to add 20 thou on one side, and SUBTRACT it on the other.  Duh.  So, you can see the bottom is 20 thousandths too big. (see how close it is to the mounting holes?)


It won’t matter. It’ll be under the cover of the steam chest.  Just makes me feel silly.

And to finish up the steam chest, a 10-32 tapped hole for the steam input port.


And, just to show you that math is out to get me today, when I went to assemble the steam chest to the cylinder, I found out that I’d transposed some numbers – the center hole was supposed to be at 0.531”, and I drilled it (very consistently mind you) at 0.513”.  So my center holes had to be expanded some to make them work.  The four corners align beautifully.  Just those pesky center holes.

Anyway, after my rework, the parts came together quite well.


Thanks for looking,
Kim

[mike mott]

Hi Kim I spent a good part of this evening going through your entire build. What a great project and you certainly went through the trials and tribulations of quite a few processes which you seem to have mastered very nicely.

Mike

[Kim]

Thanks Mike!
I've had a great time with this build.  And as I said at the beginning of this thread (a year and a half back) one of the reasons I chose this project is all the new things I would get to learn!

Kim

[Kim]

I made several small parts today.  First off was the Steam Chest Cover.

I took a short piece of 1/8”x5/8” brass bar stock, squared it up and milled it to size, then drilled the six clearance holes.  I was careful to carry forward my transposed measurement for the center holes (it was supposed to be 0.531”, but I faithfully drilled it at 0.513” on the cylinder and the steam chest!).


Here’s the family shot for the cylinder so far:


And assembled.  I do plan to do studs & nuts eventually.


Next up was the Steam Chest Gland.  Here we started with 1/4" hex brass, turned it down to 0.190” and single pointed in 10-32 threads:


Drilled and reamed a 3/32” hole for the valve rod:


Parted it off:


Then flipped it around in a 3/16” collet and faced off the other end to length.


The final part for the day was the valve.  This started as a piece of 1/4"x5/8” brass bar.  I could have used 1/4"x1/2”, but I didn’t have me some of that.  So I went with the 5/8”. After milling it down to the specified size, I used a 1/16” mill to carve out the exhaust cavity.


Then turning it over, I cut the other side down to 1/4" wide:


And, using the 1/16” mill again, cut the slot for the valve rod.


Here are the two new pieces; the gland and the valve.


And a final shot of the gland safely stored in its home on the Steam Chest.


Next will likely be the valve rod, to be followed by the piston, cylinder covers and other sundry smallish parts of the engine.

Thanks for the visit,
Kim