Steam Tractor 3/4" (Rudy K)

[Kim]

Great!  Glad the blow gun is working for you Bill.  I'm certainly making use of mine!


I left off having just made one part of the cross head.  I’ve got two parts to go.  These parts are outside edges that will ride along the left and right side of the Cross Head Guide rails. I started by cutting two chunks of 22 GA sheet steel.  I double sticky taped them together, squared them up, and shaved them down to the required 3/4" x 3/4".

Then I drilled and reamed a 3/32” hole in the center for the Connecting Rod Gudgeon.


Then I drilled four holes for the rivets (#55).


Here ‘s a family shot of the Cross Head stackup.  The brass piece is a little shim I made to widen the center opening of the Cross Head.


After riveting the pieces together, I made the 1/8” semicircle cuts in the back of the Cross Head.  Not sure what those are for, but they are shown in the plans, so I did them.  Plus, they kinda look neat


And here’s the completed Cross Head:


And slid into place on the Cross Head Guide:


After a little filing and fiddling, I was able to get it to work pretty well.  But of course, now I realize that I should have shimmed some on both sides of the center instead of just the one side... live and Learn.  I got this one working quite well though.

Thanks for taking a look,
Kim

[Dave Otto]

That looks very nice Kim!


Dave

[Kim]

Thanks Dave!
Kim

[90LX_Notch]

Nice family shot Kim.  All of your efforts are paying off.

-Bob

[Kim]

Thanks for stopping by and taking a look Bob!
Kim

[Kim]

Today, I started work on the Connecting Rod, which will connect between the Cross Head (finished yesterday) and the crank shaft.

I spent an inordinate amount of time doodling and thinking about just how to do it. It isn’t really that hard, but the part tapers, so I was figuring how I’d do that, and it also has an optional flute, that I opted for. So, I sat in my shop, listening to NPR (“Wait Wait, Don’t Tell Me”) and got it all figured out!

I was originally planning to do a 1/8” flute using 1/8" ball end mill, up both sides of the Con Rod.  But I realized the flaw in my plan - if I made both of the flutes 1/16” deep (to get the full 1/8” width) then the flutes would break through and I’d have holes in my Con Rod.  Not what I was after.  So, I switched to using a 3/16” ball end, and then tried to calculate out how deep I’d have to go to get a 1/8” width.  After applying my incredible math skills, I came up with about 23.5 thousandths of depth. And that would do just fine!

To finally get started making swarf, I cut a length of 1/8”x3/8” steel bar (1018), trimmed it down to 5/16” width (no pictures), and drilled & reamed the holes for the cross head gudgeon, and the fly wheel crank pin.


Next, I got my 3/16” Ball End Mill, and went to work on the flute for the first side.  My calculations were right on!  It came out just at 1/8" in width!


Unfortunately, it slowly started to dawn on me that my flute wasn’t coming out in the center of the part like it was supposed to.  So I checked my drawing to make sure I had correctly calculated center, and sure enough, I had.  Unfortunately, it was my brain to DRO mapping that went awry.  I just dialed in the wrong value for the Y-axis.  I used 136 instead of the specified 156.  Just one of those !Duh! moments 


Ah well.  It’s too hot in the shop today anyway.  Time to stop. 

While frustrating, I’ll be able to knock this out pretty fast next time I think. The second time always goes faster   (How do I know that so well?  )

Kim

[b.lindsey]

Been there, done that too...recently too. Just blame it on the heat Kim...

Bill

[Kim]

Yeah, that's it!  It was the heat! I'm sure of it!

Thanks Bill,
Kim

[Steamer5]

Hi Kim,
 Still following along. Think we have all been there done that!

Sounds like a soothing ale is called for! Dehydrating in the workshop isn't good!

Cheers Kerrin

[Kim]

Thanks Kerrin!
No, we certainly don't want to get dehydrated!   
Kim

[Kim]

Last we left our hero, he’d just doofed up the Con Rod.  So today, I started making a new one.  Getting back to the spot I goofed up went much faster than the first time, as one might expect.  Here we are, right where we left off, but with the flute carved right down the center.  YAY!


Now for the uncharted territory!  The Con Rod is tapered between the big and little ends.  So, as I usually do, I spent a significant amount of time calculating the exact size of drill bits to put through each hole, to get the right taper.  I finally got there, and it even looks about right:


And here we are, taper complete.  All’s that’s left is to round the little end.


And showing some level of overconfidence, I messed up this last step.    You can see where I made a deep gouge out of the left side of the Con Rod there.


I gave some serious thought to just using that one anyway, since the goof would be hidden from people, but I’d know it was there.  So, I did it yet again.

This time I chose to round the little end by hand, using a file:


The victory shot:


Here’s all three of them – the top one (first) took me ~2 hours to do and it wasn’t complete.  The second one took 2 hours but was a gnat’s breath from being complete.  The third one (bottom) only took me an hour.  So, I got better! (at least faster).

[Kim]

Next, I went to work on the Gudgeon Pin.

This was a simple turning exercise on some 3/16” CRS rod.

First, I turned a 1/8” length down to #2 size and threaded it for a 2-56 nut.


After turning down the shank to 3/32”, and the head to 5/32”, I parted it off the parent stock.


Then to the mill, where I used a 1/32” mill to cut a slot in the head.


Here’s all the pieces of the engine so far:


And assembled:


Thanks for looking in.

Thanks,
Kim

[Dave Otto]

Nice looking parts Kim!
I'm not sure I understand though how you are dealing with editing the photos; maybe for another thread.


Dave

[Kim]

Thanks Dave,

Sure, I'll make another thread about how I'm doing the pics.  Not sure if I like having them there twice, but I DO like keeping the images with the text.  It's a bit of work, but then, so was hosing the images on the Site Who Shall Not Be Named. 

Kim

[Don1966]

Late as usual Kim but staying up. Outstanding work buddy the parts are looking great...


 
Don