My A J Reeves Bolton Triple Expansion Engine

[simplyloco]

Crankshaft: An engineering solution
Pun Intended!

I didn't want to solder this crankshaft, nor did I want to muck about too much with pins and glue, so I thought I'd try a different approach: i.e. using cone pointed stainless grub screws to secure the webs on the crankpins, as well as the Loctite I might add!.It seems to have worked, so far...😇
Some pics.

After a good polish I mounted them on the sparkling clean crankshaft ready for the glue. The first one was set up vertical, Loctited and locked with the screws, and the table set to zero degrees. Once I'd set the first one I just rotated the table 120 degrees twice more.



The angle of the preceding web was doubled checked with the digital protractor.



The completed shaft was placed in the bed casting to check the fit. You can see where my earlier mistakes were when machining the main bearing supports. The crank is in the correct position relative to the end bearings, you can see the two 1.5mm drills acting as spacers, but one of the supports is out of position and I will have to do some 'additive machining' to get over it!



Now the controversial bit. I took the crank to the Proxxon, removed one of the grubscrews and drilled and tapped 3mm deep into the crankpin. I put the grubscrew back, tightened up flush, and repeated the operation. Neat or what!


I'll do the other two later, but I'm very happy with the result.

[Kim]

That seems like a pretty slick method!  Hopefully, it will hold up long term. Probably won't see a lot of hard use so it should hold up one would think! 

Kim

[simplyloco]

That seems like a pretty slick method!  Hopefully, it will hold up long term. Probably won't see a lot of hard use so it should hold up one would think! 

Kim

I agree that it isn't as good as through pinning, I just liked the idea of holding the webs in the right place while the glue dried. I can very easily slip some pins under the grubscrew...

[crueby]

Do the screw go through into the shaft?

[simplyloco]

Do the screw go through into the shaft?

Yes, about three mm.

[simplyloco]

All done and it didn't fall apart when I cut it! 
I now have to make the con rods so that I know where to put the 'adjusted' main bearings!

[Roger B]

Excellent    An interesting solution to making the crankshaft   

[TimB]

A great result John, like the grub screws, very neat!

Tim

[Jasonb]

It will be intersting to see how truely it clocks, not having seen the grub screw method used before it may or may not add side loads to the assembly which although it holds together is only half the story

[simplyloco]

Hi guys, thanks for your comments. I hope that no-one has gained the impression that is just the grubscrews holding the crank together!
The crankshaft is held together by the conventional use of properly applied Loctite in clean conditions into the correct gap. All the grubscrews do is greatly assist the setting of the angles while the Loctite is wet, and more importantly, ensure that the torque from the HP piston is transmitted without the risk of shearing the Loctite bond, I'm not expecting it to fail.

[simplyloco]

Well, I've recovered sufficiently to spend some time in the workshop at last, working on the conrods, a time consuming little trio if ever I saw one!
Here's a few pics, and I will be glad to see the back of them!

Fabricated and split afterwards to take a filing button.



Even the pins fit. NEXT!

[Kim]

Glad to hear you're feeling better!

Nice looking con rods! 

Kim

[steam guy willy]

Hi still following along and great progresss...inspiring work   beautiful
Willy

[simplyloco]

Machining the big end brasses

I took just one through the whole process today, just to confirm my method, which is completely at odds with the supplied article, in that I didn't put it anywhere near a 4 jaw chuck until I needed to put a pretty face on it!
Some pics.

Sweating together nicely. Frogs rule OK?


After machining the blocks to overall size I drilled the 3mm bolts holes and the 3/16 conrod location hole. Bolted together with a 3/8 bar inside to make sure the register stays in place when facing. You can only trust soft solder so far...


Using a 6mm profiling tool to create the pretty face on both sides.


I haven't filed the clearance in the crankshaft webs yet, so I can't try it out. Given my tendency to produce 'tight' fits then I'll probably have to ease the bearing faces a little. I'm well happy with the progress so far.

[Kim]

Looks like your process worked! 

On to the others now!

Kim