CONWAY 0-4-0 3 1/2" GAUGE LOCO

[Firebird]

Rich:

I agree, if it ain't broke, then don't fix it.

BUT, and there's always a big BUT, short of ripping everything apart is there anything that can be done now while you still have easy access that will make it easier on you when the time comes that you DO have to fix it?

It might be easier to bite the bullet and fix it now while it's still a relatively bare frame, rather than to have to disassemble a complete locomotive.

My thoughts exactly.

I am also looking at the possibility of fitting a pump that works off the crosshead. I understand they use less of the engines power.

Also my mate Julian is building some weir pumps, I might scrounge one of those 

Cheers

Rich

[Firebird]

Hi

The eccentric rods are joined to their straps with rivets. Countersunk rivets must be used as the eccentrics run very close together.

From there a great deal of fettling and bending is necessary to get the eccentrics to line up with the expansion links

Cheers

Rich

[Firebird]

Hi

The lifting links I purchased laser cut blanks.

Because of the shape they are difficult to hold so a quick jig was made in ally. Plunge in with a 5/16 end mill .110" deep. Using the DRO move the table 1.5" and plunge in again. Join the 2 pockets with a 3/16 cutter.

A bit of fettling to the end pockets and the lifting link can be held securely

Drill and ream one end then shift the clamp and drill and ream the other end

Bolt them together and clean up with a dremmel type tool

They must be case hardened so heat them up and drop into the case hardening powder

Cheers

Rich

[Kim]

Fiddly work there getting everything to line up, but it looks great!

In your hardening picture, I only see 3 links.  Where's the fourth?  did it get away? 

I thought you had to coat the parts with the case hardening powder before the heat treating?  I'd be interested to hear more about your case hardening process.

Thanks!
Kim

[Firebird]

Hi Kim

One of the links had already been dropped into the powder

Cheers

Rich

[Kim]

That last picture kinda looks like a cat litter box!

Thanks for the detailed info,Rich!  Very interesting.  Seems like a good solution for small scale case hardening, like a home shop.  I may have to see if I can find some of that.

Kim

[Firebird]

Hi

The 4 lifting arms are also laser cut blanks. After drilling and reaming they are mounted on another jig

The centre portion can now be machined away

The small end has to be case hardened

I'm not sure whether or not it's worth buying laser cut blanks. Yes you get the shape aleady cut but they are difficult to hold to finish. Starting with flat bar stock would be a lot quicker to make the blanks but slightly longer to shape?

Cheers

Rich

[Firebird]

Hi

More fettling and trial fitting with temporary bolts

Cheers

Rich

[zeeprogrammer]

Still following along. 

Loved the pics of the underside. It's really shaping up. 

[Steve17]

Hi Rich,

Fantastic work  and it's really taking shape now. I've been following your thread from the beginning.

Steve.

[Ye-Ole Steam Dude]

Hello Rich,

I agree with Zee about the undercarriage photos, looks really good and there is a lot going on under there. 

Have a great day,
Thomas

[Kim]

That is really looking neat, Rich!  Just love it   
Kim

[scc]

Trouble is when it's running all that lovely motion work is hidden from view.      Terry

[Firebird]

Hi

Thanks Carl, Steve, Thomas, Kim and Terry

The encouragement is most welcome

The next little problem I have come across is trying to figure out how to align everything and hold it in place 

There is a valve rod that comes through this bush

And screws into the die block in the link

At the moment its out of alignment but that can be overcome by moving the eccentrics along the axle a little. Once thats done the 4 lifting links can be fitted and attached to the lifting arms. The lifting arms must be held in place somehow then drilled and pinned to the weigh shaft  After about 2 hours of getting nowhere   
I came to the conclusion that a modification would be needed

This is what I came up with

Machine a small pocket into each lifting arm with a 6mm end mill

Turn 4 steel bosses drilled through 3.3mm

Each steel boss is silver soldered into the lifting arm and then tapped M4

The reason for the steel bosses is there isn't enough material to simply drill and tap the lifting arm

After a coat of paint to tidy things up. Each arm is fitted with a pointed M4 grub screw

Likewise the reversing arm has had the same treatment

Hopefully now I can set each arm correctly and lock it in place with the grub screw. If the grub screws don't hold the arms securely enough I can remove the weighshaft complete with the arms and drill and pin them

Cheers

Rich

[Firebird]

Hi

We need 2 intermediate valve rods.

I have used 5mm stainless steel rod instead of the specified 3/16" because I have some. I also have left hand taps and dies in 5mm.

First job is to measure up how long using a bit of copper wire.

Thread each end and create the first bend in the press

So far so good. But stainlees steel rod is quite hard to bend. The problem now is creating the second bend. Without making a jig of some sort I couldn't figure out a way of doing it so resorted to my little torch

Not too bad

The problem now is getting it in. I could push it through the valve rod guide but because of the shape I can't turn it to screw it into valve rod cross head, it hits the wheel and the axle  .

I had to pull the pins out of the expansion link and there is just enough room to screw it onto the valve rod

<a href="https://www.youtube.com/watch?v=QNZxrYoPFoo" target="_blank">http://www.youtube.com/watch?v=QNZxrYoPFoo</a>

Now the problem is alignment. The intermediate valve rod must be straight along its axis in all planes, this one is slightly out so the next bit doesn't line up 

A rethink needed here before I make another

Cheers

Rich