I have made a start on the cross-heads. Last night I cut out, pickled and squared up a piece of steel.

Here is the result:

I should hopefully machine the groove tonight and make a start on the counter-bored holes for the con-rod small ends. I will machine both together as mirror images and then cut in half and finish off.

My planned December work has not gone entirely according to plan but at least I have made some progress.

I managed to half machine the right hand steam chest and also took some photos of the progress, as these were missed when I did the left hand one.

The outline of the final shape was cut on the band saw and then the bosses machined in the lathe.

Here is a pic of the work. I did a test run threading the guide bar, but the die had a courser thread than the tap I used so Ill need to cut that off and re-do it. I did make these bars longer than required so its not an issue.

The random holes in the one bar are irrelevant as this was scrap that I used. The two pieces of mild steel plate are the tops of the crossheads. These will be silver soldered in due course.

Thanks Harry!

Alrighty then!

Here is a sequence of the machining of the cross heads.

The two cross heads were cut apart.

Then the backs machined flat.

Here they are almost done.

The rear radius was machined and the round part around the hole was filed to the final shape.

Finally both cross heads are finished!

Here is the LHS on a scale drawing. Note the e-clips…

I did the silver soldering of the cross head tops today and all went well!

I found that the most miniscule amount of brazing material was required and actually beat the stuff I have into a thin strip and then cut it into thinner pieces. This worked a charm and only the smallest of touches of the material to the work once at the correct temperature was enough to do it.

I have included photos of the procedure.

All parts were thoroughly cleaned from all shavings and dirt and then wiped with acetone.

A small amount of hydrated flux was eased onto the interface between the two parts.

Here they are, after brazing.

Nice wee fillet there!

Once cleaned up with hot water and a brass wire brush, the results were clearly adequate.

I did need a bit of needle filing but nothing to stress over.

The final product!

Thanks Michael, much appreciated.

I do have one issue however. As I am using the Walschaerts valve gear, the cross head needs a drop arm which needs to be brazed to the cross head. In my haste to braze the tops, I forgot to do the drop arms. In the words and music, LBSC describes doing both jobs in one heating which makes sense. I am going to have to re-heat and braze on the drop arms separately. My only hope is that the tops do not shift. I will need to concentrate the heat on the drop arm and thinner portion of the cross head. Hold thumbs!

I bit the bullet this afternoon and after finishing the drop arms, decided to silver solder them to the cross heads.

The following is an account of the procedure:

The brass bushes to hold the arms on were turned and fitted to the cross heads and then punched to flare the ends holding the arms tightly.

The items were then fluxed.

And then soldered. AND NOTHING MOVED! Hooray!

Very happy with the result!

Apart from filing up the second conn. rod, the next parts to make are the expansion link gear frames. I want to have these done so that when the cylinders are erected there will be a stable platform for the guide bars to be mounted to. As I will be fabricating the frames, I have decided to use a jig to make things easier and more accurate whilst brazing.

The below pictures are the jig I have come up with. There are two main parts, the first is a cylindrical beam that will keep the sides of the frame the correct distance apart as well as pressed firmly to the main frame piece. The second is a simple clamp that will be used to keep the little block for the guide bar mount in place when brazing.

The general idea is simple and should hopefully save some hassle.

I made a jig for the milling of the side relief of the connecting rods. This consisted of an aluminium plate, squared up and drilled with two holes at the same centers of the rods. These holes were tapped M5.

Once complete, the conn. rod was screwed lightly to the jig and using a surface gauge, aligned parallel with the jigs side to allow for perpendicular milling of the relief.

The gauge was set up so that it could be moved along the length of the jig. The center line of the rod was aligned with the point of the gauge. Once I was happy with the alignment, the two cap screws were tightened and the rod was ready for milling.

Here is the jig in the machine vice, possibly a little too low for comfort…

Here is the rod after the first pass with a 5mm cutter.

This is the finished rod after milling.

This is the other side.

Both rods with side relief milling completed.

Here are some photos I took doing a mock-up of the left cylinder assembly and associated bits.