Tag Archives: castings

Steamboat Crankshafts – Lessons & Manufacture Pt#2

This post continues/concludes the story of manufacturing a new crank for Befur from the last post.

Here we can see the re-assembled engine with new crank. We are still to install all the ancillaries (reversing gear, lubrication, condenser and feed/air pump & alternator drive.)

It took 6-man days from receiving the crank back from the grinders to reach this stage.

Once we have tested it on air, we will reinstall it on the boat and undertake this year’s boiler test and check all is as it should be.

Machining Crank Pins

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Mid 2017 Update

Progress since April

Well, it seems like high time I provided an update, as the last one was in April!

At some level it feels like not much has been achieved, but that’s because a lot of the work has been “bitty”, finishing up jobs and tidying up items that had been hanging around for a while – and then there was the distraction of needing to design/build a new garden shed (the last one literally blew down – the joys of living 900ft up in the Pennines!).

So here is a list of the items I can recall completing…. Continue reading

Trial Erection2 – and slideways

This post is slightly out of order as I did the main and pump slideways first. These were simple milling jobs, I made a small video of machining the slots in the air-pump one

But, now we made a second trial assembly of the principal engine castings, to get a feel for how we were progressing – the engine is really growing now, and I can just lift it, but could not go far – I would guess it at about 80-100lbs.. and there is no crank, auxiliaries or valve gear yet!

Chrismas eve 2011

Well, we have reached a bit of a milestone I think – I have managed to erect the main castings (cylinder block, rear columns, base).

In the end I changed the order described in the manual, and mounted the rear columns first. Fitted the lower cylinder covers to the block (to ensure accurate positioning of the bolts, and then mounted the lower covers on the rear columns with a single bolt (as suggested) then remounted the block, spotting through the other mounting holes on to the column tops.

I came to this approach for two reasons:

1 -I did not manage the  machining the “spare bits” off the HP & LP covers accurately enough so there was about a 15thou gap between them. This meant that their angular position in the bores was not “totally” fixed.

2 – when I ran I trial erection, I discovered that very small lateral changes in the location of the block (displacing it along the line of the crank) produced very significant angular displacements of the covers – I am sure the geometry would  show this to be the case. So I concluded that it was better to settle the position of the covers (and their bolt holes) and manage the final alignment of the crank/slideways/cylinders  by control of the crank end-float.

Time will tell if I am right!

Next step is the front columns (a Boxing day job)! I am looking forward to this, although I have considerable concerns that the off-set turning jig to produce the offset footings will not result in a column that correctly matches the base and cylinder bolt holes without considerable “fettling”!

Drawing Errors

I tripped over a couple of problems –

1 – LP steamchest cover mounting bolts. It may be that my Technical Drawing A-level from the ’70s was to a different standard but only 8 of the 12 holes for the valve chest cover mounting holes should be drilled through. The 8 down each side do carry through to the block, but the 4 at the top and the bottom, should be blind – as the “clash” with the port pockets.

2 – The bottom (and top) cover mounting bolts. The location of these is not well defined on the drawings,  and care needs to be taken to ensure that they miss the ports in the cylinders (I wound up needing to redrill two on the LP side, as it became clear this was to be a problem.

3 – The bottom cylinder cover-to-column mounting holes. Again the location of these are not well defined on the drawings, and in the end  I wound up re-drilling these to ensure their correct location.

A Whole New Section on Drawing errors…

I have added a section to this site to log all the drawing errors I and others have noted… You are welcome to contribute too! Please see here.

A trial erection

So we reach the point where we can see if it looks like it will fit together. The engine is makes a lot of use of jigs, something new to me, but you can see how they work.

So firstly the front columns are clamped to an assembly jig located in the main bearing slots. Then a jig to locate the lower covers of the cylinders is clamped to the slideways,  then the whole cylinder block is lowered onto these covers – and you start to get a feel for how it’s going to look! and how heavy it is!

first erection - LP valve end
first erection – LP valve end

from the rearfrom the rear… and from the HP endfrom the HP end

The Castings Arrive!

Castings for Befur's Engines

Beauty in Cast Iron!

The engine ceases being and “idea” and transforms into a few hundred pounds of cast iron!

As planned, Louise and I returned from the sailing course and hot-footed it to Paris to meet up with Bruno Martin-Neuville and his friends from the Amateurs de Bateaux á Vapeur ( The French version of the SBA) and purchase this beautiful set of castings.

Bruno, Jean-Yves, and John entertained us wonderfully with a tour of their fabulous facilities in Severes on the outskirts of Paris and a very nice lunch. (we forgot to take pictures! but saw Midship, Melusine and others…)

So the winter’s work is now clear – to commence transforming these castings into a working engine – it’s clear that there are some “deamons” lurking in the drawings, so I am pleased to have the help and advice of some of the professionals from my Model Engineering club and the support of previous builders in the SBA