Hi guy's,
I began this engine a while back and it's one of two ongoing projects that are currently 'rather dormant' - the Bentley being the other - so before we go any further I should point out this is likely to remain so for a while.
Why bother to post then? Well commenting about some images on the crank build on Robert Hornby's excellent thread on the Windemere Steam Launch he has said he would like to see them so I thought it might be worth putting it up as a separate thread rather than encroach on his. Coincidentally on Sunday I caught up with some old friends from the Norwich SME as they put on a display of members work. One of the exhibits was a nicely made version of this engine which made me realise it's too nice to leave languishing
Who know's then - it might just provide to be the encouragement required to pick it up again - but
not before the Eta engines are finished
These pics then are for Robert and anyone else who may find them of interest. As always, if theres anything not understood please do comment.
The crankshaft provided in the kit of castings is a flame cut blank of flat mild steel. Having made several other crankshafts by the composite method using dowel pins and high strength Loctite I decided to go that route. There's a spare blank should anyone want one then
The tapered crank webs were made from mild steel and shaped and finished except their inner faces. Because the original shaft was probably a forging it was felt that the holes should be blind so as to give that effect. The small feet left were to retain squareness for pressing in the shafts (using the bench drill) and would be removed later
The shaft ends and crank pin were turned from mild steel the ends reduced to a tightish hand push fit into the webs. The shaft ends were assembled to their respective webs using Loctite 638, each spigot having a very small flat filed on to allow the air to escape from the blind holes in the webs (the red line)
After assembly the webs were drilled for a mild steel dowel pin. I know I've said this before on more than one occasion but if you wish to plug a hole like this without any sign of it after finishing the hole should
not be deburred - in any way at all - to do so
will, without doubt, leave a witness
The dowel is fitted with Loctite also, tapped home and slightly peened to swell the end. This is then filed off to blend in with the web.
The web in the rear has had the pin fitted and been filed off. 'Inking' up around the pin will give a good indicator as to how close the file is getting.
The crank pin was then fitted to one web in the same fashion then two vee blocks were set against a back stop on the mill table and the two half shaft assemblies brought together loctiting the pin in the second web. It helps if this fit is slightly less tight as this needs to be carried out quickly before the Loctite grips.
Finally finished and fitted with no discernable run out -
So far I have had no failures using this method - indeed the crankshaft on the Lang Bridge engine took some of the impact when I dropped it and though it distorted slightly it was easilly tweaked back to truth once set up in the lathe and runs as well as it ever did. What I like personally about this method is that all parts can be 'finished' before assembly, theres no distortion likely from heat sources ie silver soldering and providing it hasn't
really got to
work for a living then is more that adequate for the task.
I hope that helps you Robert and anyone else with similar interest
There are some further images of the build which I'm quite happy to post about if that's what you or others would like but as I said this is a dormant project until at least those Eta's are finished
Regards - Ramon