Functionally, it’s Done and it Works!

The last component went on the machine today –  the lever, known as part 9 on the governor kit plan, it’s the little lever that picks up the vertical motion from the flyball governor and converts it to rotary motion to drive the steam shut off valve.   I didn’t make it wholly to plan (of course).   Instead of fabricating the part as per Stuart plan,  I machined the lever from a solid piece of 1/4 inch square bar.   I used the same profile for the lever as the plan but machining from

solid meant that I could create a shoulder to make space for a 7BA grub screw,  rather than rely on Loctite. Apologies for the image not being spin sharp,  but I think it’s good enough to see the design.   I’m also getting better – the grub screw is underneath the lever,  out of sight,  by design,  not accident!

When I was in the midst of designing the gear driven governor,  I got talking to a guy who had  built steam engines on a commercial basis and he explained that flyball governors do not work on this scale,  as the laws of physics don’t scale,  which is of course perfectly true.   Well,  I can smugly say that this flyball governor DOES work!   I have run the engine now on 60PSI compressed air and there is the odd air leak here and there,  but the engine just trots along,   it should go like the clappers of hell at that pressure and it doesn’t,   because the flyballs do  rise and do cut-off the air supply and the engine can’t accelerate.    In other words the energy in two 5/8 inch phosphor bronze balls spinning at 200 ish rpm can be translated into enough rotary force to drive a low friction valve.  I do owe the guy a beer,  because his comments took me down the road of thinking about needing a very low friction cut-off valve and ultimately making one to my own design.   None of the standard commercial valves I found wouldn’t have cut the mustard in this application.

So finally here she is -

Here is the engine running,  regulated by the governor.  The knocking noise is poor accuracy of machining by me of the inboard crankshaft bearing – if I pump it full of oil the noise goes away…One mod I did make was to fit the brass bearing blocks with Phosphor bronze shells,  so I just need to make a new shell,  rather than do any work on the bearing block itself.  My initial intent was longevity,  not ease of maintenance!  There is always an upside,  you just have to look for it.

http://www.youtube.com/watch?v=R6rgZ-7Y3t8

While the engine is functionally complete and working properly,  there is a cabinet to be made,  the various leaks to shut down before moving to live steam.    I don’t intend blogging the detail of that,  but will properly drop in some photo’s from time to time as the major stages are complete.   I still have to make a working Meyer expansion valve,  but that was always going to be the subject of a project in it’s own right.   I have made some fencing posts,  but at the minute I’m not minded to install a guard rail around the engine.  May be I will one wet weekend,  I have made a couple of the fence posts already.

One thing that did prove true was to minimise the number of colours in the paint scheme and I did spend a lot of time getting to the right scheme  which has worked out in the end.

This is the second project out of the workshop,  so it’s time to go for the big time – The Whittle V8 is next on the list,  I was going to build David Parkers OHV 9cc V-twin,   but time to be bold!   The plan is to machine the crankshaft first and see how that goes.   If I can produce a really good crankshaft then that will give confidence I can deal with the rest.

I’ll blog as I go,  the Stuart Victoria blog has attracted over 10,000 hits to date,  so it seems worth while to continue with the V8.   I’ve already bought the prop and glo-plugs

Best Regards

Steve

Comparisons – Old and New

If you’ve followed this adventure from the beginning,  you’ll know this project was largely inspired by an engine my Great Grandfather built around 1905,  best guess.   Take a look at my attempt to copy his design and compare:

That rather scales the achievement – and yes it is a working engine,  not a “model”.

I also thought it would be useful to show the lathe he built to build the engine -

I guess it would have made more sense to show this little homebrew lathe in context of my lathe,  but it might have got lost even against my “little” bench lathe.

This is my lathe as bought from Arceurotrade,  it’s had one or two mods since I took this.   It’s 10×22 class machine and the perfect size in my view for the sorts of models I’m seeking to build.   It’s useful speed range is now 40 – 2600 rpm and I’ve also added a digital readout to the tailstock and got rid of the clamping bolt,  which was a real nuisance when I built the Nemett.  I’ve also added locking clamps to cross & top slides.   I’ve  installed  rev counter electronics,  but never implemented the display!   Decided it was a pretty pointless exercise in the end.  Calibrating the knob once in a while with a permanent marker works just fine.

Victoria Running In on 25 PSI Compressed Air.

Victoria running in on 25PSI  compressed air

http://www.youtube.com/watch?v=xqflW9fnGhc

What I’m really pleased about is that the noise from the governor gear train is pretty low,  you can just hear it in the video.  I have been concerned throughout the build that it would be very intrusive and it just isn’t.

Form Tools Again, Comment From My Mentor…

My mentor is a time served machinist,  with decades of workshop and engineering experience.  He offers these thoughts on making a form tool (re: making the ball ends for the engine fence posts).

“With regards form tools which have the greatest cutting pressures of all tools; you are right to believe that a top rake is essential in all cases except brass.   My method of making a tool similar to the one portrayed, would be drill slightly under size at 5 degrees to the main body (front rake) turn a rod to correct diameter on lathe,  revolve and apply lapping paste to the right size.  Harden and hand grind the top rake with a spherical stone in a Dremel type grinder.   The absolute minimum front rake will assist in the prevention of dig in, chatter, etc, etc, the top rake will attempt to drag the tool into the workpiece.

My Dremel type was bought at B and Q for 20 pound 20,000revs 3m shank stones.   Maybe its time to circulate the christmas lists.  Hope my observations are of some value; I await with bated breath the crank; go for it.

As Ever

Harry.”

“The Crank” referred to is the crankshaft for the Whittle V8.    A daunting project (bearing in mind my only previous machine shop experience prior to the Victoria was building the Nemett 15cc OHC glo-plug engine).    Harry’s point is that if I can make the crank,  I can make the engine.   In any event,  making a really nice job of the crank make a nice display piece in its own right.

Finishing the Steam Cut-Off Valve

I made the core of the valve quite a while ago and now all that was left to do was to add the threaded connectors so it could actually be used.

Whats going here is that I’ve made two small stubs from 1/4 inch brass rod,  drilled them through 1/8 inch then gently made the narrow end concave to fit the barrel of the valve using a 12mm milling cutter.  The 1/8th steel rod is used to align the components for silver brazing.

The usual comment,  before attempting any soldering or brazing,  the surfaces to be brazed need to be scrupulously cleaned and painted with flux,  keeping the flux tidy to the area to braze.   The other key point is not to apply the heat directly to the joint or the rod,  but let the heat conduct into the joint and the braze will flow wonderfully into the joint.

To remove the steel aligning bar (which was not cleaned or fluxed!) hold the body of the valve and rod the rod until its free to move,  then slide the rod out.

Once all that’s done,  it’s just a case of threading the short stubs 1/4 x 40 TPI and the valve is ready to use.  (A part from a good clean and polish of course).

When you put all those bits together,  it looks like this !

I’ve soft soldered the copper pipe work,  and some of the pipe lengths need tweaking as things are not quite right. You can also see in this picture,  the 10BA screws I used to “dress” the flanges.   I bought the steam hand valve form EKP Supplies and it seems very nice.   Next job is to make the lever that connects the flyball mechanism to the rod that drives the steam cutoff valve and the joining piece between the drive rod and the spindle of the valve itself.

Starting the Plumbing trip…

Started to think about how to feed the steam pipes through the base and came up with this design:

The principle is that the flange is dressed to look like a steam flange by adding three 10BA hex head screws,  the assembly fits through a 1/4 inch hole in the base plate and a 1/4 x 40tpi nut pulls it tight.   A standard 1/4 x 40tpi steam connector can then be used to hook up to the external pipework.   It’s a pretty simple turning job.

The sequence I used was to turn the workpiece to the finished diameter of the flange.  Then turn the remainder down to 1/4 inch,  thread and drill the through hole and cut the taper.   Once I had two completed to this stage,  I swapped chucks for the independent 4 Jaw centred with piece with a clock and then finished off.   The top is simply drilled 5/32nd with the intention of soldering the steam pipe in place.

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Here the connector is transferred to the rotary table to drill the holes to tapping size to take the three 10BA screws, and on the right,  the set of components completed.   I won’t bore you with the details of how to drill a hole and make a nut from brass hexagon bar…

The next instalment is finishing off the steam cut-off valve.

Before I forget – Don’t round off the edges!

In Andrew Wilson’s book on building the Victoria,  he makes the key point that rounding off the various edges in the engine spoils its appearance.   Think of it another way – The Victoria is probably c20 th scale of factory size version,  so all the fillets and corners need to scale down too.

The other reason for flagging this to you is that it is easy to accidentally round the edges,  particularly the cast parts,  which can be pretty soft.   Always wrap the abrasive paper (emery or wet and dry) round a flat surface,  say a steel rule of piece of steel flat.  If the edges of the flywheel took on a 1/16th radius,  it would look pretty odd I think.  It’s really easy to achieve,  so take care.

Drilling the funny shaped piece that holds the shaft that drives the…

The little curly casting (Stuart call it a Bracket Pivot) under the flyballs requires a 1/8 hole drilled through it.  The piece is wholly irregular,  the little barrel is not square to the strap and the sides are not parallel either.   Spent quite a lot of time puzzling how to get a pretty accurate hole through the barrel to take the drive shaft for the steam shut off valve.

It occured to me to make a specific fixture to hold the barrel for drilling.

So this is the piece I made.  I drilled a 8.6mm hole to take the barrel and then milled a 3/16 slot to accomodate the mounting strap.

The only none obvious part is that the 8.6mm hole is the average diameter so the thin end slipped in and then some tapping to squeeze in the fat end.   Judicious use of a file helped too -

My TOS 4-jaw chuck is evident in the picture.  This is a really nice chuck which was on a deep discount.   I’ve tried to find a 3 jaw version,  but best price I’ve seen is £160 + VAT which is way out of my league.

Grindingly slow, but the Victoria is coming together…

Shot from the front – a lot of “fitting” going on which is slow work.   There is a spacer behind the large bevel wheel on the crankshaft which needed thinning to ensure a good mesh between the two wheels,  got it right after two cuts,  but lots of ops to get it done,  on the lathe (setting up the backstop I used for turning the eccentric straps) and making a long handled 2mm allen key to get the screws in and out of the flywheel that secure the bevel wheel.

Having machined,  fitted, painted, woodworked and fitted,  I’m getting quickly towards the plumbing part.  Never ends this steam engine building.   I reckon my design changes to the basic Victoria have tripled the elapsed build time.

Nothing particular to remark on from this side,  I deliberately laid the engine out so everything was “happening” from the front,  as ultimately it’s a display piece.

I’ve tried running it a couple of times today,  but the timing keeps slipping,  so I’ve used Loctite in the offending places as advised by Stuart.   On the initial run a long while back,  I had flats on the shafts so the levers wouldn’t slip.  I’ve since remade the shafts,  without the flats and hence the slip.

Actually,  there is a comment – this side of the base has a Roman flute applied,  whereas the front is plain.  That’s me just fooling around with my router to see which looks best for the final version of the base.

Fish Bellied Rods

I’d originally planned to ” fishbelly” (a new Nerb?) the slide valve pushrods,  then changed my mind and today did it anyway!

I stripped down the push rod assemblies and mounted in the lathe.  If you wind back through the blog far enough you will find I had centre drilled the rods for the purpose of creating the fishtails and I’d made a little fixture for holding the rod at the chuck end of things.   The short rod I can almost get half the rod before  I run out of travel,  the longer rod I’m about 1/2 inch short.  For the longer rod then,  I end up with a flat in the middle.    For both rods the shaping is finished with coarse emery tape with the lathe at full speed,  then cleaning up with a 400 grade emery and brasso,  followed by 800 wet and dry and brasso etc.

Here is the rod re-assembled and with the eccentric strap cleaned up.  Looks much better.

As an aside,  you will have noticed that I’ve now acquired a quick change tool post (QCTP to those that know about these things).   To be honest not sure of the value it adds,  thought it is handy for fine tuning tool heights.   It isn’t as quick as spinning round a four post tool holder in my view.