Paddleduck build from Bogstandard’s plans

[Taff Oliver]

Had a little bit of spare time today while the missus was making dinner so decided to start on one of the steam chest blocks, milled a lump of brass to 40x18x16, or within a gnats whisker, marked it up for the 5.5mm hole, centre drilled it then drilled it out to a depth of 36mm. All seemed to go well. I am waiting for a set of reamers then the hole will be reamed to 6mm. Hopefully get the reamers this week, along with M2.5 tap and die.

[propforward]

Nice work!   

[Taff Oliver]

Its been a while since I have had chance to do anything, the 3 “W’s” have got in the way.... Work, Wife and Waggy tail yappy things. Anyhow, today I carried on where I left off with one of the steam control blocks. I got my hands on s set of reamers so drilled it to 5.5mm and reamed it to 6mm. Drilled loads of holes through it as per plans and was very pleased at the slots I milled in it using a 3mm thingy I found in my fake dremmel box.

[Taff Oliver]

So all going well I marked the block up to mill the cosmetic bit for the top, that went ok too.... I then stuck the valve block to the main block with a dab of Loctite and spotted through for the holes for the 4 holding on studs. Got them drilled and tapped leaving behind 4 holes tapped to M2.5, a little pile of brass dust and an intact tap.... yey..... Last bit today was milling the blanking plate to size and sticking it to the valve block with Loctite ready to drill next time I get chance......

[kvom]

I built this engine a good while back using John's "crap-o-cad" drawings in 1.5x scale.  I converted his metric dimensions to imperial and used imperial fasteners.  As I recall, the tricky bit was getting the crosshead guides vertical to the base plate, and the multi-piece crankshaft and split bearing blocks were tedious to get into alignment.

It was my first introduction to piston valves and how they work.

[Taff Oliver]

I basically started on the bottom end first and got all the crank built up and running very freely, made the cross head guides and pistons then bolted it all together, stuck my cordless drill on the shaft end and guess what? It ran ok, was a little tight but nothing major, it was turning at high speed with the drill and I didn’t need to hold it, however I did remove one crank web bolt to turn the head a touch thinner and stripped the thread on the web putting it back in, so it looks like I will have to make another crank web 

[Taff Oliver]

I had a bit of spare time this evening so decided to start on the second steam valve block. I cut a lump of brass down to size ish then milled it to 40 x 18 x 16, nothing too exciting but it had to be done. Tomorrow night I might get round to making it look like a lump of Swiss cheese and fill it with holes........

[Taff Oliver]

Little bit of progress tonight...... Going to work gets in the way a lot. Drilled all the holes in the valve block and milled the 3mm slots out. Then marked it up for some cosmetic milling....

[Baner]

It's coming along well, good job!

I built this engine a  many years ago, and will echo Kvom's comments: It's a very fiddly engine to setup.

In the case of bearings, cranks, eccentrics and crossheads err on the side of loose fits rather than hoping they will wear in. I remember these parts shifting a little (due to the adjustability) while attempting to wear them in, and having the whole engine lock up, requiring multiple disassemblies to find the culprits

Also it is critical to get super close fits on the steam chest components and the piston valves. The first time I attempted these they leaked like a sieve. The relatively large sealing areas of the steam chest and cover coupled with the minimal fixings make this area a bear to seal. A very fine and flat finish is required, and this area would probably benefit from some sort of liquid sealant.

From memory I think the plans specified a reamed piston valve bore and nominal ground stainless rod for the piston. In my case that fit was not close enough. Instead, I would still ream the bore, but would turn and lap/polish the piston OD to the closest sliding fit possible.

It also might be worth using a bit of Loctite 243 on some of the fasteners and threads to stop them from vibrating loose when running.

Anyway, that was my experience with the engine; I think this was the third or fourth engine I ever made and I learned a great deal from it. Most of what I mentioned above are lessons I took to other engines, and I still use many of John's techniques to this day. So whilst it was a bit of a bugger at the time, looking back it was well worth it.

Dave.

[Taff Oliver]

Thanks for the advice. The valve pistons are the parts that I think are going to be difficult go make, I wonder how many will end up binned......