A Proper engine.

Discussion in 'Workbenches, including workshop techniques.' started by adrian, 29 December 2017.

  1. adrian

    adrian Flying Squad

    Earlier in the year I stumbled across a neat little live steam engine on YouTube. I posted the relevant video earlier in the year but will repeat it again here to start this thread. As my 3F build is nearing completion I thought I'd have a go at making one of these as a little Christmas/New Year project.

    I emailed Les Proper for a set of plans earlier in the year and have been slowly accumulating some of the material for the build. The dimensioning on the plans is a little unusual to what I would normally expect from an engineering drawing. You can work out the required dimensions but the formating is not what I would call conventional. Also everything is dimensioned in decimal imperial, so you have dimensions like 0.68", 0.22", 0.3" etc. I ended up using the dimensions as a guide.

    So today I made a start deciding to tackle the crank axle first. For reasons that will become apparent later on the axle is made from 2mm dia. silver steel. I then got a short length of 3/8" steel bar and using a centre drill spotted the centre. Before drilling the centre hole I marked out the 1/8" radius circle for the "big end". The centre 2mm hole was drilled in the lathe. The bar was then transferred to the pillar drill for drilling the offset hole for the crank. The bar was then returned to the lathe for parting off the two disks.

    crank - 1.jpg
    This was then assembled for silver soldering, using some soft iron binding wire to hold it together.

    crank - 2.jpg
    Having seen others use silver solder paste I was keen to try it on this job. I tried it on a test piece with some pieces of nickel-silver sheet and it worked fine so I gave it a go.

    crank - 3.jpg
    Unfortunately it didn't work out that well, I'm not sure what went wrong but the solder didn't really flash across the joint as I expected it too but rather just ended up as blobs around the work piece. So everything was taken apart as none of the joints worked and cleaned up. For the second attempt I went back to my silversmithing technique of easyflow flux and small pallions of silver solder. This worked better as the solder flowed into the joints as expected but somewhere along the route the discs twisted such that the crank pin wasn't aligned along the main axle.

    So attempt number 3 involved making the crankpin much longer so when I wired it together I could check everything was parallel.

    crank - 4.jpg

    Once I'd silver soldered together the extended crankpin was cut to length and the discs were tidied up in the lathe before finally cutting out the centre part of the axle.

    crank - 5.jpg

    So the next stage is making up the base plate and support pillars.
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  2. Osgood

    Osgood Western Thunderer

    Well how frustrating - all through the video I was trying to work out the big end arrangement, to the extent of missing bits of the commentary and having to rewind, and then Les slips in that teaser right at the end! :rolleyes:

    The only thing I can think of is a split tube somehow silver soldered together on the crank pin without sticking to the pin?
    Guess I'll have to keep watching this thread now!!
  3. adrian

    adrian Flying Squad

    When I emailed Les for the drawing he sent a short set of build notes which has a few more details. The big end arrangement is a rather basic split tube arrangement.

    This is from his notes

    Screen Shot 2017-12-29 at 10.54.21.png

    Simple and effective so I don't intend to do anything different on this part. As it's a single acting cylinder I don't think it needs anything more substantial. Although he seems to use the same arrangement on the double acting engines!
  4. ceejaydee

    ceejaydee Western Thunderer

    I love this kind of thing.

    I picked up this book by Tubal Cain a few years back following reading a couple of articles in some old and now gone Model Engineer magazines.


    Maybe I can have a go at one this year.

    Look forward to your adventure Adrian :thumbs:
  5. adrian

    adrian Flying Squad

    As usual I don't always follow the script! The plans use 4 vertical posts and then solder a brass bush between them for the main crank bearings. I had some 1/8" thick brass bar which I thought could make the end supports. It was like back to college days filing and fitting square and to length. The U slot at the top is required to clear the valve spindle linkage. The bottom of the plates then filed to match to give it "feet". The posts were then drilled and tapped 10BA. I scalloped the sides so that I wasn't drilling and tapping blind holes.

    The base plate and top plate were fashioned from a length of 1/32 brass strip.

    proper_engine - 1.jpg

    The top plate was reduced in width and drilled and cut out for the cylinder and valve tubes. I had some miniature ball races spare from another project, these are 2mm bore and 5mm o/d, hence using the 2mm rod for the crank axle.

    The flywheel and valve eccentric were turned from brass bar. The valve eccentric is grooved for a 1/32" rod. I didn't have a suitable round nosed lathe tool for this so it was a bit of a fudge using a V nosed tool to make the groove and then rounded out using a rat-tail needle file.

    proper_engine - 2.jpg

    So the bottom half was assembled to make sure everything fitted .

    proper_engine - 3.jpg

    proper_engine - 4.jpg

    With the bearings fitted it spins quite nicely! cue action shot.

    proper_engine - 5.jpg

    So onto the cylinder and valve guide next.
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  6. adrian

    adrian Flying Squad

    The cylinder and valve guide is made up from standard K&S tubing. The end cap requires turning from a bit of brass bar.

    A small hole is drilled in both the cylinder and valve guide to admit the "steam". Again the drawing is a bit convoluted in it's dimensioning. It wasn't clearly marked the dimension. I had to add and subtract half a dozen dimensions to work out a marked position.

    cylinder - 1.jpg

    The cylinder, valve guide and cap is then soft soldered to the base plate, I used a little spring steel in the "steam hole" so it didn't get blocked.

    The inlet pipe is then soldered onto the side of the valve guide, which is then drilled through into the valve guide. Just a word of warning be very careful in drilling this out, it's very easy to drill all the way through into the cylinder! No need to guess yes I made that mistake, this is the second attempt.:rant:

    cylinder - 3.jpg

    In the mean time somebody on the Guild Forum posted a link to "Clickspring". Some wonderful engineering with very informative videos.
    So whilst on the lathe I had a quick go making the "Delicate Scriber/Pick"
    Delicate Scriber/Pick

    cylinder - 2.jpg

    There's a few other projects on that site I'm tempted to have a go at. In the meantime this is the cylinder loosely placed in position.

    cylinder - 4.jpg

    The piston is next although this will have to be turned down from larger rod. Although notionally 1/4" bore in the cylinder a length of 1/4" brass bar stock was quite loose fit. So I'll have to turn it down from something larger.
  7. Dave

    Dave Western Thunderer

    Have you made any more progress with this, Adrian?
  8. Going back to the first post for a minute, decimal inches are the standard American way of manufacturing things. Fractions get messy quickly, so everything gets measured in thousandths, 0.001". If things need to be really precise you can measure them in "tenths" (or more accurately ten-thousandths) 0.0001".
    A dimension of 0.3" would be expressed as 300 thou or 0.300" but not as 3 tenths (even though is it 3/10") because most machinists would think 3 tenths is 0.0003".
    adrian likes this.
  9. adrian

    adrian Flying Squad

    Unfortunately much to my chagrin - no. :(:(:(

    It's still on my workbench to remind me to keep going with it as there is a specific long term aim with this experiment. Unfortunately real world priorities, life and work have preventing any time at the workbench over the last couple of months. I've not been completely idle as I have managed some time on the computer drawing out an idea for a steam generator, starting with the gas tank. I just need to turn this into a real world physical item! :confused:

    Screen Shot 2018-08-09 at 22.17.32.png
  10. Richard

    Richard New Member

    From my experience with small scale live steam, you need to take the gas outlet as high up the tank as possible otherwise you will be carrying over liquid into the burner unit.
    adrian likes this.