An incomplete Grasshopper

[Sanjay F]

I was going to start on a new build with a set of castings, but am waiting for some tooling to arrive and being Christmas goodness knows when that's going to be.

Here we have my first beam engine which is a Stuart Half-Beam or Grasshopper; is has some parts missing such as the link rods from the beam to the A-frame. Also there's some strange goings on such as the flywheel and pulley being incorrectly postioned on the crankshaft . The whole thing feels very tight and some things like the eccentric are just rotating on the shaft and others like the valve gear are non-operational. I think a complete strip down and bottom up rebuild is best then I get to see what's what and what's not! I have no drawings but I have the measurements for the link rods, but can always send off for them from Stuarts if need be..............

I made a start on the wooden base as the existing plinth bottom, as you can see, is a horrible piece of chipboard and there is nowhere for the outer bearing to sit during the rebuild.

Again this is another engine where I'm not sure if it has been run before given the missing bits, tight components and general finish, so let's see if we can inject some life into this Grasshopper. 

[crueby]

I've got a Stuart Grasshopper if you need any pics or measurements.

[Sanjay F]

Oh brilliant, I may come knocking for those or just for some advice as I make some headway.

From videos I have seen its an interesting movement, with both the usual up & down motion of the beam combined with a slight lateral movement

[crueby]

Its a neat movement - just needs a Hula Hoop!   
I do not have the plans, those are lost in the mists of time and many spring cleanings, but can measure parts.

[Jasonb]

A lot is similar to the other 1" x 2" Stuart engines, particularly the beam which shares the same valve gear. It is just the grasshopper bits that are particular to this engine.

Looks like most parts are there so if you have the length of the links you may not need the drawings. Link length really needs to be set with them screwed into the central brass shaft as length will alter if you drill the support ends then try to screw them into place. Not the best of designs having two rods that need to be exactly the same length but with screw threads. I'd redesign it with a solid pivot shaft. Fixed length links and retaining caps.

Check that the brass shaft in the middle of the beam is free to rotate when done up tight, some drawings show it's length as 15/32" which would clamp it tight to the beam but it needs to rotate so 0.502" would be better.

You may also want to turn the beam up the other way then the boss at the bottom can be drilled for an oil cup to lubricate the central brass shaft.

[Chipswitheverything]

Looks as if most of what you have there has been quite capably machined even if there are a few snags and the odd bits missing. Hopefully, no need to be correcting fundamental mistakes.    With a nice new base and a suitable paint job, it should be a rewarding model to work your 'fluence upon,  with your customary attention to getting these engines needing some TLC attractively up to scratch. Dave

[Charles Lamont]

It looks as though your starting point is a project in which the standard of workmanship appears to be very good (for once).

[Sanjay F]

Thanks everyone - lot's of great advice. I'll check the brass shaft length; the retainers for the rods on the A-frame barely move they are so tight, so a little bit of work needed around that whole area. The retainers are threaded too, so I'll have to think about how to get each side the same length for sure. As you can see I have managed to get the flywheel, pulley wheel and bearing into the correct order, looks more like how it should!

I thought the beam was the symetrical and never noticed it had a top and bottom with a cast area for an oil cup....I'll flip it over and hopefully that'll work; it'll look good with an oil cup at the top. The other thing I noticed was how the valve gear twists as it lifts up and down; I think that caused by each side being not being symetrically positioned on the shaft and lifting each side by a different amount?

I finished the base albeit without any varnish and this engine is very different propsect from what I have attempted before. Anyway lot's to think about and I'm sure there'll be more; let dismantling and clean up begin ..........

[kvom]

I built a grasshopper a few years ago.

Build thread https://www.modelenginemaker.com/index.php/topic,8074.0.html



Design was taken from Muncaster drawings converted to SolidWorks by Julius.

The advantage of grasshoppers over fixed beam engines include smaller footprint and no need for Watts linkage.

[Sanjay F]

That looks very different too and I like the governor mechanism; nice job. 

I see the A-frame and the ladder are made from rods. Yes, I've heard the Watts linkage can be an interesting thing to get right, I'll leave that for another beam engine in future

[Sanjay F]

The mission for today partially completed, everything is dismantled apart from the cylinder which I'll do as a unit. I found a snapped off bolt in the base and drilled that out.

Spent the rest of the day cleaning up the sole plate, flywheel, pulley wheel, outrigger bearing, beam & ladder; they look good, but my fingers are worn. I'm starting to see a few 'interesting' anomalies here and there 

[Michael S.]

The individual parts look good at first glance. I hope you won't have too much work with the engine. I'm sure it will be painted too?

[Sanjay F]

I think overall this has been done well compared to the Clarkson I just finished. I'm okay with fixing issues I find, after all that's why I buy these old and 'needy' engines; there needs to be a challenge in it for me, and with assistance from you guys, I end up with a working engine as well as a buiding up my knowledge & experience

I will be painting this one; it'll be in its usual Stuart regalia, green, black base and red on the flywheel. I try and paint other engines different colours variations or leave "Au naturel" if they are ancient.

What about your current build have you thought ahead about paint, I've like some of the colours you've painted your many previous builds or leaving this one in brass?

[Sanjay F]

The component parts are now deep cleaned and degunked. The tight parts have all been loosened and an oiler installed into the eccentric and new packing has been installed on the glands.

Tomorrow starts the reassembly and then I'll make the link rods after measuring the distance. I think I'll make sure they are correct and operational before I shape them to their fishbellies. I dug out this tailstock taper tool which fitted on my old Sieg but with an adaptor should fit the the Warco, it'll be good if it does otherwise it'll be on eBay 

[Roger B]

Another interesting project      As others have said the previous workmanship doesn't look bad but as we all know the devil is in the details