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     

[Jasonb]

The link rods are better screwed into position and then jig drill the pin holes from the ctr of the pivot rather than measuring.

[Sanjay F]

So good news on the pivot ctr section, the length is in 0.500" - 0.502" region and when tightened rotates freely.

@Jason - just to clarify, what do you mean by 'jig drill'? The brass pivot ends have both been drilled and tapped already and the A-frame swivels have been threaded (see pictures). Does this cause an issue or should I just go with the drawing measurements for now?

[Jasonb]

The problem is when the two parts hit the ends of the male threads on the link they may not line up as it would depend where the threads started radially. If you loosen them off so the clevis is lined up then the length changes.

So ideally you screw them together adjusting things so they are tight when the slot is vertical and the central pivot horizontal. You then drill the clevis hole the right distance from the middle of the pivot

[Sanjay F]

Spent the day doing reassembly and modifying the tight interfaces between parts. The engine now turns over quite smoothly by hand and after some fiddling around with the valve gland and rod, the valve it moves up & down as it should.

I didn't get as far as the link rods as I wanted to make sure the other parts of the engine are in reasonable order before making them. The beam has now been flipped over so should now accomodate a central oiler

<a href="https://www.youtube.com/watch?v=MQkOwU4SSpo" target="_blank">http://www.youtube.com/watch?v=MQkOwU4SSpo</a>

[Michael S.]

I think it looks good. Excellent movement! 👍

[Jasonb]

Thinking about those links some more there is a way you could get them the same length using the existing parts.

Drill out the threads in the ends of the forked clevises.

Turn the link rods with one end just a plain spigot to fit the drilled out clevis, thread the other end as drawing.

You can then screw the rod into the central pivot and loctite the clevis onto the plain spigot. This will allow the clevis to be rotated to the correct orientation without a threaded connection altering the ctr to ctr length.

Just check that the end of the clevis to it's pin hole are the same on both and adjust if not.

[Sanjay F]

You weren't kidding when you said this wasn't a great design! I've spent the whole morning on the 2 rods; the original measurements given on the drawing weren't even close, luckily too long than too short. I then discovered what happened to the original rods when I tried screwing the new ones into the clevises; they were clearly snapped off some time in the past 

Through trial and error, locking the brass pivot end, and as you say rotating the clevis end I've managed to get it operational; I'm very tempted to loctite the rod and clevises together now.

https://www.youtube.com/shorts/v2U8Om1OOug

Just need to try and get the engine to run and then I can pretty up the rods. Having a little trouble with the timing, the eccentric keeps coming loose on the shaft off of the valve assembly, the tiny Allen head grub can't be biting enough

[Jasonb]

Stick a big hex head or cap head in it while you get the timing set, much easier to get a grip of. Also worth putting a bit of lead or soft aluminium in thechole first so the screw bears on that rather than tearing up the shaft.

When it come sto timing forget what is usuallly said about the eccentric leading the crank by 90deg plus another 30 or so. The action of the bell  crank in the linkages reverses that.

[Sanjay F]

I got everything I could think of looking right, port openings equal either side, loosened the valve nut in the valve, got the timing worked out, no resistance anyway and guess what .......................dead as a Dodo. 2hrs later and having played about some more, still nothing until the airline popped off and nearly hit me in the face ....... again!

The air wasn't even getting into the cylinder so I started having a poke around and couldn't believe what came out.......black sand, the sand you get with new castings, both ports were blocked solid with it (see picture). This was definitely sand not the oily gunky residue you get with old engines (I know that too well). It took ages to get it out I had to clean everything as it was everywhere. I'm so confused how can both ports still be full of the original casting sand?

Anyway, here she is running, still needs the the link arms shaping and an oiler for the beam; I must admit its very hypnotic to watch and I've been doing that for quite a while!! 

<a href="https://www.youtube.com/watch?v=0-2rvdDk5v4" target="_blank">http://www.youtube.com/watch?v=0-2rvdDk5v4</a>

[Jasonb]

Quite common and I often mention it to people building from castings with cored passages. The core sand has stronger binding agents added so does not come out easily and not being seen has to be dug out. Falls out easier if it has not been soaked in oil and rust remover

[Michael S.]

Sand mixed with oil! So you can use it for sealing too...😆

Glad the engine's running.

Michael

[vtsteam]

So Sanjay, do you think the engine had been run before? 

[Sanjay F]

That's what crossed my mind too, I honestly don't know; it came in an odd condition with most of it machined and the rods missing having snapped off in the clevises. Maybe someone put it together and never got round to finishing it or running it, hence the ports still being full of sand?

Finished by fitting a little oiler to the beam and tapered the rods. The taper turning attachment and turning between centres didn't work, luckily I used a bit scrap to test it. Finally just went with the cross slide angled over a few degress and did it by eye.

Once Santa has been and I've stuffed my face I'll start painting and a maybe a new project (I can't be sitting around watching paint dry after all)

[crueby]

Running great!!  Good find on the sand, not something you'd expect!

[Jasonb]

The sand can help with running in as it helps get rid of any tight spots

I suspect the previous builder got it all made and then threw it across the workshop in frustration of not being able to get it running due to the blocked ports and that broke the links as it hit the workshop wall

[Chipswitheverything]

Nice work on this engine, Sanjay, and it is certainly an interesting one to watch in motion. The ports couldn't have been much fuller with the gritty sand!  I must have a good dig out of the ports on my Stuart T. triple castings when the time comes.  When the Grasshopper is painted up, it will look very handsome.  Dave

[vtsteam]

The sand can help with running in as it helps get rid of any tight spots

I suspect the previous builder got it all made and then threw it across the workshop in frustration of not being able to get it running due to the blocked ports and that broke the links as it hit the workshop wall

Maybe he just ran it on the beach and seized it. Reminiscent of a certain brother of mine....

It will be a beauty in paint! 

[Sanjay F]

My goodness I'm glad I took the engine apart again for painting, there was still sand sat in the bottom of the cylinder. I had another go at pushing wire through the ports and blowing air through with the compressor to clean throughly. Finally got to a point where there isn't even the finest trace of it; I guess the few minutes of running must've honed the cylinder 

I really don't think this has ever been run, not with both ports blocked, from one persons frustation to another's bit of luck! It was sold as 'for parts or repair' so someone knew all was not as it seemed with the grasshopper

I hung up the last of the Christmas decorations and will hand paint them tomorrow

[Sanjay F]

The Stuart Grasshopper is accessorised, painted and chirping away happily 

<a href="https://www.youtube.com/watch?v=q4GQFQVDVUY" target="_blank">http://www.youtube.com/watch?v=q4GQFQVDVUY</a>

[Jasonb]

looking good & running well.

[vtsteam]

Victorian elegance! 

[Admiral_dk]

Looks and Runs Great 

Per   

[Roger B]

Splendid