Building a bigger Easton & Anderson Grasshopper

[rhitee93]

Wow, that is a great start.  I am in for the rid eon this one.  Please keep up the great posts!

[Jasonb]

The cylinder top cover started as a disc sawn off a length of 80mm dia cast iron bar, this was held in the outside jaws and the internal spigot formed.



It was then revered in the chuck and held by the spigot while the top profile was machined I copied the shape in the photos rather than that of Anthony Mount's (AM from now on) design, the curve was done freehandand then fine tuned with a file.



Then over to the mill and the centre was located



The PCD function on the DRO was used to place the stud holes around the edge and the ones for the gland studs. I found on the Benson that if I doubled up the fixings then they seemed too big so on this engine I will be going buy what looks right rather than just double the size of everything.



The photo of the full size suggests there is a recess in the top of the piston rod packing gland to catch oil from the drip feed oiler so this was added rather than a plain gland as per AM's drawings. I like to make the studs and fixings as I go along so here it is done.



J

[Jo]

Wow, the size difference is very noticeable with this cover. Great stuff.

Jason, one thing I did question with my engine was providing some sort of oiling point. One the original design one of the studs handed smack on the line of the steam port I tried putting a longer stud in but in the end decided to put a dummy stud in it and use this for oiling.

Jo

[Jasonb]

The prototype has a large air pump that would have blown cold air through a condenser, this can be made as a working pump or a dummy, I'm going to do the dummy at the moment but may add some internals at a later date.

I was in two minds whether to machine the pump body from a solid lump of 40mm cast iron block or fabricate, as this will be a heavy engine when done I opted for fabrication as it will be a bit lighter. A rummage around failed to find a suitable bit of 3/16" plate for the base flange so a few offcuts were welded together and then machined to give the required 2.5" square followed buy boring out for the tube with a boring head.



While the boring head was set to the correct dia I used it to flycut the end of a 3/4" bar to form a boss for the air pipe.



The top flange was cut from 1/4" plate and a stepped hole bored in the lathe, then holding by this hole the outside was turned round but left a little oversize.



The tube that goes between the two flanges was made from some that was a bit too big in diameter so I worked out what needed to be cut from the circumference and cut out the waste. Here you can see the parts ready to be soldered together.



And after silver soldering



After sitting in the pickle while I watched the F1 qualifying and a quick scrub the assembly was put back on the lathe and the top flange turned true to the base and to final size of 2.5" dia x 7/32" thick.



A bit more cleaning had it looking like this after which I added JB weld to all the internal corners to get that filleted cast look and left it overnight to harden.



While the JB Weld was going off I made the top cover, very similar to the cylinder cover but as the curved top which is not shown on AM's drawings runs right down to the flat bolting surface it was not ideal to use a file to refine the shape without marking the flat face. Solution was to hold a bit of bar in the tool post to act as a rest and then hand turn the curve, this posed photo will give an idea of how I did it with a woodturning scraper.



This morning the JB Weld could be smoothed off and a bit of primer added, then machine the gland and screw it all together.



Jo on the photos there seems to be a small square headed plug at the top of the cylinder casting which I may use as an oil point and yes it is bloody big

J

[Jo]

I have been trying to find a few more details about the original engine. I have two of George Watkins books (Vol 7 Stationary Steam engine of GB  & The Steam Engine in Industry Vol 1) that give this engine. I am assuming you have one or other of these, they both have the same square on photo of this engine.

The later book mentions that  the main valve eccentric was keyed to the crankshaft, with the expansion valve eccentric bolted to it. The earlier book identifies that it drove the gas exhausters via the belt. 

Jo

[smfr]

Great build, Jason. I'm following along with interest!

Simon

[Jasonb]

Jo, no I don't have the books just the two photos I posted at the start which were sent to me by someone on ME forum, He may have got them from the Watkins archive that is held by English Heritage as he mentioned that in his mail. He said that when AM drew up the model he had not seen these photos, just the square on one.

I best not buy thos ebooks as I will want to be making something else, already got my eye on this little red number, would be nice at about 1/3rd scale. 

http://www.prestonservices.co.uk/

J

[zeeprogrammer]

I don't know how I missed this thread. Fantastic.
I'd never seen how a fillet was done (or at least not like that). Very interesting.

[ProdEng]

Lovely fabrication and the machining to go with it.  I bought some solder, flux and a blowlamp but have yet to dip my toe.  The possibiliites fabrication opens up are very attractive.

[Jasonb]

Next up was the pulley that would have taken the drive from the engine upto overhead lineshafting via a flat belt. The photos show a few differences between the original and AM's interpretation such as 4 spokes vs 6, a split clamped hub and a narrower rim.

I started with the hub, a bit of 1" bar was drilled 1/4" and parted off then two shallow 3/8" grooves milled in opposite sides to take a couple of lengths of 3/8" sq bar
 


The three parts were silver soldered together then drilled for the clamping bolts after which they were cleaned up and all edges rounded off. I subsequently drilled the hub out a bit under finished size so there was less metal to heat up on the next soldering stage.




I drew the pulley out full size on a bit of paper and used that to determine the positions of the various arcs to form the spokes. These were then marked out on some 1/8" sheet and cut & filed to shape, testing against the drawing for fit.




A nice man on e-bay provided some 100mm OD x 4mm wall EWR tube and a suitable length was sawn off, the ends were tidied up overlength on the lathe.



When heating the rim of a flywheel or pully it tends to expand which can make the gap between rim & spoke too large for the solder or pull against the hub and distort the finished item when it cools. I decided to solder in two stages, the first being the spokes to the rim. Each spoke was set on a nut to pack it upto height and an off cut used as a makeshift hub, the spokes were then solderd into place.



A quick clean up of the inner spoke ends and the hub was set in place with a toolmakers clamp to ensure the previously soldered lugs would not move. This way I could heat the hub and not have the rim expand.



And here it is after a dip in the pickle and a light wire brush to remove flux.



Back to the lathe held it by the inside of the rim to bore the hub true and profile the rim to a slight crown. If you look at the lines on the rim you will see it is in 5 sections, the middle is parallel to the lathe axis, the ones either side of that are at 1deg and the outer section at 2deg, these will be blended later into a shallow crown.



And here is the finished pully, you will see that before soldering I added a 1/64th slot 0.040" deep around the middle of the hub to look like a dummy split line.



Just a little work to clean up the solder fillets, coat of paint and then mount on an arbour to blend the rim and thats another part off the list.



J

[tvoght]

I really like watching you work, Jason. Thanks.

--Tim

[Jo]

Nice ,
I keep looking at my engine as you make this and thinking I really should go back and correct that on my model . But I mustn't otherwise nothing will ever get completed.

Jo

[zeeprogrammer]

That looks really good Jason.

I have to imagine there were some anxious moments while soldering the spokes and hoping nothing moved. 

[Don1966]

Jason I wish I could sit in your shop a just watch you work. You always amaze me with your skill and craftsmanship. I hope one day I can even think of doing things like you just demonstrated.

Don

[steamer]

Nice build Jason!

Dave