Potty Simpson and Shipton Short Stroke Engine

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sbwhart:

--- Quote from: Rob.Wilson on January 16, 2012, 02:03:34 PM ---I ,,, but Stew ,,,,,,,will it be ready for Harrogate :poke: :)

Rob

PS ,,,,, cracking job by the way :clap: :clap: :clap:

--- End quote ---

It will be darn close ready for Harrogate, it may be a bit rough but it will be close.

Any way got the base soldered to the cylinder, it took two goe's my first atempt the nozzle was a bit small and I wasn't getting enough heat into it, swapped to a bigger nozzle and it went like a dream, at the first attemp I tought should I swap to a bigger nozzle, but I was to lazey and went with what was fitted, came out ok in the end its slightly skiwiff, but a light skim of the base should sort that.

Next up the covers, I'm making these out of 1/8" thick brass, first job cut then off the bar and square the ends, then carfuly drill the centre holes 3mm to take dowels and a couple of 1/16 for brass pegs to locate a thickening peice.

Then cut out the thickening peice square them up and drill them for the 1/16 pegs

File a rad on each end

And this is how they fit on the cover for silver soldering

Job done:- the pic doesn't do it justice its a very neat joint.

The covers have a curved slot that the piston rod runs in this has to be on a 75mm rad, and the covers have to fix centraly on the cylinder bore. so I made a fixture to hold the covers on.

A 10mm hole was drilled and reamed in the jig 75mm from this two 3mm holes were drilled to take 3mm dowel pins, and a hole drilled and tapped to take a clamp. I also made a 10mm clamp bolt with a 10mm register dia a neat fit in the 10mm hole in the fixture, this bolt screwed into the surface plate that I made some time ago to increase the capacity of my RT.

and how it all fixes together.

Stew

doubleboost:
Stew
You are making it look easy again :bugeye: :bugeye:
John

Stilldrillin:

--- Quote from: doubleboost on January 19, 2012, 06:38:32 PM ---Stew
You are making it look easy again :bugeye: :bugeye:
John

--- End quote ---

He does that, doesn't he, John! :scratch:

I like your "surface plate" extension Stew. I use the lathe's faceplate.

Keep on, keeping on....... :thumbup:

David D

sbwhart:
Cheers John/David

I can now start treating the cylinder like a casting, the trouble with this design of engine is that its so weird, its difficult getting your head round feature that are important.

I figured that it will be important getting the slot that the piston rod moves in central with the cylinder hence the fixture I've made.

So to mill the slot first centre the RT on the mill spindle zero things up then, using the bolt secure the fixture to the table, but first clock it up level with the Rt set on zero deg.

Then index 75mm bolt the cover to the fixture and with a 8mm slot drill mill the slot.

Next drill the 2mm holes on the PCD, both ends

Onto the cylinder centre it up on the mill zero the dials. and using a boring head bore out the cylinder vertically down, advancing 1mm vertical down again advance 1mm etc etc until its long enough.

Did this for a couple of rouging cuts, then to finish advanced it 0.5mm/cut , this left a slight ripel in the bore but that will soon clean out with a bit of fine emery cloth wrapped around something flat.

Then on the centre line drill a couple of holes each side to take 3mm dowels.

Locate the covers on the dowels and spot through 2mm followed through with M2 tapping drill.

Centre the jig back up on the RT and radius the end of the covers.

And this is what the covers look like on the cylinder, only got one finished before domestic duties called, I'll finish the other off tomorrow.

Hope things are starting to look a bit clearer.

Stew

Stilldrillin:

--- Quote from: sbwhart on January 20, 2012, 01:48:39 PM ---Hope things are starting to look a bit clearer.

Stew

--- End quote ---

Now, it reminds me of a cross between a mantel clock, and a diver's helmet......... :lol:

Thinking I might be getting some idea....... Is the cover on upside down, in your last pic, Stew? :scratch:

Or, is it a test to see who's paying attention? :poke:

Or, is it just an optical illusion? :thumbup:

Or, should I just sit here, quietly?

David D

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