Potty Dake Engine

[sbwhart]

Thanks for your interest Chaps

I've now completed the drawings if any one wants a free copy just drop me a PM.

But be wanrned they are untested so there are probably mistakes..

Stew

[Bearcar1]

Many thanks Stew, for allowing us access to your work, it is always a pleasure. This looks to be a fascinating engine and should prove to be quite the challenge but after seeing some of your other accomplishments, this one should be no less doable. 


BC1
Jim

[sbwhart]

Cheers Jim 

I don't know when I'll be starting it, as i want to make some progress on the Simplex rebuild.

Stew

[sbwhart]

Well I've sortof made a start whilst I was making the link for the loco I had some long cuts to do so set the trips on the mill and just let it get on with it whilst I did a bit of work on the Dake.

The Dale is one of those engine thats best made from the inside out that way you make the part in the sequence they fit together so its just a matter of making each part fit.

So starting with the inner cylinder which is made from a 3" dia chunk of EN1A free maching mild steel.

Face of to thickness, and drill and ream a 8mm hole down the middle.



The turn up a 8mm mandrell a nice close fit on the cylinder, bolt the cylinder to it and skim the outside down to size.



Thats it for now, but every engine has to start someware 

Stew

[tvoght]

It's good to see a start on this, Stew.

--Tim

[zeeprogrammer]

Ah...just came from your other thread.
Well okay then. This is highly interesting too.

[steamer]

Hey Stew!

Great build...I've seen one of these full size in real life....damnest thing you ever seen.....like whats making this thing run!

Cool....pulling up a chair

Dave

[Stilldrillin]

Great start Stew! 

Following, quietly. Trying to understand what it does, and how...... 

Good luck!

David D

[ozzie46]

  Right! Got my chair and popcorn. Have at it mate.

 Ron

[Don1966]

Very interesting Stew, I will be pulling my chair up as well. I. Look forward to more post. Don't forget we like photos!


Don

[doubletop]

If the loco is on the shelf for now then this is the show to watch.

Pete

[sbwhart]

Thanks for your interest Guys

Bit more done today

I was unsure as to the best way to progress on this, not quite sure what I would use the mandrel for but it just seemed a good idea to have one.

To mark out mounted the mandrell on the spin indexer used this to centre the height gauge then mounted the piston to it and used the indexer as a marking aid, the marking out is just for a sanity check that everything is going in the correct direction.



One of the problems with this engine is trying to get your head round what the important features are, I recon getting the side faces of the piston cymetrical and parallel but the crown of the piston is not so critical

So strating on the side faces, set the disc up in the vice

Using a parallel to get get it leve



 Find the top of the disc and zero the vertical slide on this, then mill the required amount off.



Flip it over and mill exactly the same amount off the other side. A quick measure showed that they were cymetrical within 0.05mm that will do.

Now to do the crown.  Set it up square in the vice using a 1*2*3 block this should be good enough.



Then mill as for the side.



This took all of my shop time for today this is it so far.



Stew

[sbwhart]

Some more done this morning.

To cut the steam ports the piston needs to be positioned correctly under the mill.

First in the  lathe and using an independat four jaw chuck set the bore running true.



Then mount the chuck on the RT with the RT set on zero clock one of the faces square by turning the base of the RT when level clamp it down.



Next you have to centre the RT under the spindle to do this I used one of those indicator things located in the bore.



With it lined up zero the DRO



Then using the a combination of the PCD feature on the DRO and the RT to generate the 31deg curve machine the ports by first drilling the ends 4mm and joining them up with a 4mm slot drill.





To drill into the ports mount the piston on the mandrell in the spin indexer making sure you get it square and with the mill zeroed on the centre line.



It is now an easy job to get the correct position to drill through into the port, just indexing round to get the position on each face, repeat for the location of the M3 holes.



To complete Tap M3 using the tapping table.



Thats the first part done.

Stew

[Bearcar1]

Wow!, nicely done Stew. This is going to be very interesting to follow. 


BC1
Jim

[b.lindsey]

Nice start Stew. Great pics and description of the part set-ups as well. Looking forward to more.

Bill