Kiwi Mk2 Engine

[vcutajar]

There was a change of plans and we did not go out this evening, so I disappeared to the garage.

Set up the rotary table on the mill. I will be using these two tools (photo 1) for the next operations. They are MT2 tapers which fit the hole of the rotary table. One has a 6mm and the other a 10mm shaft. I had made these during a previous build (not an engine).

Put the tool with the 6mm shaft in the rotary table and put the small end of the conrod in it. Clamped the conrod over two parallels to the rotary table and milled the outside wall of the small end (photo 2 & 3).

 

[vcutajar]

Replaced the 6mm MT2 taper tool with the 10mm and using the same setup as yesterday cleaned up the big end.

 

[vcutajar]

Cleaned the sides of the conrod beam and marked both halves of the big end with a centrepunch.

 

[vcutajar]

Conrod finished after 8 days!!!

Drilled the oil hole in the small end with a centre drill. I was going to clean up the the "I" section of the beam but then I remembered that in commercial cast conrods that part is left rough so I left it as is (nice excuse ;D). Just gave it a lick with a Dremel wire brush.

Trial fit in the crankshaft and it turns smoothly. Removed some material from the front crankcase (where the conrod had some interference) with a Dremel and problem fixed.

I think the next item on the agenda will be the cylinder casting. Spent the rest of the time in the garage trying to figure out a plan of action for this part. Still no plan but I think in the meantime I will be doing an aluminium template for the base of the cylinder. This item is not called out for in the article but I suspect I will need it further down the line.

 

[Catminer]

Conrod finished after 8 days!!!


Way to go Vince, the con. rod turned out very well.
Almost nothing to it ;D

Peter

 

[smfr]

Nice job on the conrod, and I'm glad my mistakes helped you

Simon

 

[vcutajar]

Yes Simon it opened my eyes. I hope you have managed to save your conrod.

Peter, it's a good thing I am not doing a V8 ;D ;D.

 

[vcutajar]

Whilst marking out the position of the holes in the cylinder base template I noticed a mistake in the plans. The spacing of the holes in the water-cooled version are wrong. The diagram for the air-cooled version is correct with 1.25" spacing whilst the water-cooled version is giving two different spacings, 1.5" and 1.25".

Still haven't decided on a plan of action on the cylinder.

 

[vcutajar]

Nothing much to report. These last two days, between real work and helping my eldest daughter in printing her chemistry Masters thesis, I haven't spent much time in the garage. To compensate ;D I ordered the 2 & 3 mm keyway broach set from the UK which just became available (in stock). I need this to cut the keyway in the cam and the gear. Also yesterday I ordered off ebay a co-axial center gauge which I have been putting off for a while.

I am still thinking how best to hold the cylinder for boring and outside machining. I tried in the 4 jaw chuck but the chuck is too big for this job. I just can't machine all the outside at one go. I am now thinking of using the faceplate but still have to try it out.

 

[vcutajar]

I think I have a plan for all the setups for machining the cylinder.

As the 4 jaw chuck was still installed I faced the top of the cylinder (photo 1) and then machined the base of the cylinder to the proper height (photo 2). At least this way both faces should be parallel.

Photo 3 is showing why I can't use my 4 jaw chuck for the rest of the operations. I can bore and also make the fins but I cannot reach the bottom part of the cylinder below the fins.

So in photo 4 I am proposing to use the faceplate to hold the cylinder. For boring I will hold it with clamps and then when that is finished I will lock the cylinder to the faceplate with a threaded rod passing through the newly bored out hole and the lathe spindle. I will then remove the clamps and work on the outside of the cylinder.

We will see how it goes.

 

[mzetati]

Vince,
ain't the one to give suggestions You could follow blindfolded, but I would have machined the base and bore on the same setup. Then the external & top surfaces on a mandrel.

Marcello

 

[vcutajar]

Benvenuto Marcello

Thanks for your comments. I believe I considered that option at one time but for some reason that I can't remember I did not use that setup you suggested. I think it must have been something with the shape of the casting. For sure I needed to face of the top first and then remove the excess material from the bottom.

Well this evening I fitted the faceplate to the lathe. It has been a long time since I used it last so I checked the middle part of the faceplate (where the casting will be sitting) for trueness (photo 1). Plus/minus 0.005mm. Good enough for me.

I then held the casting to the faceplate using a 14mm threaded rod through the lathe spindle and using a DTI on the bottom round section of the casting (photo 2), centered it as much as I could considering it is still a rough casting. With the casting centered I then clamped it to the faceplate and removed the threaded rod.

I then started the boring operation (photo 3). I brought it close to dimension but will finish it off tomorrow.

 

[vcutajar]

This morning finished the boring operation and then used a threaded rod through the lathe spindle and cylinder bore and tightened it on a thick aluminium washer (photo 1).

Started work on the outside of the casting. Made the first fin (photo 2).

 

[steamer]

Gotta love a good faceplate job!

I don't see anything wrong with that ....nice one!

Dave

 

[vcutajar]

Hi Dave

I am not really a fan of the faceplate, but sometimes one just can't do without it.

Vince

 

[vcutajar]

Finished lathe work of the cylinder casting.

Photo 1 is showing the clean up of the fins at the specified 10 deg taper. There where some imperfections in the casting which I did not remove because it would have meant making the fins smaller. I will have to just live with it.

All that remains is the clean up of the sides of the base on the mill.

Just could not resist and put the cylinder on the crankcase to see how it looks.

Before I do anything else I need to cleanup the lathe and the mill table.

 

[vcutajar]

Well, I have cleaned up the lathe and the mill. They did not last long ;D. Oiled up the faceplate and stored it.

I was considering doing the hole for the cylinder liner in the crankcase platform but hesitated a little when I realised I needed to mark the centre of a hole in an already existing rough cast hole. Then I remembered somebody else having this dilemma and solving it with a broomstick (http://www.modelenginenews.org/projects/whippet/p1.html).

I did not use the broomstick but used a piece of round brass. Jammed it in the hole and now I have something solid on which to mark the centre. Thankfully I had left marks on the platform of the crankshaft axis and the split between the crankcase halves was the other axis used to mark the centre.

 

[vcutajar]

Nothing done on the Kiwi the last couple of days because of tool binge week ;D ;D.

Yesterday I received the 2 & 3mm keyway broach set and also the coaxial centering gauge. Have been playing with them instead of doing something on the Kiwi. I decided that I am not going to use the mill for broaching the keyway in the cams (drill rod). I would not like to damage the quill. So I got myself another new toy to play with. A 20 ton hydraulic press. Its a bit overkill but it was the smallest I could find.

 

[vcutajar]

Enough playing with the new toys and did some work on the Kiwi.

Located the rotary table under the mill spindle using the coaxial centering gauge ;D. Clamped the crankcase to the rotary table making sure the previously marked centre was in the centre. Milled the pocket in the crankcase and did a trial fit with the cast iron liner (photo 2). Using the same setup cleaned up the slot where the conrod passes in the same pocket.

 

[steamer]

Nice one Vince. Your well on your way there. Looks great!

Dave