Triple Orphans

[Jo]

Time for the second plate. This time I am not constrained by someone else's unique features but can make the most of the casting. So first line up on the bosses to find a potential centre line. Then check against the outside of the bearing supports.

Then measure the distance from the centre of the datum boss centre line to the outside of each of the bearing supports. As you can see the same bearing support is a bit thin on the original casting as was very tight on lucky's soleplate  So choosing the least worse point for the centre of each bearing the datum is decided on.

I think we are ready to go again 

Jo

[Jo]

I keep looking at the drawings of this engine and trying to understand why people keep telling me that the triple is a difficult engine to build. These comments are beginning to trouble me in case I have missed something   


I am assuming that the challenge is getting three cylinders timed and all the bits the right length to fit together: so why should it be any more difficult than making a three cylinder IC engine 

Jo

[Jo]

The initial aim for machining the top surface is to get below the skin but to leave as much of the casting as possible. Yes that means that I will have to use my fag paper again later to set the height of the cutter before I mill the bearing slots and thinking about it, it is probably better to make the bearing slots the same size on both engines i.e. the 15.3, so that I only need one jig for boring the bearings.

Having measured the depth of the slots in the bearing supports they were found to be 12.7mm below the top surface which is the finished depth. I want to keep as much of the casting as possible so initially I tried a cut of 0.5mm and found that three of the pads were still down and there was a mark on one of the pads  Having dropped the cutter another 0.4mm it skimmed them all but also one of the mounting screws 

The main mounting holes have been drilled and I have taken the centre slot to depth I just have to make that final decision if I should cut it at the correct measurement of 14.3mm or at the same as the other engine 15.3 so that I can use the same jig 

I also need to think about the mounting for the air pump. It has a 19.05mm hole with a tapered bottom. Luckily in amongst my hoardings of second hand milling cutters I found what looks to be the ideal cutter  Now I just need to decide if I can get away with using it as a big drill or if I should bore it first to the 9.53 depth  After that I will worry about the feed pump.

Jo

[Jasonb]

Well the guy that started it before you obviously found it difficult , its all realative to what experiance and equipment the builder has. If they have only made a 10V before and don't have a mill then its going to be more difficult than for somebody who has made lots of working models and has a suitably equiped workshop.

The crankshaft is the other part that would likely cause some people problems as it needs to be nice and straigh and freely rotating.

[Jo]

Yes the two crankshafts done using different techniques will be interesting machining jobs and in my experience a crankshaft  doesn't have to have three throws for it to end up a funny shape 

I'm still worried there might be something I have missed 

Jo

[Jo]

I am feeling cheated  I was looking forward to a nice lumpy forging to make one of the crankshafts out of. What I have found is a length of smooth 11.1mm bar with centres already in the ends with three bits of bar pinned and what looks like silver soldered into position 

I wonder, having been heated, if it will run true if I put it between centres 

Jo

[Stuart]

keep at it Jo

them cranks look lumpy to me though

when i made mine it was the valve gear that caused me problems , but with the modern cad software to model it it would have been easy to sort

Stuart

[Jasonb]

Does not have to run really true as they have left the main bar well oversize so there will be plenty there to allow for any movement that may have taken place. Main thing to check is how well the ctr holes have been drilled

Have you overlooked the painting, that may be difficult

What are you going to do about lagging? maybe one with wood and one with sheet metal would be a good way to do them.

[Jo]

Thanks for the heads up Stuart. Are the drawings wrong? Or are they just a pain to machine. Please tell me they are not as bad as some of the Anthony Mount castings from you know who 

Jason the centre holes are ok  A couple of bars ends slid over the ends to provide the centres should do but by the time they slide all the way up to those webs you will nearly need as much bar as you would need to make the crank from scratch 

Painting  Lets not worry about the lagging just yet 

Jo

[Stuart]

Jo

mine was a Reeves set

it was just impossible to get the gear to fit

but on the whole not as bad as AM

but now i model all valve gear up its quicker

Stuart

[Jo]

Numero uno's sole plate proved to be a lot thicker on the webs than lucky as you can see on the bearing supports widths before and after machining. In the end I decided to leave the bearings at the 14.3mm width and adjust the tooling accordingly for the bearings when I make them.

There is only one unique feature on Numero uno's soleplate, I will let you see if you can spot it  .

It is already time to start on the fasteners, maybe a bit of engineer's lubricant is needed to help

Jo

[Jasonb]

There is only one unique feature on Numero uno's soleplate, I will let you see if you can spot it

I suppose it depends on if the water pump holes have been drilled in the wrong place or if the pump base is cast out of position on the lower casting with red marks.

Looking at the column holes and bearing second from the right it seems that the casting may be a bit off and that the holes have been drilled to drawing to place the pump inline with the middle cylinder in which case the base casting will want adjusting by removing material from one side and building up on the other.

If its a case of the main hole and the three fixings being drilled out of place then they will want filling and redrilling which would ideally have been done at the same time as the other holes to save having to set up teh casting again.

EDIT or is there a hole in the bottom of the air pump, can't quite make it out from the photo

[Jo]

EDIT or is there a hole in the bottom of the air pump, can't quite make it out from the photo

Caught  It has been plugged and JB Welded.


Lucky's original crank bearings are now too small so I need 8 new bearing sets. In Numero Uno's I have eight halves and this bit of locomotive axle box casting has volunteered to be the other set (and one for the Workshop Gnome  )

Lots of machining one side, hacksawing, more milling and finally soft soldering the halves together I have 9 possible bearing sets. They will be much smaller when they are finished.

Work finished early tonight as I had to prepare my portable 3 ph power supply for a day out tomorrow 

Jo

[Jasonb]

I keep looking at the drawings of this engine and trying to understand why people keep telling me that the triple is a difficult engine to build. These comments are beginning to trouble me in case I have missed something   

Maybe that difficult bit is avoiding drilling through the bottom of the casting

[Jo]

  Its getting  so repetitive  9 bearing blocks carefully taken down to size.

First squaring everything up and marking the sizes, black once to size, red as oversized surfaces. Held in the vice jaws using a post-it to prevent the soft as Swiss cheese piece of gunmetal being marked and only tapped down on the parallels using a good ground surface between the work and the Thor mallet 

Finally nine blocks ready for the next bit of machining, again carefully marked up to avoid machining the wrong surface 

Jo