High Pressure Steam Table Engine

[Jo]

Note for Ray

I've just started roughing out the connecting rods and thought I better check that original reported error that the connecting rod as draw was too long....

Having measured the model and checked on all the dimensions, if the connecting rod is left at the 33.34mm ( 1 5/16") there is going to be 2mm of gap under the bottom of my table for the connecting rod yoke. So it should not hit as drawn The report that it is going to hit the main bearing at the bottom is also suspect: There should be 17mm between the bottom of the yoke and the centre line of the crankshaft so the cap of the main bearing plus its oiler needs to be a maximum of 16mm.

And as I am about to make the long connecting rods I thought I better check their lengths as well. Initially I thought the mid point was a bit high but the cylinder stuffing gland overlaps the bottom of the slot in the guide. The calculated mid point is mid way between the top of the stuffing box and the end of the slots 


What was I doing  Oh yes turning a long square bar round without a fixed steady 

Jo

[Jasonb]

The reported problem may well depend on which drawings are used as the bearing height differs between the two

[Jo]

Its only 1.6mm difference so would just squeeze under. The original person who reported the error was reporting over 6mm of interference.

My columns are still 2mm over height in case other "features" come to light 

Jo

[Jo]

I mentioned turning a piece of square round  This is it:



Its for the two long side connecting rods. Having got sufficient down to 8mm (by turning a bit, pulling another bit out, turning that bit down, the next job was to mark the length of the centre barrel section, its half and its quarters:



Pieces where held about 25mm short of the centre section and it was turned to 7.9mm - on both rods. Then the rods were moved out so that the quarter lines were at the collet, the top slide moved over so that it cut 0.4mm radi over 25mm and that cut:



That was blended into the centre section with a file. Then the other 3 ends done at the same top slide setting. Then time for the next 1/8 of the length with the top slide set to take off 0.5mm and finally a "nit more and take it down to 4.76mm blending the tapers each time:



It is easier to see the taper with the two rods together:



The problem with blending the tapers with a hand file is it causes marks which then have to be removed during polishing:



Yes I am polishing it now while there is plenty on the ends to get hold of  But there is more to do and I don't want to rush it so I will return to it tomorrow afternoon  Not forgetting that I have to use the emery in two directions at 90 degrees to each other not just the easy one of rolling over to get a polished smooth surface.

Jo

[Jo]

  I don't seem to have remembered to write up last month's stuff. Oh well no one noticed so I'll sneak the next bit in 

The crankshaft is supported by two split bearings held in place by two blocks. The casting blocks supplied are not anything like what was on the original etching so I have made some alternative castings:



Each of the new castings have been made long enough so that they can be parted off to provide both the bottom and the cap:



And as you can see the holes that were used to keep the two bars parallel while silver soldering were drilled in just the right place so that they can now be used for the two mounting studs. They can also be used with two countersunk screws through them for the boring bit. First they need to be slotted together:



These are a nice friction together and once together they can now be set up for making the hole:



However not today  because I have to get on and finish the Vincent otherwise it will never get done 

Jo

[Admiral_dk]

I don't seem to have remembered to write up last month's stuff. Oh well no one noticed so I'll sneak the next bit in 

Not quite so - but I have no right to demand it from You + you could have other priorities that has taken over, for one reason or another ....

Per

[Jo]

Pleased you are still following along Per  .. between you and me: I've got the side rods ready to be taken to length, the piston and its rod are done and connected up ... the short connecting rod is done as is the crankshaft turning. I haven't done the crank but it is on the list before I finish off the side rods as I need to check all the lengths then I plan to make the ends of the side rods

Jo

[crueby]

The other day I had realized that I hadn't seen an update in a while, just figured you were out enjoying the summer weather or taking Surus for bike rides. Great to see the progress again!

[Michael S.]

Hello Jo,
the bearings look a lot better. They are very similar to the original motor.
Do the upper parts still have the attachment for the oil cup?

Michael

[Kim]

Or as Jason said - you were likely out harvesting the goods from your garden! That's kinda what I thought.

People have lots going on in their life, so I always want to give them time to do their other hobbies without expecting moment-to-moment updates if they don't want to provide them.  Some people do, and some people don't.

Glad you just didn't get around to posting and it wasn't anything more serious!

Always enjoy seeing your updates!  I learn a lot from how you attack your castings. Thank you for taking the time to post.
Kim

[Jasonb]

Good to see you back on it. Just be carful with this fabrication of castings lark, you may become addicted

[Roger B]

I'm still following in the background and trying to find time for model making, especially when the mountains are calling     

[Jo]

Thank Guys, a few of the other bits I have found under the swarf:



Before I move on to boring the bearing stands I need to make the bearings to go into them. The casting set came complete with a round stick of bronze - not the easiest to make split bearings out of  So I have cut in half then soft soldered the of bits of brass together to form a block. This block was nearly square by adding a couple of slithers of aluminium I could make the block square which means I could hold it in a self centring four jaw chuck:



This allowed me to turn it to 19mm diameter:



Which could subsequently be held in a collet:



To make a perfectly round bar with the split dead on the centre line::



You can see the supplied piece of bronze next to my split brass bar. One last thing before starting the boring and turning activities I need some plug gauges:



There are three of them: one for each of the centres of the bearings and the third is for the outside of the bearings where it goes into the blocks 

Ready to go so back to watching the pageantry on its way to Winsor Castle 

Jo

[scc]

Nice to see this again Jo,     I have haave been quietly looking  and wondered if all is well.   Good to see that it is.         Terry

[Jo]

Welcome back Terry 

The block for the bearings can be held in a collet and bored the smaller 12.7mm diameter and the bore checked using the plug gauge:



Then half way can be bored for the wider diameter:



With the plugs in place as support the outside can be turned to diameter:



One bearing can be turned on each end of the bar:



And having parted them off and faced each if you find that the bore needs correcting then you can still do that in the collet 



A quick heat with the gas torch and they are apart and the fit can be checked on the crankshaft:



Onward 

Jo