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My first steam engine
- Thread starter savarin
- Start date
- Joined
- Aug 22, 2012
- Messages
- 4,273
Heres the cylinder, the holes all around the middle are exhaust ports.
I turned the piston on the con rod in the hope that kept it concentric with the bore.
I have no idea what I'm going to use for piston rings yet.
The width and depth of the piston ring recesses are exactly the same measurement but dont look it in the image but I expect I will have to cut them deeper when I make the decision.
Shouldnt cause a problem as I used the collet chuck on the con rod.
I have no idea if this will work as I hope it will but wheres the fun in knowing all the answers.
It should run as two two stroke cycles per revolution.
I've relieved the middle of the piston so its at ambient throughout the majority of its movement.
I turned the piston on the con rod in the hope that kept it concentric with the bore.
I have no idea what I'm going to use for piston rings yet.
The width and depth of the piston ring recesses are exactly the same measurement but dont look it in the image but I expect I will have to cut them deeper when I make the decision.
Shouldnt cause a problem as I used the collet chuck on the con rod.
I have no idea if this will work as I hope it will but wheres the fun in knowing all the answers.
It should run as two two stroke cycles per revolution.
I've relieved the middle of the piston so its at ambient throughout the majority of its movement.
- Joined
- Aug 22, 2012
- Messages
- 4,273
I have been very busy of late attempting to downsize the house and two workshops into one small house and 1 workshop in 34'C temps.
As swmbo went out for a ladies lunch I managed to squeeze in some shed time, I thought that was fair.
Set up the vertical slide to cut the slot in the cross-head guide.
I started by using a 12mm cutter but it really didn't want to go so I drilled a 12mm hole then used an 8mm milling cutter to make the length of slot followed by 12mm then 14mm.
I thought it came out mildly ok.
Then I flipped it over to do the same thing on the other side.
All was going well untill I noticed the time so did what we all know is fatal, I started trying to hurry.
Bad move, the vibration of the cutting had (un-noticed) by me tilted the vertical slide
and made a curve in the cut as shown by the red marks.
I will attempt to remove it with a 16mm cutter and hope for the best.
I'm actually surprised that no offensive language ensued, I must be growing up.
As swmbo went out for a ladies lunch I managed to squeeze in some shed time, I thought that was fair.
Set up the vertical slide to cut the slot in the cross-head guide.
I started by using a 12mm cutter but it really didn't want to go so I drilled a 12mm hole then used an 8mm milling cutter to make the length of slot followed by 12mm then 14mm.
I thought it came out mildly ok.
Then I flipped it over to do the same thing on the other side.
All was going well untill I noticed the time so did what we all know is fatal, I started trying to hurry.
Bad move, the vibration of the cutting had (un-noticed) by me tilted the vertical slide
and made a curve in the cut as shown by the red marks.
I will attempt to remove it with a 16mm cutter and hope for the best.
I'm actually surprised that no offensive language ensued, I must be growing up.
- Joined
- Aug 22, 2012
- Messages
- 4,273
At last I scrounged a bit of shed time and removed the curly wirly slot, didnt have a 16mm end mill so used an 18 mm.
That did the job.
As a design feature (lazy) I have decided not to open out the opposite side ( you never know I might need more access that side )
Also indexed and marked the cylinder head for the fixing bolts.
I used a prick punch in the tool holder and slid the saddle to make the mark then transferred the plate to the bench to go over the small marks with the centre punch.
In my usual manner of going a tad over the top with fixings it will be 12 x M3 bolts.
That did the job.
As a design feature (lazy) I have decided not to open out the opposite side ( you never know I might need more access that side
)Also indexed and marked the cylinder head for the fixing bolts.
I used a prick punch in the tool holder and slid the saddle to make the mark then transferred the plate to the bench to go over the small marks with the centre punch.
In my usual manner of going a tad over the top with fixings it will be 12 x M3 bolts.
- Joined
- Aug 22, 2012
- Messages
- 4,273
I thought I was being clever and screwed the brass cross head part to the piston rod.
Silly move, from one end to the other on full travel there was a teeny weeny amount of miss alignment so the assembly jammed.
Ok, make a joiner so it can move a little.
Better, it now can slide without jamming but... the cross head bearing/piston now sits at the wrong end of the cylinder
and pokes out at the other end of the stroke
No worries, make 6 of these
and extend the cross head slide tube
Now it sits at one end of the slide
and sits exactly at the other end of the slide on full travel.
It now moves from each end of the stroke without binding anywhere in its travel.
Silly move, from one end to the other on full travel there was a teeny weeny amount of miss alignment so the assembly jammed.
Ok, make a joiner so it can move a little.
Better, it now can slide without jamming but... the cross head bearing/piston now sits at the wrong end of the cylinder
and pokes out at the other end of the stroke
No worries, make 6 of these
and extend the cross head slide tube
Now it sits at one end of the slide
and sits exactly at the other end of the slide on full travel.
It now moves from each end of the stroke without binding anywhere in its travel.
- Joined
- Jun 7, 2013
- Messages
- 10,452
Generally speaking, Uniflow does not work very well unless it exhausts into a condenser, wherein a partial vacuum exists, otherwise there is too much compression during the remainder of the stroke, resulting in choppy running, if indeed it dos run; designing the valve events to keep the exhaust open longer would likely adversely effect the inlet valve opening/closing, unless two eccentrics were used, one for inlet valve events, the other for exhaust events.
- Joined
- Aug 22, 2012
- Messages
- 4,273
I know what you mean about the condenser and the rings around the exhaust holes will be covered to pipe the exhaust to a spray type of system that I've only given passing thought to at this stage.
I never really thought I would have got this far along on what were just exercises to see if I could make something.
I'm not going to control the exhaust events with a valve only the inlets which I am still deciding how.
So far I believe it will be two valve chests silver soldered to the cylinders controlled by one eccentric,
Still heaps to think about, flash boiler or conventional? I'm leaning towards flash steam as being safer.
So much more to think about that I cant because I dont know the questions to consider yet.
Still, who said it has to be a quick project and must work.
I'm learning heaps just playing so far.
I never really thought I would have got this far along on what were just exercises to see if I could make something.
I'm not going to control the exhaust events with a valve only the inlets which I am still deciding how.
So far I believe it will be two valve chests silver soldered to the cylinders controlled by one eccentric,
Still heaps to think about, flash boiler or conventional? I'm leaning towards flash steam as being safer.
So much more to think about that I cant because I dont know the questions to consider yet.
Still, who said it has to be a quick project and must work.
I'm learning heaps just playing so far.