Hi @Danuzzo
I used the steel grades I had on hand for the cylinder
Piston: aluminum 6061, 7075, brass, cast iron
If I use cast iron rings, I don't worry too much about the inner diameter of the cylinder, if I use O-rings, I have to bring the inner diameter of the cylinder to the outer size of the O-ring
If I don't use rings, I just need to make the piston smaller than the cylinder diameter by about 0.03 or 0.04 mm
2. and 3. : Simple way: make a piston and test compression, if compression is good - suction is good then you don't need to worry about the cylinder
This will give you more confidence ..
the young guy did this engine and it runs well !
I used the steel grades I had on hand for the cylinder
Piston: aluminum 6061, 7075, brass, cast iron
If I use cast iron rings, I don't worry too much about the inner diameter of the cylinder, if I use O-rings, I have to bring the inner diameter of the cylinder to the outer size of the O-ring
If I don't use rings, I just need to make the piston smaller than the cylinder diameter by about 0.03 or 0.04 mm
--lapping/honing the cylinder bore : No difference , depends on cylinder diameter and tool selectionAlso, many questions on lapping/honing the cylinder bore. 1. What is the difference between the lapping and honing?
2. Is the purpose to make the bore very smooth? My bore came out smooth with the lathe, at least to the naked eye and feel.
3. Is it necessary to hone or lap if rings are used, or is it dependent on the material of the piston?
2. and 3. : Simple way: make a piston and test compression, if compression is good - suction is good then you don't need to worry about the cylinder
This will give you more confidence ..
the young guy did this engine and it runs well !
![4.jpeg 4.jpeg](https://cdn.imagearchive.com/homemodelenginemachinist/data/attach/114/114011-4.jpeg)
![6.jpeg 6.jpeg](https://cdn.imagearchive.com/homemodelenginemachinist/data/attach/114/114012-6.jpeg)
![8.jpeg 8.jpeg](https://cdn.imagearchive.com/homemodelenginemachinist/data/attach/114/114013-8.jpeg)
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