I finished the calculations, now I have the main dimensions of the cylinders, like bore diameter, stroke-, collapsed-, compressed-length. All dimension came from my calculation excel sheet. As I wrote before, the material will be bronze. Currently I’m working on the production set-up, to see how can I produce the components. The tube end items, rod, piston and the oil connectors drawings partly finished. During the planning I thought about the manufacturability, so tried to apply usable dimensions, sealing components… Now I just collect the mile stones.
Cylinder tube :
Tube is a very simple item, like a pipe with some side hole and IT7 (~Ra= 0.4-1.6) inner surface quality.
At this case the most difficult step is the inner surface finishing. I think I can do this component with lathe “easily”. Every cylinder’s bore diameter is 18mm, just the tube length is variable. The longest is the arm cylinder, it has 218mm collapsed length, but the tube full length is just 178mm, so the reamer length is the main question.
End cap:
The end cap will be the fixing / turning point. It is not too difficult, it can be produce on lathe (first) and CNC milling machine (second). This item will be same on every cylinders.
Cylinder head:
This item also same on every cylinders. The cylinder head is a real difficult component…
This item will be on the front of cylinder and this is difficult, because this item has to be drives and seals the rod, so there are many sealing and driver components inside the item. As I planned there will be two seals, one driver ring and one dust removal ring in the front item. The manufacturability of this component is not impossible, but a little bit difficult, because of the small hole and small outer diameter. The most important thing is the accuracy.
- I have to do every slots and diameters through an 8mm dia hole.
- All seals have precision tolerances, so the inner grooves width and deep is very important. If the gap between a groove walls and seal is not enough big, the pressure can’t grows up, and the sealing will be bad. Or the groove diameter is smaller or bigger than the necessary, the sealing system will be too tight or loose.
- I have to work precisely, and I have to use fine and strong turning tools with very thin neck.
In my opinion the best way, if I search a cnc lathe shop… because I need 4 pcs same and precise components.
Rod :
The rod is a standard 8mm dia stainless steel rod with threaded ends. There will be a single lug eye on the end.
Pistone :
The piston is also from bronze and it will be made on lathe. This item is not too difficult, some grooves for seals, a stepped hole in the middle which is partly threaded. Grooves tolerances are same as the tolerances in the cylinder head.
