# Determining the minimal needed wall thickness between two bores in a control block

Given a control block of simplicity with only two bores. These two bores could be parallel or just could be very close to each other at a specific point in the control block.

The material of the control block is cast iron GJS 400:

• Tensile strength $$400 \, N/mm^2$$
• 0,2% proof stress $$250 \, N/mm^2$$
• Fatigue strength $$225 \, N/mm^2$$
• Elongation at break $$15 \, \%$$

The diameters of the two bores could be the same but also could be different. The pressure in bore 1 is 350 bar and in bore 2 280 bar.

My question is how to calculate the minimal needed wall thickness between the two bores.

Sadly I haven’t found anything proper – only a calculation regulation of pipes…

Or is there a possibility to transfer these pipe results to my bores within the control block?

Any suggestions appreciated and many thanks in advance!