valve seat alpping

[nazrolf]

I have designed and built a pneumatic valve (current quantity four) with a G2 cast iron body and spool ma66de of S67(Rc 50) with a lapped 45* seat and a land width of .125". It is used to control a circuit handling 250 psi for a valve gated hot runner. I have built a fixture to grind the seats concentric with the spool and have lapped the seats by hand but it is somewhat time consuming.If this design proves durable (prototype ran over two million cycles) the company I work for may wish to manufacturer a fair quantity of them.

How do engine manufacturers lap seats on a production basis?

 

[passerby]

Automotive companies do not lap valves they use precision machined valves and seats. Sometimes they use a slightly shallower valve angle 44 1/2 against a 45 degree seat which assures a line contact and tight seal. A engine operating temperaures this will pound in until the seats are parallel at 45 degrees. Be careful the direction that you measure the angle. The line contact must be at the outside edge towards the pressure side.