Making Poppet Valves Backwards

[fltenwheeler]

Hi All

I am finely back working on the Bob Shore Eagle. And the time has come to make the valve. After looking on line I decided to make them backwards from the way that I seen most of them done.

First I faced the end and centered drilled with a #0 center drill.

Using a grooving tool I removed most of the diameter for the stem.

Head and shank machined to size.

Grove for the keeper and cutoff length.

Head faced.

Finished Valve.

I found that it was very easy to make valves this way.

Tim

 

[AussieJimG]

I tried that Tim and, of course, it works. But I really wanted to check the stem size against the valve guide to get a good seal and I could not do it using this technique.

Jim

 

[fltenwheeler]

Hi Jim

I was worried about that as well. I had drill blanks of the correct size and compared the stem of the valve to the drill rod with a micrometer. Even at that I had to polish the stems just a little once I parted them off to get a smooth fit.

Tim

I tried that Tim and, of course, it works. But I really wanted to check the stem size against the valve guide to get a good seal and I could not do it using this technique.

Jim

 

[Brian Rupnow]

That is an interesting way of making valves. However, for many of us with larger lathes, the saddle is too wide to get a short piece held in the chuck and get the tailstock that close to the chuck. The saddle is simply too wide to allow that.

 

[ICEpeter]

Tim,
I do like your approach making the valves the way you described. It is the solution I was looking for. It is so simple that I kicked myself for not thinking of it the way you did. It will work perfect for making valves on the lathe I use (Myford S7)

The size of the valve stems is a concern since you can not use the valve guides to check the fit while you turn the valves before parting the valves off. When turning the valve stem, I intend to leave them about 0.01 MM oversize for finish honing them to size. I intend to make a receptacle to be held in the lathe chuck that is fitting the valve head and use an inverted tailstock center to hold the valve stem while using an external hone to size the valve stem to closely fit the valve guides.

To determine the valve guide bore dia. for turning the valve stem dia. correctly and close to size,I use a pin gauge to get the dia. close enough for final lapping

Thanks for your suggestion and method. It was greatly appreciated.

Peter

 

[fltenwheeler]

That is an interesting way of making valves. However, for many of us with larger lathes, the saddle is too wide to get a short piece held in the chuck and get the tailstock that close to the chuck. The saddle is simply too wide to allow that.

I have an old Jet 1024. It has to be set up just right. The tail stock is extended almost all of the way.

I am using a Multifix tool post that make the job a lot easier to position the tools. This is the first IC engine and I was dreading making the valves. But I found it very easy doing it this way.

Tim