Machining Valve Stems

[Richard Fryer]

You're welcome! If you're not familiar with George Luhr's astonishing craftsmanship, here is a link to his fully functional,1/8-inch bore, overhead-valve petrol engine:

George Luhrs - The Miniature Engineering Craftsmanship Museum

Builder of the world’s smallest running internal combustion engines. Winner of the Joe Martin Foundation Craftsman of the Year Award for 2001.

craftsmanshipmuseum.com

Does anyone know more details about this 1/8" bore four stroke?
Things like his spark plug design and any drawings etc?

 

[Mike Ginn]

Thanks for that . I have followed Joe for some time but haven't seen this clip before. Unfortunately the tool doesn't seem to be available and I can't identify the insert/supplier. It does show what can be done but I guess there is still the issue of surface finish and final size for fitting into a reamed hole.

 

[Shopgeezer]

Crazy way to make drill rod.

 

[Mike Ginn]

I had never heard of George Luhrs. His engines are amassing - truly amassing. Has anyone seen or have any drawings - just a small part - so we can all admire the dimensions he worked to.

 

[Longboy]

Does anyone know more details about this 1/8" bore four stroke?
Things like his spark plug design and any drawings etc?

Google his name for some insight. George went in the other direction for the same recognitions. Where even in the modeling world, larger and more cylinders is the hierarchy.

 

[DKGrimm]

There is a method where one can do it in one cut, allbeit with the correct tool.

I've made 1/8" stem valves this way, and it does work. I found it to be kind of a pain to get the surface finish on the stem that I wanted, though. I use the drill-rod-silver-soldered-to-SS-head method that John Vietti and others have described. Either way works but the latter is less work, for me at least.

 

[Mike Ginn]

DK. I will use the simple method of fabrication and if it doesn't work (distortion?) I'll do it again. I tried to do the deep cut and it needs good rigidity and the correct tool. I don't have a suitable insert and I can't use the type of holder Joe uses on my Myford (easily).

 

[Nerd1000]

Here's another trick that might sometimes be helpful



If you turn a small length to size, then one of these cup centres can be used to support the rest of the turning on the stem.

 

[jschoenly]

Being the current caretaker of George Luhrs collection and many tools, it was a wonderful thing to see and talk about his methods. For valves he was serious about them being good as machined or they were junk. For thin stems he taught me about a tool set flat to the face and machining the final stem diameter in ONE pass. This allows the full diameter of the material to be the support for the cut - no center or other devise. It's tricking getting this to cut right sometimes but it certainly works!

This reminds me I need to get in the shop more and exercise teachings from others so you don't forget.

Jared Schoenly

 

[Chiptosser]

Being the current caretaker of George Luhrs collection and many tools, it was a wonderful thing to see and talk about his methods. For valves he was serious about them being good as machined or they were junk. For thin stems he taught me about a tool set flat to the face and machining the final stem diameter in ONE pass. This allows the full diameter of the material to be the support for the cut - no center or other devise. It's tricking getting this to cut right sometimes but it certainly works!

This reminds me I need to get in the shop more and exercise teachings from others so you don't forget.

Jared Schoenly

I was always amazed at what George would build. I would look for George each year at NAMES, to see what was new or in progress. Always amazing work. Very friendly and willing to run his engines for me. I felt very privileged to be able to talk to him and see the efforts of his skills, still inspires me!

 

[jschoenly]

The spark plugs for the 1/8" bore engines are 0-80 thread with a surface gap. George made all these. I will try to snap a picture of the various plugs he made for his array of engines.

 

[stanstocker]

Being the current caretaker of George Luhrs collection and many tools, it was a wonderful thing to see and talk about his methods. For valves he was serious about them being good as machined or they were junk. For thin stems he taught me about a tool set flat to the face and machining the final stem diameter in ONE pass. This allows the full diameter of the material to be the support for the cut - no center or other devise. It's tricking getting this to cut right sometimes but it certainly works!

This reminds me I need to get in the shop more and exercise teachings from others so you don't forget.

Jared Schoenly

Hi Jared,

Darn glad someone reputable like you has Georges collection, he was a true gentleman every time I spoke with him at Cabin Fever over the years.

Quite a few years ago, there were seminars / talks at Cabin Fever, something that has gone by the by. Any chance you might do a youtube post or give a talk on some of the more interesting aspects of George Luhrs work and tools or methods? Or occasionally post some of that sort of info here maybe?

I know, you folks tend to stay busy year round, just a thought.

Stay well, keep laughing, see you next year at the show!
Stan

 

[Richard Fryer]

The spark plugs for the 1/8" bore engines are 0-80 thread with a surface gap. George made all these. I will try to snap a picture of the various plugs he made for his array of engines.

That would be great!

 

[cheepo45]

I remember George showing me this engine at the Cabin Fever Show years ago.
The only way that you could tell it was running was by a small quiver on the rocker arms!
What a craftsman!
Scott

 

[jschoenly]

Great Idea!! I do stay way too busy all year but someone should bug me. There are some awesome process jigs and tooling in the small vertical "briggs like" engine he produced. I also have a bunch of these unfinished that I talk about finihsing once in a while. I would like to make some time to call out some cool points of interest in his models!

Jared