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Valve Seat Cutters
#11
All covered in some detail very recently. Restraint necessary as once metal gone it is gone. Serious grinding with a valve to be used should be avoided but much can be done with an old valve. And not being in a hollow as ohv seats can be narrowed with fine file, scraper etc.
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#12
Dave, 
my method is a little more scientific, I had a refaced valve diamond plated. 
A few rotations By HAND with a little paraffin and job done. Then grind in valves in the normal manner.
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#13
Reckless, I could have used my dad's old valve hand grinding brace but that's too unsophisticated. Robert hmmmm thoughts about that diamond ring of my missis's.... no perhaps not....!
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#14
Hi Renaud, i just sent you a PM.
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#15
I’m impressed with your resourcefulnesso
Buy an Austin 7 they said, It's easy to work on they said !
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#16
(15-12-2020, 08:01 PM)Robert Foreman Wrote: Dave, 
my method is a little more scientific, I had a refaced valve diamond plated. 
A few rotations By HAND with a little paraffin and job done. Then grind in valves in the normal manner.

That sounds interesting.  I have heard of liquid diamond paste but not plating.

 Where would one find such a service please?
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#17
(15-12-2020, 08:01 PM)Robert Foreman Wrote: Dave, 
my method is a little more scientific, I had a refaced valve diamond plated. 
A few rotations By HAND with a little paraffin and job done. Then grind in valves in the normal manner.
Same with the little Neway:

[Image: dsc_2024.jpg]

which is tungsten carbide.
Some manual turns only are enough. Very good finish and then I also use some paste grinding.
One has to machine the "pilote" which centers the 3/8" mill in the valve guide.

[Image: dsc_1420.jpg]

As can be seen this 30 mm mill can be extended for larger valves.
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#18
I have the Neway ones, they are excellent but not cheap. Neway do the mandrels as well to guide the cutter.
Essential that the valve guides are unworn for best results
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#19
Hello Ray, 
the plating process is the same for needle files you can buy. 
   Unfortunately the company I used was about twenty years ago and I'm not sure if they are still trading.
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#20
My offer about the Neway has got interest from another member here. I'll lend it to him but as I have no mandrel for A7 I will machine one. Mandrel is 3/8" and guide 9/32" (7.144mm)
Hence I would like to know the dimensional tolerances of the valve guides. Maybe also of the valve stem?
And confirmation that the cut angle is really 90 degrees?
Thanks
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