Is this good enough

[the604tool]

I have a motorcycle i am rebuilding and i would like to grind the valves but I do not have a valve grinder and do not want to pay the premium for a motorcycle valve job.
My idea is to tram the head of my mill for the seat angle, then mount a
valve in the quill, and mount my toolpost grinder on the table to grind the valve face.
The valve stems are 5mm and I can get a 5mm R-8 collet cheap,
though I am concerned this method is not accurate enough.

I have not worked out the DYI method for the seats yet other than to acquire the proper stones and inside collet to fit the guides.
Any ideas appreciated.
Scott.

[ViperTX]

Personally I would use the lathe to grind the valve face seat, but you could chuck them up on your mill.....unless the seats can't be machined by carbide...I would use an angle plate....mount the carbide tool at the proper angle and use the table to feed the carbide tool to the valve face.

Are the seats hardened steel? Usually a variable speed drill with a holder to steady the drill will work .....you have to watch that your collet doesn't pick up too much grit and abrade the guides...

Oh, forgot....Welcome!

[bob1371]

Whatever method you use, be sure to lap the valves in. The lapping tool and compound are cheap and it will ensure a good seal.

Bob

[the604tool]

The valves are stainless The seats are hardened steel!
I have only used a seat grinder once, long ago, it used stones not carbide and the inside collet would expand to grip and center itself in the guide, and did not rotate with the stone so no guide damage could occur.
I was in a cilinderhead shop recently and saw the carbide type cutters hanging on the wall and recognized what they were.

Quote
Usually a variable speed drill with a holder to steady the drill will work

What kind of holder are you thinking of?
The carbide cutter is turned much more slowly than a stone would be I'm sure! Thats why the VS drill?
Although I have never used them.

I felt that the mill spindle probably had less runout than the lathe, for facing the valves.
I am not a beginner in the shop, Nor am I an expert, but I have not been able to get a great finish turning hard steel in my lathe, Except to grind it.
My other concern is the flex in the valve stem when using carbide cutters. The grinder applies almost no pressure to the valve when cutting.
Thanks for the welcome,
Scott.

[the604tool]

I did do a lap on the worn used valves, and it left a depression in the valve face all the way around.
Id likt to start with fresh cut surfaces then lap.
Scott