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1954 Ford 850 Tractor w/blown Head Gasket (at the very least)

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awemawson:
Steve,

Personally I would avoid heating and bending. As time passes it will probably relax back and give disappointing results.

I can see the logic in a VERY slight out of tram, so the fly cutter isn't cutting on the heel, but I don't think it's a good idea in this case. You'll get crossed over cuts in the majority of the face but not at the extreme but the difference in material removed will be insignificant in this application.

I'd set the head to be symmetrical on the bed so the 'under travel is the same at both ends, mark up your highest spot using a gauge, fit the fly cutter and bring it over the high spot having wetted down a scrap of cigarette paper of known thickness there. Adjust to wipe the paper off and zero your Z DRO, move the cutter so it is off the edge, apply a few thou down feed and start cutting. Repeat until you've removed the least possible material to clean up your 'low spot'. The ends will not have the crossed cuts - if you really need to they can be cleaned up with emery cloth on a plate glass surface but that is probably gilding the lilly.

Before all this if I were you I'd have a practice run on any old bit of suitably sized scrap.

vtsteam:
That method of starting the cut makes sense to me, Andrew.  :thumbup:

I don't have a DRO, but that's not a problem.

And no glass table, but I do have an old cast iron surface plate I won in an auction. Never have used it.

This morning I stopped down at Lester's machine shop (the old timey one with all the overhead belt drives and giant iron machines) and after we talked a bit about what I wanted to do, he sold me a 1" thick by 7-1/2" diameter steel drop for $10.

I think I'll put a 7/8" arbor in it, turn it down a little, and cut a notch for one of my carbide inserts to make a 7" single point fly cutter. Hope my mill drill will handle something that big. I need 6-1/2 inches to clear the head edges in one pass

I'll definitely try first on scrap.

Thanks for the help!  :beer:

vtsteam:
I'm having second thoughts about the big chunk of steel for a fly cutter. I just seems to big and heavy to use in my mill/drill.

Gut feel: 3 inches dia, or so, would be the maximum I ought to be using, even with a single point tool.

The head surface is 6-3/8" across, so that would mean at least two passes to cover.

I know it's better to do it in one pass with a big cutter, but if I do the sandpaper on surface plate cleanup afterwards, will it be a problem that it was cut in two passes instead of one?

I could make a 3+ inch fly cutter with the inserts I have.

Or I could use a classic style fly cutter I already have -- the type that take a 1/2" HSS lathe tool blank.

The tool can protrude maybe only a 1/2" to make the 3+ inch pass width. The cutter is 3" dia, pretty solid and has  A 3/4" shank. That would be easiest.

Thoughts?

vtsteam:
This was a good source of fly cutter info for me in the past:

http://www.cnccookbook.com/CCFlyCutter.html

I see he has an updated mention of cutter profile here:

http://blog.cnccookbook.com/2013/01/29/using-a-fly-cutter-to-increase-your-travels/

and even mentions cutting beyond machine travel.

I wish there was abetter description here of the cutter shape. Not quite clear on how it was ground.

mattinker:
Steve,

I would be inclined to follow your advice from your old time machine shop. The cuts that your going to make are going to be very light to take out 12thou. Your well balanced large diameter fly cutter would have plenty of inertia to cut and you would eliminate any risk of out of flat due to making two cuts. The shape of the tool is like a lathe tool if it's at right angles to the work piece.

My thoughts, regards, Matthew

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