Posted by concerned *but speculating* on August 27, 2000 at 21:56:34:
In Reply to: Re: Re: Venting Piston Valves posted by Rick Denney on August 27, 2000 at 17:39:49:
Hi Rick
I'm NOT certain about the plating thing, it may depend mostly on how well the nickel is bonded on. When valves are honed and plated in copper first (for dimension) and then honed again to prep for the nickel, there is normally a nice crosshatched grain from the stones, which gives the nickel good "tooth" the grain is very fine, and fills in smooth when a thou or so of nickel goes on. Knowing that it is so thin, though, makes me wary of breaking it open. I remember a discussion about the plating coming off of mouthpieces when they were dented. (It was an argument involving nickel or chrome plating, where the plated layer is a hard, brittle case over the softer brass base metal, and wouldn't adhere if it was damaged. Silver is soft, and would form with the damage more readily, and not flake off.) We have all seen worn valves with peeling plating, I think, and I was extending this argument to include a situation like this. I confess that I have only vented unplated pistons and will defer to a more experienced authority on plated valves.
I beleive a wood block set-up to be sufficient
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two Vee shapes will hold securely. I used this in a regular drillpress vise, bolted to the table. (My 'drillpress' is actually a small vertical mill.)another hint I had good luck with a Centerdrill type tool. It doesn't have as much helix in its flutes and wont grab the workpiece as it breaks through the wall, it will not flex and wander off its location, and will Chamfer the hole fairly well on its own, making your deburring simpler!
Will a plating expert please add their comments??