Tony, Like you, I dread drilling stainless. Not only does it squeal like a pig, it IS a pig! My understanding is that SS work hardens when cut (drilling, milling or turning) unless you have one of the non-work hardening grades. I am not sure which these are. The only way I feel at all confident with drilling SS is to use a new drill (even buy a couple if I have more than a few holes). For preference, go for short-series drill which are much stiffer than the standard jobber length. I also actually calculate the best drill speed, and use large amounts of one of the modern sulfonated cutting oils.
I have found that new short drills make all the difference, and are a small price to pay for the grief that they save. The sulfonated oils are magic! Also magic for tapping SS, or any other form of steel for that matter. Cheers, John [EMAIL PROTECTED] ----- Original Message ----- From: <[EMAIL PROTECTED]> To: "Sundial Mail List" <sundial@rrz.uni-koeln.de> Sent: Wednesday, July 02, 2003 8:34 AM Subject: Drilling/threading stainless steel. > Fellow Shadow Watchers, > For two current dialling projects I have some 150 > 5mm holes to drill then 'tap' (thread) to M6 in stainless steel and I've > not been looking forward to the task with any great enthusiasm! Recent > experience clearly shows that S316 SS does NOT like being drilled. It > sqeals like 'a pig killing' unless the feed rate is just right and that > in itself is heavy enough to give concern for drill breakage. > > Imagine my delight when threading these same drilled holes to find that > the S316 behaves like the mildest free-cutting mild steel and threading > is completed easily. > > Why does it resist drilling so markedly yet allow threading with no > trouble at all? As my recent query re. etching SS was so well covered > I'd be interested in any specialist response which explains this. > > Best wishes > > Tony Moss > - -
