Drilling stainless steel

[delmarrey]

One thing you do have to be careful with is that Cobalt is brittle. So when the drill is breaking thru the other side back off on the pressure so it doesn't try to grab and snap off the tips. And hand drilling is the worst for doing that.

Personally, I would use a machine wax or stick wax like for saw blades. Oil is going to stay in the core. Wax eventually evaporates. The stuff I use looks like a bar of soap and feels like a combo between wax and soap..............._/)

You could even use bar soap for that matter. Actually the stuff is made by Acculube Accu-Lube Manufacturing GmbH

[noelex 77]

I will get hold of a 5/16" cobalt bit, or maybe 2, just to be safe. Incidentally, my local Bunnings sells cobalt bits in Imperial sizes but not metric; how wierd is that?


Both Bunnings and home hardware in Melbourne had cobalt bits in imperial and metric but Bunnings had a better range in imperial and home hardware a better range in metric.
Not sure if you have both stores where you are but Home hardware may be worth a try.

Cheers John
see my blog at “Amzer Zo” Yacht Blog

[Alan Wheeler]

A word of caution. Like most metals, the harder they become, the more brittle they become. Cobalt bits of only 5/16' will snap like a twig if you allow it to crab and twist. So it is essential the drill is well held. A support stand for the drill is even better if you can get. They can be got reasonably cheaply and it could be well worth it if you have many holes to drill. For a small handful of holes, it won't be worth it.

[Trim50]

Colbalt...no other.

[Boracay]

Blackwoods: Industrial Supply, Tools, Safety Equipment, Abrasives, Clothing and more are in Victoria. I don't know about near you.

Prices maybe a little better than Bunnings, even though they are both owned by Westfarmers.

For the more serious engineering stuff they are very good.

They will order most stuff that they don't have.

[delmarrey]

So, how many holes did you have to drill?

[Weyalan]

I am pleased to report that the drilling went well and was 100% successful. I only had to drill 6 holes altogether and 2 of those were only enlarging existing holes. I didn't break any of the drill bits and I think that the cutting oil stopped the drill from getting too hot. There was generally nice long trains of swarf coming out of the hole, so all in all it was a satisfying process. Actually, the hardest job was enlarging the existing holes. I was probably only drilling out by 1mm (7mm to 5/16") so the drill had a tendency to "bite".

So now the new 6-sheave deck organisers (Garhauer stainless steel with aluminium sheaves) are all installed and looking very pretty. Thanks again for all your assistance, folks