Those fat drill bits

[IronPuppet]

What about cutting oil? I notice no one has mentioned cutting oil. Wouldn't this help?

Christopher

[John N]

To be honest ive never used a colbalt drill bit, for that matter ive never seen one used!(and ive worked in heavy engineering for a bit) , we sometimes used to use colbalt or stellite when turning pot hard material, but never used them for drill, course its all C.B.N and ceramics now,

I buy sets of the TiNi coated HSS bits (not sure of the brand) for approx £20 from the local engineering supply place (.5mm to 13mm in 1/2 mm increments). usually get about a year before a new set is needed, but mostly due to theft (sorry borrowing) / loss etc.

(all the usualy metric tapping drills are bought more regularly!)

bigger than that these its taper shank all the way!

I dont use cutting oil if i can help it. if speeds / feeds & grind is ok you can tell straight away. the smoke / mess annoys me (though do use it when tapping)

If im drilling a lot I use a water soluable coolant (in a squeezy bottle - very high tech , I dont know if it helps the drilling, but rather keeps things cool.

(cutting oil is great when milling with hss cutter coz it stops the swarf chippings sticking to the cutter, when your drilling swarf should be coming off 'twirly' so should never get chance to stick)

[MickSCollins]

There's a big difference, in my opinion, between the TiNi bits and cobalt bits, especially when it comes to harder metals. A friend of mine called me a few weeks ago needing help with a bolt snapped off in his engine block, and a chromium vanadium bolt extractor snapped off rather neatly, and conveniently might I add, in the middle of it. After an hour of nothing with the TiNi coated bits, which he swears by, I got fed up with it and got my cobalt bits. After about 30 minutes, most of the extractor was eaten away with only a bit of dulling to the tip.

At $2 a bit from Northern, it's a bit pricey, but I'd be more than willing to spend it. Since I've been using them, I've noticed that the work's been going a lot faster.

That's just me though.

[John N]

so are we talking solid cobalt drills, or hss with a coating?

[irnsrgn]

LIke lathe bits, 2% cobalt in the material the bits are made from.

[R W]

Originally Posted by Owen w

RW: are there any US dealers? There are not any listed on their site.

They seem to be some useful tools, especially for the unusual things farmers get into most of the time.

Doesn't appear to be any listed on the web site. A phone call with a credit
card handy would probably get you the required items. I have purchased
books and other items from the US in using this method.