Thread: Lubrication for & sharpening of metal drill bits

Hi Sean,
No name brand canola oil in a pressurepak can goes really well.
The cheaper the better.

Phil

thanks Phil, great and nice and simple - my wife's grocery cupboard just got more space (and she doesn't know why yet)!

Sean

Actually I should also have asked - as the bits get very hot (in timber and metal) - is it not bad practice to be using aerosol sprays of any kind?

Lots of lubricants will work, a google search will give you heaps of ideas. At a pinch WD40 will do a fair job.

But the best advice I can give you is to never seek advice at Bunnings or SuperCheapAuto.

Hi,

For lubricant in most situations I use kero mixed with compressor oil or just oil or kero by themselves. For drilling anything more than 10mm I use lubricant of some sort.

Cheers Ben.

Originally Posted by seanlark

I have been advised by a friend that it is important to ensure lubrication of drill bits when drilling metal.

A vist to Bunnings and Supercheap to enquire about such lubrication got blank responses. No-one knew what I was talking about.

Anyone with any advice and views on this? I have searched the forum but not come with anything.

thanks, Sean

if you have a blackwoods or bolt barn nearby ask them ... i asked for cutting oil or perhaps cutting fluid and they knew exactly what i meant ... i only use it for either big holes or thick metal but it workd really well for me


regards david

thanks everyone - appreciated.

Originally Posted by seanlark

Actually I should also have asked - as the bits get very hot (in timber and metal) - is it not bad practice to be using aerosol sprays of any kind?

Hi Sean,
The canola foams up around the drill and that way you don't have to keep spraying
I wouldn't use it on wood though.

Phil

I used to use Trefolex until I was told that it is only intended to be used for hand tapping. This is because it apparently produces nasty fumes when it's heated and turn to liquid form. P&N sell a drill, tapping lubricant in a small bottle which seems OK but I must admitt I like the sound of canola oil. We all eat it so it can't be too bad!

Rightly or wrongly I mostly only worry about cutting lubricant on either bigger holes or when drilling stainless.

Edit: or if I'm forcing a hole using a blunt drill and can't be bothered getting out the drill doctor!

Simon

Different lubricants work better on different metals.
This is work a quick look at Machine Shop 1 Cutting Fluids

Metho or kero works on aluminium. I prefer metho because evaporates and leaves nothing behind.
I don't like the way canola leaves a gummy residue after it dries out.
and stuff like cast iron comes with it's own built in lube and can easily be cut without any lube.

Sean
A very common product in machine shops is "Rocol RTD" (Reaming, Tapping, Drilling).
Available from engineering supplies.
A trick to stop any lubricant from going all over the place is to make a little circular dam with plasticene, and even an O-ring placed on the surrounding metal being drilled can work well.

A bit of engine oil does a pretty reasonable job as well, just don't get the nozzle of the oil can caught in the rotating drill. You tend to only do that once

Alan...

I use water but only on thick material or big holes where the bit would otherwise overheat and lose its edge. Less mess than oil and more effective at cooling... Could add some soluble oil if your worried about corrosion but i don't.

I would also advise of the necessity to run your drill at the correct speed for the drill bit diameter.

Its not stated how you are driving your drill bits ie drill press or hand drill.
With a variable speed hand drill it is quite possible to drill stainless steel with out work hardening it,if the trigger is manipulated to suit the drill bit diameter.

While a lubricant is handy, the drill bit speed is the big factor in drilling steel, stainless or otherwise.
Secondly the drill bit point angle drills stainless much better if it is ground to 115 degrees.

I can speak to this as I have been drilling stainless steel thick and thin over the last month or so at work. All I have is a 10mm Makita electronic variable speed drill. I have had ground the drill bits to 115 degrees and the drills pass through the stainless like butter.

Higher speeds for small diameters and progressively slow down as the diameters increase. I realise most cannot grind their own drill bits but its not rocket science and most people can learn the skill.

Hope this helps

Grahame

I agree with Graham, DON'T overspeed. I have a 2 litre bottle that I mix about 20% new cheap engine oil 80% kero & shake well. I then decant some of this into a trigger pump bottle (ex window clean) I use this when drilling either steel or aluminum. I also use it as a rust preventer as the kero evaporates leaving a film of oil. The spray bottle lasts a long time (depending on the amount of drilling you do) & only takes a few seconds to refill so it is not an issue that forces you to continue without filling it. Also I have been using the same pump for years & the kero/oil doesn't effect the seals.
tinkera.