Burnt Drill Bit

[suefox51]

Good Morning!
Had a strange thing happen over the weekend. Was drilling Olivewood and as the bit hit the wood, it started to smoke. I stopped, looked, and tried again. This time no smoke - kept drilling (using drill press), not pressing too hard, letting the bit do its thing, smoke again. Every 1/8 or 1/4 inch, I pulled the bit up to clear it. Was able to finish drilling with lots of smoke, even after cooling off bit.
Now, the bit has blisters on it and is black.
Thoughts? Was I pushing too hard, even though I wasn't I don't think! Was the bit defective - first time using it and it was new. Wood an issue?
All comments appreciated

 

[bjbear76]

Sounds like you're doing the right things.....new drill bit, advancing slow the clean out the bit. Olivewood is naturally oily and tends to heat quickly. I've set my drill speed as low as possible and do like you do - advance a little at a time and clean out the bit. Sometimes if the wood is exceptionally oily, I'll spray some water into the hole as I'm drilling to keep it cool.

 

[turncrazy43]

Never had that happen when drilling Olive Wood. Slow drilling and clearing often is the best way. Never heard of blisters appearing on the drill bit. My thought is the bit is defective. Try a different bit in the same wood and compare your results.
_____________________________________________
Everyday I'm vertical is a great day

 

[HamTurns]

My guess is that your new drill bit isn't as sharp as it should be.

Kind of like a new gouge to use on the lathe, it may look sharp "out of the box" but it won't cut right until you sharpen it.

Try sharpening it and give it another try.

Happy turning
Tom

 

[ironman123]

I agree with Tom. I take all my new bits and put them through the Drill Doctor. Sometimes when I need a hole in hard wood, I get out the Drill Doctor and make a fresh sharp bit to use.

Ray

 

[Jim Smith]

Is there any chance that your drill bit had some kind of a coating on it to prevent rust? It almost sound like it was the coating that was heating up and smoking, resulting in the blisters on the drill bit. In my experience, metal doesn't blister until very hot and you would feel the heat emanating from the bit if it was that hot. Just a thought...

Jim Smith

 

[suefox51]

The blank was hot to the touch when I was done -

 

[raar25]

I am not sure how HSS blisters at the temperatures you are talking about. The wood would have been in flames before the steel reached the temperature, I am beting there is some kind of coating on it.

 

[edstreet]

Drill speed was likely to fast. Drill size was likely to large. Drill plunge speed was likely to slow.

 

[suefox51]

Not to sound dumb, but what is the plunge speed?

 

[bjbear76]

Also, what size hole were you drilling? 7mm? larger?

If larger (10mm, 3/8", etc) try drilling a 7mm or even 6mm hole first, then follow with the larger drill bit. You won't have so much material to remove and it will build up less heat.

 

[hazmat74]

Not to sound dumb, but what is the plunge speed?

The rate of speed at which you feed the bit into the material, the "plunge".

 

[suefox51]

Appreciate all the replies - the idea of drilling a smaller hole first is a great one - it was a large hole - 27/54.
I'll definately try the Drill the small hole first hint!

 

[edstreet]

27/54 = 1/2"

Some may not be aware of it but it is most often not the tip that overheats but the shaft of the drill bit. There is friction heat generated by contact with the walls of the blank, throw in some dust from cutting and clogged flutes and you have even more heat.

The longer you leave the bit exposed to the walls the more heat builds up and it does not take long for the oils in olivewood to smoke. A quick look at cooking oils we see that olive oil smoke point is 360-420F and if you see that happening when drilling then that means inside the tube and the wood itself is around 400 degree's, or more.

 

[walshjp17]

- it was a large hole - 27/54.

Did you mean 27/64 -- standard Sierra/Gatsby/Le Roi/Wall Street II tube?

 

[bjbear76]

If the hole you're drilling is 27/64, then yes, by all means start with a 7mm first especially with olive wood. I think you'll have much better results.

 

[suefox51]

mistype - 27/64 was the size. Again, thanks for all the input - I will definately drill the smaller hole first and then use the larger bit.

 

[kovalcik]

Now, the bit has blisters on it and is black.

I still can't get past this line. This does not sound like a simple case of drilling too fast.

 

[suefox51]

I will try to get a photo of it.