Burnt Drill Holes

[Rockytime]

I was drilling holes with a Dremel plunge router using a 1/16" bit. The Dremel was running full speed whatever that speed is. The drill bit started smoking on the first hole and turned blue. Still kept drilling though. I pressed the drill down quite quickly. Is this common? The wood is 5 ply flooring under-layment. Very nice clear wood. I don't care about the bit, they are cheap. I does not hurt the pattern or piece to be cut. Just wondered. Use bee's wax on the bit, drill slower? Not a big deal though.

[Scrappile]

Dull drill bit.

[dgman]

Dull and too fast a speed. Next time try on scrap wood, slow the speed down till it doesn't burn but cuts cleanly. Make sure you use a sharp drill bit.

[oldhudson]

If it's 'blued' you can sharpen it, but I don't think it will hold an edge. I'd pitch it and get a new bit.

And I agree that the speed setting was too fast for a 1/16" bit. And you don't want to drive the bit through the stock, let the bit cut through the layers. Finally make sure the waste is clearing the flutes before starting a new hole. It will cut and cool better.

[Rockytime]

I have a system made in the UK made for sharpening small number drills. I have hardly used it. It is very fiddley and time consuming. I bought it about 25 years ago. I buy new from MSC 10 at a time. Fractional at Home Depot.

[Scrappile]

I also drill and back then drill some more in the same hole, to keep the flutes clear as I am drilling, if the wood is very thick.  Drill Doctor is a pretty good bit sharpener.  But on little bits it is not worth the time, to my, I just buy more bits.

[jerry1939]

All the above.  I have been sharpening drill bits for a lot of years.  Use either the side of an emery grinder or a fairly course belt sander.  You must practice on a much larger bit, until you know how & can see what you are doing.

The leading (cutting) edge must be slightly lower than the heel (trailing edge).  If it's the opposite, the bit will ride on the heel and the cutting edge will not contact the material.  Especially with metal, if the angle is too steep, the outer, cutting edge will chip off.

Just do a quick pass on one half of the bit, give it a 1/2 turn and do a quick pass on the second side.  DO NOT keep grinding & heat the bit.  You should always be able to hold the ground edge between your fingers.  Overheating will cause it to turn blue and take the temper out of it, resulting in a softer metal.

I usually line up a few bits to sharpen.  Do a quick pass on the 1st and move on to the next.  Repeat as needed.  If you learn on larger bits, it's like riding a bike.  It will become automatic to you quickly.

jerry

[ike]

I can sharpen the larger drill bits but the small ones are too cheep to mess with When it burnes the hole you are going much too fast. Drilling small holes in ply wood requires a slower speed than useal it's the glue thats is the big problem.

IKE

[Bill WIlson]

I get that quite often, with the very small, numbered bits in the Dremel.  I figure as long as it's still making holes, it's no problem.  When drilling hundreds of holes for a portrait, I tend to feed the bit too fast and I've never been able to find the sweet spot in the speed range of my Dremel.  One setting is too slow and the next one up is too fast, so I tend to err on the side of too fast. 

[MrsN]

Like Bill, this happens to me a lot. I always figured my bit was getting dull, never thought about the dremel being too fast. I learned something today.

[Karl S]

14 hours ago, jerry1939 said:

All the above.  I have been sharpening drill bits for a lot of years.  Use either the side of an emery grinder or a fairly course belt sander.  You must practice on a much larger bit, until you know how & can see what you are doing.

The leading (cutting) edge must be slightly lower than the heel (trailing edge).  If it's the opposite, the bit will ride on the heel and the cutting edge will not contact the material.  Especially with metal, if the angle is too steep, the outer, cutting edge will chip off.

Just do a quick pass on one half of the bit, give it a 1/2 turn and do a quick pass on the second side.  DO NOT keep grinding & heat the bit.  You should always be able to hold the ground edge between your fingers.  Overheating will cause it to turn blue and take the temper out of it, resulting in a softer metal.

I usually line up a few bits to sharpen.  Do a quick pass on the 1st and move on to the next.  Repeat as needed.  If you learn on larger bits, it's like riding a bike.  It will become automatic to you quickly.

jerry

Jerry I think you might have meant to say that the cutting edge needs to be slightly higher on the bit than the heel 

[oldhudson]

I looked up a couple of drill press speed charts and the one said for 1/16" bit in wood it recommend 3000 rpm (internet web site). The other said under 1/4 bits it recommended 3800 rpm (from a book in my library, Power Tool Woodworking for Everyone). On my Dremmel, the lowest speed is 5000 rpm. I'll continue using mine on the lowest speed setting. While faster than recommended it offers a couple of advantages for me.

Finally, while it was never mentioned, I ASSUMED the drill bit being discussed was a twist bit.

[jerry1939]

9 hours ago, Karl S said:

Jerry I think you might have meant to say that the cutting edge needs to be slightly higher on the bit than the heel

We are both right and also both wrong.  I was thinking with the bit in the drilling position & you were thinking of the bit held with cutting edge on top.  We are both on the same page.

The old quote, "Is the glass half full or half empty".

[jerry1939]

4 hours ago, oldhudson said:

I looked up a couple of drill press speed charts and the one said for 1/16" bit in wood it recommend 3000 rpm (internet web site). The other said under 1/4 bits it recommended 3800 rpm (from a book in my library, Power Tool Woodworking for Everyone). On my Dremmel, the lowest speed is 5000 rpm. I'll continue using mine on the lowest speed setting. While faster than recommended it offers a couple of advantages for me.

Finally, while it was never mentioned, I ASSUMED the drill bit being discussed was a twist bit.

I sharpen 1/8" bits the same way as 1/2".  I should have also added (using the side of an emery wheel as an example):  "Hold the bit at an angle of approximately 4 o'clock & 10 o'clock.  Start grinding the heel while rotating & finishing with the cutting edge.  KEEP MOVING!  Do not overheat.

I sharpen wood spiral & spade bits with a hand file.