Drilling

[brokenbit]

Was drilling a desert ironwood blank on the Lathe today ( I drill at high speed) I got about 1/4 of an inch into the blank, drill started to smoke a little bit, so I pulled the drill back out. the flute on the drill bit were full, I clean out the flutes there was a small ember in it. This has never happen to me before.
Has anyone else had this happen.


Bernie

 

[Randy_]

Do you know exactly what speed you drill at? "High Speed" doesn't really tell us a lot.

I've never had the ember thing happen to me; but there is no reason why it shouldn't happen. When you think about it, drilling a hole is not unlike the old method of starting a fire by twirling a stick in a notched piece of soft wood.

 

[PenPal]

Brokenbit,
The most embarrassing time for a while for me when doing a demo the lathe was running in reverse creating such a condition,wrecked the new bit etc.I use an identical lathe but always bypass the reverse in anything on a lathe to prevent chuck catching,not a rewarding pass time.I use the same medium fast speed for all wood drilling but you can feel the way a drill is performing certainly the method of sending smoke signals indicates a problem.
That timber is tough but so is African Ebony etc.
Question which drill,what finish,that or this wood is guaranteed to promote a healthy discussion.
Send me a pm and I will give you the specs of the only drill I use succesfully for all timbers including your problem timbers without failure and long working life,made in the USA,sold in Australia.
All the best. Peter

 

[Rifleman1776]

Sounds like a dull drill bit, possible combined with too high a speed. Sharpen the bit, slow down to about 600 rpm and try again.

 

[TellicoTurning]

Brokenbit,
I don't drill my pens on the lathe, but do my peppermills (I drill at 500 rpms)... recently I was drilling one and noticed a little smoke coming out of the drill hole.... I backed out the bit to clear the debris... noticed that the dust was getting a little dark, but cleared and resumed drilling. Later, I was cleaning the accumulated shavings etc from behind the lathe and notice I had a little circle(about 1-1/2") of burned shaving where evidently an ember had dropped ... I pay a lot more attention to the smoke now and try to keep the bits sharper.

 

[wudnhed]

Bernie, DI is the hardest wood I've ever worked with. I use a drill press but the same thing can happen and has happened to me. I have learned to sharpen my bit before drilling DI and I also pull my drill out several times and clean the drill grooves out. I use DI alot so I feel your pain or I see your smoke [][}][]

 

[richstick1]

I drill at 500 rpm on the lathe - high speed drilling is a recipe for disaster unless your bit is razor sharp.

 

[redfishsc]

Originally posted by Richstick
<br />I drill at 500 rpm on the lathe - high speed drilling is a recipe for disaster unless your bit is razor sharp.

Right on.

 

[Randy_]

Originally posted by Richstick
<br />I drill at 500 rpm on the lathe - high speed drilling is a recipe for disaster unless your bit is razor sharp.

A couple of points need to be made here.

1. Trying to drill with bits that are not sharp is a recipe for problems whether drilling at high or low speed.

2. Different sized bits require different drilling speeds and since Bernie hasn't mentioned the bit size, it is a little problematic to offer specific advice.

3. And since Bernie hasn't mentioned exactly what speed he is drilling at, that also complicated making an accurate response.

And a question for Bernie: Are you saying this is the first time the "ember" thing has happened while drilling DI or is the first DI blank you have drilled. If you have drilled DI successfully in the past, maybe it has to do with the blank, itself, and not your tools or technique. Wood, even of the same species, is some what variable and maybe you just got a blank that was predisposed to smolder. The other thing is I remember reading that there are several species of wood that all are called ironwood. Maybe what you are trying to drill now is different from what you have used in the past?

 

[RichW]

Ironwood is one of my favorite materials, but some of the pieces with the best figure are cut from crotchwood that was at ground level or below. Often they will have small inclusions of rock and if your bit hits one of those, you could get a nice, hot spark. It's just a variation on the old flint and steel and hot, dry sawdust is ideal to nurture that spark.

Take care.

 

[R2]

I've had a problem with drills due to the use of different brands. I had a particular problem in drilling Black Gidgee, an extremely hard Australian acacia so I decided to search the net. Sandvik-Dormer replied and suggested I purchase one of their TiN coated bits. I found that this did the task little better than my hss Suttons bit. That in itself was no real problem,it just meant I had to be more patient in drilling the holes.The real problem was that the S-D bit was very, very slightly over size. I have struck this several times now with different bits from different makers.
On the subject of swarf clearing, one of my mates informs me the the parabolic fluted bits are the best for this. Cannot confirm that as I haven't tried one yet. Don't forget that if you drill aat high speed friction can heat the timber, particularly harder timber, to near(or very near) ignition temperature. On withdrawing the bit the supply of oxygen to the hot fuel will give you problems.