Full Chisel Blog

May 21, 2008

Shell bit, Quill bit or Gouge bit

Filed under: Drilling,Uncategorized — Stephen Shepherd @ 6:03 pm

An early and popular bit that can be very helpful when drilling holes, especially endgrain.  These bits with their square tapered shanks (earlier versions had flat tangs for fitting into wooden bitstocks {brace}).  They get their name from their shape which looks more like a gouge, with which we are all familiar or an opened bird quill or a shell or covering.

Gouge bits

Here are some of my gouge, quill or shell bits, the ones with notches are intended for spring catch chucks on patent, plated braces, and with the others all fit in standard braces of the period that held those bits, e.g. Spafford pattern,  Common Iron Brace, &c.

They are sharpened like a gouge, so I call them gouge bits, but the other terms are interchangable.  To sharpen these make sure the flat (the inside) is perfectly flat and the bevel {bezel} on the outside is where the major grinding and sharpening takes place, so these are sharpened out cannel.  The tip is the only cutting edge of the tool the sides up the flute are not sharpened and are dull.

While I am right handed and normally twist my brace like my twist augers, center bits, nose augers and gimblets require turning in a specific direction gouge bits (and spoon bits) will cut in either and both directions.  This can be handy because you can worry the bit through particular difficult wood by going back and forth to achieve the hole.

As you can see some of the bits are sharpened fairly flat across the end and others are more oval, some look like carving gouges and some look like turning gouges.  This is how they were sharpened when I got them, so I continue and am not sure I can tell much difference in their operation, both seem to do the job just fine.

This bit and nose cutting augers (I will talk of those later) and to some extent spoon bits require a starting point.  Placed on a flat board they can walk if there is no pilot hole or depression in which to start.  A small gouge mark, an awl hole are required to get this type of bit to drill a hole in a particular location.  Because it has no center pivot to properly register, it requires a place to begin cutting.  A nail punch and hammer is all that is necessary to get a good starting point for this bit.

The fine smooth holes these create are excellent for dowels or pegs but the wood does need to be ‘backed up’ with a piece of scrap to prevent ‘blow out’ forming a spelk on the back side.  Also for blind holes (those that don’t exit the wood) there is usually a little or sometimes not so little plug left after drilling as these bits don’t have a center, so it is like a ‘hole saw’ in that it leaves a core.  Many times these just break off and are part of the dross.

I prefer a slightly round end to this bit as it offers a skew cutting edge to the wood and cuts faster than the flatter sharpened bits.  And as there is no advance screw, pressure needs to be applied during the drilling process.  An advantage of this type of bit is that if drilling becomes difficult because of grain or tension or compression in the wood can be dealt with by reversing and twisting the brace in the opposite direction.

One application I find very useful with this bit is boring endgrain.  For some reason lately I have been interested in boring endgrain.  I do a lot of repair work and am constantly drilling endgrain to repair spindles on chairs and other broken furniture parts.  Certain bits will follow the grain, but these [gouge bits], nose augers and spoon bits as long as they are sharpened properly will drill straight holes (providing I can hold the brace straight), without following the grain of the endgrain wood.

I have made a several very small drill bits which I call quill bits (other people call them that as well) that are slightly different from the normal shell, quill or gouge bit but operate in a similar manner.  These are made of some Piano Wire that I picked up when a local piano factory went out of business.  Well I have 150 pounds of piano wire of various sizes and it makes excellent little tiny drill bits.  Now this stuff is tough to cut, hard to bend and difficult to grind but other than that it is spring steel and harder than the hubs of hell.

After wrestling a short section from a dangerous tightly wound coil of pointy wire (I hear my dear departed Mother saying ‘You can poke an eye out!’) and carefully grinding it on the Indiana Limestone grind stone, takes a bit of time,  I grind a point on the end then grind off one side of the wire to form a half cylinder on the lower part of the piano wire at the point end.  This provides two cutting edges one on each side of the flat grind.  It requires a collet chuck to hold the wire in the a couple of small Archimedes drills I have.  So it works in both directions, reciprocating or it works in continual circular motion.

With these and some other bits, in order to drill a hole at an angle it is necessary to get the hole started a little straight in, making sure the entry hole is good before tipping at an angle to drill an angled hole.  Because it doesn’t have a lead or pivot spur or screw it is a good choice for chair making as it can drill the socket without the lead coming out the other side.

Another advantage of this type of bit is that because of the cutting geometry of the head it will slightly compress the wood  (on the inside of the hole) as it is drilling the hole.  When glue (and it goes without saying that it is hide glue) is put into the hole and a peg or dowel is inserted, the wood will swell back holding the piece firmly.

The only disadvantage of this bit is that no one is making them anymore.  There are some reproduction ‘spoon bits’, not traditional designs that will someday become gouge bits after they are sharpened to death.

Stephen

4 Comments »

  1. I’m loving this series, Stephen, thanks!

    Comment by Roger Nixon — May 22, 2008 @ 7:24 am

  2. Roger,

    Thanks, I hope it is not too boring, as I am going to continue, and it will be a while before I post about drilling square holes, but I will.

    Stephen

    Comment by Stephen Shepherd — May 22, 2008 @ 7:36 am

  3. […] bits are similar to spoon bits and aren't used much anymore (you can read about them here on the Full Chisel blog). I've used spoon bits in chairmaking and have noticed that they do tend to tear at the end […]

    Pingback by Woodworking blog Woodworking Magazine - Weird Wooden Nail? It's the Bit — November 17, 2010 @ 7:22 am

  4. […] are similar to spoon bits and aren’t used much anymore (you can read about them here on the Full Chisel blog). I’ve used spoon bits in chairmaking and have noticed that they do tend to tear at the […]

    Pingback by Weird Wooden Nail? It's the Bit | Popular Woodworking Magazine — February 21, 2011 @ 10:58 am

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