Full Chisel Blog

May 30, 2008

Back and forth on Reciprocating Bits

Filed under: Drilling,Uncategorized — Stephen Shepherd @ 8:20 pm

Up until this point (pun) I have discussed bits that cut in only one direction, the direction in which they cut, with the exception of the burn auger.  These bits are referred to as continuous action drill bits, in that they cut continuously when rotated in the proper direction.

Now there are a whole class of bits, probably the earliest, well no THE earliest drill bits are reciprocating drill bits that cut in both direction.  These include pump drills, bow drills and Archimedes drills.  Here some of the ones I use.

Back and Forth Drills

Here is a pump drill, the whurl or flywheel adds to the action.

Pump Drill

And here is a bow drill all put together.  Take not of this type of drill, because I have a surprise a little later on involving this drill.  I also use the bow for my watchmakers lathe, interchangable power source for two different tools, imagine that.

Bow Drill

And this is an Archemides Drill, the two in the photograph have a 4 jaw collet chuck to hold the smallest bits.  I have made a few bits from piano wire (that stuff is hards and requires grinding).

Archemides drill

These are fine drills and their bits cut in both direction.  Bits are either flat and sharpened square or they are round and sharpened like quills, with half the circle of the diameter ground off, leaving two cutting edges.  These bits require that the dreck from drilling be occassionally removed from the hole to help in the drilling operation.

Aside from a sharp antler, bone awl or knapped stone drill, the first drills, these are among the earliest forms of making holes.  Versions of these tools with the exception of the last one have been around for millenia and the last one is fairly old as well.  There is something about wood that makes us need to put a hole in it, haven’t figured that one out yet.

Still need to discuss chucks, drills of other types, drills that drill big holes, drills that drill long holes and things that fit in braces and an unusual drill bit.

Stephen

May 29, 2008

My youngest apprentice

Filed under: Of Interest,Uncategorized — Stephen Shepherd @ 8:09 pm

I am taking a bit of a brake today on the boring issue, I intended to shoot some pictures this afternoon but I had an interesting visitor.

His parents explained that he was born when they were building their house and loves tools.  He was napping before his parents and grandmother came into my shop, but he was wide awake immediately.  As I found out he likes hammers, I gave him a mallet and that wasn’t enough.  He wanted a real hammer and nails.  I got him a little hammer and he pounded that cut nail into a piece of pine.

He had remarkable control and hit the nail as often as I do.  While it was raining in the park today, they spent some time, well his parents and grandmother were there while he had fun.  He tried out all my mallets and hammers and settled on one he liked.  His mother had him choke up on the handle, that didn’t work and he knew it so got a better grip and had a great time.

They spent nearly an hour in my shop and I had to turn the tables on the guest, I took their picture (used by permission).

My youngest apprentice

Now this mallet (31″ tall), I think scared him when he saw it, but he was a good sport and posed for this picture.  While my job is rewarding, it does have its special moments.

I have hope that someday he will take up woodworking, he has a proclevity. 

Stephen

May 28, 2008

A Sharp Auger, augurs well…

Filed under: Drilling,Uncategorized — Stephen Shepherd @ 3:33 pm

and comes out where you portended it to exit.  Everyone is off to the dictionaries, I’ll wait.

An auger is a self contained tool that is capable of boring a hole.  It has some sort of handle that is usually but not always permanently attached or with a detachable handle intended for use with the tool.  Here is an example of what Mercer calls a raft auger.  I picked this up here in the mountain West for less than 20 cents a pound.  The bit is a hollow twist a la L’Hommedieu and is forge welded onto the long offset crank handle.

raft auger

The term auger does not just apply to handled drills, it can be a bit for a brace, but a drill bit with a handle is an auger, unless it is that little wimble or t-handled gimblet.  I hope that clears things up.

These tools are used by carpenters, shipwights, millwrights and others needing large holes.  There are several types of augers, from pod, gouge, shell, twist, &c., &c.,cutting ends and a couple of methods of attaching handles.  The first one is a socket auger in which the handle can be easily removed for transportation, folds up for easy packing.

Socket twist auger

Socket twist auger

Note the fancy oak chair rung handle.  Life is tough here on the frontier. 

Another type of handle is the tang, which pierces the handle and is clinched over, so it is a permanent arrangement.  This particular tanged twist auger is smith made, looks quite early and the handle is a replacement.

Tanged T-handle twist auger

Here is the touchmark of the maker ‘EVANS’.

Touch markTouch Mark

Some of these T-handle augers were threaded on the end of the square or flat tapered tang and had a nut on the end to secure it to the wooden handle.  Most of these handles are hickory, ash or white oak although any and every wood was used.  The nut/tang allowed for this to be taken apart to put in the tool box to travel to the next job.

I have a two inch Cooks Patent Auger with a screw tang that I need to make an appropriate handle and figure out where I need some two inch holes.  It looks like the tanged bit is probably the earliest, Roman relics are of this type.  Socket and tang examples from the Nova Zembla expedition of 1596, the ill-fated Dutch experience in the Arctic.

Socket augers can provide more torque as a tanged auger can split the handle under un-do force.  The longer the handle the more leverage making the boring easier.  The better shape the handle, the fewer blisters.  Boring green wood requires careful attention to removing any wet dreck from the metal parts to prevent rusting.

Lead screws are in all pitches from coarse to fine, if they have them.  Sharp, bright augers will work with less effort than those with pitted and rough surfaces.  However some old augers will work fine if just the cutting edges are in proper condition.  Also ‘Bright’ tools resist rusting the reason all most all tools were offered ‘bright’.

One workman is digging a series hole with a shovel and another follows behind him is filling them up again.  A stranger stops by and asks what is going on?  The fellow that puts in the trees is sick today.  Kind of like drilling holes then filling them up again.  Look at a ladder back chair it is nothing but drilled sockets and mortises filled with tenons.

Stephen

May 27, 2008

Boring (Twisted) Video

Filed under: Drilling,Uncategorized — Stephen Shepherd @ 7:29 pm

When someone asked to see what the Cook – Gedge pattern drill looked like in operation, I thought a video, a modern archival technique.  The bit is after Mr. Phineas Cook’s New Constructed Spiral Auger from 1772.  In America it is called the Gedge pattern

Cook Gedge Video

Cook Gedge VideoCook Gedge Video 

Video by Richard McDonald

The piece of wood is some fairly green pine.

Stephen, I think I got it right now!

May 26, 2008

Gimlet Bits

Filed under: Drilling,Uncategorized — Stephen Shepherd @ 8:04 pm

Or Gimblet bits are a special type of bit for a brace and should not be confused with the T-handled gimblets used to make holes for screws.  These bits are usually quite small and that is their intended purpose.  However people think that the brace gimblet is for the same purpose.  And of course if most people think that, then I have a reason to explore other possibilities.

The photograph shows my collection of brace gimlet bits.  The number markings stamped on them differ from other bits as they are marked in 32nds, hence a 5 would indicate 5/32″.  And this marking continues until it gets to my largest which is actually marked 5/16 in fraction form.  The smallest is 3/32″ and all up to the largest are marked in this manner.

Gimblet bits

If you look at the bit on the left and the one 4th from the left have both been ‘untwisted’ or deformed during use abuse and this can happen to these bits.  I have not bothered to twist them back as they still drill holes of the proper size in their present condition.

There are also some sources that say that these bits can’t be sharpened, maybe they couldn’t sharpen them, but I have found it possible to sharpen any and all of these bits.  It takes some fine round needle files on the insides, but it is possible, the outside flattened with a flat file.  Care must be exercised an the flat on the outside should be lightly dressed so as not to reduce the effective diameter of the drill.

Now here is where my views vary from others.  While the smaller bits can be used to make screw holes, these bits are tauted as being for screw holes and the diminutive bits perform that function just fine.  However they probably weren’t used for that purpose as a brad awl (I will get to these soon as they make fine holes) is a preferred choice for making holes for screws as no wood is removed in making the hole.  One must remember that screws were blunt prior to 1846 and only AFTER that date are wood screws pointed.

So you don’t need a pointed hole for a blunt screw and while it is a good idea to make a pilot hole, drilling is not the best option (Brad Awl), for making an entry hole.

Gimlet bits make a fairly good entry hole, there may be some splitting, but it usually isn’t bad and because no one ever uses them to drill holes through the wood, no one apparently has mentioned that they make a great exit hole without any backing as required by other bits.  Gimblet bits pierce the opposite side with a small hole then continues making it larger as it advances, but it pulls the chips back through the hole leaving a clean exit hole.  No backing required.  Got a gimblet bit?  Try drilling a through hole, you will be amazed.

When I first got gimblet bits, no one told me they were just for screws as I may have never tried them for through holes, but they work wonderfully.  And besides I don’t have any 3/8″ diameter screws for my largest gimblet bit a 5/16″ and I haven’t seen too many old examples that would require a special bit of that size.

The association of gimlet bits and screw holes I think is because of the shape of the bit to the shape of the screw.  But screws that big are rare and there are much better ways of making holes for screws.  I don’t think they were originally intended for screws, I could be wrong, but somehow I don’t think I am.

I use these bits all of the time as they are handy and work well, but I hardly ever use them for pilot holes for screws, but I have been known to do so.  Most of the time it is to drill a smallish hole through thinner boards because of the swell of the shank and tang, they can not drill holes very deep.

Stephen

May 25, 2008

Now Things Get Twisted

Filed under: Drilling,Uncategorized — Stephen Shepherd @ 3:52 pm

At some point in the eighteenth century someone came up with the idea of putting a twist to a bit in order to help extract dreck from the hole as it is being drilled.  Most bits require you extract the bit occassionally to remove the dross left over from drilling.

The theory of the twist bit is that it could extract the shavings and drill deep straight holes and not wandering like the center bit.

The first person credited with this innovation is a fellow named COOK, and here is one of his pattern drill bits.  Mercer dates this style to the 1770’s

Cook patent

This particular Cook auger is intended for a cross or T handle, I have one 7/8″ tanged bit in this pattern.

Date

The date is 1851 and that is about 4 years or so before Gedge got his patent for his bit pattern.  Incidently Gedge filed for his patent 2 weeks ahead of Russell Jennings, the latter became the industry standard.

Gedge

The unique curved cutting edge looks like it will not make a good entry hole, but the opposite is the case, it makes the cleanest entry hole of almost any bit.  And unlike the Jennings and much later Irwin patterns the Gedge can be used to drill holes at very steep angles unattainable by the other twist auger bits.

There is another type of twist bit that was developed during the very early nineteenth century by L’Hommideau which consists of a piece of metal twisted around a mandrel to produce a hollow twist with a cutting bit on the end.  Some had pivots (plain or threaded) but many had no pivot and required an excavation in order to get the bit started.  Number 10 in the lower illustration.

Drill bits and their holes

1. Button Bit

2. Center Bit

3. Counter bore center bit

4. Twisted Gimblet (gimlet) bit

5. Gouge bit

6. Nose auger

7. Pod auger (straight gimblet bit)

8. Spoon Bit

9. Duck Bill spoon bit

10. L’Hommideau bit

11. Twist bit

12. Twist bit, Jennings pattern

13. Irwin bit

The lower illustration shows the holes that the various bits produce.  I shall discuss the care, repair and sharpening of bits later and I still have to discuss the gimblet bit and my theory about these bits.

Manufacturers offered these bits in 4 ‘grades’, spur pivot point (no threads), coarse threaded for softwoods, medium threads and fine threads for hardwoods.

I believe the Jennings pattern has been in constant manufacture, and new ones are available, however the Cook/Gedge pattern is NOT being reproduced.  I think tool manufacturers are making a big mistake by not reproducing these bits as they would be a boon to chair maker’s who find this pattern bit particularly useful.

Stephen

May 24, 2008

Center Bits

Filed under: Drilling,Uncategorized — Stephen Shepherd @ 7:30 am

I don’t think I have a favorite drill bit, I like any good sharp (traditional) drill bit, however Center Bits have a special among my tools.  Not only are they really fine bits, they look great, and the hole it drills is fun to watch.

Center Bits

The Gnomon is 6″.
This is my modest collection of old drill bits, the one with a notch in the tang is for a spring chuck brace (I will get to those later), is shorter and earlier than the longer bits.  The reason I have a modest collection, is they are difficult to find and No one is making any reproductions!

Center bits are great for shallow holes, some have large center pivots that can pierce through thin work.  The reason it is used only for shallow holes is that there is nothing in the design of the bit to keep it from drifting as one drills a deeper hole.  Other bits drill straighter holes, such as gouge, spoon and twist augers (they are next).

The center point provides the pivot and as the bit is turned, the spur scores the wood prior to the lipped cutting edge, excavating the wood.  It is actually fun to watch the bit starting its cut (kids like watching the center bit & have fun drilling holes with it, however my spoon bit and twist augers are popular).

There are some variations of the center bit such as a counter-bore bit that has a solid plug center instead of a pivot point.  This plug goes into a pre-existing hole and drilles a larger counter bore (such as split saw nuts on hand saws).  Other variants include a button bit (for making clothing buttons) and some larger bits have double scoring spurs.

Now the disadvantage (that of wandering) can be used to an advantage, as once the hole is started it can be tilted and the angle of the hole changed during drilling, can’t do that with other bits.

When I attach table tops to aprons, I use center bits to drill the pocket hole on the inside of the apron, and a gimblet bit to drill the screw hole through the top of the apron.

The points, three or four sided needs to be sharp, the scoring spur honed on the outside and sharpened on the inside (so the diameter is not reduced, it much match the lipped cutter).  The lipped cutter is sharpened like a chisel or plane blade, flat on the bottom and the bevel on the top.  I store these bits in a place where I can not touch their sharp little points as they can be nasty.

When drilling through holes with this bit, you can reverse and come back from the off side, but the holes don’t always line up, they can be off a bit.  If it is important that the hole is straight, I back up the stuff being drilled with a scrap piece of wood and drill all the way through.  This prevents a spelk on the off side.

If someone, anyone were making reproductions of these bits, I think they would sell a lot of them, I would buy a few sets.

Stephen

May 22, 2008

Duck Bill Spoon Bit

Filed under: Drilling,Uncategorized — Stephen Shepherd @ 7:55 pm

There are a couple of types of spoon bits, the more common is like a gouge bit but the end forms a spoon shape with the cutting edge on the end.  It goes to a slight point and is helpful for starting the hole as it has a center that will not wander or walk when starting the bit.  There are no reproductions of common spoon bits, however there are a few makers of ‘chair makers bits’ or ‘brush maker’s bit’ and is commonly called a Duck bill spoon bit.  Here is a new made bit.

Duck Bill Spoon Bit

As you can see it is not a traditional design, neither are any of the other duck bill spoon bits using traditional design.  And how does this vary from originals?  It has to do with the awkward transition from the shank to the bit, traditional bits look like the gouge bits in the previous post except with spoon tips.  There is also the matter of the sharpening.  This bit was sharpened everywhere you can see shiney metal, unlike traditional bits that were only sharpened on the spoon end.

I purchased this one to see if I could alter it somehow to look good, I think it will take too much work.  I drilled a hole with this one (5/8″ diameter) and it when down through end grain, wonderfully.  However the sharpened sides left an oval hole as I anticipated they would, old bits are not sharpened there, just on the tip.

I took the bit out of the brace, filed off the sharp edges on the side, put it back into the brace and it drilled an excellent hole.  I certainly wish they would have gone to a traditional style as I would have bought several sets for the Living History Museum where I work but they are just not right, too bad.

These bits were commonly used by chairmakers as it produces an excellent hole and with no lead screw it won’t drill through leaving a mark.  With no lead screw, pressure needs to be applied to the brace, but properly sharpened (and properly unsharpened) these bits work well.  The round bottom of the socket can recieve a round bottom tenon on the spindle or leg.  Rounding the ends of spindles to fit better in these socket holes was done, not all the time, but frequently.

I think some of my gouge bits started life as spoon bits and were just sharpened away making them gouge bits.  Continued sharpening will eventually turn all spoon bits into gouge bits, so avoid nails and screws and try not to oversharpen.  But when your spoon bit quits working, it can be ground into a gouge bit.

As with other non twisted bits the drilling dross needs to be removed from the hole, you need to remove the bit from time to time to remove the shavings.  Sometimes the shavings will come out of the hole at other times it can jamb up the bit in the hole when it gets deeper.

This bit is good for kids to drill holes with especially if they have never used a drill before, the unique shaving it produces is facinating to the kids, it even interests their parents.

These were popular up through the first half of the nineteenth century, then were largely replaced by twist auger bits such as Jennings and Gedge, for chairmaking.  This is not always the case but later catalogues focus more on twist augers and even group spoon bits with shell or gouge bits.

Stephen

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

May 19, 2008

Brace yourself, this is going to get a bit boring.

Filed under: Drilling,Uncategorized — Stephen Shepherd @ 9:03 pm

That just never gets old.  I am about to embark on a rather lengthy diatribe on making holes.  I will not describe this all at once as it is far too complex for a simple post, so this will continue for some time.  Although I can get sidetracked and go off on a tangent at any moment, I will attempt to keep my focus.

Me

Notice the straight up and down position of the brace, lined up and sighting down the bit to make sure it is going in straight.  As cabinet makers and chair makers and woodworkers we are called upon to remove wood in a circular manner, we make holes. 

Here is how it has been done.  The first hole, aside from that handy knot hole was probably made with a sharpened (knapped) stone or bone or antler awls that worked its way through wood.  Fairly sophisticated points were knapped out of concoidal fracture stone (obsedian, chert, flint, etc.) and were good for shallow holes.  These tools were also attached to pump drills to increase the speed of boring.

Pump Drill

This is a reciprocating drill and cuts or drills when spinning in both directions.  This example has a metal bit, but a stone bit would be attached to the end to do the work.  Examples of this with horn, antler and bone tips are in existance.  I have one in my shop and I use it for shallow holes and the bit also works as a small countersink, although it needs to be made first and the hole drilled after to work properly.

With the advent of the bronze age (4000-3000 BC) metal could be heated up and burned through a piece of wood.

Burn Auger

Then iron came around shortly thereafter and steel was available after the 12th century.

The burn auger continued well into the nineteenth century as a good way to get a hole albeit rough through a piece of wood in quick order.  I actually use this method in the winter when the stove is hot.  A red hot pointed piece of iron, goes through a piece of pine in seconds and produces clouds of smoke, a rather fun experience.  Keep a wet rag handy in case of a confligration.

I would not be surprised that the first ‘modern’ drill bit was an old distorted burn auger that worked without being heated to cut a hole.  Early bits were probably pod or gouge augers that had a proper geometry to cut a clean hole.

This is a brief history of early drill bits and how people made holes.  There is also using sand to abrade wood by putting sand in a depression and using a round stick rubbed between the hands to spin it to make a hole.  Or the use of a grub to eat the center out of a branch of ash or walnut (with a collapsible pith) to make a Native American pipe stem.

What I will continue to discuss is the drills and bits in use in the nineteenth century, so that will include everything up to that point.  And being as drilling holes is so essential to woodworking this may go on for a while.  I hope this augurs well.

Stephen

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