Drilling on a Lathe
Drilling on a lathe is an odd experience the first time you do it or see it done. It is backward from the way we are accustomed to drilling. On a lathe, the wood is spun and the bit, held stationary in the tailstock in a Jacob's chuck, is pressed into the wood. It works quite well, and has a few advantages that make me prefer drilling a stummel this way over drilling with a press.
There are two main advantages to drilling on a lathe:
1. The depth of hole one can drill is limited by the length of drill bit and the length of the bed of the lathe. Since most lathes have beds of 20"-48", the limiting factor is usually the drill bit. This make it possible to drill long-shanked pipe designs that would be otherwise impossible to drill on a drill press.
2. Because the tailstock can be moved back away from the wood and out of the way, one's progress is easy to visually check on a lathe. With a drill press, it is impossible to get one's eyes in line with the hole being drilled unless a mirror is used, or the piece being drilled is moved to be examined. It is very convenient when one can simply slide the tailstock out of the way to inspect the hole being drilled, particularly when the depth of the hole is determined by where it intersects another hole -- as is the case with the tobacco chamber intersecting the draught hole.
Briefly, I will outline the procedure to drill a bent pipe on a lathe. It is slightly easier to drill a straight pipe, and I will outline the differences at the end of these steps.
1. Square the briar block. You will find every part of the drilling process easier (thus increasing the likelihood of a well drilled pipe) if you have a squared block to work with. 2. Decide on the shape you are going to make, and sketch it on the side of the squared block. Draw a line on the block for each of the three holes to be drilled. It will be these lines that allow you to align the holes. Take care to use a straight edge so your holes are drawn on the block accurately. 3. Chuck the block onto the headstock, and align the draught hole to be drilled first. This alignment will be done by eye based on the sketch on the side of the block. I typically put something with a point in the tailstock and slide the tailstock close to the block in order to aid the alignment process. 4. Check to be sure that your lathe is set to its lowest speed setting. If it is not, change it to the lowest speed. You will experience the best results with a low drill speed. (And you are less likely to get hurt...there is nothing like the surprise of turning on one's lathe with a briar block that begins to spin at 3,700 RPM!) 5. Hold the drill bit to be used for the draught hole against the line you have drawn on the block for the draught hole. Make sure you hold the bit so that the end of the bit is located where you want the bottom of the tobacco chamber and the end of the draught hole to meet. Mark the bit to the length needed to drill the draught hole. (Remember that your drill bit will be stationary, so this mark will be easy to see as you are drilling.) 6. Chuck the bit in a Jacobs chuck in the tailstock, bring the tailstock up to the briar, lock the tailstock in place, turn on you lathe, and begin drilling. NOTE: If the briar is angled such that the drill bit does not contact a relatively flat surface as it begins to cut, I find it helpful to start the hole with a 5/32" center-cut end mill. This short, rigid, very sharp bit with easily cut into the "wobbly" surface and provide a nice flat surface upon which to start drilling with your longer bit. 7. Drill slowly into the briar. Stop often and back the bit out to remove the briar chips and dust. This will keep this bit cooler and therefore keep your bit sharp longer. Also, it will keep you from scorching the inside of the hole. 8. Stop when you reach your mark on the drill bit.
You now have a draught hole!
Next, drill the mortise:
1. Hold the drill bit that will be used for the mortise (5/16" or so) agains the block and mark on the bit the depth necessary for the mortise using the same method that was used for the draught hole. 2. Realign the block in the chuck to the appropriate angle for the mortise. This is most easily done if you will place the correct bit in the Jacobs chuck in the tailstock to use as a alignment guide. Take care not only to get the correct angle for drilling, but also that the mortise hole centers exactly on the previously drilled draught hole. 3. NOTE: If you are going to turn the shank on the lathe, now is the time to do it. Always do your turning BEFORE you drill, as the strength of the wood is lessened by drilling, and a catch of a lathe tool can result in disaster with a drilled, weaker piece of wood. 4. Square the face of the shank by inserting a Forstner bit of large enough diameter to include the full diameter of the shank. Drill with the Forstner in the Jacobs in the tailstock until the full area of the shank diameter is completely flat and perpendicular to the axis the mortise is to be drilled. 5. Replace the Forstner with the bit for the mortise and drill the mortise slowly and steadily. The best hole is made if this is done with one pass instead of backing out and reinserting the bit several times. Since this is such a short hole relative to the diameter, clearing of briar debris should not be a problem. 6. Stop when you reach the mark on the bit. 7. Slide the tailstock back out of the way and look into the mortise hole. If you have done it correctly, the draught hole should be dead-center in the bottom of the mortise so that a pipe cleaner can pass with ease. With really steep bends this is not possible with doing a few drilling tricks that I will cover in the special drilling section.
NOTE: Sometimes the design makes it completely impossible to have the draught hole in the center of the bottom of the mortise. In those instances a Dremel should be used to "smear" the draught hole down to provide an opening and slope to direct the pipe cleaner into the draught hole. Last, it is time to drill the tobacco chamber.
1. Realign the block in the chuck so that the tobacco chamber can be drilled along the line drawn on the block for the tobacco chamber. Take care to align the block so that the angle of drill is correct, and that the centering of the block is correct so the draught hole will be intersected in the center of the tobacco chamber. This is not a very difficult process if the block is square and the chuck being used is self-centering. If the chuck is not self-centering, this is easiest to do if you will only loosen and the re-tighten one of the jaws to do the realignment. 2. Mark the length of the hole to be drilled on the drill bit to be used for the tobacco chamber using the same method as used for the other two holes. 3. NOTE: If you are going to turn the bowl, now is the time to do it. 4. Drill the tobacco chamber slowly and steadily. Stop frequently to clear debris and allow the bit to cool. 5. As you approach the line on the bit that is the stopping indicator, stop BEFORE you get to the line and back the tailstock out to check your progress. The goal is to have the tobacco chamber stop with draught hole exactly on the bottom of the tobacco chamber. The advantage of the lathe looms large here as you can look into the tobacco chamber to check you progress and slowly drill and check, drill and check, until you have the tobacco chamber drill perfectly in accordance with the draught hole. 6. At this point, with the block still on the lathe, you may want to sand the tobacco chamber. Some like to have this very smooth, and others like to have it a little rough. If you want it smooth, now is the time to sand while the lathe can do all the work for you. To sand the chamber, I like to wrap sandpaper around the rod that I use to open and close my chuck. It is about 3/8" in diameter. I simply wrap sandpaper around the rod and sand the inside of the chamber until it is to the smoothness I want.
Congratulations! You now have a drilled stummel! Next, it is time to fit a stem to the stummel.
Drilling a straight pipe:
The only difference when drilling a straight pipe is that the block does not need to be realigned between the drilling of the draught hole and the mortise. For that reason I change the order I do things when drilling a straight pipe.
1. Align the block with the draught hole (which is the same as the alignment for the mortise) 2. Square the face of the shank with the Forstner 3. Turn the shank, if it is going to be turned 4. Drill the mortise 5. Drill the draught hole