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Drilling
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Above you see the lathe set up for bowl drilling. The lathe allows the
bowl to be freehand turned as well as drilled. The 2-jaw chuck pictured
is an extremely heavy design custom-made for pipemaking.
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Now
it's time to get set up to drill the bowl. Our new shop offers us a
variety of options for pipe drilling. We have the lathe, which I have
used in the majority of cases in the past. We have 3 drill presses, the
workhorses. We also have 3 custom-made drilling machines with varying
capabilities, which I'll describe below. For starters though, I will
describe the lathe drilling. I reconfigure the lathe with the 2-jaw
chuck on the headstock and the drillchuck on the tailstock. This is a
bit more trouble to go to when I could simply drill it on a drill
press, but I do it for several reasons. The lathe is much stabler for
drilling, and drills a smoother hole. The spade bits work nicely in the
lathe, whereas they tend to chatter and drill off-round in the drill
press. Also, the tailstock drilling is very sensitive and I can feel a
lot more through it than I can with the drill press. I can feel by
touch when the bowl bit has reached the airhole, and can also feel if
anything unexpected comes up, such as fissures in the wood or cracks.
It's
important to get the block lined up properly with the drill. I start
by sketching the depth and location of the bowl onto the pipe shape,
and then mount the stummel in the lathe chuck using the flat lower
sides that I left in the shaping stage. I drill the mortise first,
then adjust the angle if needed and drill the airhole.
Once
these holes are drilled, I rotate the pipe in place and line up
the bowl angle with the airhole angle. Now that the block is mounted
and aligned in the lathe, it's time to drill the bowl. I've already
decided which drill/bowl shape to use back during the design, so
I pop that bit into the chuck in the tailstock.
I run
the lathe at minimum speed, which is 500 rpm for ours. Higher
speeds can chatter and also tend to heat up too much, sometimes
burning the wood. I advance the bit into the spinning block very
slowly and back out often. I constantly blow off the accumulating
shavings and make sure to allow time for cooling as heat builds
up. Drilling is a process of advancing the drill by lever for about
3/4", then moving the entire tailstock forward and using the
lever to advance the drill again. The further extended the bit and
chuck get from the tailstock, the more vulnerable they are to being
pulled off center by the hard wood, so I move in small increments.
I watch the drill bit to gauge its depth, and stay alert to the
feel of the drilling.
I can
tell by touch when the bit has reached the bottom of the pilot hole
and when it has broken through into the airhole. Once it's reached
the airhole, I pull the entire tailstock off and blow out the interior
of the bowl, then inspect the bowl with a flashlight. If there are
any flaws or problems evident it gets chunked. I check the distance
to the bottom of the airhole and replace the drill bit and go that
little bit further, to get the bowl bottom even.
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This is a custom machine made for drilling pipes and also for turning
stem tenons and fraizing bowls if needed.
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The
machine above is from St. Claude, France, and was designed for
pipemaking. This is another option we have for our drilling. This
machine works by clamping the block between self-centering jaws mounted
vertically, and sliding the entire clamp forward onto the spinning
drill which is mounted in a heavy-duty steel shaft driven by an
overhead belt-drive motor. The clamp can be raised and lowered. It can
also be slid from side to side and rotated in place by a 30 degree
axis, allowing a bowl and airhole to be drilled without loosening the
block in the clamp. The chuck jaws are designed to accept customized
wooden blocks. These blocks, softer than the briar or stem, can grip
tightly and safely and can be replaced easily. They are very
customizable by their nature and can be drilled and cut to create
specialized chuck jaws for gripping unusually-shaped stems or machined
stummels. The machine can also be mounted with various fraizing cutters
which can be used either on briar or stems - the stem or stummel is
clamped and slid forward onto the spinning blades, which cut the piece
into a pre-set shape. With stems, small diamond-tipped cutters will
turn a tenon to pre-set sizes while the stem is gripped in the
customized wooden clamp jaws.
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One of two similar drilling machines which use horizontal clamps
instead of the vertical clamping machine described above.
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Above
is pictured a third drilling option - We have two larger drilling
machines which utilize horizontally mounted clamps rather than
vertical. As with the previous machine, the block or stem is affixed in
the self-centering jaws and the entire clamp assembly slides forward
onto the spinning drill. The jaws can rotate in place without being
loosened, making it easier to keep the airhole and bowl drilling in
line. Two of the custom wooden clamp jaws can be seen on the frame bed
- they are designed to grip round stems or stock.
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