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This article was published in the Spring 2009 edition of Woodturning Design.
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Introduction
For a while earlier
this year, the break room where I work at my real job had just about turned into
a knitting circle. One of the girls had a pair of wooden knitting needles and
they were, well, suboptimally attractive. I couldn't resist trying to do better.
The size that seemed
to be most commonly in use, were long
#10 needles—which are 0.225” in diameter and about 14” long. Even with
multiple center steadies this would be tough to turn all at once. Instead I
tried choking up on a dowel rod in my collet chuck and turning a segment at a
time—which turned out to be quite easy. Dowel stock being of limited species
availability (and maybe because those sub-optimal examples looked like sharpened
dowels) I next tried chucking up thin turning squares in the collet chuck and
this also worked well as long as the stock was truly square and straight.
This article will
describe how to turn knitting needles with a decorative finial from square stock
by turning a short segment at a time. The pictures will follow using a Beall
collet chuck, but some alternative ways will be shown for those of you who don't
have a collet chuck.
Wood Selection and Preparation
Knitting needles need
to be smooth, hard, and strong enough to stand up to extended use. The wood also
has to be something that is practical to turn long and thin. Both of these
criteria pretty much eliminate ring porous woods such as oak. The yarn may catch
on the roughness of the large pores and the constantly varying density the
cutting tool encounters will generate vibrations that make turning long and thin
more of chore, so pick a diffuse porous wood. Changing grain direction, such as
in curly maple will also tend to produce vibrations at best, or work destroying
catches where the wood climbs up your tool at worst, so pick a board with fairly
straight grain. The first needles I made were from (probably) soft maple dowel
stock. While they have held up well, a close look will divulge little facets
where wood to wood contact has compressed the wood slightly. Hard maple will
work well. Hard is better than soft. The pictures will follow a set of
purpleheart needles, which also worked out well. The padauk needles shown in
Fig41 turned nicely, but my wife thinks the larger pores make them seem a little
rough. In summary a hard, fine straight grained diffuse porous hardwood is what
you need.
The turning squares
need to be both square and straight. The also need to fit into the bore of your
headstock, so first figure out what size square will fit. My lathe is bored out
to 7/16”, which means a square about 0.31”will fit.
You could carefully
rip stock in the traditional table saw manner. Another strategy would be to
select (or joint) a board with two adjacent smooth edges at right angles to each
other, rip over-size on the bandsaw, and then use a planer to reduce to final
size.
I used a slightly
modified version of my Vacuum Rip Jig (see the Summer 2004 WTD or
www.DavidReedSmith.com/artcles/VacuumRipFence/VacuumRipFence.htm)
to mill the squares. I added some 2 mm self-stick craft foam to the bottom of
the top fence, which helps it hold better. First set the blade height just above
your stock and set the rip fence to the correct distance from the blade. Hold
the stock against the rip fence and the rear of the sled and lower the top fence
to hold it in place. Push down hard enough on the top fence to compress the foam
and lock the top fence in place as in Fig01. Turn on the saw and make the cut.
Figure01: Using a Ripping Sled to
cut small turning squares. This is the first cut. The thin layer of foam you can
barely see on the bottom of the top fence markedly improves its holding power.
Turn off the saw and
release the top fence. Rotate the stock 90 degrees and clamp it in place again,
as in Fig02, and make the second cut. Repeat these steps to cut as many blanks
as you want. If you want to make the same size needles as I did, cut the blanks
16” long. If you want to model a different size, cut the blanks 2” longer than
than the needles you select to allow for the finial. Draw a line 2” from the end
(or copy existing needles) to mark the end of the shaft section as in Fig03.
Figure02: Using the Ripping Sled to
make the second cut on a turning square.
Figure03: The finished blanks laid
next to the model knitting needle to mark the shaft length.
Test the fit of your
blanks in whatever chucking option you select and in your headstock bore. If
they are only slightly oversize you may be able to avoid re-ripping by trimming
the corners. Fig04 shows a couple of
options for this, a handled leather tool for rounding edges and a corner
rounding tool from
Figure04: Corner rounding tools can
be easier to use to adjust the turning squares to fit a collet. The top tool is
a leatherworking tool from an earlier life. The lower tool is from
Figure05: Adjusting the fit of a
turning square using a drill size gauge. Just draw the square through
progressively smaller size holes.
Chucking Options
A Beall collet chuck
with the appropriate sized collet is, in my opinion, the best chuck for this
kind of work. It holds securely, even when only hand-tightened, has an
unobtrusive small diameter, will not mar even finished work, and the smooth
edges are kind to errant fingers. While any give collet has a small gripping
range, an amazing number of overlapping ER32 collets are available at an
industrial supplier such as
www.MSCDirect.com. If you do any quantity of small work I think you'll
find the collet chuck to be an excellent investment. Fig06 shows a square
mounted in a 7/16” collet in the Beall chuck.
Figure06: A turning square mounted
in a collet chuck with the correct size collet.
If you have a collet
chuck but not the right size collet you can make a sub-collet of wood or PVC.
For a narrow range a one-slit sub-collet is sufficient. Begin with a 1-3/4” x1”
blank of maple or PVC. Having the hole centered is critical, so instead of
drilling the hole on the lathe, pre-drill the hole 1/64” larger than the needle
blank diagonal on your drill press. Mount a scrap block in your chuck and turn a
tenon to mount the blank. Engage your tailstock at the other end. Turn the blank
round, and reduce all but a flange to the diameter of the largest collet you
have. Remove the blank from the late and clamp it lengthwise in a vise. Cut a
single slit with a hacksaw or the like and the result will be as in Fig07. When
mounting a turning square in the one-slit sub-collet be sure that the slit is
over flat as in Fig08, not over a corner. Fig09 and Fig10 show squares mounted
in a one-slit sub-collet held in the Beall collet chuck with a 3/4” collet.
Figure07: Three one-slit sub-collets
for mounting turning squares in over-size collet. The left is made of maple, the
center of PVC, and the right is PVC pipe.
Figure08: Turning squares mounted in the three collets in Figure07. Note that
the slit is over a flat, NOT over a corner.
Figure09: Using the PVC one-slit
sub-collet to hold a turning square in a 3/4” collet
Figure10: Using the wooden one-slit
sub-collet to hold a turning square in a 3/4” collet
If you don't have a
collet chuck but do have a 4-jaw chuck you can easily and accurately hold the
turning square in the chuck by removing the top jaws as in Fig11. The jaws
should not mar the work. The only problem is the size of the chuck body gets in
the way.
Figure11: Using a 4-Jaw chuck with
top jaws removed to hold a turning square. This is very accurate, but the big
chuck body gets in the way.
Figure12: Using a 4-Jaw chuck with
#1 jaws to hold a turning square. The edges aren't finger friendly, and the
serations on the jaws can mark finished work. The slit PVC pipe at the top of
Figure08 would prevent marks.
You can also use #1
jaws in a 4-jaw chuck. You'll have to protect finished work from the jaws when
turning the finial by using tape or a PVC sleeve. The jaws are rather unfriendly
to your fingers as well.
Extreme DIY types can
make a collet chuck from scratch as in Fig13. Start
with a round rod of PVC. Drill and tap for your headstock thread. Mount the PVC
on your lathe and turn true. Turn a recess for a hose clamp about 1/2” from the
end, leaving a flange to protect your fingers. Drill a 3/4” hole thru to the
hole for the tap, and cross-cut the body to allow the PVC to tighten. Turn a
one-slit sub-collet to fit.
Figure13: A completely homemade
solution: a collet chuck made of
solid PVC rod and a hose clamp.
If you want to leave
a square area on the needle that won’t fit thru your headstock bore it is
possible to reverse the process. To do this you would first mount the blank
between centers and turn and sand a 1-1/2” or so length at the tailstock end to
the final diameter. Then mount a chuck and reverse the blank, holding the turned
section. Turn and sand short sections, feeding it into the chuck after each
section. This is a more difficult process, as you can’t see the entire length to
ensure uniformity, and if the blank slips off the tailstock center it will
surely break.
Turning Shaft
Sharpen and hone your spindle roughing gouge and skew—it's worth the trouble when turning thin. To begin turning the shaft of the knitting needle mount the turning square so that it sticks out from the chuck about 1/2”. Use the point of your skew as in Fig14 to cut a dimple for your tailstock in the end of the square. Remount the square so that it sticks out 1-1/2” to 3” (how far depends on the diameter needle, the wood type, and how sharp your tools are) and bring up the tailstock for support. Beware of excessive tailstock pressure—it should be snug enough to turn with the turning square, but not much more than that. Use a spindle roughing gouge to round the turning square and approach the final diameter as in Fig15. Then switch to a skew as in Fig16. Check the diameter with calipers as in Fig17 at intervals along the shaft and continue to cut until the correct diameter is reached.
Figure14: Using the long point of a skew to dimple the end of the turning
square for the tailstock.
Figure15: Roughing the turning square to round with a spindle roughing
gouge—actually it's a deep P&N spindle gouge ground straight across.
Figure16: Refining the surface and diameter with a skew.
Figure17: Checking the diameter of the shaft with calipers.
Figure18: After turning the first segment of the shaft.
Remount the square so that more sticks out (the amount you can easily do at one turning decreases as the shaft gets longer) as in Fig19. Again, use the spindle roughing gouge to reduce the diameter and your skew for final cuts. You shouldn't need a center steady as long as you don't go back to the already turned segment. If necessary you can steady the shaft with your fingers as in Fig20. The completed second segment is shown in Fig21. If your chuck is accurate and the square is straight you shouldn't see a shadow in the first segment and the transition should be undetectable by your fingers. Very slight problems can probably be sanded out.
Figure19: After re-chucking the shaft to turn the second segment.
Figure20: Since you're always turning very near the chuck, a couple of fingers
should be the most steady you need, and most of the time you shouldn't even need
that.
Figure21: After turning the second segment.
Continue in this fashion until you can see the mark indicating the end of the shaft. For the last segment mount the square so that the mark is about 1/2” from the chuck as in Fig22. Use your skew to form the pommel at the mark as in Fig23. Then use the spindle roughing gouge and skew to finish the shaft. I added a small (3/32”) bead with a beading tool in Fig24. The final segment is shown in Fig25, and the whole shaft in Fig26.
Figure22: After re-chucking to turn the last segment.
Figure23: Cutting the pommel with the long point of the skew.
Figure24: Using a mini-beading tool to cut a 3/32” bead between the pommel and
shaft.
Figure25: After completing the last segment.
Figure26: The entire shaft after turning.
Sand the shaft starting with a grit appropriate to your tooling. Be careful not to deflect the shaft by pressing too hard—instead counter the pressure with your fingers on the other side. You may wish to use a foam block to back up the abrasive. Use progressively finer grits.
Figure27: Sanding the shaft. I'm using a sponge block under the abrasive and
countering the pressure with my fingers on top.
There is no home shop film finish that will stand up to constant knitting needle use, so I suggest you use wax—as it will at least wear off gracefully. I used HUT wax by applying it with the stick and then buffing with a paper towel. You can do the same thing with Beall system waxes. You can do it right on the lathe the same way as with the HUT wax—just apply the wax right from the stick and then buff by squeezing the turning shaft with a paper towel or cotton cloth. Wax, lacking an inner ear, can't tell that it's the wood that's moving instead of the buff.
Switch to a smaller collet that will hold the shaft directly. If your headstock is too deep to let you insert the tip of the shaft from the handwheel end of the lathe, insert the shaft before assembling the chuck. Mount it so that about 1” of the tip is exposed. Bring up the tailstock for support as in Fig28. Before you start turning the tip take a look at a commercial knitting needle—note that it doesn't come to a sharp point but instead comes to a small rounded point. The idea is that the tip should easily slip into the loop of yarn, but shouldn't slip in between the plies that make up the yarn. Use your skew to shape the point. Sandpaper will probably be enough to round over the point. You can compare the point with a commercial needle to check your work as in Fig29. If the shape is good then sand and finish the tip.
Figure28: After re-chucking the shaft to turn the tip.
Figure29: Comparing the tip shape to a commercial needle.
Turning the Finial
Copy or print out Drawing1 and use spray adhesive to fasten it to a suitably thin substrate. You can nick the top edge with a triangular file at the end of the blue lines to help transfer locations accurately.
Drawing01: The Finial Template
The finial template in pdf format, so you can print at true size: Finial.pdf.
To turn the finial, turn the knitting needle around so that the shaft is held in the collet and the unturned section of the square is out. Turn a dimple in the end with your skew and then bring up the tailstock center for support. Use the Finial Template you made from Drawing1 and mark off the extent of the square section with a heavy pencil line as in Fig30. Turn on the lathe and turn the pommel with the long point of your skew as in Fig31.
Figure30: Marking the extent of the square area.
Figure31: After turning the pommel
Turn the finial round with the spindle roughing gouge and reduce the diameter to 1/4” as in Fig32. Use the Finial Template to mark the locations of the beads. I turned the small beads with a small beading tool (see www.DavidReedSmith.com/SemiShearArticle.htm for an earlier version of the tool) as in Fig33. You can substitute fillets or small V-shaped features for the small beads. Turn the larger bead with a small skew or detail gouge as in Fig34.
Figure32: After turning the finial area round.
Figure33: After turning the 3/32” beads.
Figure34: After turning the larger bead in between the mini-beads
Reduce the diameter of the end portion of the finial to 3/16” and use the Finial Template to mark the location of the mini-cove and the end of the finial. Use a mini-cove tool to turn the cove and a skew to make a V-cut at the end of the Finial as in Fig35. You could substitute a small V-groove or a thin parting tool cut for the mini-cove. Use a spindle gouge to turn the shallow cove that makes the top of the vase. Then use a skew to turn the bottom of the vase and blend into the shallow cove to complete the vase shape as in Fig36.
Figure35: After turning a mini-cove.
Figure36: After turning the vase shape.
Turn the half-cove at the tip with a spindle gouge as in Fig37. Sand and finish the finial as in Fig38. Cut off the nub at the tip with your skew and sand and finish the tip. Remove the Knitting Needle from the lathe and sand the square section with a drum sander or sand by hand. You can apply wax finish to the square section by hand or more easily with a buffer.
Figure37: After turning the finial tip.
Figure38: After sanding and finishing the finial.
Figure39: The completed finial
Repeat all the steps to make the other needle. The finished needles are shown in Fig40. Another pair of padauk with a square in circle inlay in the square section is shown in Fig41.
Figure40: The completed pair of knitting needles.
Figure41: Another pair of knitting needles with square-in-circle inlay.
Tools and Materials
Diffuse porous hardwood
Spindle roughing gouge
Skew
Spindle detail gouge
Mini-cove tool (optional)
Mini-bead tool (optional)
Author
David Reed Smith is a Basement Turner who lives in