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All Wood Collet Chuck as 5 page pdf
An earlier article in More Woodturning on turning wine stoppers got me thinking about collet chucks. I wondered if I could make one entirely out of wood. I thought this would be just an exercise to see if I could do it, but it surprised me with its usefulness. Although the All Wood Collet Chuck doesn't have the holding power and range of wooden jaws mounted in a scroll chuck, it does have adequate power for turning tops, wine stoppers, and the odd bit of dowel. The All Wood Collet Chuck also has the advantage of being much faster to mount on the lathe and to convert to different sizes. Another advantage is that it's virtually free.
Preparing the Chuck Body
Start by finding some suitable stock for the Chuck Body. I used some 5/4 maple, but any fine grain hardwood in the neighborhood of an inch thick would do. Draw two circles on the wood. I used 2-1/2 inches, but again, it's not critical, as long as it's bigger than the diameter of your headstock thread. Mark the center of one of the circles.
Drill and Tap
The next step is to drill a hole the appropriate size to tap your headstock thread in the middle of one of the circles. Kind snuck that in on you didn't I? That's right, you have to have a tap that matches your headstock thread. You might have a bit of trouble picking one up at your local hardware store, but an Industrial Supplier will have one. I use J&L Industrial Supply at 1-800-521-9520. Big taps aren't cheap, but all you need to tap wood is "quality import". For example, a 1x8 tap that will fit most Delta lathes J&L part number TAP 15146C is $22.81. A 1x12, TAP 15153E, is $22.81, and a 1-1/4x8, TSP 20801A, is $44.85. Okay, $44.85 is a goodly amount to spend on a "free" chuck, but once you have one you'll find it to be very useful. You can make all sorts of special purpose accessories like quick mount jam chucks, square drives, and light duty faceplates.
After drilling clamp the wood in your workbench and tap. I'm using a homemade wooden handle, as an industrial handle big enough to take a big tap isn't cheap. Try to keep the tap as vertical as you can. There are some wonderful devices that will insure a vertical tap. Some are self contained, some are used with your drill press. I thought that I'd tried to make you spend enough already, so we'll correct for any tapping error later.
Once you've tapped the hole, cut the circles out on your band saw.
Now mount the tapped circle on your lathe. Wind it on until it makes contact with the spindle facing or the end of the threaded area, but don't jam it on hard. Unless you've done a really good job of tapping it will be a little eccentric. Take a small bowl gouge or scraper, and using light cuts, true up the face.
If your headstock has an unthreaded portion on the spindle, you can use a side-cutting scraper to turn a recess
at this time. Next reverse the circle on the headstock. It should fit much better this time. True the second face,
and mark it so you know which face to glue the other half of the body to.
After facing the threaded circle, spread some glue on the second face and clamp it to the untapped circle.
I've used a big homemade clamp, but a few regular C-clamps and a scrap wood will do just as well. Set it aside
Making Stub Morse Taper Gauge
While you're waiting for the chuck body glue to cure, you can work on the stub morse taper gauge. I got this excellent way to make a Morse Taper Gauge from a One-way Newsletter. Find a drive center or tail center that is in good condition and fits the way you like. Go to your scrap bin and find some small pieces of hardwood. For a #2 Morse taper you'll need two pieces about 3/4x3/4x1 inch, and one piece 3/4 inch thick by 2-1/4 inch wide by 1 inch long.
Find a couple of more C-clamps and glue the smaller pieces to the larger one using the fat end of the drive
center taper to space them apart. Set aside to cure.
Preparing the Collet
The first step in making the collet is to find a small piece of hard wood. I used maple again. It should be about 3 inches long, and big enough that you can turn a cylinder that will be just smaller than the root diameter of your headstock thread. For my 11/4 x 8 threaded headstock, that is about 1-1/8 inch. Mount the piece between centers and turn round. Leaving the diameter a little big at this point would be prudent.
Make Stub Morse Taper
To turn a stub morse taper on the collet, mark it an inch from the tailstock end. Set a caliper to the major diameter of your morse taper, use it and a parting tool to cut down to the major morse taper diameter at the point marked on the collet. Use your skew (or what ever you're comfortable with) to turn the end of the collet to a tenon the same diameter as the major diameter of the morse taper. Now unclamp your stub morse taper gauge, hold it in one hand, and hold your skew in your dominant hand Angle the larger end of the gauge towards the tenon and test the fit.
If it doesn't fit, take a light cut the length of the tenon. Alternate light cuts of the skew and test fits
until the large end fits. Now rotate the gauge a little bit more parallel with the tenon and test the fit. Make
a mental note of where it starts to get too tight and take a light cut with your skew from that point to the end.
Continue this way until the whole tenon fits.
If you're not comfortable holding a skew with one hand you can test with the gauge, then put it down and pick up the skew, etc. If you find the occasional event where the tenon grabs the gauge too disconcerting you can turn the lathe off to test the fit. Both of these modifications will lengthen the time required considerably, but of course you only have to do it once.
Drilling and Shaping the Collet
Mount and turn to fit inside Body
Remove the collet from between centers and remove your drive center from the headstock. Slide the tapered end of the collet into the headstock and give it a good whack to seat it properly. You can bring up your tailstock to steady the collet, but if you've gotten a good fit it won't be necessary for such a short piece, and will lengthen the time for the next step.
Taking light cuts, true the collet. Once it's running true, test to see if you can slide the threaded portion
of the chuck body over the collet. If not, take light cuts and retest until it fits. You want a loose fit, but
not a sloppy one.
Once you have the collet body trimmed to fit inside the chuck body, taper it over its length with your skew. I tapered mine about 1/8" over the 2 inch body. It doesn't matter exactly how much you taper it, but if you want to make other collets later it will be easier if you pick an easy to measure diameter.
Mount a drill chuck in your tailstock and mount a drill of the size stock you want to hold. A useful size to start with is 3/8 inch. Forstner bits are more rigid than twist bits and are less likely to drill off center. The downside of Forstner bits is that they don't drill deep well.
I wanted to be able to mount longer dowels completely through the chuck, so I drilled the first inch or so with
a Forstner bit, and followed up with a twist drill.
Drill slot stops
Next lock the indexing head and adjust the tool rest so that it is about 1/16 inch below center. Mount a 1/8 inch bit in a drill and drill through the colett about 1/2 inch from the stub taper.
Then turn the collet 90 degrees and drill another hole. These holes are to stop the collet from splitting. On
some collets I made later I omitted this step, and they haven't cracked. Yet.
Cut on Band Saw
The next step is to cut slots to the drilled holes in the collet body. You could use a hand saw, such as a hacksaw or dovetail saw, but it's easier on the band saw. This is considerably safer if you make a simple jig first. Take a short piece of scrap wood or plywood and cut a Vee notch the length of the piece. You can do this easily on a table saw with the blade tilted to 45 degrees. Then cut out a notch in one side a little past the center of the Vee. Clamp the jig to your band saw table so that the blade lines up with the bottom of the Vee. Now all you have to do is slide the collet up the Vee into the blade to cut the slots.
Save the jig, you might find it useful to cut dowels lengthwise, cut squares to rough octagons, etc.
Shaping the Chuck Body
Mount the chuck body on the headstock and turn it true with a bowl gouge. Mount a drill chuck in your tailstock and mount a drill bit about the size of the end of the collet taper. Drill through the chuck body. Do try not to hit the headstock with the drill, as it's not good for either. To make this less likely, put a plywood washer on the headstock first to move the body out a little.
Using a bowl gouge taper the chuck body so that it will be slimmer near your eventual work and not get in the way. If Fred published this photo, you'll notice that by this time I was so confused by constantly setting up, tearing down, and moving my tripod and camera that I'm cutting the wrong way. It wasn't fatal, just gave the chuck a little extra texture to grip.
Make Taper Gauge
Take a piece of thin cardboard, such as a cereal box, and slide it into one of the slots in the collet body. Trace around the body, then cut on the lines. This makes a gauge to turn a matching taper in the collet body.
Taper Body Inside
Taper the collet body using a side cutting scraper. You can rough it out to follow an even taper from the root diameter of the threads to the edge of your drilled hole. Then dismount the chuck body and check the fit using the gauge.
Made a mental note where stock needs to be removed, remount the body, and remove more wood where needed. Then remove the body and check with the gauge again. Continue in this fashion until you've got a fairly good fit.
Using the Collet Chuck
To use the collet chuck mount the collet body solidly in the headstock Morse taper. The first time you might want to apply a little wax. Then loosely screw the chuck body to the headstock. You may want to shorten the collet body a bit if it sticks out to far or true up its end. Mount your work by sliding it into the collet and tightening the body.
When taking heavy cuts, such as roughing a wine stopper (it's a pity whine stoppers aren't as easy to make) to round it's best to have the larger stock up against the collet end. You can easily loosen the chuck and slide your work out a bit to true up the end after the heavy work is done.