Hi, Alan Stratton from As Wood Turns.
On my last video, I made a bracelet using this home made expansion chuck. I’ll explain
this chuck in this video. A while ago, I made a batch of bracelets.
Afterwards, Jeff from Hawaii asked how he could finish turning a bracelet without flipping
it over from side to side. It turns out that he uses Koa which shows a difference if he
reverses the wood. I figured some sort of an expansion chuck should do the trick.
At first, I thought of mounting a bolt somehow that could tighten a wedge that would expand
to hold the bracelet. That was complicated. Finally, I came up with the idea for this
chuck. Already on my lathe, I have the bolt that I need — It is in the tail stock.
The primary components are: 8 tapered slats and 2 tapered plugs. My slats are Baltic birch
— they could be any straight grained wood. These are 5/8″ thick plywood, 10 inches
long, and initially 1 1/4 inches wide. They are tapered from the middle to ¼ inch on
the end. I used one of these slats as a template as I turned the plugs. After the plugs were
finished, I ripped the slats down to 1 inch and sanded a taper on the sides so the small
ends could fit more closely together. One of the two tapered plugs is for the headstock
— the other is for the tail stock. The only difference is how they are being mounted.
The head stock plug has a hole sized for the drive center; the tail stock plug has a hole
sized for the revolving center. In actual use, there are a lot of parts to
juggle when mounting the bracelet. I upgraded my plugs by threading each. The head stock
plug is tapped to match my head stock spindle — 1 ¼ inch and 8 threads per inch. I used
a Beall tap. The tail stock plug is tapped for ¾ inch and 10 threads per inch to match
my revolving center. I used a tap set from McMaster-Carr for $27 dollars. Now there are
two fewer parts to hold when mounting a bracelet. I’ll show threading when I video making
wood faceplates. For the plugs, I first threaded the plugs
into face grain and bored shallow recesses, then turned a cylinder with tenons on each
end and glued the tenons onto the threaded pieces. Then I turned the taper using a slat
as a guide. Finally, I separated the plugs and trimmed the ends by about 1 ½ inches
so they could come closer together for wedging. In theory, the bracelet could be the only
thing that holds the slats together. However, consider what would happen if the bracelet
fractured when you were turning it. Picture bracelet parts, slats and plugs flying all
over your studio and maybe hitting you in the face. Not a pretty picture.
For insurance, I’m using an automotive band clamp on each end of the slats. The slats
are 10 inches long to give enough room to get them far away from the bracelet. I don’t
want to accidently hit my fingers, hand, or a tool. Always orient the clamp so that the
end of the metal is opposite the lathe rotation. These band clamps are risks to my hands.
By the way, looking at this chuck, another woodturner suggested using duct tape instead
of the band clamps. Not on my life. I use duct tape everywhere except here. Duct tape
can tear. I cannot trust my life or limb to duct tape.
Now, as insurance against hitting the band clamps, I made latex rings out of tubing.
The ends are glued with medium CA to a small piece of wood dowel. One ring goes on each
side of each band clamp. If my hand did wander over to a band clamp, it would hit the soft
latex first. As final insurance and protection to my hands,
I wrap a piece of duct tape around each band clamp. This holds down the loose end of the
band. See, I do use duct tape — but only in the right situations.
To mount a bracelet, I hold the slats together with small rubber bands. On one end, I put
a latex ring, the loose band clamp, and the other latex ring. Then slide on the bracelet
and the other latex rings
and loose band clamp. I also add a little padding under the bracelet if the inside is
finished. Slide this bundle onto the head stock plug
and bring up the tail stock with its plug. Crank in the tail stock until the bracelet
is firmly set on the slats. Then tighten the band clamps. Recheck that
the bracelet is still firmly set. Finally tape down the band clamps with duct
tape. In use, I could turn the slats more round.
I expect that I will gradually wear down the slats with turning tools. Since they’re
wood, the slats are easily renewed or remade. As is, this chuck will handle a bracelet from
about 2 ½ inch diameter to about 3 ½ inch diameter. If I need a larger diameter than
this chuck permits, then larger plugs and /or wider slats and conversely for smaller
diameter — smaller plugs and / or smaller slats.
As always, you are the one responsible for your safety. This jig has made turning a bracelet
easier for me. Please “Like” this video and subscribe
to my channel. Add your comments and question below this
video. Thank you for watching. Be safe so you can
have fun. Wear your face shield.