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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.