So what is changing you ask? Mainly just the name. The new blog will still focus primarily on woodworking but will also include other ramblings and discoveries as well as a continuation of the Combat Carpenter article.
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In part 1, I talked about the cutting of segments and gluing
pairs and quarter rings. In part 2, I completed each of the rings and then
screwed up the stack. Wanting to get the most out of the project (from a
refresher / learning perspective) I decided to press on. Well the final
stopping point did not yield a beautiful bowl. Instead it showed all the flaws
and structural failures. From my perspective, it was a win! A lot of times,
people tend to stop a project and start over when they realize they have messed
up. Makes sense if you are on a time crunch. However, my objective was more
educational. So I wanted to see how these early screw ups would affect the
final product.
These two shots are opposite sides of the same bowl. Above, you can see the rough edges of segments yet to be turned true. Below, all segments are nicely rounded (and some were too thin). This is the result of the ring shift.
I have since gone back and reviewedLessons in Segment Woodturning, as well as my small library of books
on the subject. Several things could have been done different. One of the
obvious is an adjustment to my cross cut sled. Despite a dead on measure with a
digital protractor, the angles were slightly off. Instead of 18 segment rings,
the sled cut 17 segment rings! This put the angle at 10.58 degrees instead of an
even 10 degrees. Looking back at the protractor instructions, it says +/- 0.5
degrees. Note to self – DOUBLE and TRIPLE CHECK EVERYTHING & TEST EVERY JIG
BEFORE COMMITTING!
You may have notice the vertical glue joints, on one side, don’t lay in a
typical brick fashion but rather a stair stepped pattern. This was due to
mistake #2: aggressive sanding. At least one segment in every ring was significantly
shorter than the rest. No two short segments were the same length. I spotted
this during the first three ring constructs. A slight correction and the rest
improved. Too bad it was the primary or “theme” rings. The cause was excessive
exposure to the disk sander. A modification to the sanding jig made this flaw
go away. Note to self: TAKE THE TIME TO BUILD THE PROPER JIGS
The third and most deadly flaw was the stack. This was the
one thing that should have stopped the project cold. The cause, you ask? It was
“Impatience”. In other words, I let myself get rushed. I know better. I know
that this type of woodworking takes EXTREME patience. Rushing any aspect of
this NEVER ends well. I actually made two separate errors here. Either one, by
itself, may have been mitigated. However, committing both doomed the project to
the fire pit. First, since the project was too large for my vertical press, I
simply clamped the stack as seen below with the first set of rings.
Instead, I could have used any of a number of centering jigs
(more on that later).The second was
just a bad case of cerebral flatulence. During the stack of the second set of
rings, I opted to glue all three at the same time in order to save time during
the drying stage. This provided a “slick” surface on either side of three rings
(wet glue). As individual clamp pressure was applied by the above clamping
method, the rings began to shift in various directions. The result was a set of
rings so far off center that recovery would not be possible. To save 12 hours,
I destroyed the work that took 30+ hours to complete. Note to self – NEVER GLUE
MORE THAN ONE RING AT A TIME IN THE STACK!
The shift occurred between the base and first 3 rings
At this point I knew the project was doomed. Yet, I was
quite curious if a change in profile could salvage the part. I even considered
reversing the project by making a base for the wide part and a lid for the
smaller section (instead of a bowl with the small section as the base). I
powered up the lathe one more time to see how far it could go. After about 3
minutes I stopped to check and saw the show stopper.
One side of the segments was barely touched while the other
side became so thin it tore a hole. I decided to stop right there. No sanding,
no more tools. I conceded defeat to the infamous Murphy and his gremlins. I went ahead and applied a light coat of friction polish to help
highlight the flaws.
One thing that really bothered me was the centering jig. I
went to the Segmented Woodturners website and (after renewing my
membership) did some research. A few things have changed since I last worked on
segments. Somebody found an easier way to make every ring perfectly centered! See
video below
I have a feeling woodturnerpro.com is going to get an order from me soon :)
If nothing else, this was a great learning project. I
invested about 35 hours in it. It could have been done more efficiently but at
this point that is the least of my worries. When I first started segment
turning, my very first project was a stave constructed vase. Made of 8 staves,
I had messed up one stave and set it aside, then cut a new one. Later I came
back to the project, picked up the 8 pieces and started gluing them together.
However, when it was time for the last stave, I realized that number 7 was the
one I was suppose to have tossed. This resulted in a failed project. That
lesson was “note to self #1: MARK ALL SEGMENTS / STAVES.” The very next segment
project was an 7 ring bowl that turned out very well. So if history is any
indicator, I’m on target for another successful project!
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