joe greiner
8th October 2008, 11:04 PM
In addition to the normal Show'n'Tell, our woodturning club has a "BringBack." At each meeting, there's a drawing from an envelope of member names, with absentees dropped back into the envelope. The winner of the draw gets the piece turned by the previous winner, who also provides timber for the challenge. The winner has two months to complete his/her work; thus, there's a staggered schedule of two works in progress. This is the entire set of rules.
I won the draw at our August meeting. I received a bowl and two pieces of cedar (originally one piece) from the previous winner. It wasn't quite clear what was sought from the two blanks. Was I expected to make two of something? Or was one of the blanks for practise and mistakes? I thought better than to ask, and took my cue from the movie, "Butch Cassidy and the Sundance Kid." In one sequence, one of the heroes is about to conduct a knife fight. He pauses to establish the rules, and promptly asserts "In a knife fight, there ain't no rules," while delivering a boot to the opponent's groin. Sounded about right to me, so I made my own rules.
I turned both blanks to cylinders between centres, with tenons at both ends (to allow future selection). The offset strip of sapwood suggested a goblet with captive rings to accentuate its origin as a single piece of timber. I turned the outside of the rings and the outside of a tulip-shaped bowl; the inward surface of the tulip profile will accommodate the wheels of the steady rest. I completed the rings and freed them from the blank, leaving a stout stem to serve as a sanding drum for the inside of the rings. Then I mounted the blank in a chuck with tailstock assist, and sanded the outside of the bowl. With support of the steady rest, I hollowed the inside of the bowl.
I removed the steady rest, and added a DIY pressure pad at the live centre to engage the bottom of the bowl. The pressure pad is simply a jumbo LEGO(tm) block with a piece of foam padding. The hole in the bottom of the block fits nicely on the cone of the live centre. I re-sanded the outside of the bowl to remove the wheel prints. Then I reduced the stem to more pleasing proportions. Intermittently, I taped the rings to the bowl or the foot to access different parts of the stem; I never had a full view of the whole stem. I suppose it could have been made more slender, but I didn't want to push my luck at this late stage. I waxed everything, at speed for most of it, but by hand for the rings.
The easiest way I've found for completing the bottom of pieces like this, is to drive a parting tool at an angle near the chuck jaws, forming a foot ring along the way. I also like to introduce a wee outboard step at the foot ring for some finesse. There isn't enough control space for additional goodies. When I've reduced the supporting timber to about 3 or 4 mm diameter, I just break the piece loose and touch up the bottom with a utility knife.
This is one of my most successful projects with captive rings. The rings flop just about right with respect to the stem and the foot. Cedar can sometimes exhibit ill behaviour. The provider of this driftwood opined that salt water content might have made it a more orderly candidate.
Dimensions (from memory, alas): 3" (75mm) diameter; 6" (150mm) high; wall thickness about 1/8" (3mm).
Some of the pictures are exaggerated stereo pairs (PnL/R), artificially induced by rotating the goblet. They can be free-viewed as adjacent thumbnails; as blowups, use reduced windows and set the images at about 2.5" (60mm) on centres. This may, or may not, be successful. Take care to match the scales of the window dimensions, and bail out if you experience discomfort.
Comments (praise and/or condemnation) welcome.
Joe <2008_10_17/Goblet/P1L/R,P2L/R, P4L/R,P6-9
I won the draw at our August meeting. I received a bowl and two pieces of cedar (originally one piece) from the previous winner. It wasn't quite clear what was sought from the two blanks. Was I expected to make two of something? Or was one of the blanks for practise and mistakes? I thought better than to ask, and took my cue from the movie, "Butch Cassidy and the Sundance Kid." In one sequence, one of the heroes is about to conduct a knife fight. He pauses to establish the rules, and promptly asserts "In a knife fight, there ain't no rules," while delivering a boot to the opponent's groin. Sounded about right to me, so I made my own rules.
I turned both blanks to cylinders between centres, with tenons at both ends (to allow future selection). The offset strip of sapwood suggested a goblet with captive rings to accentuate its origin as a single piece of timber. I turned the outside of the rings and the outside of a tulip-shaped bowl; the inward surface of the tulip profile will accommodate the wheels of the steady rest. I completed the rings and freed them from the blank, leaving a stout stem to serve as a sanding drum for the inside of the rings. Then I mounted the blank in a chuck with tailstock assist, and sanded the outside of the bowl. With support of the steady rest, I hollowed the inside of the bowl.
I removed the steady rest, and added a DIY pressure pad at the live centre to engage the bottom of the bowl. The pressure pad is simply a jumbo LEGO(tm) block with a piece of foam padding. The hole in the bottom of the block fits nicely on the cone of the live centre. I re-sanded the outside of the bowl to remove the wheel prints. Then I reduced the stem to more pleasing proportions. Intermittently, I taped the rings to the bowl or the foot to access different parts of the stem; I never had a full view of the whole stem. I suppose it could have been made more slender, but I didn't want to push my luck at this late stage. I waxed everything, at speed for most of it, but by hand for the rings.
The easiest way I've found for completing the bottom of pieces like this, is to drive a parting tool at an angle near the chuck jaws, forming a foot ring along the way. I also like to introduce a wee outboard step at the foot ring for some finesse. There isn't enough control space for additional goodies. When I've reduced the supporting timber to about 3 or 4 mm diameter, I just break the piece loose and touch up the bottom with a utility knife.
This is one of my most successful projects with captive rings. The rings flop just about right with respect to the stem and the foot. Cedar can sometimes exhibit ill behaviour. The provider of this driftwood opined that salt water content might have made it a more orderly candidate.
Dimensions (from memory, alas): 3" (75mm) diameter; 6" (150mm) high; wall thickness about 1/8" (3mm).
Some of the pictures are exaggerated stereo pairs (PnL/R), artificially induced by rotating the goblet. They can be free-viewed as adjacent thumbnails; as blowups, use reduced windows and set the images at about 2.5" (60mm) on centres. This may, or may not, be successful. Take care to match the scales of the window dimensions, and bail out if you experience discomfort.
Comments (praise and/or condemnation) welcome.
Joe <2008_10_17/Goblet/P1L/R,P2L/R, P4L/R,P6-9