joe greiner
4th October 2007, 11:52 AM
I posted an earlier version of the Birdhouse Earrings here:
http://www.woodworkforums.ubeaut.com.au/showthread.php?t=42418
It's difficult enough to make two matched turnings of normal size, and just about impossible when they're this small. The trick is to make a large quantity of individual pieces, spread them out on a table or such, and select pieces that resemble each other enough to declare them a pair. There's nothing sacred about any of the dimensions. When worn, earrings are several inches apart, and dimensional deviations are less apparent. But deviations in proportions and angles are more noticeable, so those deserve more concentration. I'm using both Imperial and metric measurements. Woodturning is an international sport, so you might as well get used to it.
Materials:
1/2" dowel; hardwood with tight grain preferred. These are Ramin.
Toothpicks for perches (to be sanded to about 1mm diameter).
Stainless steel wire, 0.020" or thereabouts.
Fishhook hangers and plastic grips, available from craft shops.
Epoxy glue for hanger loops.
CA glue for perches.
Black acrylic paint for the doorway.
Clear spray coating; your choice of type and finish. These are polyurethane satin.
Tools:
Lathe (of course)
Drill press
1/8" drill bit - brad point preferred
1mm drill bit
Vise grip pliers
Open end wrenches (for calipers and gauges): 7/16" & 1/4"
Triangular file (for angle gauge)
Small bench chisel (1/2" or 12mm), 25-degree single bevel. I find this more suitable for small turnings. Sharper is better; I prefer to hone the chisel on a piece of 400-grit sandpaper on a piece of plate glass.
Chuck: Four-jaw with pin jaws or Jacobs. Jacobs may be preferred for single blanks.
Simple steady rest (optional). This allows faster production and less waste; example in Part 2.
Sandpaper, 80 grit for sanding the toothpicks for the perches.
Take all these instructions with a grain of salt. This is just how I've made them. Modify as you see fit; in fact, I encourage you to add your own variations.
Preliminary work: Clamp a 1mm drill bit in the vise-grip pliers, about 5/16" from the tip.
Take a piece of 1/2-inch dowel, about 12 inches long, and chuck it in pin jaws or a Jacobs chuck. Set the steady rest about 1 1/2" from the far end. Use the 1mm drill bit, placed at the center of the dowel, to set the tool rest; the tool rest will function as a locator for drilling the hole for the hanger eye. The end of the tool rest can touch the steady rest.
My preferred cutting sequence is shown in the attached sketch.
1. Shape a 60-degree cone at the end. Use the triangular file to verify the angle.
2. Cut off the tip of the cone to make a flat spot about 1/16" diameter. Use the corner of the chisel to make a small divot to assist drilling.
3. Drill the hole for the wire eye.
4. Turn the outside as shown to 7/16" diameter.
5. Plunge the chisel perpendicular to the lathe axis, with the bevel facing the end. This short bevel helps to reduce tearout at the roof edge. Only a millimeter or so parallel to the roof edge is satisfactory.
6. Turn the body to 1/4" diameter in stages.
6a. Make "stopping cuts" occasionally with the bevel facing the headstock.
7. Use the 7/16" wrench to locate a bevel cut at the bottom of the body.
8. Turn a cylinder portion for the ball finial. The "golden ratio" provides a good estimate for the diameter. That would work out to about 5/32", but let your eyes do the measuring as a proportion of the body diameter, i.e. about 0.6 times.
9. The bottom of the ball is 1/4" from the bottom of the body. (Simply because the wrench is available for a gauge.) Turn coves on either side of the ball. The easiest way I've found to turn such small coves is to plunge the chisel from each side of the cove, while rotating the chisel to about 30 degrees from vertical. Shape the ball with small slicing cuts, working around the surface.
10. When the stem is about 1 or 2mm (or about 1/16") diameter, slice through the stem and allow the piece to fall into your hand. Sand the end flat. If you hone the chisel, and take light cuts, this should be the only sanding needed.
Part 2 follows
Joe
http://www.woodworkforums.ubeaut.com.au/showthread.php?t=42418
It's difficult enough to make two matched turnings of normal size, and just about impossible when they're this small. The trick is to make a large quantity of individual pieces, spread them out on a table or such, and select pieces that resemble each other enough to declare them a pair. There's nothing sacred about any of the dimensions. When worn, earrings are several inches apart, and dimensional deviations are less apparent. But deviations in proportions and angles are more noticeable, so those deserve more concentration. I'm using both Imperial and metric measurements. Woodturning is an international sport, so you might as well get used to it.
Materials:
1/2" dowel; hardwood with tight grain preferred. These are Ramin.
Toothpicks for perches (to be sanded to about 1mm diameter).
Stainless steel wire, 0.020" or thereabouts.
Fishhook hangers and plastic grips, available from craft shops.
Epoxy glue for hanger loops.
CA glue for perches.
Black acrylic paint for the doorway.
Clear spray coating; your choice of type and finish. These are polyurethane satin.
Tools:
Lathe (of course)
Drill press
1/8" drill bit - brad point preferred
1mm drill bit
Vise grip pliers
Open end wrenches (for calipers and gauges): 7/16" & 1/4"
Triangular file (for angle gauge)
Small bench chisel (1/2" or 12mm), 25-degree single bevel. I find this more suitable for small turnings. Sharper is better; I prefer to hone the chisel on a piece of 400-grit sandpaper on a piece of plate glass.
Chuck: Four-jaw with pin jaws or Jacobs. Jacobs may be preferred for single blanks.
Simple steady rest (optional). This allows faster production and less waste; example in Part 2.
Sandpaper, 80 grit for sanding the toothpicks for the perches.
Take all these instructions with a grain of salt. This is just how I've made them. Modify as you see fit; in fact, I encourage you to add your own variations.
Preliminary work: Clamp a 1mm drill bit in the vise-grip pliers, about 5/16" from the tip.
Take a piece of 1/2-inch dowel, about 12 inches long, and chuck it in pin jaws or a Jacobs chuck. Set the steady rest about 1 1/2" from the far end. Use the 1mm drill bit, placed at the center of the dowel, to set the tool rest; the tool rest will function as a locator for drilling the hole for the hanger eye. The end of the tool rest can touch the steady rest.
My preferred cutting sequence is shown in the attached sketch.
1. Shape a 60-degree cone at the end. Use the triangular file to verify the angle.
2. Cut off the tip of the cone to make a flat spot about 1/16" diameter. Use the corner of the chisel to make a small divot to assist drilling.
3. Drill the hole for the wire eye.
4. Turn the outside as shown to 7/16" diameter.
5. Plunge the chisel perpendicular to the lathe axis, with the bevel facing the end. This short bevel helps to reduce tearout at the roof edge. Only a millimeter or so parallel to the roof edge is satisfactory.
6. Turn the body to 1/4" diameter in stages.
6a. Make "stopping cuts" occasionally with the bevel facing the headstock.
7. Use the 7/16" wrench to locate a bevel cut at the bottom of the body.
8. Turn a cylinder portion for the ball finial. The "golden ratio" provides a good estimate for the diameter. That would work out to about 5/32", but let your eyes do the measuring as a proportion of the body diameter, i.e. about 0.6 times.
9. The bottom of the ball is 1/4" from the bottom of the body. (Simply because the wrench is available for a gauge.) Turn coves on either side of the ball. The easiest way I've found to turn such small coves is to plunge the chisel from each side of the cove, while rotating the chisel to about 30 degrees from vertical. Shape the ball with small slicing cuts, working around the surface.
10. When the stem is about 1 or 2mm (or about 1/16") diameter, slice through the stem and allow the piece to fall into your hand. Sand the end flat. If you hone the chisel, and take light cuts, this should be the only sanding needed.
Part 2 follows
Joe