In case you hadn't noticed, Jig_saw was the one who started this thread a few years ago. After Jig_saw's recent posts, it is hard to resume the thread, but here goes.
I completed a mahogany baby rattle for my newborn great nephew. I am including my design and measurements; see the PDF file below. The drawings are my own, but I cannot take credit for the original design idea. I saw a similar rattle made by a member of our local woodworking club, and he was kind enough to answer my questions about it.
HINTS AND TRICKS
* Spouse and I tested several fill types. We tried popcorn, rice, dried beans, and small stainless steel ball bearings.
* We liked the sound and feel of the stainless steel ball bearings the best.
* Ordinary steel ball bearings are easier to get, but I wanted this to be an "heirloom" piece. I hope the stainless steel bearings will never rust inside, and keep their sound for a long time.
* I found two bearing supply stores in my county, and they both sell stainless steel ball bearings. Minimum quantities were an issue, but I found one who would sell me a small number. They understood the special nature of the project and went out of their way to help me out.
* The bearings are small. I would guess that they have a diameter somewhere between 2 and 2.5 mm, but I do not have access to one right now.
* I started with a piece of genuine mahogany (Honduran mahogany) - 3 x 3 x 12 inches. The 3x3 size was hard to find. There are lots of 2x2 and 4x4 pieces out there. I bought this piece at a local Woodcraft store.
* Square the blank. I cut it to 2-3/8 x 2-3/8 x 10 inches. Make sure the ends are perfectly square to the length, so that when you mount it in the chuck later, the other end will be well centered.
I kept the two long cutoffs for finish testing. See my finish examples in this thread: https://www.woodworkingtalk.com/f8/odies-oil-214645/
* Measure and mark the "rattle ends" for cutting. If you have a 12 inch piece, there will be a lot of excess on the ends.
* Make the cuts on a bandsaw to minimize the kerf.
* Sand the ends to remove the bandsaw blade marks and to prepare the wood for gluing. Remember, this will be an end grain to end grain glue-up. You want smooth surfaces, but do not take off more than you need, to leave yourself the best possible grain match-up.
* Use multiple Forstner bits to drill the cavities on each side of each cut (four sets of drilling to do). Mark the drill centers carefully.
Take your time. It took me nearly two hours to do that job. Drill slowly and patiently. Watch drill bit speeds (should be slow) and keep your Forstner bits cool!! After using the two larger Forstner bits, I didn't bother with the third Forstener bit (the smallest one). I used an old, cheap, awful drill press, but it works.
* Insert the fill material in a cavity. Hold the pieces together with your hand and test the sound. Keep in mind that the sound will be brighter and louder when the walls are thinner after turning. Test various materials and quantities until you are satisfied. I used ~30 stainless steel ball bearings on each side. (Family heirloom note: The exact bearing counts represented the birth years of my parents, his great-grandparents.)
* Be extra careful to match the grain perfectly when you glue them back together. I used Titebond III and appropriate clamping pressure.
* Use a compass to draw a slightly oversized 2-1/4 inch circle on top and bottom, then use it as a guide to belt-sand or cut the edges to form an octagon. That makes the job of roughing it to a cylinder easier.
* I mounted the blank between a spur drive and a live center for most of the turning work.
Explanation: When I made a prototype, I started with a chuck, the prototype rattle twisted apart in the middle when I had a catch on the tail side of the rattle and the chuck side kept going. It was my hope that using a spur drive might avoid that issue. Less support, more risk, but less chance of total destruction.
* I used a variety of turning tools, both high speed steel and carbide.
* Rough the blank to a cylinder.
* Mark the cylinder to define the shape. Use the two seams to guide you.
* Use calipers and take careful measurements as you turn.
* Make sure you leave enough material to give structural strength along the turning axis as you turn off the wood. I was careful to leave more on the headstock side.
* Turn the round shapes and center spindle. I did the shaping by eye and made frequent measurements with the calipers. Make sure the tools are directly and well supported. It is tempting to use the side of carbide scrapers as you move around towards the ends of each ball. That leads to twisting and catches.
* Hide the glue seams in a stripe on each end. I added two more stripes on each ball for decoration and as extra camouflage.
* Measure the diameter of the headstock/spur end to make sure it will fit properly in your chuck. Reduce it to fit if necessary. I reduced mine to fit the 2 inch chuck jaws.
* Mount the rattle in the chuck. Use a live center on the tailstock to give the rattle support as you continue to thin and shape the rattle. Shape the center spindle and tailstock ball as close to complete as you feel comfortable.
* Do your lathe-turned sanding now, while the rattle is still supported on both ends. I sanded from 150 to 600 grit using the Rockler sanding strips: https://www.rockler.com/woodturners-...l-sanding-pack
* Remember to stop the lathe and sand with the grain, too. Get all the scratches out if you can.
* Use a parting tool to finish the tailstock end. I stopped the lathe and used a Japanese hand saw to cut off the tiny end. At this point, the rattle is supported only by the chuck.
* Use sandpaper to clean up and shape the tailstock end of the rattle. Do whatever lathe sanding you need.
* Make a soft padded "cushy" to support the tailstock end. One of my friends suggested using a "dog toy", but I made one from a small piece of a sock with two thick pieces of soft foam inside. It was small, about 1.5 x 1.5 inches. I put it between the point of the tailstock live center and the rattle to give the rattle support without leaving a divot in the end. I tested it by hand and at slow speeds to make sure it was safe before proceeding. It should be small and light.
* Finish shaping the chuck end of the rattle to the point where you are ready to cut it off.
* Do any additional touch-up sanding as required.
* At some point, you bite the bullet and cut it off. I I used the parting tool and was careful to support the turning rattle from underneath with my hand. Then I stopped the lathe and cut off the final bit with a Japanese hand saw.
* Use 150 grit sandpaper to hand shape the cut-off ends. Be patient and extra careful. You can sand off, but you can't sand on. It doesn't take long.
* Hand sand through the grits from 150 to 600, as needed, to eliminate all scratches. Hand sand with the grain, of course.
* Hand sand with 500, 1000, and 1200 grit silicon carbide sandpaper.
* I buffed with 0000 steel wool before each coat of finish. I used Liberon steel wool, which is supposed to be better quality and oil free. I wish I had chosen the 3M gray pads instead, but I wanted to use a more traditional approach, whatever that means.
What I used: https://www.rockler.com/liberon-stee...000-steel-wool
What I wish I had used: https://www.homedepot.com/p/301118025
* Use a food safe / baby safe finish (duh!).
What I did:
* Buff with 0000 steel wool before each coat.
* Apply two coats of Tried and True Varnish Oil.
* Apply one coat of Tried and True Original Finish.
The instructions for the Tried and True finishes say:
* Burnish with 0000 steel wool.
* Apply a light coat of finish.
* Let it sit at least an hour, but not many hours.
* Buff off with a clean cloth until it feels dry.
Note: It never felt completely dry, but how can you tell when you have oil on your hands?
* Wait at least 24 hours to cure before the 0000 steel wool and the next coat of finish.
* No steel wool after the final coat. Just buff with a clean cloth.
PHOTOS AND FILE:
* Mahogany Baby Rattle
* Bonus: Small Mahogany Top - Made from one of the cutoffs and finished with one coat of Tried and True Original.
* Baby Rattle Plan and Drill Guide.
Sorry I didn't take the time to make it "publication ready." The small diagonal lines were used to get measurements of the cavity-to-sidewall distance. I left a minimum of 1/8 inch, not that much. Watch out!
-> Feel free to steal, copy, modify, or claim it as your own design. Enjoy!