Hi there,
Hope you're well. I'm using 3/8 inch baltic birch plywood to create dome-shapes. The attached photo was my first test in thicker, cheaper plywood, but you get the idea. Right now I'm using a tapered ballnose with 10% stepover and it's good, but I still have to do sanding before I apply a dye, stain, etc. I'm not doing a roughing pass.
Is a tapered ballnose best for this operation? Is there anything else I can do to minimize sanding? Or are there any tips on how to best sand a small piece like this?
many thanks
stuart
Hi S84 - What is your actual stepover vs a %? To minimise sanding you will need to :
1) Do a finishing pass with very sharp tool of say <0.5mm stepover
2) or you can use a form tool such as a 1/2" coving tool and do it in one pass vs many small passes.
either way very sharp tools are required. For sanding use a sanding sponge not paper and seal the timber with shellac, PVA or a sander sealer before you sand. This will lock up the grain and make sanding much easier.... dye prior to sealing by the way...Cheers Peter
Hi there,
Many thanks. Attached is what I did with my tapered ball nose.
In another forum, a user suggested doing 1/4 ballnose roughing pass, then a 1/8 ballnose finish pass. Any thoughts on that?
The coving tool suggestion blew my mind-- I hadn't thought of that.
Same for the sanding sealer... I'm trying to do a row of 8 pendants or so each with different settings so I can take notes and compare.
thanks again and all the best
stuart
Unless you are doing this for fun, there may be faster ways to do this with manual machines and get a better finish when complete. Because of the opposing grain of the cross plys, it will be difficult to get a clean cut with conventional cutters.
You may want to consider cutting you blank with a hole saw without the centering drill. CA glue the blank to a wood mandril and take it to a belt sander. No torn grain from the cutter (which is clearly visible in your photo), and a much smoother finish after different grades of abrasive. Many folks that do manual wood turning take it a step further and apply stain and then CA glue for finish while still on the lathe. Part off and you're done.
optimizing plywood
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