Disc Sander for Segmented Turnings

[John K Jordan]

I havent convinced myself to buy a drum sander yet. To flatten the rings, I am going to try Cole jaws and turn the face flat followed by face sanding on a flat plate.

It might be worth having! I have both turning and flatwod tools but don't do much flatwood. However, I do use my drum sander a lot for wood turning. For example, when preparing blanks for bowls and platter from dry, rough sawn wood I almost always sand both sides to examine the surface for defects, reveal the color and figure, and let me better decide which side should be up. Parallel faces simplifies marking and drilling recesses and such too.

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I also resaw wood into "thick veneer" and use use the drum sander to flatten before gluing it between other pieces for turning. The goblet uses a piece of walnut between the other layers, not only for accent but to allow a better glue bond since the cherry and basswood are both end grain.

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When I glue up layers to get thicker stock, flattening the pieces before I start makes things easier, such as with these Beads of Courage boxes.

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My drum sander is a Performax 22-44 but that's overkill for woodturning - a much shorter drum would work as well and be easier to align and the sandpaper strips would be cheaper! My guess is once you get a drum sander you won't be able to do without it!

Oh, and one other thing - when making beads of courage boxes from dry wood the deep hollowing can be a pain. It's far easier to hollow the individual layers before glueing them up so most of the hard work inside is already done! In this case, to flatten the rims for gluing I use a method Harvey Meyer shows in one of his videos - when on the lathe first true up a rim a bit with tools then flatten perfectly for gluing by holding a strip of sandpaper against the wood with a flat stick. I glue 80 grit paper to a flat edge of a 2x2 and hold it across both sides of the rim to make it perfect for gluing. (I support the 2x2 on the tool rest to make it easier.) I don't have a photo of this in action, but this drawing shows three such pieces and how I use recesses to hold the pieces for prehollowing and for flattening the rims on both sides with the big sanding stick before glue-up.

BOC_drawing_A.jpg

The holding method wouldn't work on segmented rings, of course, but the sanding stick method might be useful.

JKJ

[David Bolson]

John, to clarify, you’re prehollowing by mounting a layer on a chuck, flattening the edges for gluing, and then hollowing most of the way through (so you don’t run into the chuck), and then when all the layers are glued together you complete hollowing by breaking through the remaining thin layers of remaining wood?

David

[John K Jordan]

... this drawing shows three such pieces and how I use recesses to hold the pieces for prehollowing and for flattening the rims on both sides with the big sanding stick before glue-up.
BOC_drawing_A.jpg

John, to clarify, you’re prehollowing by mounting a layer on a chuck, flattening the edges for gluing, and then hollowing most of the way through (so you don’t run into the chuck), and then when all the layers are glued together you complete hollowing by breaking through the remaining thin layers of remaining wood?

David

Yes! Some require holding on one side to create the recess on the other, then reversing and hollowing and cutting away the first holding method. I actually hollow before flattening the rims but I'm not sure that matters.

Pieces before glue-up. (As shown, I generally partially shape the outside before glue-up.) I think this was the one for "Jack", basswood in the center for chip carving.
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Drawing, simplified, ready to turn. (I usually remove more wood inside to better match the final shape. But I did these sketches in a hurry late one night.)
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I like to show how easy it is at demos! I usually see turning demos where the demonstrator starts with the wood, describes and performs each step, then completes the project. Sometimes the "big picture" gets lost in the details.

For a Beads of Courage demo I like to do it backwards. I start with one all glued up and turned to final shape on the outside. It has the thin "webs" obscuring the inside so it looks solid. I mount it in the lathe and with a parting tool cut through and discard the two internal webs in about 20 seconds then pass the piece around. I've not only hollowed all the way to the bottom but I've shaped, sanded, and already applied finish to the "bowl" of the bottom layer! (It is SO easy to get that bottom curve perfect with this method.)

I like to do this exposing irst to get everyone's attention and show them how this completely avoids the dreaded punishment of deep dry-wood hollowing, All the piece needs then is smoothing the sides inside which is easy. I then go in to the details of doing one from scratch, including different ways of holding and turning, and of course, the sanding stick method of perfectly flattening for gluing, and ways to clamp.

[warning, soapbox lecture] Then I show a method I developed to make a lid that is guaranteed not to stick! Once at a symposium I looked at 10 Beads of Courage boxes that had been turned in for distribution to sick kids at the cancer hospital. But FIVE of the ten vessels had lids that were stuck and needed effort to open. Some kids have limited strength and manual dexterity and shouldn't have to deal with sticky lids. [end of lecture]

Note that for minimum turning effort some pre-planning is needed. I start by sketching out some possible designs. Then for the one I pick I make a full-sized drawing of the profile of the sides, bottom, and top. From this I can take measurements with dividers and determine exactly how wide the glue flats need to be, how to shape each layer to leave enough wood for final turning but not too much that it is a chore to turn. When I started doing this things got SO much easier! Instead of letting the wood "speak to me" and let the shape evolve, I speak firmly to the wood and make sure it knows I'm the boss! I've started using the "stetch first" method for lots of turnings and am accumulating notebooks full of sketches.

This, BTW, is one of my sketches. Not only does it guide me in preparing the blanks for glue-up, it also lets me calculate the internal volume which can be important.

boc_drawing_smaller.jpg

The horizontal lines represent the thickness of each layer.

For anyone isn't aware of the BOC program, search google or at least watch this video about the reason for the beads.
https://www.youtube.com/watch?v=WMCcJxO9mnY

A friend who has been making these for years said the whole thing hit home when two parents told told him they used his BOC boxes for urns for the children's ashes...

JKJ