Nested Bowl Set:
Andy Coates looks at using a bowl saver to make a set of nested bowls to decorate.
Andy Coates looks at using a bowl saver to make a set of nested bowls to decorate
No matter how we acquire our wood for turning, bought in or sourced for free, we ought to make the most of it. Alongside hollow vessels, the bowl is probably the most wasteful object we turners make. Most of the outside and the inside end up as shavings on the workshop floor; not only is it wasteful, but it also means we have to clear the shavings up and dispose of them. So what can we do about it?
The most obvious thing we can do is to core the inside of the bowl in order to produce one, two, three, or possibly more blanks from the original ‘mother’ bowl. I think people are often put off from bowl saving because the initial outlay for a dedicated bowl saver is not inconsiderable; however, a 330 x 100mm ash blank could cost about £23, and from that blank you can produce around £40 worth of ‘blanks’, so the initial outlay is soon recovered. On the plus side also, you get to produce nested sets which, while not big sellers, are lovely things to make.
Another consideration is ease of use, but as you will hopefully see here, the process is not in the least difficult to master. I will turn two bowl sets in this project; one from green wood and one from a pre-turned and seasoned set.
Plans and Equipment
• Rough-cut blank 355 x 125mm
• Woodcut bowl saver
• 10mm bowl gouge
• 10mm parting and beading tool
• Point tool
• Strip of Formica
• Abrasives 180–400 grits
• Cellulose sealer
• Danish oil
• Spirit stain
• PPE: Facemask, gloves, dust mask/respirator
Other coring systems
Other coring systems are available. The coring system from Oneway also works in a similar way to the woodcuts, which also cuts semi circular hemisheres. The Coring system from Kel McNaughton provides for more variation in core size and shape, and may therefore prove more versatile; however, this other system has a bigger learning curve when getting to know how to use it to get the shapes you want.
Drawings and how to resize them
To enlarge or reduce the size of drawings right click on the image to download it and then go HERE to watch a video on how to use paper with a grid to do exactly that.
The Woodcut bowl saver I used in this project is very simple to set up and use, and having done the initial setting up there is less to do when you next use it. This unit cuts semi-circular hemispheres only.
It does have some restrictions though. The largest core the rig can cut is 305 x 125mm, from a blank approximately 368 x 150mm. You could core from a larger blank, thereby saving the middle, but it would not produce a ‘nested’ set in the traditional sense. Do not feel hamstrung by the setting for wall thickness. You might decide you want thicker walls to allow for a shaped rim, or you may not wish to ‘nest’ the bowls and simply wish to save the material rather than waste it to shavings. You may also wish to make different shaped bowls rather than scaled down versions of the mother bowl. The choices are yours to make.
The number of bowls possible from a blank using the Woodcut coring system:
• 75mm thickness will produce two bowls
• 100–125mm thickness will produce three bowls
• 150mm thickness will produce four bowls
Marking out the face of a blank for coring:
• For wet wood allow a 25mm wall thickness. For dry wood allow 20mm
• Mark this on the face of the ‘mother’ bowl
• Mark the width of the cutter next to this line (approximately 6mm)
• Mark off the next 25mm
• Mark the cutter width again
• Repeat as blank allows
1. Firstly, double check everything is locked down and secure on. Big blanks can cause big accidents. Mount the blank using a faceplate ring with double helix wood screws for security. Bring the tailstock up for support during the truing process. Begin turning at slower speeds if the blank is out of balance, and increase speed as balance is achieved
2. Using a long-ground bowl gouge true the side of the blank to a clean cylinder and then move on to the face surface and true as close to the revolving centre as possible. The tailstock can be removed once the blank is balanced and the face surface finished. Because this bowl will be cored I will turn a very classical salad bowl shape
3. Turn a tenon for the largest jaw set you have. I always use large Gripper jaws for security. This bowl saver produces hemispherical blanks so the ‘mother’ bowl needs to accommodate this shape. As with any piece of work you should constantly be on the lookout for faults in the wood. As you can see here, there was a fault
4. Some people like to include faults, inclusions and holes as part of the finished item, but if you are preparing rough-outs to dry, these faults can often lead to failures during drying. They can also make the finish turning more prone to accidents; so here I back-filled the fault with wood dust and glue and used a pull cut to remove the excess once the glue was cured
5. Now, mount the bowl on the tenon and true the face. You can utilise the faceplate ring or remove it and turn a tenon. I prefer the former option. Set the rig height by a locking collar that puts the cutting tip on centre. Support the rear of the bowl saver by a 2MT fitting which sits in the quill of the tailstock and lock in place. The tailstock, banjo and stem are locked securely
6. Mark the wood as per the instructions in the side panel and align the large (if appropriate) cutter with the first cut. You can see here that the position allows for the faceplate ring to remain. If this were not the case I would remove it and turn a tenon for mounting the core
7. In order to core to the correct depth a template is provided. It sets the distance between bowl base and the centre of the pivot bolt. This is a critical step. NB: The bolt itself does not need to be at the centre of the blank. The template ensures that you don’t cut through the base of the bowl
8. After checking everything is set correctly and all components are locked securely, you are ready to begin coring. Set the lathe speed to 600rpm. Use your right hand to guide the handle and your left to hold the blade down on to the guide plate. This inhibits vibration
9. Turn the lathe on and take up your position. Gently pull the cutter to the wood and feed in slowly and evenly. Do not force the cut. Withdraw the cutter frequently to remove the shavings. As soon as you are able, bring the handle against your body to further aid control
10. When you reach about this shown depth internally you may experience some resistance to the cut. This is because you are beginning to enter end grain. Slow the cut down, hold the handle firmly and apply downward pressure to the blade. Take it easy and you will get there
11. As the cutter approaches the centre of the bowl the noise will change. At this point you could stop the lathe and pushing on one edge of the core, break the last section. You can also cut straight through with little difficulty. The first core will spin in the hole and you can turn the lathe off
12. Now you can mount the first core on its faceplate ring. On this bowl cut a tenon to suit your standard jaws. Shape the bowl as close to the ‘mother’ bowl as possible. Because you are using a standard tenon take the next coring stage more carefully as the hold quality is reduced
13. With the first core mounted on the tenon you need to reset the bowl saver using the template. As this bowl exceeds 200mm I am still using the large cutter, and because the bowl is less deep the rig will be further away from the face of the bowl. This can lead to increased vibration, so be aware of it and support the blade firmly
14. For the second core remove the faceplate ring and cut a tenon on the face. Having cored the bowl again remount the third core on the tenon and turn the final bowl. NB: You may find you have sufficient wood left to make a third core. Your wet bowls can now be set aside to dry, or your dry bowls completed
15. For the next step swap to a pre-turned and dried set of ash bowls. Your first job is to true the warped surfaces of the dry wood. The original 25mm of thickness should allow for this. Turning here is as for any usual bowl of dry wood. Abrade to a 320 grit finish but do not seal the surfaces
16. Next we mark out some definition lines on the rim. They are matched inside and outside the bowl. Mark 20mm from the rim and then 3–4mm inside this line and the same from the rim edge. Also mark 5mm from the base edge, and mark a circle in the interior base about 30mm diameter
17. The next step is to make V cuts on each of the scribed lines. You can use the tip of a skew chisel, but I find a small-handled point tool is easier to use, especially inside of the bowls. Mark the cutting tip with a lack marker to ensure a uniform depth of cut
18. Now you need to scorch the V cuts. Use a sharp-edged wedge of a dark, hard wood for this, such as ebony or lignum vitae, but I find the very best material to use is Formica. This material was made to withstand heat so builds up heat through friction extremely well. Push firmly into the V cut
19. The blackened lines create a pleasing decorative feature by contrasting with the surrounding natural wood, but more importantly they also seal the inner surface of the cut which can help reduce stain wicking through to the natural wood. Be careful as broken Formica is terribly sharp. Repeat on each V cut
20. Between the scorched defining lines at the rim and base now cut a series of shallower V cuts. Mark the cuts if you wish, but I prefer a random approach. I use the same point tool and make a new depth mark. Make the cuts as clean as possible
21. Before we stain the surface we need to abrade the whole bowl. Be careful not to remove definition. Once abraded, seal and oil the outer and inner rim and the area at the base. This will help resist wicking, and should also mean any splashes can be wiped off before they damage the natural areas
22. Stains and dyes work best for colouring here, because they fill the cuts easier than paints. Apply with a soft brush and avoid flicking the stain on to the rim and base band. Because you have cut through the grain with the V cuts you can often end up with an effect similar to chatoyancy
23. Once the stain is dry inside and out, mount the bowl on either a jam plate or Cole jaws and carefully remove the mounting tenon. Finish the base as far as possible and then remove the stub with a carving chisel or craft knife. Finish the remainder then seal and sign your name and wood species
24. While re-turning this set of air-dried bowls I found the smaller bowl had warped further than the larger two and decided I would not finish it as the wall would have been too thin relative to the larger two bowls. But still, making two bowls from a single blank is a 100% improvement on the norm