Back before I acquired my “big lathe” I was given a large piece of what I assume is sapele by my Physics tutor which she was able to salvage, so thanks to her! I decided I had to turn it resulting in what I called… Pushing a lathe to the max.
I took a few photos along the way so here is a brief overview of the process. Perhaps if you own a mini lathe you will re-think the size of piece which can be achieved be achieved with it?
As with just about any bowl that I turn I begin work on the bandsaw, either using a template or a compass I mark out the largest circle achievable with the blank which I have. Using that I can rough it into shape on the bandsaw, when it comes to bowl turning you can save yourself a lot of time by simply knocking off the corners with a saw. Even a handsaw could be used to take off the corners if you do not have access to a bandsaw. Spindle turning on the other hand is a situation where you will likely spend more time sawing off the edges than it would take using a roughing gouge on the lathe.
Next as you can see in the right image above I used a forstner bit to drill out a circle for mounting the blank to a chuck. Using a large forstner bit is by far the quickest way of initially mounting a blank to the lathe. A faceplate is an alternative to this but is a little harder to mount central. By using a forstner bit I was able to line up the drill using the centre point which had been marked on the wood when roughing out the circle.
This meant that I had to offset the tool rest to one side of the bowl, this did present a little bit of a challenge as the little 6″ tool rests that come with these types of lathes aren’t really long enough for this type of operation. Nevertheless despite the lack of support I was able to rough the bowl into shape.
It is always a good precaution to use the tailstock to support the bowl whilst turning (where you can). In truth I find the tailstock can get in the way whilst turning the bottom of the bowl but the initial stages of turning are where there is the most potential for something to go wrong, with the bowl not completely round there is always the chance of the tool catching, the force of which can actually pull the blank off the chuck- If I’m honest I don’t think I could afford to have lump of wood this size bouncing around my little workshop!
When turning out this bowl it was a little more dusty than usual, perhaps the bowl gouge which I used was not as sharp as it should have been but I am sure the wood has some part to play as it was fairly dry. The actual cuts were quite clean with little tear-out so I proceeded to turn the outside of this bowl to shape.
With the outside of the bowl turned to the desired shape I was able to remove the tailstock and turn a foot on the bottom of the bowl. The foot allows the bowl to sit flat on a surface but also raises the bowl slightly giving a slight shadow at the bottom of the bowl improving the overall appearance, this avoids a common mistake where the bowl appears to merge into the surface it is sitting on. Not having a foot is fine for some pieces, commonly smaller bowls, but can give the bowl an odd look.
In addition to turning a foot I also hollowed a small part inside the foot to allow me to reverse the bowl on the chuck and hollow the inside of the bowl. To do this I carefully work with a spindle gouge to avoid the tool “catching” so that I have a clean cut-out which slopes inwards slightly so the dovetail shaped jaws of the chuck have a more secure fit.
Before finally removing the bowl and reversing it I sanded the outside of the bowl, the difference may be visible between the two images above. I neglected to photograph this stage but I sure you will take my work for this. I will mention the fact however than when I sand the outside of a bowl I will usually use a random orbit sander. This makes the process of sanding a bowl much quicker and I find will give a cleaner finish. In most cases I will sand from 80 grit working my way through to 300 grit which is easily fine enough.
Hollowing out the bowl was very simple, it was a case of making progressively deeper cuts until I had reached the desired depth. I would recommend using some sort of gauge so you know exactly how deep to go ( also leaving room for sanding). All to often I have been a little too enthusiastic and cut too deep. In some cases this has meant me bursting out the bottom of the bowl but most often has simply left the bottom of the bowl a little more flimsy than I would like. Although no one would ever notice, it is something you will always be aware of!
Before sanding the inside of the bowl I used a round nose scraper to smooth out the inside of the bowl- with a suitable “burr” a scraper will cut pretty cleanly as it happens!
For this bowl I used a lacquer finish. I used to use lacquer a lot for finishing on the lathe and to a certain extent I still do. Lacquer does give a great hard-wearing glossy finish which can look great. When it came to this bowl you could say that it has a “delicate” appearance by being turned it fairly thin. I would say the wall thickness of this bowl was between 7 and 8mm. I have found that this sort of appearance can benefit from a smooth glossy finish, so despite the extra time it takes to apply a lacquer finish, that is what I decided upon.
Lacquer looks great on most small projects, particularly goblets and bud vases, although of course looks good on much larger pieces. I use an oil based varnish for many of my higher figured turnings and larger bowls as it is easier to get a consistent or striking finish.
When applying a lacquer finish on this scale it can be easier to either spray or brush it on, off the lathe. I didn’t use either of these methods for this bowl but simply wiped on the lacquer with a cloth without the lathe running.
I allowed each coat to dry (that is what takes the most time- the waiting) before burnishing very lightly with 0000 grade steel wool then applied the next coat. In total I probably used a generous 5 coats before I felt enough had built up for me to “rub out the finish”.
By taking a cloth with a small amount of lacquer thinner on it I gently wipe the surface of the bowl, this will remove the more prominent “high spots” and scratch marks left in the lacquer, this will save time and a lot of headache when it comes to polishing or “rubbing out” the finish. You don’t want to do this too aggressively as you could undo much of the work done applying the lacquer. You could dissolve too much of the lacquer which will then be soaked up by the cloth.
A closely positioned lamp can also be useful to help any unevenness in the finish to show up.
Although I did not take any pictures of “rubbing out” the finish it is a very simple process. When the bowl has been mounted back onto the lathe, running at a lower speed, ideally bellow 800rpm, I again use 0000 grade steel wool which I have applied finishing wax to. Finishing wax acts as a lubricant whilst sanding giving a cleaner finish. Steel wool , is surprisingly effective at cutting through the finish- so don’t go crazy! Next I begin using sandpaper starting at 800grit and working my way through the grits up to a 4000grit sanding pad, whilst still using paste wax as a lubricant (an oil will also serve the same purpose).
“Rubbing out” a finish is effectively a process of making progressively finer and finer sanding scratches to the point were they are no longer visible to the human eye, this gives a clean, shiny appearance and a smooth texture.
Just before the bowl is finished I use a cloth or tissue to buff off the wax on the surface of the bowl, I will usually raise the speed of the lathe at this point to somewhere in the region of 1500rpm, depending on the size of bowl. With the wax buffed off the finish should be silky smooth and have a fair shine to it. The highest grit you sand to will often determine the level of shine your finish has so polishing compounds such as “rottonstone” can be used to get a glass-like finish.
The final step to the bowl was to sign, date and finish the bottom of the bowl- simples!
With all that work here is the finished bowl, let me know what you think!