Intro: Creating a Natural Bark Edge Wooden Bowl
In this Instructable I will detail out my process of making a natural bark edge bowl. The result of this process is a turned wooden bowl with the bark on the rim...if I ever make a mistake in the process or the bark is naturally loose and comes off...it's just a natural edge bowl -- still very cool looking but not as nice in my opinion.
Bowls with bark on the rim and with the contrasting sapwood and heart wood are very pleasing to the eye. They also appear to be oval in shape, although they are round. Many customers that see these bowls ask "how did you do that?"
I consider this an advanced turning process and I will assume that you have accomplished regular bowls before attempting this style bowl. I will not be covering in detail what I would consider beginner and intermediate turning skills, but rather more advanced skills and the processes that are required to create a bowl like the ones I've shown above. Some of the techniques can be applied to regular bowls as well...so even if you are not an experienced wood turner, read on.
In the pictures above I am displaying three different bowls. The first two pictures are of an ambrosia maple bowl, the second two are a camphor wood bowl and the final two are of a walnut bowl.
If you are interested in seeing more of my woodworking visit my facebook page https://www.facebook.com/WelchWoodWorks
I would like to win the Epilog contest so that I can laser engrave my name/date and wood type on the foot of my bowls to make them more professional looking. I currently use a wood burning tool by hand. I'm including pictures of some of my laser engraving on the last page.
Step 1: Getting Gtarted: Preparing the Bowl Blank
In order to keep the bark attached to the sapwood, it is best to harvest the tree in the fall and winter when the tree is not trying to supply water and nutrients to the leaves. A log is more likely to shed the bark if cut down in the spring or summer.
The first two pictures above are is my log being cut/split. I used a Carter Log Mill and my bandsaw to divide the log. The Carter Log Mill (picture 3) holds the log securely preventing it from moving while sawing it. Since the log cant move except on the sled it makes it very safe to rip the log in two. Do not attempt to saw a log without some device that holds the log preventing it from rolling or twisting. If the log rolls or twists while you are sawing it your bandsaw blade will bind, twist or break none of which are good events!
This saw mill works by clamping the wood between the black stop and the threaded handle. There is a miter guide under the sled to guide the mill along the blade. Little effort is required to cut the log, and another advantage of using the saw mill is that the bottom of the bowl is flat...more on that in a minute...
In the third picture I have mounted a circle disk on the top of the log. This provides a guide to cut the log into a circular bowl blank. I've created a series of these disks all with different diameters, from 2 1/2" - 16". Each of these disks has a hole in the center where I use a screw to attach it to the bowl blank. I select the disk that will produce the largest bowl possible, attach it with the screw and then cut the log using the disk as a guide. My bandsaw blade is 3/8" and 3 tpi (tooth per inch) blade. The low tpi helps to clear the saw dust which reduces the strain on the motor as this log was about 10" deep. The 3/8" width provides a good turning radius for much smaller bowls.
Having cut the log so that the bottom is flat makes cutting it round on the bandsaw much easier and safer. When I've used a chainsaw or split the log with a wedge, the bottom is not flat. When the bottom is not flat and the bowl blank spins around it can roll slightly and bind the saw blade, or even break it.
The final two pictures above show the log after being cut into a round bowl blank.
Step 2: Mounting the Blank on the Lathe
To mount the bowl on the lathe I'm going to use a stub drive spur in the headstock. The bark on the top of the bowl will have to be removed so that the stub spur will contact a solid wood surface. The bark is much too soft to hold the bowl safely. I used a forstner bit to remove the bark, the hole I drilled was slightly larger than the drive spur. The screw hole that was left from attaching the guide disk is the center of the log, and thus where the bark should be removed.
The first picture shows both the stub drive spur and the forstner bit. The following 3 pictures show the process of removing the bark and exposing the sapwood.
Insert the drive spur into the head stock and align the hole in the bark so that it is centered on the spur. Next bring the tailstock up approximating the center of the bottom of the bowl and tighten it just enough to hold the bowl in place. I do not add too much pressure at this time so that I can adjust the bottom position of the bowl blank.
I think that a natural edge bowl looks best when the heights of the "sides" are the same. See the finished bowl in the fourth picture above and note that the high points are approximately the same height. The way to do that is to align the high points as you mount the bowl blank on the lathe. I move the tool rest up next to the rim of the bowl and place my index finger on it marking the top of the bowl, then I spin the bowl 180 degrees to ensure that the other side of the bowl is also at my finger tip. If it is not, then move the bottom of the bowl until it is (I have not tightened the tailstock in place yet). See the last two pictures above.
We also need to do this process for the low spots as well. Repeat the steps above but having your fingers at the low spots of the bowl vs the high spots. Only move the bowl in one direction to make the low spots match, be careful not to move the bowl to mess up the high points. In other words with one of the low spots next to the tool rest move the blank towards or away from the tool rest -- do not adjust the bottom of the bowl up and down at all.
Once the low spots have been aligned, check the high spots to make sure that there was no movement in that direction. At this point the blank is properly positioned and you should crank down on the tailstock pinching the wood securely between centers.
Step 3: Starting to Shape the Bowl
Now that the bowl is securely mounted on the lathe it is time to start turning. See picture 1
This is a large block of wood I have mounted on my lathe, and no mater how hard you try, there is no way to balance it perfectly. Therefore I start the lathe at 0 RPM and slowly increase the speed (my lathe has electronic controls that permit that -- if you dont, adjust your belt to the slowest speed). Make sure that the tool rest does not contact the wood by hand spinning the blank before you turn on the lathe. I increase the speed of the lathe until I feel mild vibration. My lathe weighs nearly 700lbs and even with that mass I sometimes have to start as slow as 200-300RMP.
SAFETY NOTE! Wear a face mask -- this is a lot of weight that could fly off the lathe!
I use a 3/4" bowl gouge to start to round the bottom of the bowl which is facing the tailstock. I remove some wood then tighten the tail stock and then increase the speed of the lathe until I get that nasty vibration again...remove more wood, tighten the tail stock and increase the speed. This is very repetitive until you blank has enough wood removed to be balanced. The faster the bowl is spinning the easier the wood cuts and that will produce a smoother surface on the bowl. Before removing too much wood from the bottom of the bowl I measure the jaws of the chuck that I will use when I turn the bowl around to hollow it out.
Measure across the inside of the jaws of your chuck with them slightly open. Having the jaws almost closed will provide a much better hold on the tenon than having them wide open. More contact between the jaws and the wood is possible when the jaws are almost closed, but when the jawas are fully open only 8 points (the 2 end points on each jaw) will contact the tenon. Mark the diameter of the jaws on the bottom of the bowl as a guide to create the tenon.
My chuck jaws are slightly dovetailed, so I also taper the tenon slightly so that it seats securely. The other important part of forming a tenon is to make sure that the bottom of the bowl is flat where the top of the jaws will touch. If this area is not flat the bowl will "out of round" when you mount it in the lathe. The resulting error will be noticeable when the bowl is completed because the wall thickness will be different across the rim of the bowl. Pictures 2 and 3 above show the tenon on the bottom of those bowls. To create the dovetail tenon I lay my skew on it's side and slightly undercut the tenon.
I switch tools from my 3/4" bowl gouge to a 1/2" bowl gouge while turning the outside of the bowl. The bigger bowl gouge helps round the outside to when the bowl is out of round, however, once it becomes mostly round I prefer to cut using the 1/2" gouge.
Now is when the difficult turning begins. Since the top of the bowl is not flat (it has peaks and valleys, most obvious in picture 4) the tool will be "cutting air" then cutting wood air/wood/air wood... as the bowl spins. The tenancy for most turners is to push the tool into the wood so that the bevel is rubbing...but the problem is that this will cause the tool to be pushed in by the turner and out by the wood as the bowl spins leaving a very rough surface. It also increases the risk of damaging or knocking the bark off the rim of the bowl.
I turn the speed of the lathe up as fast as I feel comfortable (recall that the bigger the diameter of the bowl the faster the linear speed is for the same RPM -- therefore the larger the diameter the slower the speed should be! A good reference -- multiply the diameter of the piece in inches by the RPM of the lathe, and adjust the speed to have that resulting number be between 6,000 and 9,000). At 6000 the linear speed (how fast the wood is moving past the tool) of the wood is about 18 miles per hour, and at 9000 the linear speed is 27 miles per hour.
Another technique I use to keep the bark attached is to cut the wood from the top of the bowl towards the bottom. This is backwards to what I normally do -- normally I turn from the smaller diameter to the larger so that I have supporting fiber. I've found that cutting from the bark side towards the bottom of the bowl produces a better surface and I've had less bark separation. I also take very light cuts and try to not push the bowl gouge into the blank but rather follow the curve towards the bottom of the bowl.
Stop to check your progress often when cutting the bark. If a small section of bark is coming loose, use some thin CA glue to attach it back. I will sometimes wet the entire bark edge with CA glue to harden the bark and secure it to the sap wood.
Occasionally I finish the outside of the bowl at this point -- I start sanding at the lowest grit that I think I need and move up...80, 120, 150, 180, 240, 320, 400, 600 and sometime higher. I also power sand, especially on the "wings" of the bowl. Hand sanding with the lathe will round one side of the wings. Sometimes I'll wait until I turn the bowl around and sand/finish both the inside and outside at the same time.
I typically dont put a shiny finish on these style bowls...I just dont like the look with the bark. These bowls are not going to be handled much, so I use sanding sealer, shellac, various oils or a wax finish. Since I'm not using a friction finish I can even wait to apply the finish until the bowl is off the lathe. On the walnut bowl above...I was very excited to see it with a finish on it because of the branch inclusion in it...I couldn't wait to see it lol (pictures 3 and 4) so I applied a coat of wax right away!
Step 4: Turning the Inside of the Bowl
Now that the outside of the bowl is completed, it is time to start the inside.
I lay the bowl bark side down on a "bunched up" towel on my bench so that it does not roll around. Then I bring my chuck over and set it down over the tenon. The weight of the chuck will seat it on the flat part of the bottom of the bowl automatically. I then tighten the jaws of the chuck on the tenon. Taking the bowl to the lathe, I thread the chuck on to the headstock and slowly spin the bowl by hand inspecting the mating surfaces between the bowl and the chuck making sure there are no gaps. I tighten the chuck one more time at this point since it is now anchored and I have more leverage to tighten the jaws.
After tightening the chuck I move the tailstock up to the bowl and force it into the hole were the drive spur had been. With the tailstock out of the way, I turn on the lathe (slow speed) and make sure everything is good. I then turn off the lathe and move the tool rest across the top of the bowl and start to hog out the inside of the bowl again using the 1/2" bowl gouge (see picture 1 above). It is easy to cut away at the center of the bowl -- the bark comes off easily and the wood is nearly flat. However, as the opening of the bowl becomes large the tool will start to "cut air" again.
WORD OF CAUTION: The top of the bowl will be hard to see when spinning...ALWAYS be aware of those wings!
The same principals apply to removing the wood from the inside of the bowl. Dont force the tool into the side of the bowl when cutting air, but rather cut towards the bottom of the bowl, then across the bottom of the bowl. I only work the first inch or so when I'm establishing the diameter of the bowl. Having the mass in the center of the bowl helps to keep the wood from releasing stress and moving (going oval). For the final thickness of the bowl, well I rely on the looks. I find the rougher the bark the thicker I leave it. The camphor and maple bowls (page 1) were about a 1/4 inch thick, while the walnut bowl with its rough bark was about a 1/3 of an inch thick.
Once the top inch of the inside of the bowl is completed, I remove another inch of wood making the bowl deeper. I continue to remove about an inch at a time until the tool is cutting wood continuously i.e. I'm below the lower bark edge on the bowl. Once I'm that deep, the cutting of the interior of the bowl is like any normal bowl. The only difference is those wings make it more difficult to position the tool. Watch your knuckles!
Remember to move the tool rest inside the bowl to limit the overhang of the tool. ALWAYS stop the lathe before moving the tool rest! Also, DO NOT attempt to go back to clean up the wings at this point -- you will only cause yourself more trouble -- even if you attempt cut with BIG scraper! Dont ask how I know...UGH... Pictures 1-3 show the progress of the inside of the bowl, picture 2 shows the bowl spinning on the lathe - note how the tops of the wings are not visible.
Once the inside of the bowl is completed, sand the inside as you did the outside. Again, I powersand with a drill especially on the wings (See picture 4). Now apply any finish you did to the outside.
Step 5: Removing the Tenon
OK we are almost done...but how are we going to hold the bowl in place to remove the tenon? Well I use a jam chuck.
Remember the disks that I use for the cutting template to make the round blanks? I select one that fits inside the bowl. I like this more than cutting a chunk of wood because this disk holds the bowl near the top of the bowl rather than at that bottom. I also have made a bunch of these so they are always available.
I've turned a piece of wood with a tenon on it and mounted that in my chuck. I have also drilled a hole in the center of it. The disk has a hole in it at the center as well. I thread a bolt and nut thru the disk and the wood in the chuck and once that is tightened it becomes rock solid. See pictures 1 and 2
I cover the edge of disk with some soft material to protect the bowl where they will contact. A foam piece is shown in picture 2 and in picture 3 you can see part of a shelf liner that has been folded over several times to serve the same purpose.
Place the bowl over the disk and move the tailstock into the hole in the bottom of the bowl that was created when turning the outside. Using this hole will center the bowl very nicely and will provide access to shape a foot, or remove the tenon all together. In pictures 3 and 4 you can see that I have removed most of the tenon -- all but about 1/4" of wood. I dont remove any more in fear that this piece will break and the bowl will go flying. I sand the bottom of the bowl and the foot as I did with the rest of the bowl.
Once I have sanded the bottom of the bowl, I remove it from the lathe and with my thumbs push on the side of the nub snapping it off. Very little pressure is required to snap this nub off. A small bit of sanding and the bottom of the bowl, and it is ready for whatever finish you desire.
Step 6: Completed Bowls
Here are three of the bowls that I have made recently.
The first is camphor -- WOW what a fun wood to turn. My shop smelled like Vicks Vapor Rub for a week from the oils in the wood. I love this wood.
The second is ambrosia maple -- On this bowl you can see the holes where the beetles bored into the wood (lower right side) and the color that they create in the wood.
The third is walnut -- There was a "dead" branch that was hiding in this log -- I did not know it was there until I started to turn it, and it gave this bowl great character. In addition, the sap wood started to spault as well adding even more character...and if that was not enough, down the left side there are some insect holes as well.
I hope that you have learned something useful from this set of instructions and you make a natural bark edge bowl. If you do make one, post a picture so I can what you created. If you have any questions leave a comment or visit my facebook page and leave on there https://www.facebook.com/WelchWoodWorks and I'll answer it.
Thanks for viewing my Instructable,
Step 7: What Could I Create With the Epilog Zing Laser?
I currently own a Chinese laser engraver that I purchased second hand. The software to control the laser is difficult to use and not intuitive. I have had to develop many "work a rounds" to resolve issues I've come across like placing a sheet of cardboard on bed to make an outline so that I can properly align my work, multiple passes to create "layers" of graphics, and importing almost all of my graphics using other software. With my machine there are no suggested speed and power settings, so I always have to make a test burn (I've created my own cheat sheet). And sometimes the software reverts to Chinese...and I have reload it. I have a 110v to 220v transformer to step up the voltage. Even with all of these issues I still like my unit because I can create unique plaques for people that I know that retire, engrave on pens that I either sell or give away, but having a quality laser engraver would reduce my set up time and increase my productivity.
I've attached several pictures of engraving that I have done.
Pictures 1 & 2 -- Two wine holders that I made, the wine bottle is being held by a maple board and the second is pine displaying an engraving.
Picture 3 -- A set of cherry coasters that I made. One for a friend that loves wine, and the second was a Christmas gift for my wife this year
Picture 4 -- This cherry plaque was made for the girlfriend of a soldier that was being deployed
Picture 5 -- My uncle passed this year, and I gave this plaque to my aunt
Picture 6 -- A wedding gift that was purchased by a co-worker
Picture 7 -- A hand turned maple platter that I made and engraved for a friend's 10th anniversary
Picture 8 -- A custom Christmas ornament (minus the hanger) engraved on a slice of onamental pear tree
Picture 9 -- Another cherry plaque I made for my wife
I hope that you like my engravings and that you consider me for the grand prize! I would certainly put the Epilog Zing to good use.