The half round dish is one of those projects that can stymie some woodworkers. Most think it is made on a lathe ... and it could be, but for those who don't have lathes, this handy little dish can actually be made on the table saw with a jig designed to create it, and it's not complicated and once you have made one, you will want to make more because these little items are quite popular because they look great, sit flat on most surfaces and perfect little serving dishes, or they can be used as a catch-all on your entryway table ...
Watch it on Youtube: https://youtu.be/sZKSvD4v514
The jig won't take you that long to make, so if you want a decorative wood to use, even for your first attempt, now would be a great time to cut and glue something up because by time the glue is dry and hard enough to use, you will likely have your jig made and be anxious to use it .
Like most jigs, this one was made from bits of wood I have laying around my shop. For those of you who follow my channel and website, you will wonder where the endless supply of "bits of wood around the workshop" comes from. Everywhere, swap meets, garage sales, neighbors, friends etc. I always seem to stumble across or people are offering me wood from some DIY project they have reno'd and it all ends up in my stockpile of bits of wood.
For this jig, I used 3/4 plywood and predrilled all my holes so that the plywood would not split, and it didn't. I don't really like driving screws into the edge of plywood but if you do it carefully and predrill, you have much better luck.
I'm not going to give exact parts dimensions because this jig, like many others I make, straddle my table saw fence and because there are so many different sizes, you will have to figure out what works best on your fence.
The first thing you need to make is the box that will straddle your table saw fence. 10 to 12 inches is a good length for this, the height needs to be at least 3/4 of an inch higher than the front of your fence and level with the back. The reason for the higher side on the front is to build in the safety stop for the arm you will be attaching shortly.
You are probably best to cut all the components at once and assemble them after they are cut to size. I made the cutaway in the from part of my jig after it was assembled and it would be easier to make that cut before assembly and it won't make any difference to the assembly.
The next component to make is the arm, I wanted mine to be fairly sturdy so I made it also from 3/4 inch plywood and cut it 2-1/2 inches wide 18 inches long (a bit longer is OK too, you could cut if off later of just make more holes). This should give you enough room for the hinge on the back and still have plenty of reach on the front for carving your dishes. What's important right now is the 2-1/2 inch width.
Now that you know the length of the straddle box and the width of your arm, you can easily figure out what the top pieces will need to be that will secure the jig to the fence.
Before you assemble .. NOW is a good time to make the cutaway in the front of the straddle box.
Now is the time you can assemble the main part of the jig, and you can make the pivot block that the bolt will go into as well.
One note on the bolt - I prefer to cut the head off my bolts and use the smooth part of the bolt and not a bolt that is threaded from end to end for 2 reasons, the plain bolt pivots easier and when there is no thread wearing away the hole in the pivot block, they last MUCH longer and stay more accurate.
Making your pivot block is also an important step. You want to make sure it is wide enough that the screws you use will not penetrate your dish wood and come in contact with your table saw blade. This isn't really a safety hazard, more an issue of possibly ruining a good table saw blade ... so I make my pivot block extra wide and you can easily measure this with whatever table saw blade you expect to use. For this project, my pivot block was 7-1/2 inches square.
Setting the Saw Blade and Winding it Up
Your dish blank will want to be slightly bigger than the finished product because you are probably going to want to trim it down slightly just to make it look better.
You will also want to make some elevation tests to see how high you will crack the blade up. My wood was 1.25 inches and I could crank my blade up 6 revolutions, but you NEED TO CHECK YOUR OWN.
One tip on the cranking, the first 2 or 3 lifts of the blade, there is not much material being taken off so it is easier to spin the wood on the blade, after 3 lifts of the blade I will often only take a half lift of the blade .... this means turning my elevation wheel on my table saw by only half a turn, then another half turn to 4, and from then on only a half elevation turn each time. It just seems to make a safer and better quality cut doing this ... but that could also depend on your wood being used. There is nothing wrong with doing a half and elevation each time you spin the dish blank, just don't lose count.
When the elevating and spinning are finished, just turn the table saw off and wait for the blade to stop, then lift the finished dish off. Sometimes you get a small burn, but that is easily sanded off.
For this project, I used a Freud 10 inch glue line rip blade, I prefer any full kerf blade, but thin kerf will work also, just take half turn elevations, and I have even used circular saw blades to make even smaller dishes so there are lots of options for size.
As always, work safely ... take your time and you will be amazed at the cool things you can make.
Copyright Colin Knecht