Hi folks, here is the blog I promised which describes my new method of open segment construction. Before I begin, let me just say that this project is my first normal open segmented construction. I am not an expert or even experienced with open segment construction and turning. This is more of a woodworking journey to tell about my experience than a tutorial.. I hope you will join me and enjoy yourselves. I warn you though, it’s lengthy, so I hope you have the time to stay with.
What is it all about?
I had been looking at some open segment turning websites and after having tried regular segment turning I wanted to try the open type too. The only problem was that after looking at the websites it looked like I would need a lot of special equipment to do it, which was either shop-made or purchased. This equipment included the following items:
1. Indexing wheel for my lathe: fairly easy to make
2. Drum sander: I didn’t have room for one, didn’t want to make it and couldn’t afford to buy one
3. Segment gluing jig: Could make one, but takes space and time to make
Ok, it looked like I was finished before I started, but I began thinking how wonderful it would be if I could just glue it up into rings like the regular segment construction. Then I started thinking about how this could done, and to make a long story short, I came up with the solution pictured below. This blog will describe how I managed to construct these rings and still stay true to the “normal” construction result without needing any of the above mentioned special equipment. For some of you this picture will be enough of an explanation. Others might want to see the steps I went through to make them. The solution was to make a ring using spacers which would be turned off while shaping the vessel. Here was the goal as pictured below. An open segment ring glued into a ring using temporary spacers as shown below.
what are the advantages to the ring construction?
- You don’t need perfectly sized segments (talking about height only here) because you can flat sand the ring on the glue-up side with a disc sander and then turn and sand the other side flat after it has been mounted on the lathe.
- You can construct rings from thick materials and then split them into two or more rings to make more than one work piece. This at least effectively almost halves your construction work. It doesn’t take much time to saw a ring in half.
- The lathe isn’t tied-up during construction as in the “normal method” and it would be easy to share the work with another person. One cutting and sanding segments and the other gluing-up for example.
Summary of the whole process;
1. Prepare segment stock
2. Cut segments
3. Sand segments in sanding jig
4. Prepare spacer stock
5. Cut spacers into segments
6. Cut spacers from spacer segments
7. Glue-up rings
8. Flatten one face of each ring on disk sander
8. Glue rings onto work piece. Use the sanded side for the glue joint
9. Turn and flat sand the the top of the ring to prepare it for gluing to the next ring.
A List of things you will need
1. A lathe ( I’ll bet you knew that)
2. A disk sander to dimension your individual segments with. A 6” disk sander work fine for this.
3. Another disk sander with a little larger diameter than the diameter of the the largest ring you will be making. I made a 12” one that mounts on my lathe and which equals the swing of my lathe. This is used to flatten one face of each ring
4. A tablesaw, mitersaw, or bandsaw. If you use a bandsaw, you will have to do more segment sanding.
5. A segment cutting jig for the tablesaw or something like Tibbett’s mitersaw set-up which I use, or a bandsaw jigof some kind. Sorry, don’t have a reference for that one, but would me similar to a tablesaw jig.
6. A segment turning computer program. This will give you detail drawings of the rings and stock dimensions for each ring. You can mark your stock right off the drawings, and check the actual cuts the same way. Not an absolute must if you can and are willing to figure everything out on your own. (very time consuming).
7. I recommend you buy a segment turning how-to book. I have Malcom Tibbett’s book “The Art of Segmented woodturning. This book doesn’t cover the open segment method, but it is packed with how to info which you will find very useful. It might also be interesting to buy Smith’s book on open segment work. He is at Smith Art on the web, although you won’t need it for this method. Also it would allow you to compare the two different methods in order to weight the merits of each. I’m sure I will be buying this book soon for that reason.
The following text and pictures mainly describes the process of producing the rings. The first photo shows the stock I prepared by cutting the ring widths described on my segment computer program. You don’t absolutely need one, but it sure makes life easier and they are relatively cheap. Just pay for it and download it from the web. My stock was just pine used to experiment with (again!)
I found that it was more efficient to cut all the segments for all the rings at the same time. I then put the segments into recycled sour cream containers, one for each ring. I cut a piece of sandpaper into strips (durable) and wrote the ring no. on each, and then I put the ring numbers into the appropriate containers with their segments. Organization is important for me as I get easily confused. What were we talking about? Oh yeh, here’s a picture of them organized.
The next job is sanding the segments in my Malcom Tibbetts designed sanding jig. The segments won’t be glued together but they will be joined by spacers, so accurate sizing is essential here in order to get the ring round as possible and with the right diameter. Also the inside edges need to look smooth and nice.
Ok, now it’s time to prepare the spacers which will be glued into the ring. In order for the the permanent segments to be positioned correctly you need to have to have spacers that will maintain that thin pie shaped space between the segments, In these rings I have used 30% space to 70% segment length.
The spacers on the outboard and inboard sides of the ring must be exactly the width of the space between your segments as specified by your computer program. My program only tells me the length of the opening on the outer side of the ring. But if you cut it at the correct angle it will be the right width on the inside edge too.
In order to meet the above criteria, I performed the following steps:
1. Cut the spacer segments based on the width of the ring (outside edge to inside edge of ring). The resulting spacer should just fill the space on your ring printout. Make sure you have marked the two top edges on your stock with a very thin line. This line will tell you which way to place your spacers. The wider spacers used on the outer edge of the ring will have the blue line facing outwards, and the narrow spacer inwards towards the center of the ring. This is important because the spacers are angled on the long-grain glue joints.
2. Cut the actual spacers from the spacer segment wdges. I made a simple bandsaw jig to insure accuracy, speed and safety. Here are some photos of the process. You have to cut both sides along the blue lines.
Spacer width setting on tablesaw based on the segments they will be glued to.
cutting spacer stock. Before cutting these segments you will need to know the the length of the opening between the the permanent segments. Do not confuse with stock width. The length runs around the circumference.
Finished spacer stock with outside edges marked
Spacer segments are cut with the grain. Make sure they are of uniform and the sides as close to vertical as possible. Perfect would be good. If they are not vertical it will affect the accuracy of the ring glue-up.
Spacers placed in the bandsaw cutting jig in the same order they were cut on the mitersaw, that is: wide-end, narrow-end, and so on in order to make them rectangular for putting through with the jig.
16 spacers from the first cut
16 spacers from the second cut
“Making !the second cut after turning the stack around to cut along the other blue line for the
You now have 32 spacers, 16 wide ones and 16 narrow ones. All the spacers are then sorted by size. The wide ones for the outer edge of the ring and the small ones for the inside edge of the ring ready for glue-up.
1. The ring segments have to be have to be de-burred after sanding. It pays to do a good job on this because burrs will tilt your segment to a wrong angle as you glue up and also might prevent the glue joint from being being tight. I do not de-burr the spacers as these are cut as long-grain glue-jointed segments. I do the de-burring on a sanding board as shown below.
2. Starting the glue up. All rub joints, first two, then combining the twos to fours.
This last picture shows that I have glued spacers onto the same end of each the 4 segments sections(make sure the spacers are glued onto the same end of each spacer). I did this after letting the 4 section glue-up set for a few minutes. After gluing the spacers onto the ends, I let them dry for an hour or so and then I sanded those spacers with the segments laying flat on the sanding table on my sanding disk as necessary to make whatever adjustments were needed to insure that the rings were as round as possible and to get good enough glue joints with the permanent segments to insure strength for turning.
Here I have applied glue and put a steel hose clamp around it to dry for an hour or so. Another new ring is born!
Let’s see if it is in accordance with the computer image printed from my segment program. Eureka! It fits.
NowI am finished making the rings. I could have made one nice vessel out of these rings as they are, but I wanted two for all my work, so I doubled the number of rings by splitting them in half with my Japanese handsaw. It took not more that 3 or 4 minutes for each one. I held them clamped between the movable tops in my Work Mate folding bench. I took my time and cut very carefully. You don’t want a ring that took 1-1/2 hours to make destroyed in just a few seconds!
Here are the two work pieces resulting from splitting the rings.
Next, I disk sanded one side of each ring flat on my lathe mounted sanding disc.
The other side of each ring will be trued up after being glued to the workpiece and mounted on the lathe. After that the next ring with one side pre-sanded flat side will be glued on to the ring and so on. Here are the rings being glued on, etc.
Here I have begun turning to get top ring flat and ready to glue the next ring on.
Captain Hook enters perilous waters!
The still unfinished result. But I did get the blog out there.
Before I go, I would just like to thank you for reading this. I hope it was a little interesting if not useful. I am not claiming this is a better method, because I have never done the usual method and so can’t compare. This is pioneer work. I’m sure a lot of improvements could and will be made. Especially if you LJ’ers help out.
I hope that those of you who are knowledgeable about this kind of work will join in and discuss the pros and cons of the method and the process. I’m not even sure if I am the first person to have done open segment construction this way, so if you have already been doing this let us hear from you. I hope there will be a good discussion, about this, especially with us turners.
I probably left a lot of questions unanswered but please don’t hesitate to contact me either on the blog comments or a PM. and I will be happy to answer you.
-- Mike, an American living in Norway.