2 - Ancient Hollow Cherry-Tree-Slice Side Table

Just the other day….

A couple of years ago, I had access to a complete wood-shop for a couple of months - a couple of hours every other day = much too short, but great!

The supervisor told me that I could make whatever I want - if I pass the entry test and don’t cut my hands off during the walk through the premises…. (Deja vue)

While I was allowed to play in the workshop, a couple old trees were cut down as firewood in the nearby garden - it broke my heart. From what information I could gather, some of the felled trees in the garden dated back to over 100 years! And they simply wanted to burn the wood!

I was able to get one of the guys to cut a cut off a slice from the stump of an old and hollow cherry tree. They wouldn‘t let me handle the chainsaw myself - insurance reasons - so I had to make do with someone cutting a haphazard and partially damaged slice, off the still remaining stump.

I could have gotten another slice from one of the other trees, but those were whole, without the rotted center, so not nearly as interesting - to me anyway. Also, the hollow tree still had all the trunks of Ivy attached, that had grown up the tree during the past couple of decades!

Ivy doesn‘t hurt the trees by climbing up, though its weight and wind resistance might later damage the tree. But Ivy is usually treated like it‘s a parasite anyway and often torn off from time to time. Since people never want the Ivy-wood, it is normally removed before, or after felling the tree and thrown away. So you never get a slice of a trunk with the Ivy still attached!

Ivy has a really light wood, while the Cherry wood has lots of colors, red-orange-yellow and even purple in this case, all going to black where the wood was rotted and burrowed by ants. I had seen the broken parts of the tree and immediately knew that I needed to get a slice!

So I got one and let it dry to make a small - ca. 40 cm diameter - side table from it….

When they saw how the slice turned out, they decided to try and salvage most of the still usable wood for further projects!

The Top:

1. Hollow tree slice
2. Nylon strap
3. Something to plane a tree slice - NOT a belt sander!
4. 2-Component Epoxy resin
5. Wood-Oil
6. Clear lacquer for wood floors

The Legs:

1. 5 cm of a wooden dowel - as height-adjustment for the uneven tree slice
2. 3 R-L double-sided bolts - to attach the top to the legs
3. Wood from bed-frame (reclaimed)
4. Japanese Kataba saw
5. Files
6. A Chisel
7. Glass pane from Shower Stall (reclaimed)
8. Glass Cutter
9. Soldering Iron
10. UV epoxy glue
11. Clear lacquer for wood floors

Tree sections tend to split when drying due to uneven contraction of the different parts of the slice. I never had a hollow slice of a tree-trunk before, but figured that it might split anyway, so used a nylon belt to apply pressure to hold it together. Also, I didn‘t want to risk the sections of Ivy coming off.

I let it dry for around two months before working on it.

The section had been cut rather crude and uneven, so that it was a bit difficult deciding on a clear plane to clear as a surface. You may want to maximize the surface area by choosing an angled, oval plane, but I wanted a final surface as close to perpendicular to the trunk, as possible.

The side and plane I chose had a chainsaw cut partially through, but looked otherwise promising, so I did a vertical cut on the side where the saw had penetrated the ring and simply shifted the resulting triangle wedge in further to fill the cut - a simple way to hide the damage a bit.

To make the wood ring stabilized and manageable, I decided to fill the holes caused by rot and borrowing ants and to secure the Ivy. I used some clear 2-component epoxy resin.

Though its seems thick and viscous during mixing, epoxy resin is quite sneaky and treacherous until it hardens! It tends to slowly flow even through the tiniest holes until it finally sets, so that a whole lot can end up on your floor during the night and create a nice surprise in the morning - so make sure to seal even the tiny cracks in your wood, that look like they are unconnected to the other side before pouring the resin. Tape is usually no good to seal cracks. I used cardboard strips and UHU glue and it worked fine - silicone is good to, but nothing likes to stick to surfaces where it has been.

To keep the small wedge from floating up in the cut, I placed a small weight on it, and I needed to pour additional resin a couple of times, because I underestimated the volume in holes and cracks and cuts and Ivy fibers that needed to be filled a bit. The cardboard and bits of glue were later sanded off.

Since I employed a relative quick-setting (15 min) resin, I was also able to use it to stabilize the remaining bark and the attached Ivi vine sections by painting them with the resin. The center of the ring stayed free/hollow.

Since I still had access to the wood workshop at the time, I decided on planing one side, in order to see what the final thing might look like, while I had the chance. To do this I used a vertical belt sander - to the horror of the supervisor of the wood-shop! At the time I didn‘t have a router at home, so I did this quick-and-dirty….

Please don‘t do this like me!

We are all trained professionals…. - NOT!!!

What I did to plane the slice was simply stupid and I could have caused damage to the belt sander, or (worse) the slice. I was certain that I could do this without hurting myself and managed to do so, but this could have resulted in bodily harm - so please use proper tools, if you decide to start such a project!

For my „real“ project at the time, I had some Tung-Oil, so I applied it lavishly to the sanded side of the ring to give it a preliminary finish. It ended up looking quite impressive with the many-colored wood - which made the responsible people quickly reconsider simply burning the remaining cherry wood. So, it was worth the risk and effort, in my eyes.

To plane the section properly, I later used a router and the sled I had built at home to plane a couple of other tree sections.

To finish the surface, after extensive sanding, I used oil and later some clear lacquer for wooden floors.

Of course I didn‘t want to buy ready legs for my table - I didn‘t want to buy wood either though.

So why not reclaim and repurpose some other wood?

A while before, I had come across a king-size slatted bed-frame someone had put on the sidewalk to be taken away as garbage. Since it was fairly clean and the wood like new, I broke it up and carried it home, because „well, you never know….“

I figured now, that the bed-frame was just what I needed.

The wood of the frame is quite light in color and hard, though only ca. 2,5 by 6 cm, so I decided to glue them doubled to have a thicker profile. The edges are rounded, but I decided not to hide that it is repurposed wood and therefore left them as is, after sanding everything, naturally.

Deciding on a design for the legs had taken far longer than the actual work, of course, because you don‘t want to have to live with the wrong choice for the rest of your life. Three legs are less stable than four, or five, or six. Round dowels, or rectangular, or square, straight, or bent, perpendicular, or angled - the possibilities are endless….

I like wooden puzzles. I also enjoy making things, so people need to think to figure out how it was done. As a child, I made a wooden star-puzzle that looks like the six square profiles pass through each other. Since I still love the two times three-part simplistic design, I thought that I could adapt it to table legs. Others have done that before me, of course, and I found a couple designs with three boards crossing in the center, online - just what I wanted to do!

I could have more easily taken the exact design from the net, but I find it much more rewarding when you figure 3D problems out yourself. It took me a while, but I came up with a satisfying solution for my slightly asymmetric profiles to intersect in the middle and stay together without glue and bolts, while stable enough to stand upon - nothing budges, but you can easily pull them apart again. The legs are the long axes of an octahedron, i.e. the space diagonals of a cube. I built two models with Schaschlik sticks to test the feasibility. It worked best if the bars intersect at 90 deg angles, of course, and half the width of each bar is removed so that each bar seemingly wraps around half of the next bar.

The cuts were done with the Kataba, the rest removed with chisels and files. Due to the design one quarter additional material is left to fill the remaining space on one bar and add stability - see the pictures.

As mentioned, the resulting structure is extremely stable and needs no additional components to stay together - a friction hold.

One problem with the construction using bars with a square shape is that I would like to put them on a horizontal surface (the floor) and thus would prefer not to have point contacts, but rather diamond shaped surfaces to form the contacts to the floor and the top. Therefore, the bars need to be cut at 36 degree angles at each end. Of course, you need to calculate the length of the bars accordingly in advance to get the height of your table correct.

The next problem is the actual cutting since you need to have the bars oriented at a 45 degree angle to make a vertical cut. Since I used the old vise by Zyliss, that has plastic adapters with 45 deg molds that part was easy. To manage the 36 deg cuts, I placed an additional jig on top of the bars, with an additional block of wood to keep the Kataba oriented vertically. I‘m sure this could have been done easier in a different way, but it worked pretty well….

Since I was using reclaimed wooden profiles, and glued together to make them thicker, getting a rectangular instead of square cross section, it turned out to be a bit tedious getting all the calculations correct. Especially the diamond cuts were a bit of a pain, because you cannot calculate with square-diamonds, but have a stripe missing due to the rectangular cross-section. Especially the length of the legs is a bit of a headache because of this.

But, it turned out ok - just take your time and think things through twice, or thrice, and calculate twice, or thrice….

To prevent accidents, I finally cut back the pointy ends on each bar.

I used a thin coat of clear lacquer as a finish on the parts.

Hollow tree sections have an obvious big problem: They have a hole in them.

Holes in tables are usually disdained, because they tend to attract accidents to happen. That is, unless you intend to place a garbage pail beneath….

Fore some time, I had wanted to build an infinity mirror, so I took an acrylic pane and cut two pieces to fill the hole top and bottom. This did end up working but not really pleasing my aesthetic tastes, so I planned on buying a circular glass top instead. Putting a transparent pane on top of a wooden surface may add protection, but it quite effectively hides the wood surface and its color and grain though. To be able to appreciate the grain and colors of the wood, you need to look close to perpendicular through the material, because the internal reflections interfere otherwise a lot.

To fill up the hole in my tree slice - so glasses would not fall through - I finally use part of a repurposed old clear glass door pane from a shower stall. And, instead of putting the glass on top of the wood, I decided to create an insert with both surfaces on the same level.

This way you can also look through the table to the knot in the legs below.

For this process I forgot to take pictures, but I‘ll try to describe it as best as possible - It‘s easy though….

Cutting glass with a glass cutter is pretty easy and not really dangerous, so (almost) anyone can do it.

Please, wear gloves nonetheless AND wear protective goggles!!!

Glass edges can be used as scalpels and you almost always get small shards when you cut glass. Tiny bits of glass can fly large distances when glass if put under pressure until breaking, and getting them in your eyes is not a good idea.

Cutting curvy lines in pane glass is a bit more difficult than straight ones, getting more and more difficult the thicker the glass gets and the tighter the turns. The glass from the shower stall had 6 mm, so it is relatively simple to cut. I cut a rectangle just able to cover the hole in my wood. Cutting an ellipse would have been fairly simple, but it would have required the removal of a lot of wood to fit it, so I decided to follow the shape of the hole as exactly as possible. Cutting a 1 cm radius in 6 mm glass was impossible for me, of course. Using a diamond grinder was a ridiculous option to me also.

So I decided to fall back to the most simple way to cut glass: Hot and Cold.

Using a felt pen, I marked the exact shape of the hole on the glass. Using the glass cutter, I scored a line into the glass surface along the line with all the small turns.

Then came the tedious part of heating the glass in really small steps at a time and letting it cool again. The easiest way to do this is to use a cheap soldering iron. You simply hold it onto the scratch you made with the glass cutter for a while and removing it again to let the glass cool. If you start at the edge of the pane, ideally with a vertical scratch on the edge also, and heat, and cool with a wet paper cloth, a crack in the glass will quickly form - no external pressure needed!

It is really important to take your time and be patient!

The crack in the glass is often not easily visible, because the viewing angle may be not steep enough to notice the internal reflection, so look from different directions. Once a crack has formed, it is quite simple to lengthen it by slowly following the drawn line with your soldering iron. Do this slowly, because, especially with tight turns, the glass tends to prefer breaking in longer straight cracks. Especially along the smaller corners, the glass also tends to not form cracks perpendicular to the surfaces, so expect to do some sanding post cutting. I didn‘t take pictures of the process, but you‘ll probably get an idea.

To break all the edges on the cut glass and remove and straighten angled breaks, I used short pieces of sandpaper. This takes a bit of time, but the danger of accidentally breaking the pane are minimal that way.

The resulting glass pane was an almost perfect fit, slightly larger at just a few spots. To fit it into the wood ring, small sections were removed at these sections using a Dremel with a router bit a - knife would have done the job too.

Silicone would probably have been a good material to glue the pane in place, but I decided to use a crystal clear UV epoxy resin instead.

The UV activated epoxy resin is a great material to work (play) with, because it is quite viscous. You can apply it drop-wise, let it flow into cracks just as far as you want and set it just at the right moment with a small UV-LED. Using this method, I slowly went around the glass pane to permanently glue it in place and fill the gap, even with the surface. Finished, it looks just like it actually is part of the glass - perfect!

I ended up coating the surface of the wood with a clear wood floor lacquer to create a nice durable shiny surface.

Keeping the top of a table on its legs is important - so much for that.

My table top was not of equal thickness on all sides, but I had decided to keep all parts of the legs the same length, so I needed to add a piece of wood at the thin section. I decided to glue a short section from a wooden dowel onto one of the table leg-bars.

Since one of my objectives in most projects is to be able to take things apart again - just like the legs in this case - I decided to use bolts to attach the legs to the top. Drilling holes through the legs and into the top and using long screws would have been easiest, but no fun. I decided to use double-sided L-R bolts instead. With these bolts, you just need to drill matching holes in the parts you want to connect. When you turn the bolt to screw it into one part, it also turns into the other, pulling the parts together with tightening. In this way you can also adjust the surface of the table, if it‘s not level.

I could have used inserts to secure the bolts in the wood, but if your wood is hard enough, and if you drill your holes straight, and if you use a bit matching the size of your bolts, the bolts will end up sitting really, really tight without them.

That‘s It!

The table ended up as a present to my father, because he had complained for a while that he had nothing next to his favorite armchair to put his books and tablet and glasses on….

He was quite amazed and really happy. He has shown it off to all his friends too and tells me how much he likes it on each visit.

I love the cherry tree wood and I‘m pretty satisfied with the leg construction.

Because of my frequent pauses, the project ended up a bit lengthy. The actual work was not really that long, however. The whole thing didn‘t cost much in materials and can be done in your basement - if you have a router to plane the tree-slice.

So, basically it was a simple project and very well worth the effort.

Try it - it‘s fun!

And ok, I had to sign it with my labyrinth - of course….

Always stay fascinated!