Bamboo Dining Table and Benches

I wanted to make a dining table that would last a lifetime. I had enjoyed having bamboo furniture at our office and I had a lot of 1'x8' lengths to work with. I used a waterjet by OMAX for all of the cutting to experiment with a new kind of CAD/CAM joinery.

I used Autodesk INVENTOR for the CAD for this project. Any cad would be fine as it is fairly simple 2D plates. I suspect you could even make this with illustrator or coreldraw as all the parts are just 2.5D (2D + thickness)

I exported the bunch of files I wanted / needed for making the table as dxf's.

The only two really important files are:

benchpieces_1to10scale.ai

tablepieces_1to10scale.ai

they have the pure geometry and are at 1:10 scale. I'll upload dxf files if anyone wants those instead...

it is very important to use exactly 3/4in thick material as the finger joints require high tolerance sheet.

I originally thought i could get all the pieces on two sheets of plywood, but that's obviously not true.
It takes about 2.2 sheets. see attached images....

ALso, below find the water jet cutting stats:

Estimated time to make this part: 2.5134 hours
Estimated cost to make this part: $62.84
Estimated abrasive needed: 121.67 Lbs.

Estimated time to make this part: 2.9491 hours
Estimated cost to make this part: $73.73
Estimated abrasive needed: 143.97 Lbs.

Estimated time to make this part: 24.688 min.
Estimated cost to make this part: $10.29
Estimated abrasive needed: 20.43 Lbs.

Around $150....

HERE IN DETAIL:

sheet 1:

Material: bamboo

Machineability: 500

Thickness: 0.7500 inches

Tool offset: 0.0150 inches

Taper offset: 0.0000 deg (0.0000 inches)

Cut stand off: 0.0600 inches

Rotation: 0 deg

Estimated time to make this part: 2.5134 hours

Estimated cost to make this part: $62.84

Estimated abrasive needed: 121.67 Lbs.

Piercing: High pressure | Intelli-PIERCE(R)

Pierces: 65 (0 are wiggle pierces)

Cutting: High pressure

Width of path: 95.9883 (inches)

Height of path: 48.1242

Length of tool path: 2597.8700

Length of cutting: 1940.2480

(Values reported after tool offset applied.)

Pressure and nozzle setup:

High pressure setting: 45000.00 PSI

Low pressure setting: 20000.00 PSI

Mixing tube diameter: 0.0300 inches

Jewel diameter: 0.0140 inches

Abrasive flow rate: 0.8500 Lb/min

Abrasive size: 80.00 Mesh (US Std.)

Abrasive index: 1.00

---

Feed rate breakdown: (inches/min.)

---

Ideal linear quality of 1 speed: 34.99

Ideal linear quality of 2 speed: 30.01

Ideal linear quality of 3 speed: 18.83

Ideal linear quality of 4 speed: 13.52

Ideal linear quality of 5 speed: 10.46

Ideal minimum taper speed: 6.27

Definition of "Minimum Taper": 0.00100

Ideal dynamic pierce speed: 23.29

Ideal dynamic pierce length: 0.242"

Time for ideal dynamic pierce: 0.62 sec.

Dwell time for stationary pierce: 14.02 sec.

Average speed for entire part: 17.64

Fastest speed when cutting: 21.17

Slowest speed when cutting: 1.17

Average speed when cutting: 13.56

Total time spent cutting: 143.14 min.

Total time spent traversing: 4.09 min.

Total time spent cycling relays: 3.57 min.

Number of corner passes added: 283

---

Error mapping is not enabled.

Tilt-A-Jet(R) is enabled.

---

sheet 2:

Material: bamboo

Machineability: 500

Thickness: 0.7500 inches

Tool offset: 0.0150 inches

Taper offset: 0.0000 deg (0.0000 inches)

Cut stand off: 0.0600 inches

Rotation: 0 deg

Estimated time to make this part: 2.9491 hours

Estimated cost to make this part: $73.73

Estimated abrasive needed: 143.97 Lbs.

Piercing: High pressure | Intelli-PIERCE(R)

Pierces: 68 (0 are wiggle pierces)

Cutting: High pressure

Width of path: 95.8210 (inches)

Height of path: 48.0593

Length of tool path: 2941.8500

Length of cutting: 2340.7760

(Values reported after tool offset applied.)

Pressure and nozzle setup:

High pressure setting: 45000.00 PSI

Low pressure setting: 20000.00 PSI

Mixing tube diameter: 0.0300 inches

Jewel diameter: 0.0140 inches

Abrasive flow rate: 0.8500 Lb/min

Abrasive size: 80.00 Mesh (US Std.)

Abrasive index: 1.00

---

Feed rate breakdown: (inches/min.)

---

Ideal linear quality of 1 speed: 34.99

Ideal linear quality of 2 speed: 30.01

Ideal linear quality of 3 speed: 18.83

Ideal linear quality of 4 speed: 13.52

Ideal linear quality of 5 speed: 10.46

Ideal minimum taper speed: 6.27

Definition of "Minimum Taper": 0.00100

Ideal dynamic pierce speed: 23.29

Ideal dynamic pierce length: 0.242"

Time for ideal dynamic pierce: 0.62 sec.

Dwell time for stationary pierce: 14.02 sec.

Average speed for entire part: 16.98

Fastest speed when cutting: 22.00

Slowest speed when cutting: 1.17

Average speed when cutting: 13.82

Total time spent cutting: 169.37 min.

Total time spent traversing: 3.83 min.

Total time spent cycling relays: 3.74 min.

Number of corner passes added: 201

---

Error mapping is not enabled.

Tilt-A-Jet(R) is enabled.

---

sheet 3:

Material: bamboo

Machineability: 500

Thickness: 0.7500 inches

Tool offset: 0.0150 inches

Taper offset: 0.0000 deg (0.0000 inches)

Cut stand off: 0.0600 inches

Rotation: 0 deg

Estimated time to make this part: 24.688 min.

Estimated cost to make this part: $10.29

Estimated abrasive needed: 20.43 Lbs.

Piercing: High pressure | Intelli-PIERCE(R)

Pierces: 4 (0 are wiggle pierces)

Cutting: High pressure

Width of path: 75.8726 (inches)

Height of path: 10.5950

Length of tool path: 385.0765

Length of cutting: 312.2366

(Values reported after tool offset applied.)

Pressure and nozzle setup:

High pressure setting: 45000.00 PSI

Low pressure setting: 20000.00 PSI

Mixing tube diameter: 0.0300 inches

Jewel diameter: 0.0140 inches

Abrasive flow rate: 0.8500 Lb/min

Abrasive size: 80.00 Mesh (US Std.)

Abrasive index: 1.00

---

Feed rate breakdown: (inches/min.)

---

Ideal linear quality of 1 speed: 34.99

Ideal linear quality of 2 speed: 30.01

Ideal linear quality of 3 speed: 18.83

Ideal linear quality of 4 speed: 13.52

Ideal linear quality of 5 speed: 10.46

Ideal minimum taper speed: 6.27

Definition of "Minimum Taper": 0.00100

Ideal dynamic pierce speed: 23.29

Ideal dynamic pierce length: 0.242"

Time for ideal dynamic pierce: 0.62 sec.

Dwell time for stationary pierce: 14.02 sec.

Average speed for entire part: 15.74

Fastest speed when cutting: 21.17

Slowest speed when cutting: 1.75

Average speed when cutting: 12.99

Total time spent cutting: 24.04 min.

Total time spent traversing: 0.43 min.

Total time spent cycling relays: 0.22 min.

Number of corner passes added: 54

---

Error mapping is not enabled.

Tilt-A-Jet(R) is enabled.

---

I am in love with this material:

http://www.plyboo.com/

which i bought locally at:

http://www.pals4wood.com/

I got the 3/4” x 48” x 96” 3-ply | vertical cross core

it costs roughly $180.00 per 4x8 sheet, and you'll need two sheets for this project.

You could use old school joinery techniques and cut all these parts the old fashioned way (table saw, chisel, cross cut saw), but as I had the opportunity to, I tested using an OMAX waterjet for the parts.

I created a custom material in the OMAX library called BAMBOO with a hardness setting of 500 and cut the parts on a quality of 3. I used a longer than standard lead-in to minimise splitting of the ply.

Other cool tricks while cutting wood on this machine:

lower the water tank level so the ply isn't soaking in the water during the cut.

constantly force a jet of compressed air around the parts during the cut to prevent water soaking into the top of the plywood. This also blows away any garnet or discolored water that can discolor the parts.

in preference in future I would use plastic supports in the tank instead of the steel ones because when the jet was cutting over the steel the backwash was a discoloring liquid.

I took care to align the parts in the layout program to align the wood grain with the parts where i wanted it.

Wanted to make sure all water was removed before finishing and assembling.

I used a combination of bench router and hand edge router to do 1/8in rounds on all edges.

220 grit was perfect for a light sanding to finish quality.

this step is really an excuse for a cheesecake photo.

you can see the 53 components required to make both benches and the table!

With all the parts I followed the sequence implied by the schematic to put the whole table together.

similarly assemble the bench.

a clean rubber mallet is very useful.

also use some scraps of the plywood as the surface to be hit with the hammer (place between hammer and finished parts).

I wasn't satisfied with the squeeze fit, so i put it under the 80tonne hydraulic press. While this was an enormous amount of fun, i later found that lubricating the joints with bathroom soap, then using the rubber mallet with high frequency taps did just as good or better job, without being as nerve wracking.

on the plus side, i found out that each side of the bench supported a massive 10 tonnes... YES, 10 TONNES !!!!

that's 2 elephants sitting at my dining table....

I also found that good old G-clamps and other clamps worked a treat.

This is the exciting bit. Closed to finished.

I decided on linseed oil over polyurethane because it is easier and not quite as toxic.

Apparently Linseed oil is like an eopxy that sets exothermically as it reacts with the wood. That's something really cool that I didn't know.

http://en.wikipedia.org/wiki/Linseed_oil

I used boiled linseed oil, and it has worked really well. I applied with brush then wiped down with rags.

It needs to sit in sun and air for a few days for the smell to dissipate.

All up it took about 3 days.

About 4-6 hours for the CAD.
About 6 hours for the cutting.
About 4 hours for the sanding and the edge routing.
About 3-4 hours for the assembly.
About 4-6 hours for the Oiling.

Materials cost was around $400 and the cutting costs if you were to do it at a waterjet job shop would be about $300-400.

You can find a job shop here:
http://www.omax.com/jobshop.php

So all in all it's an expensive table, but I'm very proud of it's beauty and it looks great in my apartment.

Sure I'd change a few things about the design before building another one, but not too many. All in all a fabulous material and construction method for furniture.