Hi all,
Yesterday I finally found some time to pick up my Mobile MFT/3-CTL26-Systainer Port project that I announced almost a year ago here.
A good thing about the delay is that I have had a lot of time to think things over once more and this has led to some changes in the design here and there that I will explain in more detail as I come across them during the build.
Some of the design changes were inspired some of the other mobile workbench and systainer port threads that others have posted over the year. Thank you all for sharing and inspiring me!
To keep everything together I will keep updating this first post with all the build steps but a note for those impatient readers on the FOG: this will still take many weeks to complete.
I tend to do this type of woodworking project the hard way because:
Step 1: The Base
2012-01-08
As explained in detail in the original thread, the base of the workbench is a torsion box filled with expanded polystyrene sheets to aid in strength but mainly to prevent the whole thing from resonating with the CTL26.
Based on experience gained with building a window sill I decided to reduce the thickness of the top sheet from 12 mm to 6 mm to save weight.
(The window sill is also an MDF torsion box. It is 30 cm deep, 2 m long and 5 cm thick in the front and 9 cm in the back. It is anchored to the wall with five 8 mm threaded rods and turned out to be so strong that I [110 kg :
] can stand on the edge without it even bending.)
Other than that the design is still basically the same.
I started out by cutting the top sheets (I had to join two pieces) to size and then the corner blocks (18 mm + 9 mm multiplex for caster attachment) and pine frame edges and internal pieces (these support the dividing walls).
These were then glued to the top sheet.
Next step was to cut the expanded polystyrene sheets to size and for that I used my new Carvex PS 400 and the special Wavy blade (S 155/W) for cutting soft materials. And it works like a charm with just two minor issues: any overhanging piece of the sheet needs extra support to prevent it from violently flapping up and down and the Carvex consumes such a little amount of power when cutting foam (on speed 1 and 2) that the CTL26 doesn't really know if it should kick in or not.
But the cut quality is great and even if the vacuum stays of there is hardly any debris (and due to the antistatic hose any debris just falls down instead of clinging to everything else!
The panels were then glued into place with a special paste type glue.
As you can see in the above image the polystyrene is slightly thicker then required so with a homemade hot wire cutter I trimmed it to size.
(And as requested by Alan M in the original thread I will describe the construction of the hot wire cutter in a separate post.)
My power supply was able to supply just enough power to cut; but I had to go slow.
(The power supply was designed to provide a lot of current at a very low voltage (to drive a model plane motor) and due to the high resistance and the length of the wire I needed a bit higher voltage than it could provide.)
After a cleanup run with my DTS 400 sander of the polystyrene panels to get rid of the roughness left by the hot wire cutter, I applied the special glue to the polystyrene panels and polyurethane glue to the wooden frame.
I then closed the torsion box of with a sheet of 4 mm multiplex.
To apply pressure during the curing time of the glue I stacked a couple of sheets of 18 mm MDF on top of it and all the loaded Systainers I could find on top of those.
2012-01-31
Although I had initially decided not to rework the original model I made in Sketchup (because I considered it to be too much effort) I have picked it up again.
I had to make some design choices that were hard to visualize on paper and I wanted to keep a good record of a lot of dimensions to be able to add/alter stuff later (as I am working with hollow panels a lot, I need to remember where the supports are).
And I am already glad I did make the model; I made two measure-twice-cut-once mistakes :-[ and the model helped in finding a solution and reassuring me that the internal base structure could handle the deviation ;D.
For those interested you can find the model here.
Just beware that it is still under construction, there are still some elements missing (back wall for the vacuum bay, MFT/3 supports, wheels, and the drawers will change).
Here is a screenshot:
I have also been working on finishing the base by trimming the bottom sheet using the TS55:
And applying a 12 mm thick beech trim along the edge to give it a nice finish and some protection:
The Bessey edge clamps proved to be very handy for this application!
(Although I did not have enough to cover the full length of the trim and had to improvise with shims and wedges.)
I then cleaned the trimming up with a copying bit in the router and proudly looked at the result, did a test fit with the MFT/3... and discovered an error!
When measuring and marking the top sheet I should have marked it at 1106 mm but in fact marked it at 1116 mm. And believe me I checked the drawing and my measurement a couple of times, but still got it wrong!
Luckily I had to much material and used the TS55 to cut of 5 mm on both sides in a couple of shallow passes.
So I now have a finished torsion box that is very sturdy, nice and flat, and doesn't weigh too much!
In the next update I will describe the construction of the first side wall and it's attachment to the base.
I hope you have enjoyed the read.
Warm regards, Oscar.
Yesterday I finally found some time to pick up my Mobile MFT/3-CTL26-Systainer Port project that I announced almost a year ago here.
A good thing about the delay is that I have had a lot of time to think things over once more and this has led to some changes in the design here and there that I will explain in more detail as I come across them during the build.
Some of the design changes were inspired some of the other mobile workbench and systainer port threads that others have posted over the year. Thank you all for sharing and inspiring me!
To keep everything together I will keep updating this first post with all the build steps but a note for those impatient readers on the FOG: this will still take many weeks to complete.
I tend to do this type of woodworking project the hard way because:
- I am a perfectionist
- I have some very specific functionality demands (it needs to be able to come apart for transportation for instance)
- This is just one of those projects that is mainly there just for my relaxation
- I just can
Step 1: The Base
2012-01-08
As explained in detail in the original thread, the base of the workbench is a torsion box filled with expanded polystyrene sheets to aid in strength but mainly to prevent the whole thing from resonating with the CTL26.
Based on experience gained with building a window sill I decided to reduce the thickness of the top sheet from 12 mm to 6 mm to save weight.
(The window sill is also an MDF torsion box. It is 30 cm deep, 2 m long and 5 cm thick in the front and 9 cm in the back. It is anchored to the wall with five 8 mm threaded rods and turned out to be so strong that I [110 kg :
] can stand on the edge without it even bending.)Other than that the design is still basically the same.
I started out by cutting the top sheets (I had to join two pieces) to size and then the corner blocks (18 mm + 9 mm multiplex for caster attachment) and pine frame edges and internal pieces (these support the dividing walls).
These were then glued to the top sheet.
Next step was to cut the expanded polystyrene sheets to size and for that I used my new Carvex PS 400 and the special Wavy blade (S 155/W) for cutting soft materials. And it works like a charm with just two minor issues: any overhanging piece of the sheet needs extra support to prevent it from violently flapping up and down and the Carvex consumes such a little amount of power when cutting foam (on speed 1 and 2) that the CTL26 doesn't really know if it should kick in or not.
But the cut quality is great and even if the vacuum stays of there is hardly any debris (and due to the antistatic hose any debris just falls down instead of clinging to everything else!
The panels were then glued into place with a special paste type glue.
As you can see in the above image the polystyrene is slightly thicker then required so with a homemade hot wire cutter I trimmed it to size.
(And as requested by Alan M in the original thread I will describe the construction of the hot wire cutter in a separate post.)
My power supply was able to supply just enough power to cut; but I had to go slow.
(The power supply was designed to provide a lot of current at a very low voltage (to drive a model plane motor) and due to the high resistance and the length of the wire I needed a bit higher voltage than it could provide.)
After a cleanup run with my DTS 400 sander of the polystyrene panels to get rid of the roughness left by the hot wire cutter, I applied the special glue to the polystyrene panels and polyurethane glue to the wooden frame.
I then closed the torsion box of with a sheet of 4 mm multiplex.
To apply pressure during the curing time of the glue I stacked a couple of sheets of 18 mm MDF on top of it and all the loaded Systainers I could find on top of those.
2012-01-31
Although I had initially decided not to rework the original model I made in Sketchup (because I considered it to be too much effort) I have picked it up again.
I had to make some design choices that were hard to visualize on paper and I wanted to keep a good record of a lot of dimensions to be able to add/alter stuff later (as I am working with hollow panels a lot, I need to remember where the supports are).
And I am already glad I did make the model; I made two measure-twice-cut-once mistakes :-[ and the model helped in finding a solution and reassuring me that the internal base structure could handle the deviation ;D.
For those interested you can find the model here.
Just beware that it is still under construction, there are still some elements missing (back wall for the vacuum bay, MFT/3 supports, wheels, and the drawers will change).
Here is a screenshot:
I have also been working on finishing the base by trimming the bottom sheet using the TS55:
And applying a 12 mm thick beech trim along the edge to give it a nice finish and some protection:
The Bessey edge clamps proved to be very handy for this application!
(Although I did not have enough to cover the full length of the trim and had to improvise with shims and wedges.)
I then cleaned the trimming up with a copying bit in the router and proudly looked at the result, did a test fit with the MFT/3... and discovered an error!
When measuring and marking the top sheet I should have marked it at 1106 mm but in fact marked it at 1116 mm. And believe me I checked the drawing and my measurement a couple of times, but still got it wrong!
Luckily I had to much material and used the TS55 to cut of 5 mm on both sides in a couple of shallow passes.
So I now have a finished torsion box that is very sturdy, nice and flat, and doesn't weigh too much!
In the next update I will describe the construction of the first side wall and it's attachment to the base.
I hope you have enjoyed the read.
Warm regards, Oscar.
