LumberJocks Woodworking Forum banner
16K views 31 replies 11 participants last post by  Grumpy 
#1 ·
Sketchup - Torsion Box Design and Layout

I have been working on the design of the Cabinet of the RAS for sometime now. I finally got the Sketchup done for the frame of the Torsion Box.


I have been working on it for several hours this evening and have many more details worked out but that is gonna have to be for tomorrows blog.

The outside frame is of 3/4" MDF and the ribs are 1/2" MDF. I could as easily go with 3/4" ribs. But I think I will have minimum deflection in this configuration. Anyone disagree?
 
See less See more
1
#2 ·
Hi sIKE;

For a table that small, it is approaching overkill.

Actually, you passed overkill a while back, and I'm just being polite.

I doubt there be any deflection, even if a helicopter lands on it.

Looks good though, very nice sketch up work too.

Lee
 
#3 ·
Lee,

I am sure there is a bit of overkill going on here, the problem is the math of course. You want mare than one or two ribs going in each direction. After that you have to find some that work mathematicaly. Trust me the math and Sketchup damn near drove me crazy.
 
#4 ·
The Cabinet Design and Sketchup

Well here is the drawing for the cabinet base for my RAS.


The design for this has been challenging as not only do I have to level the table to the Saw and its carriage but I also want to level the RAS Table to my Miter Bench. After digging around I found some leveling feet that will screw to the side of the cabinet and then be adjustable though access holes drilled into the shelf. This will allow me to level the Saw to its' table then I will level the cabinet/table to the Miter Bench.

It dawned on me as I am writing this that I will need to drop the torsion box supports down another inch to take in account the top/bottom that will be added to the frame of the torsion box shown in the previous blog. The other thought it that I might want to shorten the height of the cabinet sides by a 1/4" - 3/8" to give some travel room for the leveling feet.

I am still considering 1 drawer and and doors below or two drawers. I have 2 extra sets of 28" drawer slides left over from the Miter Bench Project. Just got to figure out how often I will be leveling this cabinet. Any advice from you RAS owners?
 
#5 ·
Hi sIKE;

I no longer own a RAS, but I doubt you will have to level anything after the initial setup.

Let me throw a monkey wrench in your design.

If it's not too late to work with your existing conditions, why not build the cabinet with levelers?

This method will increase the amount of sides that can be cut from a sheet of plywood from 4 to 6, and make leveling an easy task.

http://www.prowoodworkingtips.com/Base_Cabinet_Construction_Sketch.html

Lee
 
#7 ·
Getting started with the case

As previously posted, I had worked out the details to my RAS cabinet using Sketchup. I started working on the cabinet this weekend and the reality of my previous work objected to the finest of my plans. With the miter bench not being sqaure, I have going to have to adjust my plans for the RAS cabinet.

I am going to have to take an inch off of the width of the cabinet and the torsion box. This is so I can make the cabinet square. I will then have to set the cabinet into its place and scibe filler strips in on each side to make up the difference. Oh well! Hopfully I can get this taken care of tommorow.
 
#10 ·
The Case work is done

Started working on the case this weekend and got it done this evening. Here is the Sketchup drawing of the case:

and here is the final result:


and here is the leveling configuration:


I need to go back to Sketchup and redo the torsion box as I had to reduce the width of the cabinet by one inch.
 
#16 ·
Torsion Box is started

I started the torsion box this weekend. This is my first one and it has been a learning experience. David Marks makes it look easy, but it is not. I got my work surface straight and level and started building the grid work. I quickly learned that brads are not a good substitution for finishing nails, as they like to follow a random path. I had to push on as SWMBO would not allocate additional budget for a finishing nailer. The gird work is done and I got the first skin on this evening. I hope to finish the Torsion Box tomorrow and get the RAS base mounted to it then that to the cabinet and then take a first pass at leveling the rig.

 
#17 ·
Hey looks just like the sketchup diagrams - how cool is that! Off to a good start. Maybe your first torture-box should have been something for the sweetie, like a potting bench or a sewing table, then maybe the you could have bagged the nailgun. Oh, well.

Seriously, wouldn't glue be enough? other than there being a lot of pieces to hold in place - though it could have been glued iin stages. I've never used any fasteners when gluing mdf to mdf and never had an issue ( that is mdf, right?) I'm assuming the nails are to hold the pieces while the glue sets? for speed?
 
#23 ·
Testing the Assembly

Finished up the Torsion box early this afternoon, after the glue dried I laid out the mounting holes for the RAS Base and put in the threaded inserts (not allot of fun in MDF). I temporarily mounted the RAS base to the Torsion box and placed the assembly in the cabinet and the I place it in its home to get a look at if and how everything will go together. I am very pleased with how things are looking at this time. The cabinet is square, the Torsion box is square, and everything is fitting like it should. I hope to be able to finish this tomorrow but there many small details to finish up this project.




Question for you RAS guys. Can I take several inches off of the front of the RAS table. You can clearly see in the second picture how far this extends out beyond the miter bench.
 
#24 ·
Hi sIKE,

Good progress mate! as a I beaver away at work. I truly have a "labor" day today. The good news is that 1 Sept is considered the first day of spring here and we have glorious sunshine.

wrt the front of the RAS table, my take it on it is that there are two factors
1) Safety thing. How far does your blade extend? You don't want the blade coming past the table. The blade buried in the table is a good thing. RASs are already dangerous enough.
2) How wide a board will you want to cut? In order to cut a board on the RAS, the back of the blade has to come past the outer edge of the board, so you need an extra distance equal to the diameter of your blade on this side of the table.

From the looks of it, you could mount the RAS base further back. Is that an option? or the space back there for some sort of dust collection?
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top