i want to make a 'shelfing unit' that is an upright with slits across for the shelfs (with matching slits) to fit into.

The shelf will have two purposes: one for putting plant pots on and secondly as security against someone breaking in.
I have to keep drilling to the minimum as its rented property so the uprights which are 4 x 1in will be wedged from sill to ceiling with just small (maybe 1in) angle brackets to fasten to wooden sill.
Few questions:
1. How can I get a perfect fit between sill and ceiling? I know I can measure but it isnt even.
2. How to get those slits perfect? Would there be a certain type of jigsaw blade that will make the job easier? 
3. Are there any other measures I can take eg. to stop the wood splitting at the end of the slit.

Re-design7 years ago
What I would do if I were building this is.

1.  Make the frame out of 1 x 4 to fit snuggly in the opening.  Each piece should be cut to fit since it's probably not square.

2. then instead of slits (dados), cut 2 pieces of 1 x 4 to fit inside the frame for the shelf to sit on.  Glue and nail that all together.

3.  Do the same for all of the other shelves.

4.  Cover the joint at the front with a piece of trim.

Unless you are quite lucky dados are difficult even with power tools.  the extra wood makes a stronger frame.
merimaid (author)  Re-design7 years ago
Thanks. Yes decided a frame would be the best option for the reasons you mentioned.

Yes, cutting each piece to fit is a nightmare. I am sure there is a tool/technique for getting the end angles right - something that maybe is made up of two pieces that allows one to slide up and down to fit. I know that would only solve the 'smaller' height but then I guess you could 'eyeball' the 'triangular' space that is left. Aaaah or...you put a piece of cardboard there and trace it off!!

Oh it's so good to have a place where as I air my question I end up finding an answer! Well half an answer as I still need to work out how to slide the two pieces up and down each other. Actually what has probably happened is I have seen this solution to something else, somewhere else and it's just come to mind!