Boxes - what am I doing wrong here?

NatatorNatator Posts: 2
I forgot to take a photo, so I'll attempt to explain the problem I am having building boxes.

I'm using the method where I built the entire box, including lid and base, and then use the table saw to cut through and separate the lid from the body. Then problem I keep encountering isn't with the building, so I'm not worried here about how that is built, but this separation of the parts.

Every time I do that, rather than getting the nice even cut,it never quite joins up evenly. I get about a 1 mm (1/16") step at the end. As a result I need to recut both the top and bottom where they meet, negating the neat idea of that single cut making a "perfect" join between the two halves.

I set up the table saw as follows: Blade up just enough (an a tiny bit more) to cut through the walls of the box. Fence at correct distance from blade for either the main part of the box or the lid, it doesn't seem to make a difference to this which way I do it. Using feather board, from the side. I also seem to get the same result if I just cut or use spacers to fill in the previously cut walls (hope that makes sense.

I just can't work out what I'm doing wrong but it keeps happening.

Any thoughts?


  • frehleycometfrehleycomet Posts: 1,167 ✭✭✭
    Have you checked the table saw fence to be the same distance at the front and back of the blade for accuracy
  • Dan McLeodDan McLeod Posts: 5,451 admin
    @frehleycomet is right it is blade alignment with the fence. That being said you may have a little off cut with your box and the second cut starts showing the error. The other is to make sure your box is not slightly tweaked which would rest it on the saw a little off angle.
  • TimG45TimG45 Posts: 117 ✭✭✭
    I think both @Dan McLeod & @frehleycomet are hitting the nail on the head. If your fence is not parallel to the blade, any rip cuts to make the box sides could cause the box to be slightly tweaked. Running the assembled box through that misalignment will compound the issue. Another contributing factor can be the fence face not being square to the table
    Once assembled, both the top and bottom of the box should sit flush on a flat surface (table saw top), as should all 4 sides. When doing separation cuts, always run the same surface against the fence. I install an extra tall auxiliary fence over my normal fence so I have more of the box's lid or base in contact to reduce any fluctuations caused by surface irregularities. I've also changed from cutting where the blade just cuts through the walls to cutting just shy of cutting through the walls (leave about 1/32" connecting the top and bottom). This eliminates issues caused by shimming/taping the halves together to complete the cuts. The mismatches I see now are typically less than .010" and are easily sanded flush with some 180 grit affixed to a flat surface. Alignment is even better when I got my band saw that can handle a 13" box depth (and the kerf loss is only .025" instead of .125").
  • Ted BergTed Berg Posts: 483 admin
    agree with everyone above and I wonder if your zero clearance plate has any gaps the box can fall into, thus lowering, cocking the box. My zero clearance plate was slightly higher than the table and that small ledge screwed up some similar cuts till I found it.
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