Measurements (or, some math help)

[Cochese]

Is there a layout program I can use for an upcoming project that will allow me to calculate dimensions of cuts I'll need to make, which take into account rabbets and dados and such? I'm a smart guy, and I can add, but without being able to put hands on I'm getting very confused. And I really, really suck at SketchUp.

Or alternatively, perhaps someone can check my math:

My new router table, for all intents and purposes is going to be a box 30" wide, 22" deep, and 34.325" high. Those are inclusive measurements, and everything needs to fit in there. I'll be using 3/4" ply all around and my dados and rabbets will be done at 3/8" depth.

Now, here's what I have:

Bottom - 30" wide, 22" deep. Pretty straightforward. Rabbets on three sides.
Sides - 34" tall, 22" deep. Rabbet on back side and top; fits into rabbet on bottom.
Back - 29.25" wide, 34" tall. Fits into rabbet on bottom, sides fit into rabbet.
Shelf - 29.25" wide, 21.625" deep. Fits into dados on sides and back.
Bottom vertical divider - 13.625" tall, 21.625" deep. Fits into dado on bottom, shelf and back.
Top vertical dividers - 20.625" tall, 21.625" deep. Fits into dado on shelf, back and dado/rabbet on top.

The top is going to fit into rabbets on three sides, and accept the two dividers and be 29.25" wide and 21.625" deep.

Does that sound right?

[cabinetman]

I have a few suggestions. First, make your dadoes and rabbets only 1/4" deep. That is sufficient for a good glue joint. Using 1/4" also makes all your other measurements more simple.

The ends can be done a few ways. You can rabbet the bottom of the ends to accept the floor, or, you can rabbet the floor to accept the ends. Doing it the second way will allow the edge of the floor to show when viewing the end. Or, you can configure a toe kick integral to the cabinet by dadoing the bottom into the ends the distance you want revealed above the floor. The back edge of the ends can be rabbeted to accept the back.

At the top, a front and rear cross rail about 3/4" x 2 1/2" can be let into a rabbet at the top edge of the ends to tie the two ends together. The underside of the back edge of the rear rail can be rabbeted to accept the back. The underside of those rails can be dadoed to accept the dividers. These two rails are also used to screw down the top from underneath, making the top removable and replaceable.

You didn't say if the cabinet would be on casters, or if it will have a toe kick integral to the cabinet, or a loose toe kick. These are my general suggestions, and will try to answer any specific questions you may have.
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[Cochese]

Some good thoughts. It will be on casters. The rest I will think about for morning.

[Cochese]

Okay, I've adjusted to a 1/4" rabbet and dado depth and incorporated the stretchers instead of a full top. Here's what I've got so far:

Bottom panel – 21.5”d * 29”w
This panel will go into rabbets on the side and back panels. It will hold a dado for the lower divider. Dado for lower divider is 14 1/8" from either long side.

Side panels – 22”d * 34 3/8”h (x2)
This has a full rabbet on bottom, a divided rabbet on top at front and back for the stretchers, and a dado to accept the shelf. Will be adding scrap wood for the drawer guides. Dado for shelf is at 20.25" from top.

Top stretchers – 3”d * 29”w (x2)
These fit into rabbets at the top of the sides, and also accept the top dividers via dados. This is what the top screws into, and the back panel fits into a rabbet. Dados for top dividers are at 8.25” from both sides.

Back panel – 29”w * 34 1/8”h
This fits into rabbets on the side and bottom panels, and has a dado for the shelf and bottom divider, and rabbets for the top dividers. Cut out between the top dividers to create a recessed spot behind the router. Dado for shelf is at 19.75" from top. Dados for top dividers are 8.25" from both sides. Dado for bottom divider is 14 1/8" from either side.

Top divider – 21.5”d * 20"h (x2)
Fits into rabbets on the back panel, and dados on the shelf

Bottom divider – 21.5”d * 12 5/8"h
Fits into rabbets on the shelf, bottom and back panels

Does that sound right? I think all my math has added up correctly.

[cabinetman]

Okay, I've adjusted to a 1/4" rabbet and dado depth and incorporated the stretchers instead of a full top. Here's what I've got so far:

Bottom panel – 21.5”d * 29”w
This panel will go into rabbets on the side and back panels. It will hold a dado for the lower divider. Dado for lower divider is 14 1/8" from either long side.

Side panels – 22”d * 34 3/8”h (x2)
This has a full rabbet on bottom, a divided rabbet on top at front and back for the stretchers, and a dado to accept the shelf. Will be adding scrap wood for the drawer guides. Dado for shelf is at 20.25" from top.

Top stretchers – 3”d * 29”w (x2)
These fit into rabbets at the top of the sides, and also accept the top dividers via dados. This is what the top screws into, and the back panel fits into a rabbet. Dados for top dividers are at 8.25” from both sides.

Back panel – 29”w * 34 1/8”h
This fits into rabbets on the side and bottom panels, and has a dado for the shelf and bottom divider, and rabbets for the top dividers. Cut out between the top dividers to create a recessed spot behind the router. Dado for shelf is at 19.75" from top. Dados for top dividers are 8.25" from both sides. Dado for bottom divider is 14 1/8" from either side.

Top divider – 21.5”d * 20"h (x2)
Fits into rabbets on the back panel, and dados on the shelf

Bottom divider – 21.5”d * 12 5/8"h
Fits into rabbets on the shelf, bottom and back panels

Does that sound right? I think all my math has added up correctly.

The best way to check your math is to do a quick pencil sketch. This can be done as a front or side view, or as a perspective. Make it an explosion sketch, i.e., Show the pieces with the joinery. Make a note for the overall dimensions when together. Then add up all the parts that go into that dimension.

For example, you said the ends are 22" x 34 3/8". That is an overall dimension. You said the back is 29" x 34 1/8". The total height for the rear of the assembled cabinet can be figured this way:


Add the back dimension - 29" x 34 1/8".
Add what's left at the top rail from the rabbet - 1/2" (if the rabbet is 1/4).
The total comes out to 34 5/8", and the ends are 34 3/8".
I might not have understood your description of machining and assembly, and apologize if I didn't, but your figures sound a bit off.
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[Cochese]

Forgot to take into account that back stretcher, so I think the height of the back needs to be actually 33 3/8"

[cabinetman]

Forgot to take into account that back stretcher, so I think the height of the back needs to be actually 33 3/8"

It's much better to find out from adding measurements up on a drawing than when the parts are fitted together. You have me confused now. How did you come up with 33 3/8"? If all the overalls are the same, and the ends are 34 3/8", deduct from that the 1/2" left at the back of the rail rabbet, and the back size should be 33 7/8". 33 7/8" + 1/2" = 34 3/8"...right?

I didn't check your sizes for the interior dividers, so add them up the same way and see if the parts match the overalls.
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[Cochese]

I have the back sitting on the bottom with that measurement. I could do it with the opposite way and your numbers would be right.

See why it's so hard for me to add? I've printed some graph paper and am going to see if it all fits together.

[cabinetman]

I have the back sitting on the bottom with that measurement. I could do it with the opposite way and your numbers would be right.

See why it's so hard for me to add? I've printed some graph paper and am going to see if it all fits together.

I'm just going off what you said about the bottom panel...that it fits into rabbets on the side panels and the back panel.

Okay, I've adjusted to a 1/4" rabbet and dado depth and incorporated the stretchers instead of a full top. Here's what I've got so far:

Bottom panel – 21.5”d * 29”w
This panel will go into rabbets on the side and back panels.

.

[Cochese]

I probably worded that wrong. This is very frustrating.

[Cochese]

I'm laying it out on graph paper and I must say it's been much easier figuring things out by marking the final dimension outline out and working in.