My head was spinning last night

[Michael Cole]

Now, I am fairly well educated, masters degree and lots of extra credits, but am new to this woodworking. I was trying to figure out the dimensions for my cabinets for my shop last night. I am going to build frameless base cabinets using plans from a site on the internet. It is a good site and gives very specific directions on how to figure the dimensions and I am thankful I have it. My problem is that I am using cabinet grade plywood that is 23/32". When you get to those 32nds it taxes your brain figuring the exact numbers! Not sure it matters anyway as I am quite sure I am not skilled enough to cut to 1/32! I think I have all the dimensions figured out and will start working as soon as my wife quits giving me "projects" to do for her. I appreciate all the help I have been given here.

[Dave Richards]

How critical are the exterior dimensions of the cabinets you're making? I do a lot of design work for a cabinet maker who has asked me to use 23/32" for the thickness of plywood for cases. In most situations, the exterior dimensions aren't that critical. I make the lengths of the horizontal pieces to the nearest 1/16 in.. Dadoes to receive those horizontals are always 1/4 in. deep which is plenty. So the horizontals are 1/2 in. longer than the inside dimension of the case. It works out fine.

I do the design and layout work digitally in SketchUp and let the program tell me how big to make the parts.

[David Hawxhurst]

My problem is that I am using cabinet grade plywood that is 23/32". When you get to those 32nds it taxes your brain figuring the exact numbers! Not sure it matters anyway as I am quite sure I am not skilled enough to cut to 1/32! I think I have all the dimensions figured out and will start working as soon as my wife quits giving me "projects" to do for her. I appreciate all the help I have been given here.

that is why i changed to metric. the so called 3/4" ply i've been getting measures 18mm which is a nice easy whole number to work with.

[Peter Quinn]

It's funny how daunting the simple math involved with cabinetry can be at first. I have been using a ruler since I was a child, I tested pretty well in high school aptitude tests for spacial rellations and geometry, I left a Phd program to pursue other things which led me to wood working. Still, the first time I had to lay out a run of cabinets from a set of plans it made my head spin and hurt too. It's mostly nerves and unfamiarity with the salient variables. You don't need a computer program or a Phd in geometry to do this. I've seen some of the most complicated elevations I experienced layed out on a piece of drywall tape in the field! Learn to make a story pole, the rest takes care of itself. Your story pole (mine are usually made on a white piece of poplar or a strip of left over plywood) is a full size drawing that shows where every piece of plywood and solid lands. Cut the pole to fit the run, lay out full scale on the pole, build accurately to the pole, done. I do one for the run, one for elevations, occasionally one for depth too if things are odd or tricky.

if this run is wall to wall and frameless boxes, I'd include loose scribes at each side, and make them at least 1". A loose scribe is just a plywood or solid wood L (solid is easier to actually scribe) that gets screwed to the outside of the case at the end of a run, this allows you to over come out of plumb walls, bad drywall, and the occasional errant sized plywood. On long runs I measure my plywood and will usually add 1/16 to my horizontal parts to overcome my missing 1/32" on each piece of plywood. I'm usually within 1/16" over all on 16' of run that way. On installation I'll usually set a box at each end after leveling the ladder kicks (loose toe kicks that the actual boxes rest on) , then build from one side to the other. When I reach the second side I measure the last cabinet to go in, scribe the necessary amount off the loose scribe on the end box, then shove the last one in. Don't try to fit boxes wall to wall, walls are rarely dead straight and plumb, you need to build in this wiggle room, looks more seamless when you get to doing cabinets for finished space like your kitchen.

[Erik Christensen]

couple of suggestions...

first I use a spreadsheet to reduce the number of math errors in standard calcs - for example - if the cabinet case is A inches wide and I am using slides from XYZ co that are B inches long - what are the lengths of the drawer sides & front/back for the joinery I am using & size of the bottom... once you get the spreadsheet formulas nailed all you have to pay attention to is the height of each drawer and make sure the as-built cabinet width is as specified - all the nasty detailed math is done by the spreadsheet formulas.

second use sketchup to build your cabinet cases, let the space & design drive the exterior cabinet case dimensions and don't worry about 1/16th of slop on the interior - focus on getting cases square and built to fit the room - i then make doors, drawers & drawer fronts to fit the as-built cases

YMMV - others build the other way around to minimize the impact of having assembled cases filling the shop - I am not good enough to build a case to 1/32 accuracy to keep slides from binding but I can build a drawer to those specs

[John TenEyck]

What Peter said. Learn how to use a story pole. Direct measurement is always correct and requires no math.

John

[Michael Cole]

I will have to research the story pole. I read a couple of short articles but still don't quite understand it. About SketchUp - I tried downloading it once to use for USPSA stage write ups and had problems including getting a virus. Is it safe to download? Probably was just a fluke. Recalculated the cabinets again as I keep changing my mind on height. I have a window in the middle of the wall and was trying to be able to get the window trim and a back trim on the counter top. I think I will use the back trim as the bottom trim for the window and make them a little taller.

[Bob Hoffmann]

It sounds like -- at least for this project -- that you are building your cabinet to fit a house wall. Nice -- but, take into account that the house wall is not square and the floor not level. Building your cabinet to fit tight to your wall / window is a daunting task. This is usually done with a filler strip -- that allows a square cabinet to fit an existing wall / window. This filler strip can be cut to match the space between the cabinet and the wall / window -- which will most likely be at an angle, and could also not be a straight line.

Another thing to take into account is that your cabinet and wall / window will expand and contract -- neither are stable and will move in summer to winter. Painters caulk to fill gaps and that allows for movement.

The point that I am making is to make sure that there is some gap in what you are building so that it will fit. I have built stuff that I was sure was the right size to find that it fit in every dimension except one that had to be persuaded to get in place. Building in a filler strip or a way level your cabinet will make it a lot easier to get in place -- and leaving yourself a gap, even without a filler strip -- say 1/8", is a good idea. You may find that that 1/8" is good in one spot, but disappears on the other side.

[Robert Engel]

Michael,

You rarely need (or want) to make cabs this exact, so don't sweat the small stuff!

I'm not an expert, but I've built my share of cabs and I'll tell you, its gets as complicated as you want to make it.
(Now how do I know that???:rolleyes:). Here's my take on it:

You didn't give your layout parameters, but even without knowing that, you usually don't have to fret over the exact dimensions because:

1)If the cabs fit between two walls, you're gonna have filler strips on each ends so the doors can open all the way. So there is your fudge factor.
Take distance between walls - 4 or 5 inches and calculate all my cab widths from there. If I'm off due to cumulative error no big deal. Add the fillers to each end and scribe to wall.

2)If cabs have one or more ends open, then its even easier because your cabs just end where they end. Just get them close. If there is a wall on one side and a doorway on the other, leave a couple inches short of doorway to give you some leadway.

If you need an exact dimension, then the width of your bottom will be the total width of the unit minus (2 x 23/32=1 7/16) instead of (2 x 3/4=1 1/2).
But you rarely need to be concerned about building them this close.

I highly recommend the book by Danny Proulx on building frameless cabs.
Good luck!

[Pat Barry]

Michael, you should convert to metric dimensioning. Its incredibly simpler and more intuitive. For example, your 23/32 plywood is actually 18.25 mm. Believe me, convert and it will make your whole project much better . :) JK

[Rod Sheridan]

Good luck Michael, I'm sure you'll do a fine job.

Time for you to switch to metric and avoid those pesky fractions :-), I converted about a decade ago and haven't looked back

Since you're building boxes, the only critical dimensions are the outside dimensions. That should simplify your predicament.

Regards, Rod.

[Michael Cole]

Have to look into metric conversion!

[Phil Thien]

I just pretend the plywood is the nominal dimension, so 23/32" actual I'd treat as 3/4". You obviously have to accommodate the reduced thickness in your dados, but having a project come out 1/16" smaller (so 23-15/16" wide instead of 24" wide) has never been a problem for me.

For drawers and doors, I cut those parts to actual size after I have the cabinet built, which is really the safest way to do it anyhow.

Sometimes I work in metric but often I have a bunch of fractional dimensions of a space, so I keep everything fractional through the entire project.

[Peter Quinn]

The biggest issue I see is on a wall to wall installation the width at the front of the cabinets is almost always different then the back corners. Framing, drywall buildup, go figure, but if you build them too tight they will not fit. Better to include a loose scribe at each end, learn to scribe, and have a seamless built in look at the front where it matters. Once the top goes on and perhaps a back splash, all is covered and looks great..

[Tom Ewell]

Good advise given so far like don't count on the structure being plumb, level, square or flat. A long spirit level and/or laser level helps to predetermine how bad the room is so you can design in your 'fudge factor'.

Measurements wise, once the design is established, is fairly straight forward, as mentioned above you can adjust for the 3/4" nominal 23/32" fractional stuff, two sides with bottom/top 'butted' to sides is unit width less the 1-7/16.

If you're going groove/dado joinery at the sides then set the depth of the groove/dado so you have a nice number to work with left on the panel...ie. make the cuts so you have 1/2" thickness left on your sides. This will make it unit width less 1"... the dado's of course will be something less than 1/4" deep. (7/32 for you sticklers)

The biggest key I've found is plan ahead enough (cut lists etc.) so each machine setup gets used to cut all parts requiring that setup and it does not hurt to double check measurements while your cutting every so often to make sure the setup is not 'wandering' (bumping the fence type stuff). Resetting to cut a forgotten piece always seems to be a whisker off but not impossible to deal with, better to get it the first go around.

Try to use the same tools for all your measurements be it tape, foldable rule, story pole, squares, etc. or at least check any different measuring devices against one another in case one is really off.

Hardware (hinges/slides) should also be chosen during the planning stage so you can account for drawer/door sizes and any overlay/inset/offset specs required for that hardware.

The inevitable hassle of curvy plywood can be mitigated some with a fixed shelf, back panel and eventual installation with well placed fasteners.

[Michael Cole]

I just pretend the plywood is the nominal dimension, so 23/32" actual I'd treat as 3/4". You obviously have to accommodate the reduced thickness in your dados, but having a project come out 1/16" smaller (so 23-15/16" wide instead of 24" wide) has never been a problem for me.

For drawers and doors, I cut those parts to actual size after I have the cabinet built, which is really the safest way to do it anyhow.

Sometimes I work in metric but often I have a bunch of fractional dimensions of a space, so I keep everything fractional through the entire project.

The drawers (at least that is the way I am leaning) will be done after the cabinet carcasses, probably a while later as I have other projects that need to be done after I have a counter top/ work bench.

[John Lankers]

Michael, I hate to repeat what others are saying, imperial is good but metric is better - this and a glass of wine at the lake make life while a lot easier :-)

[Chris Parks]

Have to look into metric conversion!

Don't bother converting measurements as you will just get a bigger headache, buy a metric tape and rule and use that for everything. Measure the wall in metric and start from there, I was given a set of plans for a workshop in metric never having used it before and that is what I did, worked off the plan.

[Phil Thien]

So here is a dumb question for you metric heads.

Here in the US, the "standard" kitchen countertop height seems to be 36".

That would be 91.44 cm I suppose.

But I doubt you guys use 91.4, what do you use as your standard kitchen countertop height?

Our framing is spaced 16-inches on-center, what do you guys use?

A door is 36" wide and 80" high, which again would be 91.44 and 203.2 cm respectively. So are your doors 90 x 200 or something?

Just curious.

[John Lankers]

Phil, this is relatively easy. I grew up in metric Europe, came to Canada some 25 years ago and was happy to convert to the imperial system but I have come to realize that the imperial system in 1/4, 1/16, 1/32, 1/128, ... is very error prone but the metric system always stays in 1/10 no matter what. I have decided to go back to metric, at least in my hobby shop, and many pro shops (not all) do the same, it's just "easier". 50 mm or 2", who cares, 80" is close to 2 meters - close enough for me, nobody will ever notice ;-)

[Pat Barry]

I was actually joking about converting to metric - the JK at the end of my post (JK = just kidding texting shorthand). For you, do what Phil suggested above. Going metric for this project is not a good idea IMO.

[Phil Thien]

Phil, this is relatively easy. I grew up in metric Europe, came to Canada some 25 years ago and was happy to convert to the imperial system but I have come to realize that the imperial system in 1/4, 1/16, 1/32, 1/128, ... is very error prone but the metric system always stays in 1/10 no matter what. I have decided to go back to metric, at least in my hobby shop, and many pro shops (not all) do the same, it's just "easier". 50 mm or 2", who cares, 80" is close to 2 meters - close enough for me, nobody will ever notice ;-)

Yeah I get all that I'm just curious what you metric guys set a counter height to, like what is your standard? And what are the standard door height and widths. I'm just curious.

Not picking on metric at all, I'm just curious. Like, what is a 4x8 sheet of plywood in metric land? Shelves here are commonly said to be one foot or 12" deep, home centers sell strips of sheet goods with 12" width stated as nominal.

[Rod Sheridan]

Hi Phil, if you're using metric to design items, you don't normally convert measurements.

A counter height of 36" would become 920mm.

A table leg that's 2" square would be 50mm, a shelf that's 3/4" would be 20mm.

For items like kitchen cabinets you would use the 32mm system.

If you're going to hang a standard house door, you would do that in imperial measurements.

Regards, Rod.

[Jim Dwight]

Michael,

All the plywood I've used recently has been metric in thickness and imperial in length and width. Not a serious issue, it is about 1/32 under, as you note. If I were cutting the uprights for my cabinet, I would figure based upon 3/4 thickness (in my case with a butt joint, I reduced the uprights height by 1.5 inches for the top and bottom), then add 1/16 for the thinner plywood. Easier to me than subtracting 46/32 from the desired height.

I do not ever plan to use metric because I cannot visualize it. I don't see a benefit, for me. It seems like the younger you are, the more likely you are to convert. I am not young enough, I guess. I know that 3 inches is a pretty good base height and 2 inches is about a minimum but I cannot go directly to a mm equivalent. I have to convert everything to do mm which is too much effort and makes me error prone.

Remember that it is a good practice to not put untreated wood in direct contact with concrete. Garage floors can be wet which would complicate the issue. I put a PT base under my cabinet and will do so with the next one.

I made my cabinet slightly less (about 1/4 less) than the height of my table saw. I have my router table the same height. I want things arranged like this to facilitate moving material between tools and so that one tool can be a support for feeding work over another tool. So my base cabinets are a little over 38 inches high. I made the one for the wall without windows first but when I do the rolling workbench that goes against the wall with windows in my shop, it will be the same height. It will fit between the windows. I wouldn't adjust my workbench based upon the windows unless it turns out to be a good height for it and your tools. You can always make a shelf or something to go directly in front of the window.

My projects get a paper and pencil sketch. Sometimes I use an old parallel board (small drafting table) but often it is just a sketch. I need to write things out to avoid mistakes but I don't need everything dimensioned to the n'th degree. A few decades have taught me what works for me. Early on, I had more detailed drawings and it helped. It also helps to sketch out how you will cut up sheet goods. I often still do that, even though my "drawings" are very simple. The more intricate the project is the more detailed I make the plans. Shop cabinets are on the low end of complexity.

[Phil Thien]

Hi Phil, if you're using metric to design items, you don't normally convert measurements.

A counter height of 36" would become 920mm.

A table leg that's 2" square would be 50mm, a shelf that's 3/4" would be 20mm.

For items like kitchen cabinets you would use the 32mm system.

If you're going to hang a standard house door, you would do that in imperial measurements.

Regards, Rod.

Right, but in Europe they don't use imperial measurements for doors, right? And they must have some standard door heights and widths (like we have 80" high).

And their plywood can't be 4x8, right?

Just wondering what those are.

It isn't important, really, just curious.

[Chris Parks]

I don't see why a one off project in metric is any harder than me doing a one off in imperial. Why do you need to visualise anything, get a story stick and metric measuring tapes and rules and start measuring, draw a plan if needed and start building. I never build to a "standard" height for cabs, I build to suit my height and the purpose I am building for. In our metric land cabs are generally built 600mm deep off the wall and sheets are 1200mm x 2400mm nominal and what that is in imperial I have long forgotten. We never use framing for cabs at all, everything is built to system 32 by commercial builders and all kitchens etc are built off site mostly on CNC machines, having a kitchen built on site is unheard of. A lot of cab work is now being sourced from China so there goes another industry down the slot. Coincidentally I was looking at a project in FWW tonight and I will build that in imperial and I don't see the issue even if it is at least 30 years since I have used it. I shudder to think of all those stupid fractions that I was long ago taught and now could not use if I tried.

[Rod Sheridan]

Hi Phil, the metric plywood size available in Canada is 1200 X 2400.

No idea on EU door sizes though...........Rod.

[Michael Cole]

After a few more revisions and recalculations, I finally made one carcass today. Everything seemed fine except the bottom was about a quarter inch too long. Have to go back to my numbers and see where I went wrong, but I left them in the shop so will have to do that tomorrow morning before I start on the second one. All the other measurements seemed right on or at least very close to right on. Anyway, one carcass done and three more to go for that area and then 2 for the desk area (they will be a different size). Thanks for the help.