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post #1 of 24 Old 04-20-2019, 09:44 PM Thread Starter
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Newbie question about following plans

Maybe a dumb question:

I've been woodworking for a couple of years now and being able to follow other people's plans from the internet in combination with videos has really been an amazing experience to produce things way beyond what I would be able to otherwise. I keep running into a problem though that when I follow the plywood cut diagrams for the plans and rip up all the plywood at the beginning of the project, things are slightly off during assembly due to differences in the plywood thickness. I am buying decent quality Baltic birch that is very uniformly 23/32" but it's almost like all the plans I've been using actually assume that the plywood is exactly 3/4" and the 1/32" discrepancy starts to stack up when you for instance are building a miter saw stand with many cabinets or drawers. This results in me having to recut pieces as the error starts to add up. The more sane thing to do would be to rework all the numbers on the plans accounting for the missing 1/32" but I was hoping that maybe I'm missing something and this isn't necessary?

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post #2 of 24 Old 04-20-2019, 10:05 PM
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Quote:
Originally Posted by roverson View Post
Maybe a dumb question:

I've been woodworking for a couple of years now and being able to follow other people's plans from the internet in combination with videos has really been an amazing experience to produce things way beyond what I would be able to otherwise. I keep running into a problem though that when I follow the plywood cut diagrams for the plans and rip up all the plywood at the beginning of the project, things are slightly off during assembly due to differences in the plywood thickness. I am buying decent quality Baltic birch that is very uniformly 23/32" but it's almost like all the plans I've been using actually assume that the plywood is exactly 3/4" and the 1/32" discrepancy starts to stack up when you for instance are building a miter saw stand with many cabinets or drawers. This results in me having to recut pieces as the error starts to add up. The more sane thing to do would be to rework all the numbers on the plans accounting for the missing 1/32" but I was hoping that maybe I'm missing something and this isn't necessary?
Usually 1/32" don't hurt anything in woodworking. It's usually when you make a tall cabinet with a lot of shelves the spacing shows up. Instead of going by what the plywood is suppose to be you stack up the six or eight shelves and see what the total thickness of all of them is and divide what is left.

The problem with the plywood thickness is because it is gauged in metric dimensions today. What is being called 3/4" plywood is 18mm. If you need that accurate dimensions you might consider converting your plans to metric dimensions.
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post #3 of 24 Old 04-20-2019, 10:58 PM
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Exactly what is the problem that you keep having? Is it dado slot size or what?


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post #4 of 24 Old 04-20-2019, 10:59 PM
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Quote:
Originally Posted by roverson View Post
...Maybe a dumb question:...
Hi Roverson,

Perhaps "dumb"......yet are there really any "dumb questions" from the perpspective of the person asking...I don't think so...

Quote:
Originally Posted by roverson View Post
....I've been woodworking for a couple of years now and being able to follow other people's plans from the internet in combination with videos has really been an amazing experience to produce things way beyond what I would be able to otherwise...
Well...that's a big positive...good for you that you have developed those skill sets. Not all "plans" are the same in quality that's for sure...

Quote:
Originally Posted by roverson View Post
...I keep running into a problem though that when I follow the plywood cut diagrams for the plans and rip up all the plywood at the beginning of the project, things are slightly off during assembly due to differences in the plywood thickness....
Are you measuring the...exact thickness...of the plywood stock or assuming its the thickness it claims to be?

Quote:
Originally Posted by roverson View Post
... I am buying decent quality Baltic birch that is very uniformly 23/32" but it's almost like all the plans I've been using actually assume that the plywood is exactly 3/4" and the 1/32" discrepancy starts to stack up when you for instance are building a miter saw stand with many cabinets or drawers....
Hmmm...???...I can't speak to that without seeing the ply stock you are using or the actual plans being followed?

I can share, as a designer and practitioner, I work in metric. Most plans today are actually done in metric and converted to imperial.

I also design to "zero" tolerance as I design with CAD and I draw to "perfect ideal." Neither of these are in the real world so I "build" (and plan to build...be it a book shelf or timber frame) to a tolerance of 0.5mm minimum...over total distance. This follows the old adage of: "...aim small...miss small."

So I don't thin you are missing anything...per se. Yet perhaps (???) your logistical approach could do with some fine tuning. Make sure you know the exact dimensions of the stock you are using?

Try working from "empirical fact." In other words, take the plans and render them into tradtional "story poles" that have the "exact" geometric ratios on them that you require to facilitate the plans as presented graphically. I say "geometric ratio" as you really don't even need "measured numbers" when doing woodworking. Traditionally (and in my work in the craft originally) I didn't touch a tape measure until I had already designed and built several timber frames and many woodworking projects. Learning to make these "plans" your own by learning to "build by eye" and empirical geometry will take you forward by taking you "backward" to the actual traditions of woodworking, and thus, (perhaps?) freeing you up from some of these current challenges. Another way of thinking about it, is to approach the plans from trying to measure only once or the least often as possible. Make your action steps as empirical as possible.

I might also offer converting over to metric? I don't work in "inches" anymore for the most part at all...yet rather metric, (when I do measure...lol...) This craft has many ways of being done, the most practical are usually the most traditional, but too many have left that side of the craft behind...

Good luck and let me know if I can expand on anything?

j
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post #5 of 24 Old 04-20-2019, 11:33 PM
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Manufacturers have gone to metic dimensions ...

What used to be 3/4" plywood, the industry standard for years, is now 23/32":
https://www.hunker.com/12464023/what...zes-of-plywood
Nominal and Actual Thicknesses
The nominal thicknesses of plywood range from 1/8 inch, or 3.2 mm, to 1 1/4 inches, which is equivalent to 31.75 mm. These often aren't the actual thicknesses, however, because sanding during manufacturing removes up to 1/32 inch of material. Thus, a plywood sheet with a nominal thickness of 3/8 inch is actually 11/32 inch thick. Standard nominal thicknesses include 1/8, 1/4, 3/8, 1/2, 5/8, 3/4, 1 1/8 and 1 1/4 inches. These correspond to actual thicknesses of 1/8, 1/4, 11/32, 15/32, 19/32, 23/32, 1 1/8 and 1 1/4 inches, respectively. In metric terms, the nominal thicknesses are 3, 6, 10, 13, 16, 19, 28 and 32 mm.


This means that all the plans that were drawn up prior, will use the 3/4" dimensions and those drawn afterward will indicate 23/32" or 19 mm. It's all too confusing and difficult to translate into working dimensions for your projects. I feel your pain.....
Is there an easy solution? I don't know of one. There are some tricks we use to keep our sanity, like actual width dados:


Actual dimension dado bits for your router:
https://www.infinitytools.com/routin...outer-bit-sets


A metric to Imperical calculator conversion:
https://www.calculator.net/conversion-calculator.html


Between those three, you may find it easier to build from the older plans....?

The answer to your question will only be as detailed and specific as the question is detailed and specific. Good questions also include a sketch or a photo that illustrates your issue. (:< D)
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post #6 of 24 Old 04-20-2019, 11:58 PM
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I went to one of the purported to be "Premier" plywood suppliers in the Los Angeles metro area. The fork lift driver and I cut open the steel bands on a lift of ¾ plywood. We discarded the top sheet due to edge damage from the steel bands. This was what I would consider to be "Cabinet Grade" plywood.

I got home and had cut the first sheet which measured 23/32 as expected. Then I cut some dadoes. Nothing fits. What I discovered was while the first sheet was 23/32, another sheet was ¾ and the third sheet was 49/64. So much for cabinet grade quality and consistency.
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In furniture 1/32" is a Grand Canyon
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post #7 of 24 Old 04-21-2019, 12:03 AM
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You got bigger problems than that out there ....

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Originally Posted by NoThankyou View Post
I went to one of the purported to be "Premier" plywood suppliers in the Los Angeles metro area. The fork lift driver and I cut open the steel bands on a lift of ¾ plywood. We discarded the top sheet due to edge damage from the steel bands. This was what I would consider to be "Cabinet Grade" plywood.

I got home and had cut the first sheet which measured 23/32 as expected. Then I cut some dadoes. Nothing fits. What I discovered was while the first sheet was 23/32, another sheet was ¾ and the third sheet was 49/64. So much for cabinet grade quality and consistency.

You better be gettin' ready for the "big one", as you're way overdue. Nothing you couldn't solve by following Sleeper out to Nevada. I'd at least find a campground on the West side of the fault line, just in case. Do shipping containers float?
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The answer to your question will only be as detailed and specific as the question is detailed and specific. Good questions also include a sketch or a photo that illustrates your issue. (:< D)
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post #8 of 24 Old 04-21-2019, 12:57 AM Thread Starter
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Quote:
Originally Posted by GeorgeC View Post
Exactly what is the problem that you keep having? Is it dado slot size or what?

George
I haven't had the problem with dadoes yet (but good to know for the future). One problem I had recently was making a large assembly table from plans that had storage underneath it that had basically cabinet carcasses underneath with many stacked cubbies and drawers. Because I pre-cut all the pieces before starting the assembly. Once I started, the cabinet box came together but the dividers that were supposed to partition the cabinet box into cubbies were off in some places because of the difference in the plywood thickness. I had the same problem with the drawers I made—since the plans assumed that the plywood was 3/4" the back panel of the drawer was off by 1/16" and wasn't flush.

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post #9 of 24 Old 04-21-2019, 12:58 AM Thread Starter
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Thank you everyone. It's very helpful just to hear everyone's approaches!
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post #10 of 24 Old 04-21-2019, 01:03 AM Thread Starter
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Thank you! Great advice

Quote:
Originally Posted by Jay C. White Cloud View Post
Try working from "empirical fact." In other words, take the plans and render them into tradtional "story poles" that have the "exact" geometric ratios on them that you require to facilitate the plans as presented graphically. I say "geometric ratio" as you really don't even need "measured numbers" when doing woodworking. Traditionally (and in my work in the craft originally) I didn't touch a tape measure until I had already designed and built several timber frames and many woodworking projects. Learning to make these "plans" your own by learning to "build by eye" and empirical geometry will take you forward by taking you "backward" to the actual traditions of woodworking, and thus, (perhaps?) freeing you up from some of these current challenges. Another way of thinking about it, is to approach the plans from trying to measure only once or the least often as possible. Make your action steps as empirical as possible.

I might also offer converting over to metric? I don't work in "inches" anymore for the most part at all...yet rather metric, (when I do measure...lol...) This craft has many ways of being done, the most practical are usually the most traditional, but too many have left that side of the craft behind...

Good luck and let me know if I can expand on anything?

j

Thank you—great advice!
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post #11 of 24 Old 04-21-2019, 09:37 AM
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If you know that the problem exists you are already half way to the solution. Don’t believe cut lists.





In woodworking there is always more then one way to accomplish something.
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post #12 of 24 Old 04-21-2019, 11:24 PM Thread Starter
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Quote:
Originally Posted by Terry Q View Post
If you know that the problem exists you are already half way to the solution. Don’t believe cut lists.





In woodworking there is always more then one way to accomplish something.
I was afraid that was the answer :)
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post #13 of 24 Old 04-21-2019, 11:24 PM Thread Starter
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I was afraid that was the answer :)
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post #14 of 24 Old 04-22-2019, 01:01 PM
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Unless you are milling your own lumber you can't be sure of any dimensions, S4S lumber may vary in thickness as well as plywood, cut lists are a good guide to give a rough estimate of the size of parts required. It is up to you to determine if you are building to an outside dimension or an inside dimension and cut the parts accordingly, preferably as you need them.

Wise men speak because they have something to say; fools because they have to say something -Plato

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post #15 of 24 Old 04-22-2019, 01:21 PM
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To be honest, I never worry about it 23/32 vs 3/4. I have a 3/4" router bit and base my shelves and spacing off of that and haven't had any problems. Even with the missing 1/32", I still have to force the ends of the shelves into the dados sometimes.



Beyond that, I figure my skills aren't accurate to the point that 1/32" will make any difference.
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post #16 of 24 Old 04-22-2019, 02:37 PM
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As a practise, I NEVER cut all my pieces at the same time, even when using my own plans.
It is always a 'cut as you go ' routine. Always cut the mrror image pieces together. It is more important that they are exactly alike than they be exactly to specification. If for example, you are making a small box or cabinet, cut the both sides at the same time without changing your saw settings. This includes any rabits or dados. Then cut the tops and bottoms at the same time (same saw settings).
Next, make the face frame - same practice of opposite or mirror images first. You might notice that the outside dimensions of the face frames might in actuality be a 1/16" off from the original plans. So cut these pieces to fit the cabinet, not the original dimensions on the plans. The same goes for the shelves and also if you made a rabit cut along the backside to insert a back panel .

if you cut everything to spec all at one time, more than likely, you will have to re-cut or re-shape or trim up some pieces. Or worse, you cut a piece too small, and now you have to lengthen it.

Anyway, take your time and be patient. If you screw up, we are here to help with solutions.
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post #17 of 24 Old 04-22-2019, 04:16 PM
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I bought two consecutive sheets of melamine laminated particle board off the rack at Lowes.

I cut the pieces to size and then milled the dadoes for the shelves.

My mistake was making the shelves from parts of both sheets of particle board. Half the shelves fit neatly in the dadoes and the other half were too tight.

I eliminated that problem going forward: I now use dowels.

You would assume that two sheets of particle board, taken consecutively from the same rack would be the same dimensions. Not so.
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post #18 of 24 Old 04-22-2019, 04:36 PM
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Tool holder

Freddy

Make 4 strips of 1/2" anything about 1" wide and 3 1/2" long
Glue of screw them vertically with the narrow 1" end 'up' on the rear 2X6 with the narrow end flush with the surface of the workbench. Put one piece near each end and equally space the other 2 pieces along the the 2x6 rear rail. Then take a 1x4 and glue or screw it along the 4 strips you just put on. So now you have gaps between the the new strips you just put up. In these gaps you will be able to set your screw drivers, chisels and whatever else will fit in there. If you are working on a large project you might have to temporarily remove these tools from your new tool holder. Besides, the tool holder just added an additional 1 1/4' to the workbench surface.
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post #19 of 24 Old 04-22-2019, 04:44 PM
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......................You would assume that two sheets of particle board, taken consecutively from the same rack would be the same dimensions. Not so.
The erroneous assumption is that Lowes and Home Depot are real lumber yards.

I equate Lowes as the Walmart of Lumber and Home Depot as the K=Mart of lumber.

Go to some of the local cabinet shops and ask where they buy their lumber or start a new thread "Quality Lumber - Where to Buy"
And in the body of the text, tell us what town and state u are in. Surely someone here lives nearby.

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post #20 of 24 Old 04-22-2019, 05:37 PM
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The erroneous assumption is that Lowes and Home Depot are real lumber yards.

I equate Lowes as the Walmart of Lumber and Home Depot as the K=Mart of lumber.

Go to some of the local cabinet shops and ask where they buy their lumber or start a new thread "Quality Lumber - Where to Buy"
And in the body of the text, tell us what town and state u are in. Surely someone here lives nearby.
It is a 2 mile drive to Home Depot from my house, and 2¼ mile drive to Lowes. (Lowes is probably less than a half mile if I hike through the nature preserve to their building).

For things that I believe are of uniform quality (low quality at that), like particle board I will go to Lowes or Home Depot. I will also go there to pick up brand name screws and some hardware.

But for real lumber I go to Condon's Lumber in White Plains. They have everything that ever grew on a tree. Though I'm not sure they sell particle board or MDF. I never asked.

http://www.condonlumber.net/

They list 17 species of plywood in several thicknesses and in three grades. I don't see MDF or particle board listed on their site.
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