Woodworking Math

[Brian Kent]

I am beginning to get the hang of some woodworking math. If anyone could add to my math knowledge, I would appreciate it.


4/4 = 3/4

6/4 = 1-1/4

1 Thou = The thickness of bragging rights for a smoothing plane

7’ 11-3/4” = the length of a board that needs to be 8’

2x4 = 1.5x3.5

1/64” = accuracy goal

1/8” = daily wood movement of board fitted to 1/64” accuracy

[Larry Fox]

Here goes for me. However, I need to go to some higher math and throw in a few variables. :)

0 = the number of pencils or tape measures within reach at any given time.
X - 1 = the number of thing Y you have when you absolutely need X
X + 1/8 = the length of what you are trying to clamp if your clamps are X inches long
2X = the volume of the contents of my dust collection bin (whose volume is supposed to be X) before I realize it is full, backed up into the filter housing and need to empty it.
10X = the amount of time it takes me to actually do something when I extimate it will take X (same formula applies to the cost)

[Doug Palmer]

I've cut this board 3 times and still too short!

[Bobby O'Neal]

I've cut this board 3 times and still too short!


Well put. Sometimes when something fits just a little too loose, I make another pass or two through the planer.

[Brian Kent]

That's some good algebra, Larry!

[Ron Kellison]

As a breed, we woodworkers tend to devote enormous mental energy towards working to minute tolerances that have little relevance to the material we regularly turn into sawdust, chips and occasionally something worth keeping. I've become fond of less precise terms such as "skosh", "smidgen" and "hair", the latter having several derivatives usually related to colour. According to Wikipedia, human hair can vary in diameter from 17 to 180 µm (0.00067 to 0.0071 inches) which should be an adequate alternative measurement standard since our material moves more than that on a daily basis. Perhaps I have too much time on my hands...

[Larry Heflin]

I've experienced every one of those math examples. It's funny reading about it here. I don't recall laughing at the time I was looking at that math in the shop.

[Ken Fitzgerald]

I've experienced every one of those math examples. It's funny reading about it here. I don't recall laughing at the time I was looking at that math in the shop.

Was that before or after you threw something across the room?

[Keith Westfall]

Well put. Sometimes when something fits just a little too loose, I make another pass or two through the planer.

Bobby, that is hilarious!!

[Curt Putnam]

Loved it. Thank you.

Now, for the older among us who can remember the early days of computing.

2 + 2 = 5 for very large values of 2 and very small values of 5.

[Brian Kent]

Power tools multiply.

Hand Planes and Routers multiply exponentially.

[Rich Engelhardt]

Festool Wants /Harbor Freight paycheck = me.... :(

[Paul Wunder]

Thanks, fellas. I needed a laugh this morning.

[Tom Cornish]

.5 of a sawblade's width of intended cut = 1.5 sawblade's width of actual cut

[Jeff Monson]

21 3/4" measurement for needed cut = 20 3/4" of actual cut......This is especially useful on highly figured wood, or on the last piece of any given wood you have at the time. The final dimension of the project is then reduced by 1".

[Joe Angrisani]

21 3/4" measurement for needed cut = 20 3/4" of actual cut......This is especially useful on highly figured wood, or on the last piece of any given wood you have at the time. The final dimension of the project is then reduced by 1".

If you're lucky. :D

I had a wall shelf end up two cuts smaller.

[Jeff Monson]

If you're lucky. :D

I had a wall shelf end up two cuts smaller.

You can multiply?? Definitely light years ahead of me Joe.

[Jerome Hanby]

Was that before or after you threw something across the room?

Now it's still too short and has a few dings. I think all of that added together add character to the project.

[Jim Rimmer]

More algebra: X+ 1/16 = the length of the screw, when the combined thickness of the materials to be joined is X.

[Kent A Bathurst]

.....The redesigned final dimension of the project is then intended to be reduced by 1"......

Corollay to Jeff's corrected theorem: Reduced by 1" plus 0.125", which is the actual correction applied to the mating parts because the TS blade was on the wrong side of the line for the very last one of the recut tenons.

[Mike OMelia]

Loved it. Thank you.

Now, for the older among us who can remember the early days of computing.

2 + 2 = 5 for very large values of 2 and very small values of 5.

Bwahahah! All of these are funny. Thank you!

Mike

[Mike OMelia]

21 3/4" measurement for needed cut = 20 3/4" of actual cut......This is especially useful on highly figured wood, or on the last piece of any given wood you have at the time. The final dimension of the project is then reduced by 1".

This is how the ukulele was invented.

[Chris Padilla]

10X = the amount of time it takes me to actually do something when I extimate it will take X (same formula applies to the cost)

100X for me TIMES 3...and then I'm still a month away. :(

[Jim Matthews]

13 hammers = the number of receipts required before I will clean the shop, to find the 12 hammers I already own.

[Neil Brooks]

Three.

The number of total trips to the hardware store AND lumberyard, after you bought "everything" for the project.

One.

The number of those trips that ... will fail, because that store will be closed, just as you get there ;)

[Jim Summers]

More algebra: X+ 1/16 = the length of the screw, when the combined thickness of the materials to be joined is X.

I know that equation all to well!

[Jacob Reverb]

0.00001"

What some people consider the maximum runout of a table saw blade that they use to build birdhouses with.

[Danny Hamsley]

Neil,

That reminds me of the corollary........"One trip to Lowes = Two trips to Lowes".............because you never get everything that you need to fix something the first time, especially if it has anything at all to do with plumbing.

[Doug Palmer]

Time to resize the whole project. I just wanted a minature scaled model anyway.

[Roy Turbett]

<100 = cheap trip to Home Depot

[Larry Heflin]

I'm experiencing a sort of sick pleasure in knowing that I am not the only one who experiences "woodworking math." Please forgive me!

[Brian Kent]

0.00001"

Yup. That's the accuracy standard for making wooden fences and wooden violins.

[Kent Chasson]

7,431 = the number of things you have to do right to make money

1 = the number of things you have to do wrong to lose money

12 = the number of hours it takes to get 8 hours worth of work done

0% = the likelihood that any of us is smart enough to give up woodworking due to any of the above

[Marty Paulus]

Neil,

That reminds me of the corollary........"One trip to Lowes = Two trips to Lowes".............because you never get everything that you need to fix something the first time, especially if it has anything at all to do with plumbing.

I know this one all too well. A simple check valve swap for my sump pump resulted in 3 trips to the borg for fittings because the project morphed from a check valve change to re-plumbing from the pump to the top of the wall. I can't wait until I have to re-do the pump at mom's house. I figure that will be worth at least 4 trips becasue I have to rebuilt the manifold at the top.

[Anthony Whitesell]

2 - The number of projects required to complete the project you started on. ie., Mow the lawn is not just put on mower deck and go. It actually means = go to hardware store buy missing parts and pieces to mount the mower deck AND rebuild carb, then go mow the lawn. When the LOML asks what is taking so long, I just respond "and one project becomes two"; and she knows that I ran into something else that has to be done first. Lately, she doesn't even ask what project #2 entails.

[Darius Ferlas]

1/8” = daily wood movement of board fitted to 1/64” accuracy
That's why I always add (or rarely,subtract) a hair to hair and a half from most dimensions. That way I don't have to cut as many times. I just trim.

[Ben Hatcher]

t = when you actually stopped working for the night. t - "son of a..." = when you should have stopped.

[Neil Brooks]

t = when you actually stopped working for the night. t - "son of a..." = when you should have stopped.

Ouch.

I may well BE the poster child for this one :(

;)