Common issues face by DIYers The Tolerance

Today we will show how to calculate thickness plan when you are planning your weekend DIY project.

Tolerance calculation is very important if you are planning a complicated woodworking project, because it can affect how the pieces fit together and what kind of material you will need to buy.

The concept of tolerance may be confusing at first, but after reading this article, you’ll better understand what tolerance is and what factor affect the tolerance of your woodworking project.

The need for tolerance arises from the fact that every piece of wood is unique. For example, two pieces of kapur timber that are cut from the same log will not necessarily be exactly the same size. Each piece is subject to slight variations in density, moisture content and grain pattern, which combine to produce a unique product each time.

Therefore, different sized pieces of wood must factor in few mm to be able to fit together.

4 of the most common tolerance in woodworking MUST take notes of!

1) MEASURING TAPE ERROR

1st and before you start your project, your humble measuring tape!! This is often overlook by DIYers or people starting with diy journey. ALL Measuring device have tolerance.

Beside is a few of the measuring tapes we purchase all over different parts of Singapore Hardware shop. 

From the picture you can clearly see, if you can using the different on just these 4 measuring tape is about 2.5mm!!!!

2) PARALLEX Error

In it simplest form it is the human error of looking at the point of measure from different angle. (You can read more in https://en.wikipedia.org/wiki/Parallax)

Basically it can take about 1-2mm off what you read and what another person in your household will read.

3) Wood Shrinkage and Expansion!!

Wood like all element on earth will shrink and expansion due to changes in enviroment. Do remember wood used to be natural living thing. It made up of cell. 

Bascially

– Wet air expands wood (raining), dry air shrinks it (in aircon room for singapore context) This is due to the fact wood are highly hygroscopic, meaning it will absorbs moisture from environment. (You can google why wood is hygroscopic)

(Sourcing for reading: https://www.popularwoodworking.com/materials/how-to-calculate-wood-shrinkage-and-expansion/)

4) Manufacturer process tolerance

In a perfect world, a factory will produce a perfect product without any variation.  But Anyone who have ever live in a real world will know that often we buy household equipment there is some different or some will break down. 

Therefore the wood or plywood manufactured by factory too will have a 1-2mm off their thickness. 

In Conclusion

It is common to to expect a few mm of different in wood as they are natural products from God or the universe. They will not be perfect, but that is the beauty of it. 

From the list above, you will notice if a 1-2mm is so important to your projects, you might want to consider other material like metal.

Infact for us professional woodworker / carpentry our tolerance is actually a massive +- 50mm!!! YES you read right 50mm not 1, not 2 not 5mm but 50mm!!!

Then you will ask how to address the different in these small few mm different?? 

Wood are like our mother nature, very forgiving. we can simply amend it with…….. just some sand paper / metal file, /pen knife, saw dust and glue and water. Will go into detail on the tricks and method we use in the next article.

Have fun, woodworking will train your patience, tolerant making you more magnanimous and humble