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Perfect Screws !!

November 3, 2018Olen Murriel

If you have been in the industry for long, than you most probably realize that getting the right length gauge and size of wood screws can be very hard sometimes when you want to go on with your woodworking projects. What makes the issue more complicated is the including other factors like the material of the screw, the type of wood, the probability that there might be pilot holes and the lateral vs. sheer forces.


Here are some of the sizes of common wood screws


4 Gauge        5 Gauge           6 Gauge            7 Gauge           8 Gauge

Head-Bore Size                            15/64              1/4                   9/32                   5/16                 11/32
Shank-Hole Size                            7/64              1/8                   9/64                   5/32                  5/32
Hardwood Pilot-Hole Size           5/64              5/64                 3/32                   7/64                  7/64
Softwood Pilot-Hole Size             1/16              1/16                 5/64                   3/32                  3/32
Typical Available Lengths      3/8 to 3/4      3/8 to 3/4      3/8 to 1 1/2       3/8 to 1 1/2       1/2 to 2


It is important to note that apart from the sizes of the gauges all the other sizes are in inches. The head-bore size is the actual diameter of the screw head. The diameter of the soft part of the screw which is above the thread is referred to as the shank-hole size.


The Gauge The Pilot Holes The Length; How Does The Screw Work?

When it comes to understanding the topic of wood screws, even the basic knowledge you have in it will help you a lot. If you are looking forward to increasing your understanding of wood screws, or you need help in choosing the best wood screw to work with, then this is the article for you. We will take you through the following factors

  • Pilot holes
  • Length
  • Gauge

By the end of the article, you should be able to know how each of the factors works and how they affect the functionality of the wood screw.


1. The pilot holes

The first factor to look at is the pilot holes. When you drill a pilot hole into some hardwood with a counter stick or with a regular bit, even before you drive the screw, you will be doing yourself a favor. Usually, hardwoods like walnut and oak are more likely to split on the other hand softwoods like cedar and pine have a small probability of breaking. A pilot hole can be able to reduce the grip of the wood around the threads of the screw leading to a reduction of the grabbing power of the wood screw this can only be achieved if you cut and remove the fibers.


2. The Length

The other factor is the length. Normally wood screws ought to have the perfect length so that they may be able to hold together the two boards securely. In the event that the screws turn out to be short, there will be a tiny probability of them holding the two boards together. On the other hand, if the screws become very long, they might end up piercing through to the opposite side of the wood.


3. The Gauge

The last factor to look at is the gauge. For a wood screw to be able to hold on to the two boards perfectly, it should be thick enough. The screw might pull out the wood if it becomes very thin. On the other hand, if the screw becomes very thick chances are that it might make the piece of wood useless by splitting it apart. Wood screws gain power by friction and by the pressure of wood fibers gripping the threads.

Lateral Vs. Withdrawal Loads


1. Lateral Loads.

Lateral pressure may also be referred to as sheer pressure. Lateral pressure can be demonstrated where two boards which are attached flat to one other are introduced into a sliding motion. A perfect example of lateral pressure is a kitchen wall cabinet which is screwed to a wall stud.

2. Withdrawal Loads.

Withdrawal pressure is the type of pressure which tends to pull boards straight apart. When a force is applied, and the pressure wants to split the two boards, then the ample screw threads are added to the board receiving the force. In order to be safe, you can try to get 1 to 1 1/2 inches of thread to the board receiving the force. However, you will still not be certain if the length of the wood screw pokes through the other side of the board. You can prevent this problem by using a shorter screw, but you will still have to cover for that by making the short screws more.


Utility Screws Vs. Steel Screws.

1. Utility screws.

It is possible to find utility screws in several types of steel you can even find some which are from metals that are resistant to corrosion. This particular types of metals were built to overcome any threats from chemicals in treated lumber. Utility screws are essential since they help a lot in woodwork projects for outdoors and framing projects.

2. Steel or stainless steel screws.

The stainless steel wood screws are different from utility screw because of their thick nature and are very important in indoor furniture and precision woodworks. You can identify a stainless steel wood screw in the market by looking at how long they are and how thick they are. A screw with a bigger gauge number shows that the shafts of the screw are thicker.



Professionals from all over the world advice you to use a screw with a diameter of 8 to get the most out screw in most of your utility projects. As for the screws you can use 1-1/4 inch screws, however, that is just for simple woodworks where you will not need that much strength to attach them to the board. If you get yourself in a situation that requires a lot of sheer strength, it is okay to use 1/4-inch diameter screws. It is always advisable to first drill pilot holes with the specific countersink pilot bit since this type of bit can drill a hole of less diameter perfect for sunk flushing the head with the wood’s surface.

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