Mar 15, 2009

Wood Screws: drives, threads, and tips


Wood Screws are measured by how much screw is actually in the wood. Below is an illustration demonstrating this exact fact.

In this discussion we will go over the basic anatomy of a wood screw. We touch on each aspect to consider when buying screws for your next job. At Getneds.com we supply what we feel is the most efficient and cost effective product. We will go into greater detail on our particular screws later on.
Let's get started.....



Types of Drive:

The type of drive you choose should depend on its functionality. Sometimes you only need a Phillips because of the funny install angle (installing in a corner or under a counter). Sometimes a square drive to apply torque when power is needed (like a stud). And other times you will need the finish appearance and you'll use pozidrive. These choices should be considered before you actually purchase anything.




Types of Heads:





Photo courtesy http://www.wikipedia.com/

A: Pan head- These look like a frying pan upside down. Commonly used to attach metal to wood, but can but used where a finished head application is needed.

B: Button Head- Used and acts much like the pan head. Smaller head to thread size ratio.

C: Round head- These screws are most commonly found with a flat head drive. Used a lot in older construction. This was before the screw manufacturing technologies went to a modernized technique. Still used in today's applications but not as common as pan head.

D: Truss Head- This head type has a low profile to allow clearance when moving parts are involved around the screw. The specially designed low profile head allows drawer slides to function with no interference from the fastener.

E: Flat head- This design is intended for a flush mounting application. Where the screw head must installed below the working surface. Very common in the cabinet trade for the ability to hide the screw with caps or plugs.

F: Oval head- This type of head is commonly used for mounting hardware to finished products. The head is a decorative design intended to enhance the look of your final product. The finish comes in wide varieties to match any style.

To finish up this topic please keep in mind I only discuss screws related to woodworking because that what i know. I will not try to explain machine screws unless it applies to hardware we supply at Getneds.com.

For greater explanations on types of machine screws visit: http://www.wikipedia.com/


Types of Tips or Points:


Screw Points in general can be a long and bumpy road. I will cover only four here because woodworking only has so many tips that function properly. The choice of tip is critical when choosing the proper screw for the job. Tips will make your life easier or hard depending on your decision

A: The first type is commonly known and used everywhere. Not too sure on the proper term but it is a regular point. Nothing special just tapered towards the tip of the screw.

B: The second is most commonly used in production work is a type 17. This has a special slot cut into the tip to allow chip clearance, and eliminates the need to predrill certain woods and substrates.

C: The third is a self tapping metal tip. Widely used for mounting to steel studs. Has a special tip designed for drilling and tapping through metal studs.

D: This final tip is Spax brand. They have a special corrugated tip to grab instantly and pull the screw the rest of t he way eliminating the need for excessive pressure while driving.

For great photos and excellent descriptions on screw points visit:
http://www.engineeredpartsinc.com/screw-point.htm
Good information on helping determine which point to use.


Types of Thread:

For thread choice most commonly used are deep threads. The allow for maximum grab and holding power as time causes woods to shrink and dry. Fine threads are used for very hard woods. When minimal thread diameter is needed. Like i said, deep thread are most often your best choice. Partial deep threads allows for a stronger hold without damaging the first piece you penetrate, while holding the the work piece fast and firm from below. Carefully examine the photo to better understand the concept.
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2 comments:

  1. Currently there are excellent offer of screws easily accessible for those of us who like to create a bit of Do-it-yourself consisting of zip screws and tek screws. For anybody who is a novice to the DIY scenario then you might feel that it is all somewhat complicated. Your most important reference when it comes to challenges like these are websites like allpointsfasteners.

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  2. You surely have provided an excellent primer for those who plan to work with these kinds of screws. Through this article, those who aren't used to working with screws would be able to determine which one they'll need for a certain task.

    ReplyDelete