Having the correct size for your pilot hole is crucial when it comes to threading bolts in home improvement projects. Using the wrong drill bit or making the wrong hole can ruin your project and make you spend more money because you have to buy new materials. You need to make sure you are carefully planning all drilling and holes before you start the project.
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What Size Drill Bit for a 3/8″-16 Tap?
A 3/8″-16 tap should be used with a 5/16″ drill bit.
| Tap Size | Drill Bit Size | Fraction |
|---|---|---|
| 3/8″-16 | 5/16” | 5/16” |
| 3/16″-32 | #22 | #22 |
| 3/16″-24 | #26 | #26 |
The drill bit size you use is very important. If you drill larger holes, you will have weak threads and you might end up stripping them off as you do the project. If you drill holes that are too small, you might cause the tap to be able to break and split out.
Other drill bit sizes you might considering are the standard 3/8″ tap and the 3/8″ NPT tap.
Use a Drill Press
If you have the extra money in your project budget, consider buying a drill press as well. If you are using a handheld power drill though, you might want to start with small drill bits and smaller projects so that you can support your arms better.
Remember that even slight movements of the drill when cutting can cause the finished hole to become too big or could cause the drill to break. If you are not comfortable holding the drill, consider asking someone else to do it for you or practice on scrap materials until you feel comfortable enough to do it yourself.
Correct Hole Size
Having holes that are too big or too small can cause some other problems as well. With a hole that’s too small, you will not be able to extend the tap into the center which makes it almost impossible to bold into the hole.
If you have a hole that is too large, the bolt will not be able to make proper contact with the thread which can ruin the project.
Keep in mind that once you drill a hole, it’s almost impossible to make a new one in the same place. If you ruin the base material, you will be stuck with a hole that’s the wrong size and you will not be able to use the base material. This can cause you to have to go and spend tons of extra money because you will need to buy new base materials and possibly even a new drill if you broke it.
Material Choice
The material also affects the type of hole you will need.
Although you will almost always use a 75% drill, there are some cases where you will only need 50%. This can be the case with harder material. These harder materials require a tighter connection with screws and bolts.
Soft and thin materials often need a smaller hole and stronger threads while harder materials require a larger hole since you need to have less pressure on the tap while you are cutting.
Harder materials that require a different thread percentage are stainless steel, iron, and steel. These will not work with the standard 75% thread percentage.
If you aren’t certain what thread percentage you need to be using, you can always check the manufacturer’s instructions to see what they say.
If you can’t find the instructions from the manufacturer, then you can ask a worker at the home supply store or hardware store to see what they recommend. Some of the workers have knowledge of these subjects and they can advise you on what thread percentages are appropriate for each material.
Materials like aluminum, plastic, and brass are not considered hard materials even though they might seem hard to you when you are working with them. They are considered average hardness and the standard 75% thread percentage will work for them perfectly fine.
Using a different thread percentage also affects the drill bit size. You need to check the manufacture details to see what they recommend for each specific thread percentage.
How to Use a3/8″-16 tap
When using a 3/8″-16 tap, you will need to create a threaded hole for a screw or bolt to enter into easily. Without making the pilot hole, it will be almost impossible to get the screw or bolt into the material. You also should have the bolt handy when starting so that you can make visual comparisons.
You might also want to do a practice hole in some scrap material if you have it. This will allow you to know for sure whether the holes you are making are right for the bolts and screws that you want to use.
When to Use 3/8″-16 tap
You can use the 3/8″-16 tap when you are doing home improvement projects that require metal or wood. The tap and the drill bit sizes are very versatile and you can change the thread percentage if you are working with something that is thicker or harder.
You can also use this tap when you are looking to make pilot holes into the material or surface you are drilling into.
Other Considerations for 3/8″-16 tap
Make sure you always decide what material you are using before you begin tapping. You need to make sure you have all your project materials ready because it affects the drill bit size and the thread percentage.
If you don’t decide on the materials beforehand, you might end up getting the wrong drill bit size or you might realize you need a different thread percentage after you have already started.
Final Thoughts
Choosing the right drill bit size is very important because it can make or break a project. If you make the wrong size holes, you risk ruining the project and having to start all over. This can cost a ton of money and can also be discouraging because you will have to start over and spend more time than you originally anticipated. If you have any doubt on what to use, get some professional advice.
