US Tap and Drill Bit Size Table
| Tap | Fractional Drill Bit | Number Drill Bit |
| #0-80 | 3/64" | - |
| #1-64 | - | 53 |
| #2-56 | - | 50 |
| #3-48 | - | 47 |
Full Answer
What size drill bit for a 10-32 tap?
Starrett's tap and drill card (which every one of us should carry in his shirt pocket,) says the tap drill for a 10-32 screw is a No. 21, .159 diameter. 5/32, .156, is just a bit tighter, Always use a lubricant when tapping, even if it's beeswax. (No 20 is .002 larger yet).
How to find tap drill size?
- Hold the gauge against the light and see if there are any gaps between the gauge and threads.
- Get an OD caliper and measure the male thread caliper and the female thread caliper.
- Make sure you use a seat angle gauge and place it on a flared surface. The centerlines need to be parallel with the gauge to ensure there is no leak.
What size drill bit do you use for tap?
You’ll see that for heavy duty materials like steel, the correct tap drill size is “10” (or a 0.194 inch diameter tap). Finally, determine if a tight fit or one with a more “open” clearance is adequate. Consider the material you’re securing your attached piece to.
How to calculate drill size for tap?
Tap Drill Calculator
- Only enter numbers in the fields.
- Do not enter any units of measurement.
- You can enter fractions. (i.e. 1/4)
- If you don't know the %, just enter 70 Example: 1/2 - 20 Thread
- 1/2 = Major diameter
- 20 = Threads / Inch (TPI)
How do I know what size hole to drill for tapping?
Rules of Thumb A good tap drill is 90% (± 2 pp) of major diameter for fine threads. For metric V threads, the concept of major minus pitch (i.e., the major or widest diameter of the intended screw in millimeters minus the pitch of the threads of that screw in millimeters per thread) yields a good tap drill diameter.
What does a 1/4 20 tap mean?
Example: 1/4 - 20NC The 1/4 represents the diameter of the thread in inches. The 20 represents the number of threads per inch or TPI. Standard taps are either standard coarse series threads NC (1/4-20), fine series threads NF (1/4-28) or extra fine series NEF (1/4-32).
What drill bit do I use for a 3/8 tap?
Nominal Size (inches)T P ITapping Drill Size1/41911.8 mm29/64"3/81915.25 mm19/32"24 more rows
What size drill bit do I use for 1/2 inch tap?
Tap Drill Size ChartBolt SizeDrill SizeClosest Fractional1/2-13 NC27/64"27/64"12mm-1.25mm*10.9mm27/64"1/2-20 NF29/64"29/64"1/2-24 NS29/64"29/64"90 more rows
What size hole do I need to drill for a 1/4-20 tap?
The best overall size drill bit for 1/4″ 20 UNC tap thread is a #7 drill bit, the measurement being 13/64” (0.203″diameter).
What is the drill size for 1/4-20 tap?
0.228"-Thread-Forming Taps For example, the recommended drill size for a 1/4-20 UNC thread is a No. 1 (0.228"-dia.) on a tap/drill chart.
What size tap do I need for a 3/8 bolt?
Most drill charts recommend a 5/16 drill for a 3/8-16 bolt. Cutting holes that are smaller will leave more material for the tap to cut out, risking tap breakage.
What size drill bit do you use for a 3/8-16 tap?
To Tap This Size Screw Or Bolt:Use This Drill Bit:Decimal Inches8mm-1.00mm7.1mm.27955/16-32 NEF9/32".28129mm-1.25mm7.9mm.31103/8-16 NC5/16".312544 more rows
What size drill bit do I need for 3/8 NPT tap?
37/64"NPT Tap Drill ChartTap SizeDrill SizeTap and Drill Set3/8" NPT Tap37/64" Drill Bit3/8" NPT Tap and Drill Set1/2" NPT Tap23/32" Drill Bit1/2" NPT Tap and Drill Set3/4" NPT Tap59/64" Drill Bit3/4" NPT Tap and Drill Set1" NPT Tap1-5/32" Drill Bit1" NPT Tap and Drill Set10 more rows
What size tap do I need for a 1/2 hole?
Contact us for more information....Tap and Drill Size Chart.THREADSIZEDRILL DIAMETER Coarse ThreadTAP DRILLSIZE7/16-20.390625/641/2-20.453129/649/16-18.515633/645/8-18.578137/6436 more rows
What is a #7 drill bit?
A number 7 drill bit is 0.2010 inches. As a fraction, the 0.2010 decimal is 201/1000.
What is a drill and tap chart?
A drill and tap chart is what specifies the right size of drill bit that one can use to create the correct sized opening that would complement tap dimensions. A tap drill chart is key in matching pairs of female and male thread that tightly secure together. Often it is the corresponding dies and taps that you see together when buying either ones.
How do drill and tap charts work?
Drill and tap charts rely on comparing the size of a drill bit in the chart, to figure out what drill bit makes the right sized hole. After this, manufacturers then drill the hole of the right length, put the tap, and start making the guides. When they twist the taps it carves out guides of the right size. It also ensures a snug fit ...
What is tap and die chart?
The tap and die chart corresponds to different drill sizes and diameters. All you have to do to read it is to match the size of drill with the right characteristics like the thread count for every inch and the material type of a drill. Taps cut internal threads to suit different applications.
What is a taper tap?
Taper taps are used to cut threads that travel through a hole. Plug taps work on threads that only halfway go through a hole. Machine screw taps are the smallest you will find and are meant for small diameter holes. You can easily find the size of a hole that you have to drill, by going through the chart.
What is the difference between a round rod and a drilled hole?
The only difference is that they are applied on a round rod and not a drilled hole. The size of the die that you pick out has to be the same size as the rod. For instance if you want a rod that is 3/8”, your die has to be of the same size.
What is a die for a screw?
The die is required to make a male screw thread and has a tiny split on its side that allows for adjustment of the screw, it also allows it to be a bit altered for different degrees of sharpness and different materials.
What is the correct tap drill?
A rule of thumb is that the right tap drill is around 85% for coarse threads and 90% for fine threads which feature a higher number of threads per axial distance . In our case, the correct tap drill would be the closest to 3.4 mm from below, and that is the 3.3 mm or 0.13-inch tap drill. Lower percentages such as “75% of ...
What is a tap drill?
Jump to Tab Drill Chart. Taps are cutting tools used by machinists to cut or form screw threads. The first recorded use of taps in metalworking is placed sometime in the 18th century, while the British engineer and industrialist Joseph Clement popularised the tool in the mid-19th century. We then saw standards emerge in threading with ...
What is the tap used to make a thread?
To create a thread properly, one would need a set of three taps that correspond to the same bit size; namely the bottoming, the intermediate, and the taper tap . The intermediate, or plug tap, is used first to start cutting out material from a non-threaded hole.
When was the tap chart invented?
Tap Drill Chart – The Ultimate inch and metric table (mm and inches) Although popularised in the 19th century, the first recorded use of metalworking taps goes back to the 18th century. British engineer and industrialist Joseph Clement popularised the tool in the mid-19th century. Creating a thread requires a set of three taps corresponding to ...
Who invented the tool?
British engineer and industrialist Joseph Clement popularised the tool in the mid-19th century
Can a bottoming tap start threading?
However, the bottoming tap cannot start the threading on an uncut hole, so it can only take part in the cutting process as the second or third tap. The taper tap is only used in certain situations such as when the material is very hard or the hole is too small.