How to Use a Tap and Die Set

Summary

In this workshop, the host delves into the basics of tap and die sets, essential for creating and repairing threads on bolts and rods. They explain the difference between taps for internal threads and dies for external ones, highlighting the SAE and metric systems. The importance of using lubricants like 'Rapid Tap' is stressed, along with the necessity of knowing the correct hole size for threading. Practical demonstrations include cleaning a 7/16 bolt with a die, cutting new threads on a rod, and the use of a thread gauge and chart for accuracy. Tips for using taps, like starting with a smaller drill bit and the advantage of a one horsepower bench grinder, are shared to ensure success in DIY projects.

Takeaways

• 🔧 The video discusses tap and die sets, essential tools for creating and cleaning internal and external threads.
• 📏 It differentiates between a tap, used for internal threads, and a die, used for external threads.
• 🇺🇸 In the U.S., threads are measured in threads per inch (TPI), with SAE threads being either fine or coarse.
• 📏 A 7/16 inch wide bolt with fine threads has 20 TPI, while a coarse version would have 14 TPI.
• 📏 Metric bolts measure thread size differently, by the distance across the top of the threads.
• 🔩 A thread gauge is a useful tool for confirming the correct thread size, such as ensuring a 7/16 fine bolt has 20 TPI.
• 📊 Thread charts are helpful for determining the correct number of threads per bolt and the appropriate drill size for tapping.
• 🇬🇧 Whitworth or BSF British Standard Fine threads are an older standard still found in some older cars and require special taps and dies.
• 💧 The use of lubricants like 'Rapid Tap' is crucial when using taps and dies to reduce friction and prolong tool life.
• 🛠️ When tapping a hole, it's important to drill to the inside diameter (ID) of the bolt, not the outside diameter (OD).
• ⚙️ The video demonstrates the practical use of taps and dies, including cleaning threads, cutting new threads, and the importance of using the correct hole size.

Q & A

What is the primary purpose of a tap and die set?

A tap and die set is used for creating and repairing threads. A tap is used to create internal threads, while a die is used to create or clean external threads.

What is the difference between SAE and metric threads?

SAE threads are measured by threads per inch, while metric threads are measured by the distance across the top of the threads.

What is a thread gauge used for?

A thread gauge is used to measure the number of threads per inch on a bolt to ensure it matches the standard for that size.

Why is it important to use lubricant when using taps and dies?

Lubricant, such as Rapid Tap, is important to use when working with taps and dies as it reduces friction, prevents tool breakage, and extends the life of the tools.

What is the significance of the beveled edge on a bolt?

The beveled edge on a bolt is designed to make it easier to start the nut, reducing the force needed to initiate threading.

How does one determine the correct hole size for tapping?

The correct hole size for tapping is determined by using a chart that specifies the appropriate drill size for the given tap size, ensuring the internal diameter of the hole matches the bolt's internal thread size.

What is the difference between a standard tap and a bottoming tap?

A standard tap, also known as a plug tap, does not go all the way to the bottom of a hole, whereas a bottoming tap is designed to reach the bottom of a hole, allowing a bolt to be fully inserted into a solid piece of metal.

Why is it recommended to start with a smaller drill bit when drilling for tapping?

Starting with a smaller drill bit and gradually increasing the size is easier on the driller and the equipment, reducing the risk of breakage and ensuring a more precise hole size for the tap.

What is the purpose of a thread chaser?

A thread chaser is used to clean and reform threads, especially useful for minimally damaged bolts or when cleaning up external threads.

Why is it important to back the die or tap out after each turn when threading?

Backing the die or tap out after each turn helps to break and clear away metal chips, reducing resistance and preventing the tool from jamming or breaking.

Outlines

00:00

🔧 Introduction to Tap and Die Sets

The video begins with a discussion on tap and die sets, emphasizing their simplicity and utility despite the presenter not being a professional machinist. The workshop is divided into a clean side and a fabrication room, where a bench vise is essential for using dies. The difference between a tap, used for cleaning or creating internal threads, and a die, used for creating or cleaning external threads, is explained. The video introduces the concept of SAE threads, measured in threads per inch, and metric threads, measured by the distance across the top of the threads. A thread gauge and thread chart are highlighted as useful tools for identifying thread sizes and determining the correct drill size for tapping. The video also touches on the Whitworth or BSF British Standard Fine thread, which is an older standard still found in some older cars. The importance of using lubricant, such as Rapid Tap, when working with taps and dies is also mentioned.

05:03

🛠 Practical Demonstration of Tap and Die Usage

The second paragraph delves into a practical demonstration of using tap and die sets. It starts with cleaning the threads on a 7/16 bolt using a bench grinder, emphasizing the importance of tapering the edge for easier threading. The video explains the two sides of a die and the correct side to start with, highlighting the need for lubrication and the technique of turning and backing off to break chips and clean threads. The difference between a thread chaser, used for cleaning and reforming threads, and a die, used for cutting new threads, is clarified. The video then proceeds to demonstrate cutting new threads on a 7/16 inch rod, discussing the increased resistance when cutting threads compared to cleaning them. Tips for using an air hose to keep the work clean and the appropriate pressure to apply are shared. The video concludes with a demonstration of threading a rod into a piece of steel, explaining the types of taps, such as standard taps and bottoming taps, and the importance of choosing the right hole size for threading. The process of tapping a hole in steel is also shown, including the use of a smaller drill bit as a starting point and the importance of lubrication during drilling.

Keywords

💡Tap and Die Sets

Tap and die sets are essential tools in metalworking, used for creating and maintaining screw threads. In the video, the speaker discusses the basics of using these tools, emphasizing their importance in various projects. Taps are used for cutting internal threads, while dies are for creating or cleaning external threads. The video provides practical advice on using these tools, such as the importance of using a lubricant and the correct hole size for threading.

💡Threads per Inch (TPI)

Threads per inch (TPI) is a measurement used to define the coarseness of a screw thread. In the video, the speaker explains that in the United States, threads are measured by TPI, with different standards for fine and coarse threads. For example, a 7/16-inch bolt may have 20 TPI for a fine thread and 14 TPI for a coarse thread. This concept is crucial for selecting the right tap and die for a specific task.

💡Metric Bolts

Metric bolts are a type of fastener with threads measured by the distance across the top of the threads, as opposed to the threads per inch standard used in the United States. The video mentions that there are different types of metric bolts, and while they are not the focus, they are part of the broader discussion on thread standards and the tools used to work with them.

💡Thread Gauge

A thread gauge is a tool used to measure the number of threads per inch on a bolt. In the video, the speaker demonstrates using a thread gauge to confirm the TPI of a 7/16-inch fine bolt, which should have 20 teeth per inch. This tool is essential for ensuring that the correct tap and die are used for a given project.

💡Thread Charts

Thread charts are reference materials that provide information on thread specifications, such as the number of threads per inch and the appropriate drill size for a given tap size. The video highlights the usefulness of thread charts in helping to determine the correct tap and die sizes and to guide the process of tapping and threading.

💡Whitworth and BSF Threads

Whitworth and British Standard Fine (BSF) threads are older British standards for thread measurements that are still found in some older machinery and parts. The video mentions that while these standards have been largely replaced, they are still relevant for working on vintage equipment. Understanding these thread types can be important for those restoring or maintaining older vehicles or machinery.

💡Lubricant

Lubricants are substances used to reduce friction between moving parts. In the context of the video, the speaker recommends using a lubricant like 'Rapid Tap' when using taps and dies. This helps to extend the life of the tools, makes the threading process easier, and reduces the risk of damaging the threads or the tool.

💡Drill Size

The correct drill size is crucial when preparing a hole for threading. The video explains that one should not simply drill a hole to the bolt's outside diameter but rather to the inside diameter of the bolt, which is slightly smaller. Using a thread chart can help determine the appropriate drill size for a given tap size.

💡Tapered Edge

A tapered edge on a bolt or a die helps to start the threading process more easily. The video demonstrates how to create a tapered edge on a bolt using a bench grinder, which facilitates the initial engagement of the die with the bolt, making the threading process smoother and more accurate.

💡Thread Chaser

A thread chaser is a tool used to clean and reform existing threads. In the video, the speaker explains that a thread chaser can be used for minor repairs or cleaning of threads, but for more significant damage or for cutting new threads, a tap and die set is necessary.

💡Bottoming Tap

A bottoming tap is a type of tap designed to cut threads all the way to the bottom of a hole, which is useful for threading through holes in solid pieces of metal. The video contrasts bottoming taps with standard taps, which may not cut all the way to the bottom, and explains when each type might be used.

Highlights

Introduction to tap and die sets and their usage in the workshop.

Explanation of the difference between a tap and a die, and their functions.

Discussion on SAE threads and their measurement in threads per inch.

Metric bolt measurement and its difference from SAE threads.

The importance of using a thread gauge to ensure correct threading.

Utilization of thread charts for determining the correct number of threads and drilling sizes.

Mention of Whitworth and BSF British standard fine threads and their relevance in older cars.

The necessity of using lubricant like Rapid Tap when working with taps and dies.

Guidance on choosing the correct drill size for tapping a hole.

Demonstration of cleaning threads using a tap.

Technique of tapering the edge of a bolt to facilitate the use of a die.

Instructions on using the correct side of the die for starting the threading process.

Advice on applying pressure and using a back-and-forth motion when cutting threads.

Difference between a thread chaser and a die in terms of their use and effectiveness.

Practical demonstration of cutting threads on a 7/16 inch rod.

Tips for using an air hose to keep the work area clean during threading.

Explanation of different types of taps, such as standard and bottoming taps.

Advice on starting with a smaller drill bit when drilling for threading.

Conclusion and call to action for subscribing to the channel and visiting the website for more information.

Transcripts

all right we are

back out here in the classic motorsports

workshop today we're going to talk a

little bit more about tap and die sets

while i'm not a machinist by trade

i've been using tap and die type

equipment

most of my life and it's fairly simple

but there are a few tricks that

hopefully we can help you with your

projects we've got our shop separated

into a clean side and this is our

fabrication room and this is where our

vice is so we're going to do it out here

because any time you're using a die

you're usually going to want to have a

bench vise let's start by discussing

what's the difference between a tap and

a die

so this is a tap used either to clean

out a nut

or it's used to make internal threads so

this is a die it's used to create or

clean external threads

in the united states we have sae threads

either fine

or coarse and the way they're measured

is threads per inch this is a 7 16

inch wide bolt it will it'll have

20 threads since it's fine and a coarse

version would have 14 threads in an inch

on a metric bolt the measurement is done

differently it's actually the distance

across

the top of the threads so it's kind of a

totally different system

but there are at least two or three

different metric bolts as well

a good tool to have on hand is one of

these thread gauges so this 7 16

fine bolt should have 20 teeth per inch

and we put the gauge on it that's the 20

gauge obviously

and lo and behold it fits perfectly

another good thing to have is one of

these thread charts

this will tell you how many threads each

bolt is supposed to have

another thing it has on it that we'll

get more into later

is what size hold to drill if you're

trying to tap something out

so let's say you're working on an old

english car and you get your thread

gauge out and you just cannot make the

numbers work

what you have is a whitworth or bsf

british standard fine thread england

went away from this standard back in

about

1955 but you've got to remember that

anything

used in a later car if the part wasn't

re-engineered

it would still have these threads and

and naturally

any whitworth threads you will not find

the taps and dies in a standard set but

those sets are available as well

again from moss or from other companies

so one important thing to do when using

taps and dies

is to use some kind of a lubricant rapid

tap is a

popular brand a little of this will last

you for years but let's get back to the

hole size

discussion when you're trying to tap out

a piece of metal

so as we said this is a 7 16 bolt if you

drill a 7

16 hole through this piece of metal the

bolt will slide

right in so you need to remember when

you're tapping out a hole you need to

get to the id

of the bolt and not the od which would

be the outside diameter

which is the edge of the threads so

you'll need to go with a little bit

smaller drill size

again a chart like this will tell you

exactly what size drill

you should use for what size tap all

right that's enough theory for now

let's go play around with the vise and

see what we can learn

all right so we're going to clean before

we cut we're going to clean the threads

in the 7 16 bolt

this bolt i think has actually been cut

so what we want to do to make this a

little easier

is taper the edge

you'll you'll notice any new bolt has a

little bit of taper right at the edge

just to make getting the nut started a

little easier so it doesn't take much

you just use a bench grinder and by the

way a one horsepower bench grinder is

about

50 times better than one of those little

half horse bench grinders so get

yourself a decent bench grinder

so as you can see we've tapered the end

of the bolt a little bit

and that'll make running a die over it

much easier

the next thing you need to know is

there's two sides to a die

there's a tapered side and that's the

side you need to start on

there's usually marking right on the die

that says use this side or start on this

side or start on other side

what we're going to do is just clean up

these threads

so you put a little lubricant on

you've got this on the right side

so with that beveled edge it took a

second to get it on straight

and now it is obviously on straight it's

easy it's following

the path so is if you're getting any

resistance what you want to do is you

want to do one turn

and then go back about half a turn one

turn

going back and forth breaks the chips

cleans them out

and basically makes the tool work a lot

less hard

so a thread chaser cleans and reforms

threads where a die cuts if you're just

cleaning up some minimally damaged

bolts a thread chaser will work fine if

you've got a lot of rust

or if you're cutting new external

threads then you're definitely going to

need a tap and die set

so let's get into something a little

tougher let's actually cut some threads

on this 7 16 inch rod so the first thing

we're going to do

is bevel this down again and make a nice

easy start for our die

all right so we've got the edge nice and

beveled you don't need to do very much

16 of an inch is fine you just want to

give

the die a nice easy start

obviously there's a lot more resistance

when you're actually cutting threads

than when you're just cleaning threads

you know i'd say you're putting

somewhere between 10 and 20 pounds of

pressure on this would be my guess

it's not exorbitant if you're trying to

do stainless steel that's much more

difficult and there are

actually special tap and die sets made

for stainless steel nuts and bolts

another thing you can do we're not doing

that today but another thing you can do

if you're doing a lot of this is have an

air hose right next to you and you can

kind of blow it off and that that keeps

things even cleaner

not imperative but a nice little tip to

to make this a little easier

always back and forth nice and easy you

don't want to break the tool

and don't spare the lubrication yeah you

can see the chips falling i mean we're

literally cutting new threads into this

all right we'll clean this up quick and

then we'll see if we can put a nut on it

all right as you can see it's got

beautiful new threads it looks just like

a bolt

here's a 17 16 nut goes on easy as pie

so all right so just for kicks we'll

drill a

hole into this piece of steel and see if

we can thread this rod that we just

built

into this piece of steel so

another thing to understand about taps

is there are different kinds

this is a standard tap often called the

plug top and this is what's called a

bottom top

the idea of this is assuming this was a

solid piece of metal

that you could go all the way down to

the bottom and get a bolt all the way in

a standard tap will not do that so

that's something to remember

but in this case we just need a standard

tap

so our chart tells us that we need a 25

64

inch hole to put a 7 16 inch threads in

here's another little trick first you

should probably do this in a drill press

if you have one but just to keep this

demonstration simple we're going to do

it this way

but i like to start with a smaller drill

bit it's a lot

easier on you and it's a lot easier on

your equipment to start small and go big

again does not hurt to have some

lubrication

even when drilling

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so you will then you'll want to get the

right size handle out of your case

again use some lubrication

and make sure you get everything

straight going in

and you got to go a little bit to get it

started

and again backwards forwards

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all right so that's the basics of using

a tap and die set if you like

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and go to our website

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