Cutting internal threads becomes much easier when you pick the right tap for the job. If you use the wrong one you will break your tool or end up with poor threads.
If you want clean and accurate threads then this blog post will help; because here we will explain the well-known thread taps and give you tips to select the right one.
What is a Thread Tap?
In simple terms a thread tap is a cutting tool to create threads in an already drilled hole in plastic or metal. It cuts spiral grooves that match screw or bolt sizes so that fasteners can fit tightly. Most of the taps we see in our surroundings have grooves between 2 and 5; these grooves not only help clean chips but form even threads too.
Also See: Threaded Holes Machining_ A Complete Guide
Well Known Tap Styles in the Market
1. Hand Taps
Hand taps are the basic tools which are sold in sets of 3. These taps are so simple that they can be used by hand and can also work with the help of a machine.
Taper Tap_ To cut with Ease
It’s an initial tap which basically has a lengthy chamfer at its first 8 or 10 threads. This helps it to start a cutting process. Moreover its gradual cutting action minimizes the force needed to cut any material. Therefore all this proves it a great choice for starting threads in hard materials.
Plug Tap
Unlike taper tap it has a short chamfer of about 3‐5 threads. It is a well-known tap used for general purposes i.e., if you have to cut threads a little deeper inside through holes or when a taper tap has done its work.
Bottoming Tap for Finishing
Next step is finishing your blind hole and for this purpose you need to cut full threads which must reach the endpoint therefore you have to use a bottoming tap. Interestingly it has a very short chamfer of 1‐2 threads and you can end your work with it.
2. Machine and CNC Ready Taps
You can use machine taps with the help of electric equipment such as CNC‐machines. These taps are so fast that they can cut threads in only one step. Just firm guidance is needed to avoid flaws. But they are designed to work through machines, so don’t use them by hand.
Spiral Point Taps for Through‐Holes
Gun taps or spiral point taps have parallel flutes and an angled cutting edge at their tip. This shape kicks chips in and out of the hole and this avoids clogging. Basically they work best for through‐holes and high speed jobs; and also help remove chips proficiently.
Spiral Flute Taps
In spiral‐flute taps the actual thing which works is helical flutes that wind up the tap. These flutes pull chips back and out from a blind hole. In fact this design is great for blind holes or for materials like aluminum that make long and stringy chips. In addition it helps clear chips and avoid tangles as well.
Interrupted Thread Taps to Lower Friction
Interrupted‐thread taps have spaces between some cutting threads. These spaces are helpful as they lower friction, increase chip space as well as let coolant flow well. Moreover they are good to use on soft, stringy or ductile nature of materials that mostly clog threads with chips.
3. Niche and Specialty Taps
You can find many specialty taps for unique materials, uses or tough machining situations. These go beyond standard machine taps.
Thread Forming Taps to Shape Material
As the name indicates a thread‐forming tap does not cut material. Actually it pushes and shapes the metal to form threads which work‐hardens the area and forms stronger threads. This tap is good for ductile metals like copper and aluminum. Surprisingly it can last up to 20 times longer as compared to a typical cutting tap.
Extension Tap
An extension tap is a type which lets you thread deeper holes or allow threading in hard to reach places. In fact it extends the length of a standard tap. You can use it to tap places that would otherwise require some custom length taps; and also save time and money.
Master Tap for Gages Perfection
A master tap is a kind of reference tool to check either the thread gages or thread quality. Its high precision helps you confirm that threaded parts or production taps fulfill not only dimensional but quality standards as well.
Pipe Taps
Pipe taps are used for threading fittings as well as for pipes. They can cut tapered threads that form a tight seal for any type of gas or liquid. In most cases NPT taps need a sealant. NPTF (Dryseal) taps on the other hand can handle high pressure jobs & they do not need any sealant.
Solid Carbide Taps for Abrasive Work
Solid‐carbide taps are made up of extremely hard carbide which is extraordinarily resistant towards wear. You can use them to machine tough or even abrasive substances up to 63 HRC because they are designed to work on such types. In addition they offer long tool life which outperforms in consistency when threading hardened cast‐iron, steels and other hard metals.
Stay Bolt Taps
Boilermakers use stay‐bolt taps in order to tap holes inside steam‐locomotive boilers. These taps are long—up to 18 inches—and are strong enough to keep alignment as well as cut threads with the help of thick steel in two things i.e., the outer shell & firebox plates.
If you’re not sure which specialty tap is actually right for you than our team at RICHCONN can help. Our engineers will give you practical advice and can create custom taps for your project requirements.
How to Decide Which Tap is better for You
Workpiece Material Type
Always tally your tap material to the workpiece. For mild steel or aluminum use HSS taps as they really work well. For tough metals like stainless steel use TiN or cobalt coated taps; but for hardened steel use carbide taps.
Match Speed, Holder and Automation Level
If you need high speed work or some kind of automation in CNC work then choose taps that can clean chips quickly and are also resistant towards wear. Spiral‐flute and spiral‐point taps definitely work well in these environments. By the way if you have a plan for manual tapping then use a traditional hand tap set. Start with a taper tap then use a plug tap and finish with a bottoming tap.
Know Your Hole Type
The type of hole you need to tap will guide your tap selection.
- For through holes you can go for a spiral point tap which can pass the material. This design pushes chips back and forth.
- Blind holes end inside the material therefore use a spiral flute tap to pull chips up & out.
- For deep or interrupted holes some particular shapes of flute are mostly needed to help in easy chip removal & coolant flow.
Plan for Chip Control
Good chip control keeps your taps from breaking, jamming or making bad threads. Technically use spiral flutes to work with blind holes. Adjust your speeds if you see chip problems. For tough or sticky materials use high pressure fluid. All this not only helps your tools last longer but increases your production too.
Don’t Forget Tap Material and Coating
HSS taps are cheaper and can work for many jobs. Solid carbide taps on the other hand give better results in hard materials. Some coatings like Titanium Nitride (TiN) lower friction and help taps resist wear as well. But if your work is in high heat then Titanium Aluminum Nitride (TiAlN) coatings are best.
If you’re not sure what to choose, ask RICHCONN’s engineering team and they will recommend the right tap geometry, tooling and coating for your project. We assure you will get strong & high quality threads whenever you contact us.
To Sum Up
Thread taps are key to form strong and accurate threads during production. If you want a defect free work which is a good fit and also gives your tool a longer life then wisely choose a right tap. Anyhow if you need top quality CNC machining, custom parts or any expert level thread tapping then you can contact Richconn anytime.
Related Questions
No you can’t. This is because it only starts the threads but your hole’s bottom will still be incomplete. If you wish to have a full cut then go for a bottoming tap
Just look at your material cost and also its hardness. Actually carbide taps are harder and can handle harsh materials even at high speeds. HSS taps are cheaper but work well with softer materials．
Spiral flute taps pull chips upward and out but spiral point taps move chips forward. First one is important for blind holes and other one is for through holes．
Yes you can. But it’s not the best option. Regular taps may recut and damage the threads. Therefore a thread chaser is safer and less aggressive for this job．
Use an NPT tap for standard tapered threads that need sealant. In contrast you can go for NPTF tap if you are willing to have a dry seal and don’t want to use a thread compound．
