| Taps and dies are tools used for cutting threads | | | | 3.0 2.5 |
| while usually sold in sets they are in fact individual | | | | 3.5 2.9 |
| tools. A tap is which looks like a bolt if used for | | | | 4.0 3.3 |
| making the female thread (nut) and the die which | | | | 4.5 3.8 |
| resembles a nut is used to make the male thread | | | | 5.0 4.2 |
| (bolt). | | | | 6.0 5.0 |
| Usually made from HSS (high speed steel) alloy | | | | 7.0 6.0 |
| steel and are extremely robust and have very | | | | 8.0 6.8 |
| hard cutting edges. This is needed as both the tap | | | | 9.0 7.9 |
| and dies have threads like those on nuts and bolts | | | | 10.0 8.5 |
| that are used to bore threads in smooth metal. A | | | | 11.0 9.5 |
| tap screws into a hole and makes it in to a | | | | 12.0 10.2 |
| threaded hole and a die puts a thread in to | | | | Once you have the correct size hole using the "T" |
| smooth shafts. | | | | handles turn the tap in to the hole. As the tap |
| These tools are most commonly used to repair | | | | cuts strips of metal will be pushed out of the |
| threads that have been striped or crossed. | | | | flutes (grooves). To prevent the flutes becoming |
| Using a Tap | | | | clogged up, this is done by turning the tap |
| When using a tap care must be taken not to | | | | backwards and braking the metal strips up. Ideally |
| break the tap off mid repair. Due to the type of | | | | you should turn the tap one half turn or until you |
| steel and heat treatment used to get the hard | | | | feel increased resistance then turn back a quarter |
| cutting edge taps can be quite brittle. If a piece of | | | | turn. On very deep holes it would be advisable to |
| the tap id broken off in a hole it can be | | | | completely withdraw the tap from time to time. |
| extremely hard to remove it and as the tap will | | | | It is also advisable to use some king of cutting |
| probably harder that the average drill bit even | | | | fluid you can buy special cutting fluid but if you |
| drilling it out is not always an option. | | | | are using the tap but hand any general oil will do |
| However if used properly you shouldn't have any | | | | the job. |
| problems. Usually they get broken by bending not | | | | Using a Die |
| twisting and in most sets a "T" handle will be | | | | To repair a crossed threads on a bolt simply |
| supplied allowing you to easily turn the tap without | | | | select the die from your set that is an exact fit |
| bending it. Generally most problems are caused by | | | | for the bolt. It's advisable to apply a drop of oil to |
| trying to turn a tap with an inappropriate tool like | | | | the bolt and run the die down the bolt. If the die |
| mole pliers. | | | | gets tight and you feel high resistance just run |
| When preparing to you a tap to create a thread | | | | the die back up the bolt and start again. |
| its essential that you drill the correct size hole for | | | | To create threads on a smooth shaft select a die |
| the tap that you are using to small and will be | | | | that just smaller than the size of the shaft and a |
| very hard to cut the thread and you will likely | | | | couple of drops of oil on the die blades and work |
| break the tap and too large and the thread will | | | | the die down the shaft. As with the tap a half |
| not be cut deep enough and easily striped. | | | | turn should be followed by a quarter turn back to |
| Tap Drill Chart | | | | prevent the die from becoming clogged. |
| Tap Size mm | Drill Size mm | | | | For a comprehensive range of tap and die sets |
| 2.3 1.9 | | | | see Tap and Die sets. |
| 2.6 2.1 | | | | |