What do you know about the screw tap?

ST tap, is used for processing stainless steel screw sleeve mounting hole special tap, also known as screw sleeve special tap, (where "ST" is abbreviated from" screw thread "), structure size in accordance with the national standard "fine handle machine and hand wire" GB3464-83 and other standards of manufacturing, can be used by machine or hand.

ST tap according to its range of use can be divided into light alloy machine, hand tap, ordinary steel machine, hand tap, special tap three kinds.

1. Light alloy machine, hand tap: used to add non-ferrous metal alloys such as aluminum, magnesium alloy and copper alloy, the pitch is less than 2.5mm for single tap, and the pitch is greater than or equal to 2.5mm for double tap. Marking method: STd×pST is the code for the special internal thread of the wire screw sleeve. Marking example: Special tap for machining and mounting 8×25 steel wire screw sleeve bottom hole thread on light alloy, marked ST8×1.25;

2. Ordinary steel machine, hand tap: used for processing steel, cast iron, cast steel and other metal materials on the internal thread, is a double tap;

3. Special tap: According to the needs of users to design and manufacture a variety of special varieties of thread bottom tap, such as soft aluminum, copper tapping machine, hand extrusion tap, a single ordinary steel tapping machine tap, stainless steel tapping tap, flat tap for blind holes, spiral groove tap, screw tip tap, etc.

ST tap selection:

1. Straight flute tap. The versatility is very strong, through holes or blind holes, non-ferrous metals or ferrous metals are available, the price is also cheap.

2. Spiral flute tap. It is more suitable for processing blind hole threads, and the chips are discharged backward during processing. In the processing of black metal, the helix Angle is selected less, generally about 30 degrees, which can ensure the strength of the helix teeth. In the processing of non-ferrous metals, the helix Angle is selected less and larger, generally about 45 degrees, so that the cutting can be sharp.

3. Forming tap. It is more suitable for processing non-ferrous metals, especially aluminum alloy castings, which are mainly internal threads formed by metal extrusion, deformation and deformation. Extrusion forming is a non-cutting process, the thread hole processed by extrusion forming process has high tensile and shear strength, and the roughness of the machined surface is also better, but the bottom hole of the extrusion tap requires higher, too large, and the strength is not enough; Too small is easy to break the tap.

The use of the ST tap includes the following four steps, it should be noted that in the entire process to ensure cleanliness and accuracy, so as to get a high quality threaded hole.

1. Drill holes: Use a standard drill bit to drill holes at a depth greater than or equal to the sleeve installation depth. Be careful not to drill the hole into a cone shape, and the chips do not fall into the hole. After drilling, the countersink should not exceed 0.4 pitch depth, because too large the countersink is not conducive to screw in the sleeve.

2. Tapping: Use the special tap for the screw sleeve marked with the specified thread specifications for tapping. The length of the tap must exceed the length of the screw sleeve, and for all through holes, tap. The accuracy of the tapping determines the tolerance zone of the final standard inner hole, so the user needs to choose the tapping method and lubrication appropriately. When tapping blind holes, appropriate force should be applied to prevent breaking the tap. After tapping, the threaded holes should be cleaned, generally purged with compressed air spray gun, blind holes should also be cleaned from the bottom up using a long spray gun with radial holes, and the threaded holes can also be cleaned by cleaning. When the precision of the threaded hole is high, the special screw sleeve bottom hole plug gauge is used for inspection.

3. Installation: Install with the help of a special wrench for screw sleeves. In general, manual installers are used for screw sleeve installation. Put the screw sleeve into the installation tool, so that the installation handle is embedded in the guide rod slot, turn the installation tool handle to screw the screw sleeve into the screw hole, and leave 0.25-0.75 turns of empty thread from the surface. When a small amount of screw sleeve is installed and the coarse tooth screw sleeve is installed above M14×2, a simple tool can be used to install the T-shaped slotted or threaded head, and be careful not to apply a large axial force on the screw sleeve mounting handle to prevent random buckle.

4. Remove the tail handle: this is the last step of the screw sleeve installation, but also a very important step. To remove the tail handle is to ensure the normal use of the screw sleeve and extend the service life.

ST tap tapping difficulties treatment:

(1) The bottom hole bit selection is too small: according to the base material change with the right diameter bit.

(2) Serious wear of the bit leads to bottom hole drilling

(3) Into a cone: change to a new drill.

(4) The bottom hole is distorted: the bottom hole is scrapped.

(5) The selected tap is not suitable for the base material: change

(6) Use a tap suitable for the base material.

(7) Caused by the direct use of the forming cone: First use the working cone tapping.

(8) The tap is seriously worn

(9) Check with wire screw sleeve special inner thread bottom hole plug gauge, if the gauge is not through, change to a new tap.

(10) When tapping, tap and bottom

(11) Hole different heart: correct operation.

The above is a detailed introduction to the ST tap, if you have any questions and needs, please contact us anytime.