Month: August 2021

China Hardware Tells You Nine Reasons for Screw Tap Fracture

Keywords:reasons for screw tap fracture

1. The Poor quality screw tap:

Main materials,tool design,heat treatment, machining accuracy, coating quality, etc. For example, the size of the transition section of the tap is too different or the design of the transition corner is not rounded, resulting in stress concentration, easy to fracture at the stress concentration during use. The cross section transition at the junction of shank and blade is too close to the welding port, resulting in the complex welding stress superimposed with the stress concentration at the cross section transition, resulting in a large stress concentration, which leads to the fracture of the tap in use. For example, the heat treatment process is improper. In the heat treatment of taps, cracks may occur if the taps are not preheated before quenching, overheated or overburned during quenching, not tempered in time and cleaned too early.This is also an important reason why the overall performance of domestic taps is not as good as that of imported taps.


2. Improper tap selection:

High quality taps, such as cobalt-containing HSS taps, hard alloy taps, coated taps, etc., should be selected for the workpiece with too much hardness. In addition, different tap designs are used in different workplaces. For example, the number of tap chip slot head, size, Angle and so on have an impact on the chip performance.


3. The tap does not match the processed material:

The problem is taken seriously more and more in recent years, before the domestic manufacturers always feel that the import of good, expensive good, it is actually suitable for good. With the continuous increase of new materials and difficult to process, in order to adapt to this need, the variety of tool materials are also increasing. This requires before tapping, choose the right tap product.

4. The bottom hole aperture is small:

For example, when machining M5×0.5 thread in ferrous metal, the cutting tap should be used to drill the bottom hole with a 4.5mm diameter bit. If the 4.2mm bit is used to drill the bottom hole, the cutting part of the tap will inevitably increase during the tapping, and the tap will break. It is recommended to choose the right bottom hole diameter according to the type of tap and workpiece material, if there is not a full match of the drill bit can choose a larger stage.


5. Tapping material problem:

The workpiece material is not pure, and there are some hard points or pores in local parts, which causes the tap to lose balance instantly and break.


6. The machine tool does not meet the precision requirement of tap:

Machine tool and clamping body is also very important, especially for high quality taps, as long as a certain accuracy of machine tool and clamping body can play out the performance of the tap. The common thing is lack of concentricity. At the beginning of tapping, the starting position of the tap is not correct, that is, the spindle axis is different from the center line of the bottom hole, and the torque is too large in the tapping process, which is the main reason for the tap breaking.


7. Poor quality of cutting fluid and lubricating oil:

Many domestic enterprises have begun to pay attention to this point, many companies have purchased foreign tools and machine tools have a very deep experience, cutting fluid, lubricating oil quality problems, processed product quality is easy to appear burr and other bad conditions, at the same time, life will also be greatly reduced.


8. Unreasonable cutting speed and feed:

When processing problems, most of the domestic users is to reduce cutting speed and reduce feeding, such tap propulsion strength is reduced, the production of thread accuracy was greatly reduced, it increased the roughness on the surface of the screw thread, thread aperture and cannot control precision, burr problem, of course, such as more inevitable. However, the feed speed is too fast, resulting in excessive torque is also easy to lead to the tap broken. The cutting speed of machine attack, general steel material is 6-15m/min; Quenched and tempered steel or hard steel material is 5-10m/min; Stainless steel is 2-7m/min; Cast iron is 8-10m/min. In the same material, tap diameter is small take a higher value, tap diameter is large take a lower value.


9. The techniques and skills of operators do not meet the requirements:

These problems above all need operators to make a judgment or feedback to technical personnel, but the vast majority of domestic operators do not pay enough attention to. For example, when processing blind hole thread, when the tap is about to contact the bottom of the hole, the operator did not realize that the tapping speed is still not at the bottom of the hole, or forced to feed when the chip is not free, resulting in the tap broken. It is recommended that operators strengthen their sense of responsibility.


As can be seen from the above, the causes of tap fracture can be described as a variety of machine tools, fixture, workpiece, process, chuck and cutting tools and so on May be possible, only by paper talk may never find the real cause. As a qualified and responsible tool application engineer, the most important thing is to go into the field, not just by imagination. Take the simplest example, if the tap cutting cone length is too long, tapping hit the bottom of the bottom hole and break, if you do not go into the field, only by guessing the tap performance, workpiece material, processing technology, etc. How do I know?

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Agricultural machinery spare parts

Product Details


Key Specifications/Special Features:

Materials: iron,  ductile iron, steel,  carbon steel, alloy

  • Process:  investment casting and so on

  • Standards: GB, ASTM, DIN and JIS

  • Weight range: 0.02-30kg

  • Casting process: client drawings-pattern-raw casting-machining-packing and delivery

  • Quality control:

    • Machinery properties and chemical components testing after raw casting

    • Hardness checking after heat treatment

    • Dimensions testing after marching

    • Drawings Mold making raw casting sandblasting rough machining or finish machining surface treatment packing delivery strict

  • Packaging:

    • Wooden case, pallet or as the customers' requirements for the castings, If the customers allowed, we will choose the suitable package for the customers

    • Generally we choose the 20 container for the product of the largest weight, we are promised that we will make the best package for the product at the reasonable price

  • Service:

    • Confidentiality

    • Check

    • Control

    • Confirmation  

  •  Our  advantages:

    • We have more experience in the casting industry for more than 25 years

    • We have development and design center formed by our experienced engineers

    • We have a big warehouse combining quality control, inspection, packaging

    • Better quality with delivery on time service

    • Competitive price by efficient working and capacity of large foundry

    • OEM services

Primary Competitive Advantages:

  • Brand-name Parts

  • Country of Origin

  • Experienced Staff

  • International Approvals

  • Product Features

  • Reputation

  • Service

Main Export Markets:

  • Asia

  • Australasia

  • Eastern Europe

  • North America

  • Western Europe

Payment Details:

  • Payment Terms:T/T

Any third-party trademarks or images shown here are for reference purposes only. We are not authorized to sell any items bearing such trademarks.

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Ways to improve the processing efficiency of precision parts

Earlier, we introduced to you where the main advantages of precision parts processing are reflected. Today will introduce some methods to improve the efficiency of precision parts processing:

In the processing of non-standard equipment parts, common problems such as accelerated tool wear, poor processing appearance, and difficulty in chip removal will occur. This has seriously affected the quality, production cycle and processing cost of precision parts of such materials.

The processing of non-standard equipment parts requires super-lubricated processing appearance and high processing accuracy, which requires the knife to have a high standard life. Whether the tools of CNC precision processing plants are worn or not will be based on whether the processing surface quality is reduced or not. The standard life of diamond tools is very high, and the tool wear is very slow during high-speed cutting. Therefore, the cutting speed is not restricted by the tool life during ultra-precision cutting, which is different from the general cutting rules.

The cutting speed selected for non-standard equipment parts processing practice is often selected according to the dynamic characteristics of the ultra-precision machine tool used and the dynamic characteristics of the cutting system, that is, the speed with the smallest vibration is selected, because the surface roughness is the smallest and the processing quality is at this speed. The highest, to obtain high-quality non-standard machining appearance is the primary question for non-standard equipment parts processing. Good quality, especially good dynamic characteristics, ultra-precision machine tools with low vibration can use high cutting speeds and increase processing power.

The selection of processing parameters of non-standard equipment parts mainly includes the selection of cutting tool viewpoint, the selection of cutting speed, the selection of cutting depth and feed speed, etc. From past experience, we know that if you choose a larger rake angle when processing plastic materials The tool can effectively inhibit the formation of built-up edge. This is when the rake angle of the tool increases, the cutting force decreases, the cutting deformation is small, and the contact length between the tool and the chip becomes shorter, which reduces the basis for the formation of built-up edge.

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Precision Investment Casting Automobile Machinery Parts

Basic Info

Surface Roughness


Machining Tolerance


CE, RoHS, ISO 9001:2000, ISO 9001:2008

Application Area
Auto Parts

Inch 3.425*3.425*1.36

Transport Package
Cartons and Wooden Pallets

42CrMo, 20Mn5


Product Description:

1)  Our factory locates in Zhejiang province, we have ISO 9001:2016 certificate.
2)  We has 26years' production experience  could help customer design the Mold and offer valued suggestions to reduce costs for customer
3)  Can handle with A360, A380, A383, AlSi10Mg, AlSi9Cu3, ADC3, ADC6, ADC12, 
4)  OEM/ODM is our strength

casting Information:

Material stainless steel, carbon steel ,alloy steel,,ductile Iron,grey iron, etc,according to customer drawings and specifications.
Casting  Silica Sol casting ,composite casting, soluble glass casting, sand casting, gravity casting, permanent mold casting, high pressure die casting, low pressure die casting, ect.
Machining turning , milling, drilling, grinding, threading, cnc machining, etc.
Surface   sand blasting, shot/ bead blasting, polishing, plating, acid treatment, anodizing, painting, powder coating,passivating,electropolishing ect.
Drawing & Samples→Mould making→ Die casting  →  Deburring  →  Drilling and threading →  CNC Machining  → Polishing  →  Surface treatment →  Assembly  →  Quality inspection  →  Packing →Shipping
Application Auto & motocyle & bicycle  parts, Furniture accessories, Power tool housing, Pump housing,
Mechanical parts, 
Machine Die casting machine 120 ton/280 ton/400 ton/500 ton/800 ton/1250 ton 

Material Available:

Stainless Steel SS201,SS301, SS303, SS304, SS316, SS416 etc.
 Steel Mild steel, Carbon steel4140, 4340, Q235, Q345B, 20#, 45# etc.
Brass HPb63, HPb62, HPb61, HPb59, H59, H68, H80, H90 etc.
Copper C11000,C12000,C12000 C36000 etc.
Aluminum AL6061, Al6063, AL6082, AL7075, AL5052, A380 etc.
Iron A36, 45#, 1213, 12L14, 1215 etc.

1. How many days it will take to develop one new item?
It will take about 20days to make molds and make samples for your checking.

2. What is your common delivery time for a bulk production?
Commonly 30days after prepayment paid

3. What is common payment terms?
T/T full payment for molud, then samples confirmed. 30% T/T prepayment should be arranged, then balance against BL copy.


Link to this article:Precision Investment Casting Automobile Machinery Parts

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