Drilling holes in round tubes causes significant damage to the drill bit; what should be done?

The round tube needs to be fixed properly; it’s best to use a drill machine for drilling. Additionally, it’s necessary to mark the positioning points before drilling, otherwise the drill bit will wobble too much

The plate was fixed using a drill; there was little vibration, as it was a 5mm thick tube and the drill bit had a limited range of effective operation. Additionally, no lubricant was used. I’m not sure if it’s a problem with the manufacturing process or the quality of the drill bit.

If the operator uses a drill bit made of ordinary carbon steel, it is not suitable; stainless steel, due to its high plastic deformation capacity and thermal strength, tends to experience work hardening during processing, which increases the cutting resistance and tool wear. It is also more difficult for the chips to curl and break apart. Therefore, processing stainless steel is relatively difficult. Choosing the right tool material is an important condition for ensuring efficient cutting of stainless steel. Given the cutting characteristics of stainless steel, the material used for drills intended for cutting stainless steel must possess good heat resistance, high wear resistance, and a low affinity for stainless steel. The commonly used tool materials at present are super-hard high-speed steel, powder metallurgy high-speed steel, and cemented carbide. 1. High-speed steel materials generally include cobalt high-speed steel (M35 with 5% cobalt, M42 with 8% cobalt) and powder metallurgy high-speed steel (ASP23, ASP30, etc.). However, its drawback is its high cost, which is 3–5 times that of ordinary high-speed steel. 2. Structural design of high-speed steel drills: Firstly, a large helix angle (35°–40°), a large rake angle, and a wide flute design are used, which helps to reduce friction between the chips and the drill flutes, thereby facilitating the removal of chips. Secondly, the core drilling thickening design enhances the strength of drilling operations. 3. The surface of the stainless steel drill bit is coated with TiN; a thinner TiN coating can increase the cutting speed and extend the life of the drill bit by more than 30%. 4. The cemented carbide used is of the ultra-fine grain type, which offers better toughness without compromising hardness. The cutting edge of this type of cemented carbide is stronger, allowing the drill bit to have a larger rake angle and a sharper edge than those made from conventional cemented carbides, resulting in smoother drilling and easier chip removal. It is also advisable to grind an appropriate positive rake angle on the cross-cutting edge, which can **reduce axial resistance**. Additionally, appropriately increase the inverted cone and apply a coating. 5. If conditions permit, it is advisable to use a solid carbide internal cooling drill, as this facilitates cooling of the cutting tip and enables timely removal of chips.

Can I just weld a hole and then grind it with a grinder?

This post was last edited by bh8yu on 2012-7-16 23:06. The material of 304 is soft; fix the round tube in place, use a smaller drill bit to mark the drilling position, and then start drilling, adding cooling water while drilling! This thing is very easy to drill! Of course, it’s also very important to have a well-sharpened drill bit! For national standard drill bits, the angles need to be ground to 120° and 60°; for materials like 304, 130° and 50° are sufficient, as being too sharp can easily cause the bit to crack Make sure a groove is made on the opposite side of the drill bit’s cutting surface! It’s too easy: if the L drill can’t drill, then don’t try to drill; if it catches fire, things will get very troublesome

Actually, drilling holes in 304 round tubes is quite troublesome; the drill bit tends to deviate easily, and it also gets dull quickly. In cases like this, electrical discharge machining can actually be used. This method is not restricted by the hardness or viscosity of the material, and it allows for easy processing of 304 stainless steel tubes. If you encounter such a situation, you should consider looking into electrical discharge drilling machines.

Electrical discharge machining is good, but it’s quite troublesome.

Practical Techniques for Drilling Circular Tubes Cases: At the request of a client in Jiangmen, the technical team at Meigao sharpening machines addressed issues such as uneven hole walls, difficulty in positioning, and burrs at the hole edges during tube drilling. Processing conditions: Workpiece: SUS tubes Machine tool: Manual bench drill Drill bit: HSS Cooling method: None Solution 1 Method: Conventional twist drill Click on the image to view in slide mode Results: 1. Good positioning ability. 2. During drilling, burrs bulge outward on both sides. Click on the image to view in slide mode Solution 2 Method: Double-peak angle grinding method Click on the image to view in slide mode Results: 1. Poor positioning ability. 2. Burrs formed. Click on the image to view in slide mode Solution 3 Method: Concave-shaped thin plate drilling and grinding method Click on the image to view in slide mode Results: Excessive vibration prevented further drilling. Click on the image to view in slide mode Solution 4 Method: An improved version of the convex-shaped thin plate drilling and grinding method, developed based on the first three solutions. Click on the image to view in slide mode Click on the image to view in slide mode Click on the image to view in slide mode Results: 1. Low vibration. 2. High precision in hole positioning. 3. No burrs. 4. Good positioning ability. Click on the image to view in slide mode Conclusion: The workpiece remains fixed, while the drill bit varies constantly. In the choice between the \"spear\" and the \"shield\" to determine victory, a perfect combination of technology and tools is necessary in order to create an unparalleled \"spear\". 　　Click the image to view slide mode. Click the image to view slide mode 　　

1. Drilling using a drill jig. 2. Grinding of drill bits: cluster drills, three-flute drills. 3. Using an opening drill (also known as an opener or broach – a small-diameter drill bit at the center serves as a centering rod, with a concentric annular sawtoothed cutter on the outside, which is mounted on a drilling machine)