Tag Archives: drill bit grinder

Drill grinding attachment mounting and use instructions

With the drill grinding attachment of PURROS brand for drill bit grinder PG-13D you can now sharpen drill bits with high precision. The optimal point and clearance angles can be set according to each drilling requirement, which depends upon the drill size and material being drilled. You can completely restore worn drills as well as broken drills back to new. When sharpening broken drills, much time may be saved by roughly shaping drills free hand before using drill grinding attachment. Dip drill in water when shaping free hand to prevent overheating.

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The Check of Standard Twist Drill Bit after Grinding

Step 1: Checking the point angle (cutting lip angle) of standard twist drill bit is correct or not, and whether it is symmetric with the axis of the standard twist drill bit? (The correct point angle of standard twist drill bit is ±118°, if it be used to drill harder materials that the point angle can be extended to 120°;  if there are the softer materials, the point angle should smaller than before, but keep mind, do not smaller than 90°.)

Step 2: To check the length and height of two major cutting lip (major cutting edge) are consistent. Because the quality of the machined holes are affected by whether the length is the same.
The check method for step 1 and step 2 is that: Place the cutting part of twist drill bit keeps in a vertical position, keep eyesight at the horizontal level, and then repeatedly rotate 180°, where is the center axis of standard twist drill bit, to observe whether the length of two major cutting lips are same in rotation. It is an assumption that to observe the length of two major cutting lips at the center of axis; If the lengths of two major cutting lips are different, that the shorter side should be grinded.Continue reading→

Operations Guide of Drill Bit Grinding

First: Preparation Before Grinding

A: Assembly of Drill Bit and Fixture

Assembly of Drill Bit and Fixture

  1. Checking the diameter of drill bit shank, then select the suitable collet chuck and cutting sets.
  2. Insert the collet chuck into the fixture and lock the nut.
  3. Put the drill bit into the collet chuck, and keep 35~50mm out of the collet chuck.
  4. Adjust the scale to suit the outer diameter of the drill bit, and adjust the angle of point angle.
    Attention: Keep some margin for adjusting before locking the chuck sets.

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How to use the Drill Bit Grinder?

1. First, check the material of the drill bit, because it is used to select the appropriate grinding wheel(types of grinding wheel: CBN and SDC; CBN for HSS(High Speed Steel), SDC for Carbide), that to be assembled the drill bit grinder.

2. Second, checking the diameter of drill bit, and then to select the appropriate collet chuck. In general, the types of collet chuck as follow: ER20, ER25, and ER40, but the exact dimensions are subjected to the manufacturer’s standard.

3. Third, clamping after selecting collet chuck, and adjusting the measurement of grinding, then you should to press the power button to start the drill bit grinder, now observing the situation of the operation drill bit grinder.

4. Fourth, if the situation of drill bit grinder is working properly, next step to grind the drill bit. The step below to:
1. Point Angle Grinding
2. Chisel Edge of Point Angle Grinding
(Note: The size of chisel edge of point angle depends on the screw above the dead center grinding hole of grinder, which can be adjusted the size. Also the adjusting range depends on the diameter of the drill bit.)Continue reading→