Sitemap: TAPS, DIES, DIENUTS, Drills, Reamers, Milling Cutters, Slitting Saws, Toolbits

The Tap & Die Co
445 West Green Road
London N15 3PL - UK
Tel:+44 (0)20 88881865
Fax:+44 (0)20 88884613
Email:
sales@tapdie.com

www.tapdie.com

LARGEST
On-line for
TAPS DIES Drills
or click:  ‘Products’
Established since 1978

CURRENCY Converter

SITEMAP

Drill Regrinding

Drill Regrinding or How to regrind drills:
(For unknown terms, please view ‘Drills Terminology’, by clicking on button on left)

 Most drill troubles arise from inaccurate pointing. Correct drill pointing will to a great extent eliminate drill breakage and in accurate holes. Drill pointing should be varied depending upon the materials to be drilled.  General purpose drills, have a point angle of 118o included 12o to 15o clearance angle and with a chisel edge angle of from 125o to 135o

 Most operators do not have the skills required for good hand pointing, The use of standard drill pointing machines is highly recommended. Drills are machine pointed at the factory to a 118o angle to ensure a correct and uniform point angle, equal cutting lips and correct chisel edge angle

 For general purpose drilling a point angle of 118o included angle is recommended. The point angle may vary somewhat one way or the other, but the variation should be uniformin both cutting lips. A twist drill point grinding gauge should be used for checking the point angle of both cutting lips.

 CAUTION: When high speed steel (HSS) drills are sharpened by dry grinding, care should be taken to prevent overheating. If the drill does get too hot, do not cool in water, but let it cool by itself in air. Sudden cooling of HSS drills in water or other cooling mediums will usually produce grinding cracks, which may result in chipping of the cutting lips or breaking of the drill point

 CUTTING LIPS: The cutting lips must be of equal length. Even though the point angle is equal on both sides, if the cutting lips are not equal in length the chisel edge will not be central, and the drill will cut oversize. Ascale should be used to check the lengths of the cutting lips.

 LIP CLEARANCE: Sufficient clearance behind the cutting lips must be provided so that the cutting edges can enter the work. Usually 9o to 15o lip clearance is sufficient for average work if the point is ground with the proper angle and the proper clearance, but without the proper contour back of the cutting edges, the cutting lip will be weakened.

PRINT any Technical Data page you are viewing - [To help you do this, go to: File menu (click on it), click on Page Setup (in dropdown menu) - set Margins at 6mm for Left, Top, Right, Bottom - click OK. -Go back to: File menu (click on it)- click on Print - type Number of Copies required - click on Print. It will now print the information

©=copyright - ‘Technical Data’ shown in our site can be freely used.  This information must NOT
be reproduced or published in any article or website, without the written permission of:
 The Tap & Die Co, London