Content on this page requires a newer version of Adobe Flash Player.

Get Adobe Flash player

Contact Us
Hammond & Company Ltd
Finway Road
Hemel Hempstead
Hertfordshire
HP2 7PT
England
+44 (0)1442 212 211
+44 (0)1442 252 003
Send a Message
We'll respond within 48 business hours
Gundrill Diagram

Before drilling commences the gun drill must be suported by a guide bush or pre-drilled start hole. Coolant is delivered directly to the cutting edges through the hollow shank and the chips are evacuated back along the V configuration of the tip and shank.

The periphery of the cutting tip is contoured in such a way as to provide both support pads and lubrication galleries. The forces generated by the single sided cutting action act directly on the support pads creating a burnished surface finish and size control down to IT7 tolerances.

Gun drill tips can be manufactured with a step that has either a cutting, or non cutting pilot. Coated tips are also available upon request. These may have a TiN (Titanium Nitride) coating, or a TiAlN (Titanium Aluminium Nitride) coating.

A regrinding service is available at our Hemel Hempstead factory for gun drills, Ventec drills and Speedfeed drills.
Hardened steel guide bushes and whip guides are available for purchase. See accessories.
Driver Design Ref d h h1
View PDF
HAMMOND STANDARD
Diagram
CA 16 40  
CB 25 50  
CC 35 60  
AMERICAN STANDARD
Diagram
Diagram
AA 1/2" 38 26
DM 3/4" 70 46
       
       
       
AC 1.00" 70 55
AD 1.25" 70 55
AE 1.50" 70 55
EUROPEAN STANDARD
Diagram
AF 10 40 24
AK 16 45 31
AG 20 70 34
AH 25 70 34
AJ
32
70
34
 
Driver Design Ref d h h1
Diagram AN 16 50 47
WELDON
Diagram
  BF 16 48 24
h2 BG 20 50 25
17 BH 25 56 32
19 BJ 32 60 36
19
BK 40 70 40
Diagram DG 10 60 M6X0.5
DH 16 80 M10X1.0
DK 25 100 M16X1.5
DL 36 120 M25X1.5

Ordering Information


When ordering Gun Drills please state diameter, overall length, driver design and, where possible, the material to be cut. There are numerous cutting geometries available for the Gun Drills carbide tip.
Alternatively, go towards the end of this website and order by Product Codes.


Cutting Head Contours



   
View PDF
   

Tubular Shank Dimensions


Hammond gun drill shanks are manufactured from high quality chrome molybdenum steel and are designed to achieve maximum coolant flow, chip clearance and torsional rigidity.

Ø Range Ø Tube Ø D Range Ø Tube Ø D Range Ø Tube
3,00-3,14 2,8 6,50-6,99 6,2 13,90-14,89 13,4
3,15-3,39 2,95 7,00-7,29 6,7 14,90-15,89 14,4
3,40-3,64 3,2 7,30-7,59 7,0 15,90-16,89 15,3
3,65-3,87 3,45 7,60-7,94 7,3 16,90-17,89 16,2
3,88-3,99 3,65 7,95-8,34 7,6 17,90-18,89 17,2
4,00-4,19 3,8 8,35-8,54 8,0 18,90-19,89 18,2
4,20-4,44 4,0 8,55-8,94 8,2 19,90-20,89 19,2
4,45-4,74 4,25 8,95-9,34 8,6 20,90-21,89 20,2
4,75-4,97 4,55 9,35-9,94 9,0 21,90-22,89 21,2
4,98-5,24 4,75 9,95-10,64 9,6 22,90-23,89 22,2
5,25-5,49 5,0 10,65-10,94 10,3 23,90-24,89 23,2
5,50-5,74 5,25 10,95-11,94 10,6 24,90-26,89 24,2
5,75-5,94 5,5 11,95-12,54 11,6 26,90-28,89 26,2
5,95-6,29 5,7 12,55-12,94 12,2 28,90-30,89 28,2
6,30-6,49 6,0 12,95-13,89 12,6 30,90-33,00 30,2
Updated August 2013

Hammond Recommended Geometry for Various Materials



View PDF
Drill Diameter. Primary Land Chamfer at 20°
Ø 3,0 to 12,0 0,4 – 0,6 0,4 – 0,6
Ø 12,0 to 25,0 0,6 – 0,8 0,6 – 0,8
Ø 25,0 to 32,0 0,8 – 1,2 0,8 – 1,2
Diagram Diagram

Facet Description NG4 Aluminium
(Order code B)
NG13 Grey Cast Iron
(Order code E)
NG80 Flat Bottom
(Order code G)
Horiz. Vertical Horiz. Vertical Horiz. Vertical
A  Outer Primary +15° +15° +40° +12° +1° +12°
B Outer Secondary +14,5° +20° +39,5° +25° +1° +20°
C Inner Relief -20° +15° -20° +12°
D  Front Clearance +25° +35°
E Oil Dub-Off -25° -15° -25° -12° 25° -12°
Point Position D/4 D/4 D/2
Facet Description NG82 Super Alloys
(Order code H)
NG86 Wood Grind
(Order code K)
NG90 Malleable MATL
(Order code L)
Horiz. Vertical Horiz. Vertical Horiz. Vertical
A  Outer Primary +42° +14° +30° +20° +20° +20°
B Outer Secondary +41,5° +25°
C Inner Relief -17° +14° -20° +20° -20° +20°
D  Front Clearance +30° +30° +25°
E Oil Dub-Off -22° -15° -25° -15° -25° -15°
Point Position D/5 D/3,5 D/4

Cutting Parameters


Gun drills operate at relatively high cutting speeds with low feeds per revolution. Approximate starting values are shown in the charts on this page.


View PDF
Diagram
Feed rates are critical to chip formation. The values shown here may need to be adjusted for optimum results.


Diagram
Reliable chip evacuation and good surface finish can only be ensured if sufficient coolant volume and pressure are available.

Pressure and volume vary according to length/diameter ratio.


Diagram
Chart shows maximum unsupported flute length


Diagram