|
|
|
Regrinding Systems
Grinding |
Gun Drill N-8
Half Round Drill HA-1 |
|
Step 1) |
Position horizontal register at +30° , (half round drills at +20°), vertical register at +12°. Grind until all
wear is removed. |
|
Step 2) |
Position horizontal register at +29°, (half round drills at +19°), vertical register at +20°. Grind to establish
the primary relief width of approximately 5% of the diameter. |
|
Step 3) |
Position horizontal register at -20°, (half round drill at -15°), vertical register at +12°. Grind to establish
the point position width of drill diameter. (Dia./4). |
|
Step 4) |
Position horizontal register at 0°, vertical register at +25°. Grind front clearance until the triangle created
reaches the rear edge of the primary relief. |
|
Step 5) |
For gun drill only. Position horizontal register at -25°, vertical register at -12°. Grind until the triangle
formed reaches the center of the tip "V". |
|
Step 6) |
Remove drill and freehand a periphery chamfer around the radial surface at approximately 20°, stopping just short
of the primary relief. |
|
DM-41 Gun and Half Round Drill Regrind Fixture |
The Sterling Gun Drills manual regrind fixture provides a fast and easy method of resharpening gun
drills and half round drills with the popular facet style grind. Drills of a large diameter range are positioned
and ground without the need of expensive bushings or collets. The universal nature of the fixture allows standard
or custom regrinds. |
 |
|
|
The Sterling Gun Drills DM-41 Gun Drill Regrinding Fixture Consists of Three Elements:
|
1) |
The Workhead with clamping device to hold either a single flute gun drill or half round drill in position. |
|
2) |
A Scale, graduated in degrees, to allow the drill to be aligned in the vertical plane. This scale is
mounted on the vertical member of the fixture that holds the workhead. |
|
3) |
A Scale mounted on the diamond - shaped base of the fixture to allow the drill to be angled in the
horizontal plane. This scale is graduated in degrees. |
Both scales have locking levers to maintain vertical and horizontal positioning, and when used together allow
compound angles to be ground on the nose of the drill mounted in the workhead.
The fixture is normally used on a tool and cutter grinder equipped with a 11V9 or 11A2 style diamond wheel (120 -
180 grit). Some may chose a metal or plated bond wheel with concentric roughing and finishing faces, the roughing
face having a coarser grit than the finishing faces. The spindle of the grinding wheel will start at 90° to the
table slideway. |
|
DM-42 Sharpening Head for Gun Drills up to 2 1/8” Diameter |
Sterling Gun Drills, Inc. announces a new sharpening head for single flute gun drills to increase the range of our Manual Regrind Fixtures to over 2 1/8" (54mm).
Part # DM-42 Large Manual Sharpening fixture has a range of .75” (19mm) to approx.
2 1/8” (54mm), and is offered complete with the base assembly for $1795.00.
Part # DM-42-A, Large Sharpening Head, is offered as an option* for a (modified)
DM-41 Manual Regrind Fixture at $599.00.
|
 |
|
|
No additional collets or adapters are necessary to sharpen single flute gun drills of any manufacture with the popular “facet” nose grind to virtually any configuration required.
* To cope with the additional weight of very large gun drills, we recommend strengthening the clamping screws and handles of DM-41 fixtures already in use before fitting the DM-42-A head. The vertical and horizontal adjustment studs of DM-41 fixture should be increased in size to a ½ x 13 thread, along with more substantial locking handles. If desired, existing owners can return their DM-41 fixture to Sterling Gun Drills, Inc. for modification at $199.00. New fixtures ordered as DM-42, or DM-42 with the DM-41-A option, will have this modification included as standard. Price for the DM-42 with DM-41-A "standard" Sharpening Head is $2490.00. Price of the DM-41-A "standard" Sharpening Head alone (diameter range .16” – 1.25”, 4 – 32mm) is $695.00
Changeover of the standard sharpening head DM-41-A to the DM-42–A large sharpening head on the base fixture involves just two screws to swap the vertical register from the standard fixture to the large fixture.
Due to variation in flute shape from size to size and from one manufacturer to another, a fine adjustment feature is built into the clamping wedge that allows leveling the cutting face on gun drills with flute angles from 105º - 120º. A 1/8” hex key is furnished for this purpose.
Existing sharpening instruction is suitable for all diameters.
Part# reference
| DM-42 |
Manual Regrind Fixture (large) |
DM-41 |
Manual Regring Fixture (std.) |
|
|
| DM-42-A |
Head Assy. (large) |
DM-41-A |
Head Assy. (std.) |
|
|
| DM-42-B |
Base Assy. (large clamping) |
DM-41-B |
Base Assy. (std.) |
|
|
| DM-42 + DM-41 A Head assy. Includes the "large" fixture base assy., large head, and standard head allowing gun drill sharpening from .156 (4mm) to 2.125" (54mm). |
|
|
|
TWINMASTER Regrinding Information
TWINMASTER
two flute drills can be resharpened many times, maintaining optimum performance. Used up drills or damaged drills with good
tubes can be retipped. The grind can be reproduced on universal tool and cutter grinding equipment; this diagram shows basic
geometries. Sterling Gun Drills offers regrinding services with next day turnaround.
 Learn more about the TWNIMASTER
|
|
|
Portable
grinding machine