SPADE & INDEXABLE DRILLING
TECHNICAL INFORMATION
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Basics of... Spade Drills and Indexable Drilling
Spade Drills
- A drill bit, which contains a replaceable flat-end cutting blade with two cutting lips, used for deep hole drilling or larger holes ranging from 1�? to 6�? diameter
- Has special shanks called Holders and Blades (Inserts) may be quickly replaced which saves time during set-up
- Allows the user to drill many different diameter holes simply by changing the blade
- Types: Universal and High Performance
Straight Flute
- Recommended for horizontal machining center applications to maximize chip evacuation
Helical Flute
- Recommended for horizontal machining center applications to maximize chip evacuation
Modular Drills
- Offers performance levels commonly achieved with solid carbide drills
- Unique locking system requires no screws or clamps
- Insert blades can be changed using a simple provided tool
- Drill body does not require removal from the machine or holder to change the insert blade
- Insert blades may be used on different drill bodies but must be of the same seat size
Indexable Drills
- More complex in design vs. spade drills and modular drills
- Uses two inserts: the inner insert cuts the inner portion of the hole while the outer insert responsible for the final hole diameter cuts the outer portion
- Reduces machine cycle time by producing higher penetration rates, lowering chip friction and allowing for chip control
- In addition to drilling applications, they can perform boring, facing and turning operations
Types of Inserts for Indexable Drilling
Straight Flute
- Inside insert leads the cutting edge of the outside to cut a clearance path for the lead corner of the outside insert
Trigon
- Outside insert leads the cutting edge of the inside
Tool Material
High Speed Steel (HSS: M1, M2, M7, M50)
- Combines good tool life and productivity with minimal cost
- Works well in free cutting and carbon steels, as well as soft non-ferrous materials like aluminum, brass, bronze and copper
- Able to handle less than ideal set-ups
Cobalt (M35, M-42, T-15)
- Provides better wear resistance, higher hardness and toughness than HSS
- Very little chipping or microchipping under severe cutting conditions, allowing the tool to run 10% faster than HSS
- With the right point angle and helix, cobalt is the most cost effective for machining cast iron, heat-treatable steels and titanium alloys
- Able to handle less than ideal set-ups
Solid Carbide
- For high-performance applications: carbide can run faster and withstand higher temperatures, while providing good wear resistance
- Provides better rigidity than HSS, yielding a higher degree of dimensional accuracy, often eliminating the need to ream
- Carbide is brittle, and tends to chip when conditions are not ideal; heavy feed rates are more suitable for HSS and Cobalt tools
- Carbide is used in abrasives and tough-to-machine materials: cast iron, non-ferrous alloys, glass, plastics and composites
Coatings
TiN (Titanium Nitride - Gold Color)
- Multi-purpose coating which increases tool life and performance
- Hardness and heat resistance allows tools to run at higher speeds and feeds (approx. 25% to 30% higher than uncoated tools)
TiCN (Titanium Carbonitride - Violet Gray Color)
- Harder and more wear resistant in moderate temperatures
- TiCN can provide the user the ability to run the job at higher spindle speeds, especially in stainless steels, cast iron and aluminum
- Requires an increase of 35% to 50% in machining speeds
TiAlN (Titanium Aluminum Nitride - Violet Black Color)
- For high temperature and/or abrasive conditions
- Use in stainless steel, high alloy carbon steels, nickel-based high-temp alloys and titanium alloys. Not to be used in aluminum
- Requires an increase of 75% to 100% in machining speeds
FIREX®
- Exclusive by Guhring, alternating ultra-thin coating layers combines the performance benefits of single layer coatings: universal applicability of TiN,hardness and heat resistance of TiAlN and shock resistance of TiCN