Cobalt Long Length Drill Bit

Cobalt Aircraft drill bits are manufactured to NAS 907 Type J specifications, 135° split point, surface treated with jobber flute lengths for drilling holes in hard-to-reach places. Heavy-duty construction for portable or machine drilling in high tensile strength alloy steels, stainless steels, titanium, and other difficult to machine materials.

Products
6" Lengths
12" Lengths
Drill Feeds & Speeds

12" Lengths

12" LengthsHSS Long Length Drill Bit

SIZE	DECIMAL EQUIVALENT	FLUTE LENGTH	OVERALL LENGTH
1/16	0.0625	7/8	12
5/64	0.0781	1	12
3/32	0.0938	1 1/4	12
7/64	0.1094	1 1/2	12
1/8	0.1250	1 5/8	12
9/64	0.1406	1 3/4	12
5/32	0.1563	2	12
11/64	0.1719	2 1/8	12
3/16	0.1875	2 5/16	12
13/64	0.2031	2 7/16	12
7/32	0.2188	2 1/2	12
15/64	0.2344	2 5/8	12
1/4	0.2500	2 3/4	12
17/64	0.2656	2 7/8	12
9/32	0.2813	2 15/16	12
19/64	0.2969	3 1/16	12
5/16	0.3125	3 3/16	12
21/64	0.3281	3 5/16	12
11/32	0.3438	3 7/16	12
23/64	0.3594	3 1/2	12
3/8	0.3750	3 5/8	12
25/64	0.3906	3 3/4	12
13/32	0.4063	3 7/8	12
27/64	0.4219	3 15/16	12
7/16	0.4375	4 1/16	12
29/64	0.4531	4 3/16	12
15/32	0.4688	4 5/16	12
31/64	0.4844	4 3/8	12
1/2	0.5000	4 1/2	12

All dimensions are in inches.

Drill Feeds & Speeds

Material	Hardness	Drill Type	Point Style	Point Angle	Speed (SFM)	Feed	Coolant
Aluminum / Aluminum Alloys	-	High Helix	Standard	118°	200-300	Medium to Heavy	Water Soluble
Aluminum Bronze	-	High Helix	Standard	118°	50-100	Medium to Heavy	Water Soluble
Brass, Free Machining	-	Low Helix	Standard	118°	100-250	Medium to Heavy	Water Soluble
Bronze, Soft Medium	Below 200	General Purpose	Standard	118°	70-150	Medium to Heavy	Water Soluble
Bronze, High Tensile	-	Low Helix or Half RD	Standard	118°	50-100	Medium to Heavy	Water Soluble
Copper / Copper Alloys	-	General Purpose	Standard	118°	100-200	Medium	Water Soluble
High Temp Alloys, Cobalt Base	180-300	Cobalt	Split Point	135°	5-20	Medium	Activated Oils
High Temp Alloys, Iron Base	180-300	Cobalt	Split Point	135°	5-20	Medium	Activated Oils
High Temp Alloys, Nickel Base	180-300	Nitro® or Cobalt	Split Point	135°	5-15	Medium	Activated Oils
Iron, Soft Case	Up to 150	Heavy Duty or Nitro®	Split Point	135°	75-150	Medium	Dry / Air
Iron, Medium Case	150-250	Heavy Duty or Nitro®	Split Point	135°	50-100	Medium	Dry / Air
Iron, Hard Case	Over 250	Carbide	Standard	118°	40-75	Light to Medium	Dry / Air
Plastic & Related Materials	-	Low Helix	Low Angle	90°	100-200	Medium to Heavy	Dry / Air
Steel, Low Carbon Alloy	125-275	General Purpose	Standard	118°	50-70	Medium	Water Soluble
Steel, Medium Carbon Alloy	275-325	Heavy Duty or Nitro®	Split Point	135°	40-55	Medium	Water Soluble
Steel, High Carbon Alloy	Over 325	Cobalt	Split Point	135°	30-50	Medium	Water Soluble
Steel, Low & Medium Carbon Alloy	Below 175	General Purpose	Standard	118°	45-95	Medium to Heavy	Water Soluble
Steel, High Carbon Alloy	175-225	General Purpose	Standard	118°	45-65	Medium	Water Soluble
Stainless Steel, Austenitic	Below 300	Heavy Duty or Nitro®	Split Point	135°	40-60	Medium to Heavy	Water Soluble
Stainless Steel, Precipitation	Over 300	Cobalt	Split Point	135°	20-40	Medium	Cutting Oil

Feeds – Feed rates for drilling are governed by the drill diameter, machinability of materials and depth of hole.
Speeds – The speed of a drill is determined by the rate which the outer periphery of the tool rotates in relation to material being cut. In general, the SFM at which a drill will operate is within a range based upon the workpiece material, its condition, hardness and depth of hole. It is usually advisable to start the drilling process at a slower SFM and then increase to the maximum.
RPM = (SFM x 3.82) divided by TD = Revolutions Per Minute
SFM = RPM x TD x .262 = Surface Feet Per Minute
TD – Tool diameter in inches

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Cobalt Long Length Drill Bit

Technical Data

6" Lengths

6" LengthsCobalt Long Length Drill Bit

12" Lengths

12" LengthsHSS Long Length Drill Bit

Drill Feeds & Speeds

Drill Feeds & Speeds