1. Machining Recommendations for C69300 & C87850
Larry Muller
Manager, Metallurgy and Technical Services
Chase Brass and Copper Co., LLC.
Montpelier, OH
Confidential – do not distribute without permission
Version: 8/18/16

2. Property Impact Physical properties related to machining ECO BRASS
303 Stainless
Tensile Strength (ksi)
Turning forces, heat buildup
99.8
76.7
87.3
Work Hardening Coefficient
Thread rolling, knurling
0.13
0.11
0.31
Thermal Conductivity (Btu/ft2/ft/hr/ºF)
Heat removal from drilled holes, tool breakdown
21.8 67
8.8
Version: 8/18/16

3. Recommendations for turning and form tools to increase productivity
Limiting factors (compared to C360):
Higher strength, lower thermal conductivity, intermetallics rather than lead particles
Counter with:
Higher grade of HSS such as T-15 vs. M-2
Carbide with high temperature ceramic coatings e.g. TiAlN
Larger top rake (e.g º); start skive tool at 20° draft and clearance
Lower rpm (350 sfpm), higher feed rate (≥0.010 ipr)
Minimum dwell time
Clearances for 1215
ECO BRASS vs C360 is analogous to:
Stainless steel vs alloy steel or 1215 vs. 12L14
General comment – parameters are part and machine specific; common problems are sfpm are too high while feed rate is too low (watch for heat related problems)
Version: 8/18/16

4. Recommendations for turning and form tools to increase productivity
Depth of cut
/mm
Feed /mm/rev Cutting speed:100m/min.
Feed /mm/rev Cutting speed:200m/min.
Feed rate (ipr) RPM = 325
Depth of Cut
0.007”
0.020”
0.060”
0.120”
Depth of Cut
0.007”
0.020”
0.060”
0.120”
Feed rate (ipr) RPM = 650
Best feed rates to produce small chips are ≥ ipr.
Chase recommends a minimum of ipr.
Version: 8/18/16

5. Recommendations for deep hole drilling to increase productivity
Limiting factors (compared to C360):
Slightly larger type 1 chips can cause clogging,
Lower thermal conductivity results in heating that will collapse the hole diameter
Counter with:
Higher helix angle
Increased flute width, thin web
Increase the number of flutes (to decrease how much is removed per flute)
Lower rpm, higher feed rate than C360 (start at ipr), 350 sfpm
Clearances like 1215 to reduce frictional heating (higher back taper)
Carbide insert drills (such as Allied)
Through-drill coolant
Version: 8/18/16

6. Relationship between feed rate and rpm on chip size for deep hole drilling
Feed Rate (ipr)
Drilling speed (fpm)
130
200
260
325
Best feed rate to produce small chips and get best productivity is ≥ ipr
Version: 8/18/16

7. Recommendations for producing threads
Thread chasing –
+3° clearance
Thread milling –
Thread whirling
Version: 8/18/16

8. } Summary of Recommended Machining Practices Compared to C360:
Increase feed rate
Decrease speed
Use positive clearances and rake angle (like steel machining)
Use higher grade of HSS or switch to ceramic coated carbide
Potential for shorter tool life by up to 30% and higher tool forces }
Decreases chip size and frictional heating
Version: 8/18/16