Here in the Goodson Tech Department we get a lot of questions about which brake lathe cutting tip to use and why. We tested our most popular brake lathe cutting tips - RT-A and RT-312 to get some concrete answers for you.
Tests were conducted by the same operator on an Ammco 4000 Brake Lathe. The rotor being turned was mounted using a Quick Chuck Mounting Adaptor equipped with a CE-8 Rubber Silencer Band.
The titanium coating is applied to a carbide substrate. It is specifically developed for cutting, turning and boring most materials at a moderate to low speed. Its unique mechanical and thermal properties make it ideal for cutting drums and rotors while providing longer life and more cuts per tip.
Test #1
Standard v. Honed Edge v. Titanium Coated v. Standard Round v. Titanium Coated Round
| Standard Triangle | Honed Edge Triangle | Titanium Coated Triangle | Standard Round | Titanium Coated Round | |
|
Single Pass Cut: .006" off each side |
135Ra | 121Ra | 109Ra | 73Ra | 77Ra |
| Single Pass Cut: .010" off each side Rotor Diameter: 11" Machine Speed: Medium |
123Ra | 131Ra | 97Ra | 74Ra | 65Ra |
|
Fast Cut: .006" off each side; Slow Cut: .002" off each side |
50Ra | 50Ra | 49Ra | 35Ra | 33Ra |
NOTE: An Ra finish of 14 to 70 off the production line is recommended. The lower the Ra number, the better the finish.
Test #2
Triangular Cutting Tips v. Round Cutting Tips
Test Conditions:
Single Pass Cut: .006" off each side of rotor
Rotor Diameter: 11"
Machine Speed: Fast
Each test is another pass with the same cutting tip. For example, Test D represents four (4) passes with the same tip.
Standard Carbide Tips
| Triangle : RT-A | Round : RT-312 | |
| Test A (1 pass) | Temp: 136º | Ra: 133 | Temp: 110º | Ra: 73 |
| Test B (2 passes) | Temp: 138º | Ra: 136 | Temp: 109º | Ra: 74 |
| Test C (3 passes) | Temp: 138º | Ra: 138 | Temp: 110º | Ra: 76 |
| Test D (4 passes) | Temp: 136º | Ra: 140 | Temp: 109º | Ra: 77 |
| Test E (5 passes) | Temp: 139º | Ra: 143 | Temp: 109º | Ra: 78 |
Titanium Coated Carbide Tips
| Triangle : RT-A-T | Round : RT-312T | |
| Test A (1 pass) | Temp: 103º | Ra: 101 | Temp: 94º | Ra: 77 |
| Test B (2 passes) | Temp: 103º | Ra: 101 | Temp: 94º | Ra: 65 |
| Test C (3 passes) | Temp: 121º | Ra: 101 | Temp: 96º | Ra: 68 |
| Test D (4 passes) | Temp: 128º | Ra: 127 | Temp: 104º | Ra: 71 |
| Test E (5 passes) | Temp: 136º | Ra: 132 | Temp: 110º | Ra: 74 |
As always, if you have any questions about this or any other technical topic, contact the Goodson Tech Service Department by phone (1-800-533-8010) or email