[metalworking] machine shop essentials - lathe tool sharpening
TRANSCRIPT
© 2008 Metal Arts Press Extracted from Machine Shop Essentials: Q & A
Lathe Tool Sharpening What are typical rake and clearance (relief) angles for HSS tool bits? See Figure A–1 and Table A–1.
Face
CuttingEdge
NoseNoseAngle
Side Cutting Edge Angle
Body
Front Cutting
Back Rake Angle
Side Rake
Side Clearance
Edge Angle
Angle
End Clearance AngleAngle
Figure A–1. Tool bit nomenclature.
Material Side Clearance
Front Clearance
Side Rake
Back Rake
Aluminum 12 8 16 35
Brass 10 8 5 to −4 0
Bronze 10 8 5 to −4 0
Cast Iron 10 8 12 5
Copper 12 10 20 16
Machine Steel 10–12 8 12–18 8–15
Tool Steel (unhardened) 10 8 12 8
Stainless Steel 10 8 15–20 8
Table A–1. Clearance and rake angles in degrees for common metals.
© 2008 Metal Arts Press Extracted from Machine Shop Essentials: Q & A
What is the procedure for sharpening HSS general-purpose lathe tools? Begin by dressing the grinding wheel. Next, look up the typical angles for the workpiece material, and then follow the steps in Figure A–2. Dip the tool in coolant frequently to keep it from overheating and annealing. Any discoloration on the bit indicates it may no longer be hardened. If this happens, consider starting over again from the beginning. Tool bit angles are not critical and most tools will cut material satisfactorily, just less effectively.
Top
Top
Top of Tool8°
Set Tool Rest Angle1 Move Tool Side to 2Side Across Wheel
Side Cutting3Edge Complete
Move Tool Side to 4Side Across Wheel
Front Cutting5
Break Point to61/64" Radius
Apply Back Rake7
Cutter Complete8
Do Not Remove This EdgeWhen Grinding Rake
on Grinding Wheel
Grinding Wheel Tool Rest
Edge Complete
Figure A–2. Steps for sharpening HSS tool bits