cinematechnic
Cast Iron
- Joined
- Apr 11, 2005
- Location
- Walnut Creek, CA
I'm about to get started with carbide insert threading tools. I'll be using the tool on my Hardinge HLV-H for manual single point thread cutting.
I'm trying this out because I've been disappointed with the quality of brazed carbide threading tools (the ones coming out of CN these days are pretty rough) and the finish I can get with them. I can't find HSS threading tools for some of the threads I need to cut (or that can work close to a shoulder), and I'm hoping for better thread finish needing less work after cutting..
I cut fine pitch threads with relatively large diameters for the pitch. Always in 6061 or 7075 aluminum, 360 brass and sometimes free machining steel (C12L14, C1215).
Examples:
1.000" - 32 TPI Helix 0.58º ("C" lens mount)
1.035" - 40 TPI Helix 0.34º ("SM1" lens thread)
M28.0 x 0.75 Helix 0.50º
M30.5 x 0.50 Helix 0.30º
I've cut all of these before but I usually need to either run an adjustable die (when available) to clean up the thread, or run a CNC machined matching female thread with non-embedding lapping compound to clean up the thread.
I know the insert holder (will be using 16ER for external) has a 1.5º helix angle, and a "neutral" shim. I'm trying to get the other shims that will give me a choice of helix angles.
How closely do I need to match the angle of the insert with the helix angle of the thread I want to cut?
Thanks!
I'm trying this out because I've been disappointed with the quality of brazed carbide threading tools (the ones coming out of CN these days are pretty rough) and the finish I can get with them. I can't find HSS threading tools for some of the threads I need to cut (or that can work close to a shoulder), and I'm hoping for better thread finish needing less work after cutting..
I cut fine pitch threads with relatively large diameters for the pitch. Always in 6061 or 7075 aluminum, 360 brass and sometimes free machining steel (C12L14, C1215).
Examples:
1.000" - 32 TPI Helix 0.58º ("C" lens mount)
1.035" - 40 TPI Helix 0.34º ("SM1" lens thread)
M28.0 x 0.75 Helix 0.50º
M30.5 x 0.50 Helix 0.30º
I've cut all of these before but I usually need to either run an adjustable die (when available) to clean up the thread, or run a CNC machined matching female thread with non-embedding lapping compound to clean up the thread.
I know the insert holder (will be using 16ER for external) has a 1.5º helix angle, and a "neutral" shim. I'm trying to get the other shims that will give me a choice of helix angles.
How closely do I need to match the angle of the insert with the helix angle of the thread I want to cut?
Thanks!