cpreston
Plastic
- Joined
- Oct 9, 2019
- Location
- Michigan, USA
Long time Forum reader, first time poster.
Need help tapping M2 x .4, M2.5 x .45, and M3 x .5 holes in aluminum with 75% thread percentage. Taps snap with correct tap drill. Trying a drill the next size up drops the thread percentage causing ripped threads at assembly. Form taps and thread percentage is mandated by our customer. Torque specs for the assembly screws are mandated by our customer's customer.
6061 T6511 aluminum
2015 Haas VF-4SS. Tapping retract is set at 4, but we've tried both slower and faster
Spotting with a 1/4" x 120° NC spot drill
Using appropriate size solid carbide drills - 118° drill tip
Formula for determining appropriate drill size for 75% metric threads: Tap O.D. - ( desired thread% x pitch ) / 147.06
Example: (M2x.4) 2 - ( 75 x .4 ) / 147.06 = 1.796mm (.0707"), we're using a 1.8mm drill (.0709")
Rigid tapping. We do not have any floating tap heads. We have tried multiple brands of taps. Emuge. Guhring. OSG. Union Butterfield. Balax. Probably another 5 or 6 brands that I can't remember. All coated for aluminum. TiN or similar. We have purchased new tapping collets. We have purchased an Emuge Softsynchro high performance tap holder.
The coolant we use is a local brand I think, AFT (Advanced Fluid Technology) 619M2. The coolant concentration is nominal. I'm not a fan of the coolant, but there's no getting away from it. Coolant flow is great.
We've tried Tap Magic for aluminum - comes in a red/white spray can and is supposed to be cinnamon scented. We've tried Moly-dee. And some other off-brand, thick as molasses, tapping compound.
Maybe there's something simple that I just haven't thought of. Maybe there's something I just don't know about. Any help or advise would be appreciated, Thanks
Thanks everyone! A lot of great stuff here!
Need help tapping M2 x .4, M2.5 x .45, and M3 x .5 holes in aluminum with 75% thread percentage. Taps snap with correct tap drill. Trying a drill the next size up drops the thread percentage causing ripped threads at assembly. Form taps and thread percentage is mandated by our customer. Torque specs for the assembly screws are mandated by our customer's customer.
6061 T6511 aluminum
2015 Haas VF-4SS. Tapping retract is set at 4, but we've tried both slower and faster
Spotting with a 1/4" x 120° NC spot drill
Using appropriate size solid carbide drills - 118° drill tip
Formula for determining appropriate drill size for 75% metric threads: Tap O.D. - ( desired thread% x pitch ) / 147.06
Example: (M2x.4) 2 - ( 75 x .4 ) / 147.06 = 1.796mm (.0707"), we're using a 1.8mm drill (.0709")
Rigid tapping. We do not have any floating tap heads. We have tried multiple brands of taps. Emuge. Guhring. OSG. Union Butterfield. Balax. Probably another 5 or 6 brands that I can't remember. All coated for aluminum. TiN or similar. We have purchased new tapping collets. We have purchased an Emuge Softsynchro high performance tap holder.
The coolant we use is a local brand I think, AFT (Advanced Fluid Technology) 619M2. The coolant concentration is nominal. I'm not a fan of the coolant, but there's no getting away from it. Coolant flow is great.
We've tried Tap Magic for aluminum - comes in a red/white spray can and is supposed to be cinnamon scented. We've tried Moly-dee. And some other off-brand, thick as molasses, tapping compound.
Maybe there's something simple that I just haven't thought of. Maybe there's something I just don't know about. Any help or advise would be appreciated, Thanks
Thanks everyone! A lot of great stuff here!
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