04-01-2013, 01:12 PM
Wong,
Try with 1.7mm use plenty of cutting fluid. If you feel it is getting 'tight' withdraw the tap completely and give it a clean as well as cleaning the hole out, air blow should do it. Try it again.
If you feel it is still getting too tight then you may have to use a 1.8mm drill, so long as the set up isn't moved it shouldn't cause a problem re-drilling it.
Don't forget to keep it 'square' take it slow and careful, try to feel it and watch carefully the tap isn't twisting too much. Keep backing off.
DaveH
Try with 1.7mm use plenty of cutting fluid. If you feel it is getting 'tight' withdraw the tap completely and give it a clean as well as cleaning the hole out, air blow should do it. Try it again.
If you feel it is still getting too tight then you may have to use a 1.8mm drill, so long as the set up isn't moved it shouldn't cause a problem re-drilling it.
Don't forget to keep it 'square' take it slow and careful, try to feel it and watch carefully the tap isn't twisting too much. Keep backing off.
DaveH