I've been fighting this process where I have to drill and tap fourteen 1/4-20 on this 4140PH shaft shoulder that I have to reach in about 6 inches but doesn't give me enough clearance around the shaft to get a proper tap extension. My best solution is using a hand tap extension. I bent the extensions to turn as true as possible since it does wobble a bit. I'm rigid tapping.
In the beginning it was tough, then I got it dialed in and ran great, then suddenly it's breaking taps again. I tested the material and it's on the low end of the spec. I'm drilling using a 5.3mm (0.2086). Tapping using OSG HSS and carbide with no difference in performance. Seems to only break on the slow down as it comes to the end. Tapped fast and slow and the sweet spot is around 400.
I bypassed the door so I can clean and lube each hole and then blow off the tap after teach tap.
I've been using Crisco and it did well. Then I bought some general cutting/tapping aerosol I use for broaching and see no difference. I had a guy suggest Emuge tapping fluid. Said he watched where people were amping out the spindle tapping huge holes but with some Emuge, it cut it down to 20% load.
Any other magical lubes out there? Emuge is like $130 for a small bottle but if people can vouch for it, then that's an easy buy since we won't have to rework these shafts.
Thanks
In the beginning it was tough, then I got it dialed in and ran great, then suddenly it's breaking taps again. I tested the material and it's on the low end of the spec. I'm drilling using a 5.3mm (0.2086). Tapping using OSG HSS and carbide with no difference in performance. Seems to only break on the slow down as it comes to the end. Tapped fast and slow and the sweet spot is around 400.
I bypassed the door so I can clean and lube each hole and then blow off the tap after teach tap.
I've been using Crisco and it did well. Then I bought some general cutting/tapping aerosol I use for broaching and see no difference. I had a guy suggest Emuge tapping fluid. Said he watched where people were amping out the spindle tapping huge holes but with some Emuge, it cut it down to 20% load.
Any other magical lubes out there? Emuge is like $130 for a small bottle but if people can vouch for it, then that's an easy buy since we won't have to rework these shafts.
Thanks