My limited experience has been that plastic does not hold on to cut threads very well. Repeated assembly/disassembly cycles cause my threads to wear rapidly. So . . . have you tried using a roll tap? For me, roll tapped threads seem to form tighter toleranced threads which also wear better. This makes sense, as a roll tap compresses the material into the thread geometry instead of cutting material away. Subsequently, the threads do not spring back to their original unformed state, even if the threaded holes is not occupied with a screw. I should mention that the materials I thread are mostly clear acrylic, Delrin, Teflon, UHMW plastic, G-10, and carbon fiber epoxy matrix.
It should self-feed within reason. Using the weight of the drill and your arm should be enough. I suppose if you were to go full speed horizontally with no weight pushing it into the hole, it may strip where the first few threads would be until it bites and starts feeding properly. That's why he recommends using a bottoming tap (doesn't have a taper at the tip, normally used to put the last 2-3 threads into the bottom of a blind hole after a tapered tap's point bottoms out).
I thought the same thing. Maybe on smaller sizes his method provides more float. Less likely to break the tap. Also, when possible use a 2-flute gun tap. Much stronger and designed to push threads out the end when tapping through holes.
That is not how to make threads. You need to turn three or four turns and then go backwards to break the chips from cutting the threads. You run the risk of damaged threads or breaking the bit if you go too fast in one direction.
Ready for some nitpicking..? You should chamfer the hole before tapping it to avoid damaging the thread. Truth be told, that hardly ever happens but it just seems the most logical order to me and I just had to get it out of my system.
My limited experience has been that plastic does not hold on to cut threads very well. Repeated assembly/disassembly cycles cause my threads to wear rapidly.
So . . . have you tried using a roll tap?
For me, roll tapped threads seem to form tighter toleranced threads which also wear better. This makes sense, as a roll tap compresses the material into the thread geometry instead of cutting material away. Subsequently, the threads do not spring back to their original unformed state, even if the threaded holes is not occupied with a screw.
I should mention that the materials I thread are mostly clear acrylic, Delrin, Teflon, UHMW plastic, G-10, and carbon fiber epoxy matrix.
Q. Distilled water. Why? Great vid!
It should self-feed within reason. Using the weight of the drill and your arm should be enough. I suppose if you were to go full speed horizontally with no weight pushing it into the hole, it may strip where the first few threads would be until it bites and starts feeding properly. That's why he recommends using a bottoming tap (doesn't have a taper at the tip, normally used to put the last 2-3 threads into the bottom of a blind hole after a tapered tap's point bottoms out).
RPM is your enemy. Too fast = melt Keep that in mind. Coolant really helps as well.
A very cleanly tapped hole...I'm sure there's a sex joke in there somewhere. :P
I usually just put the tap directly into the drills chuck :)
I thought the same thing. Maybe on smaller sizes his method provides more float. Less likely to break the tap. Also, when possible use a 2-flute gun tap. Much stronger and designed to push threads out the end when tapping through holes.
That is not how to make threads. You need to turn three or four turns and then go backwards to break the chips from cutting the threads. You run the risk of damaged threads or breaking the bit if you go too fast in one direction.
Ready for some nitpicking..?
You should chamfer the hole before tapping it to avoid damaging the thread. Truth be told, that hardly ever happens but it just seems the most logical order to me and I just had to get it out of my system.
isn't there a risk that the teeth of the tap bit will just chew a non-grooved hole into the plastic if you don't feed it through at the right speed?
Any experience trying it with aluminum? (Seems like it could have potential with a softer aluminum alloy if the drill speed was sufficiently slow.)