Wade mount hot end

Hi all,

I got my Prusa/Wade parts from Nophead and find it hard to mount the Teflon (PTFE) barrel. The instructions say that one should use a M3 for mounting, but the holes in the ABS are just 2.3mm wide. Wade suggests to drill the Teflon cylinder with 2.3mm. This seems awfully tight for an M3 that has a suggested hole size of 2.5mm for thread cutting???

How can I drill the holes correctly into the Teflon? The only way I can imagine that gets the holes into the right place is to drill trough the ABS with the PTFE in place. This is a dangerous procedure and will for sure widen the holes in the ABS. Is that the correct way?

Am I getting something wrong? I dont want to use a wrench and break some parts if possible. And I need to buy the right drill for that.

Thanks for any help.

Edited 1 time(s). Last edit at 08/11/2011 01:23AM by katzlbt.

If you got the part from me the holes are drilled out to 2.5mm. That is the correct size for an M3 tap. I insert the insulator and drill through again 2.5mm and then tap and insert M3 bolts. If you don't have a tap you could drill a bit bigger and use the screw to make the thread, or perhaps use self tapping screws.

I must admit this aspect of the extruder does not work very well. The drill tends to wander when it goes through the insulator, even with a drill press. I would be interested to hear what other people do. Maybe 4 small wood screws would work out easier.

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[www.hydraraptor.blogspot.com]

Hi Nophead,

Ahh, thanks. That makes sense. Its definitely your parts, they are very high quality. All screws just snap in. A job well done.
Indeed, they are drilled to 2.5. I did not notice at first, but my 2.5mm drill fits through very tightly.

I have a M3 tap drill, but do not like to use it on plastic, because it does not give good threads.
I guess the task is to mount the extruder as tight as possible so it does not wiggle.

Maybe someone should change the 3D model to simply increase the size of the holes? The wall of the holes gets really thin after drilling.

Otherwise Wade's is a pretty neat design.

Ok, its done and was not that bad.
The drilling enlarged the holes in the ABS carrier and thread-forming with the M3 was not hard.
It actually was really easy in the Teflon (almost no friction to feel).

Unfortunately my drilling was a bit off so the hot end is not straight by a few degrees. But that should be ok.

Ok, here is my summary for nophead (I posted it on the Wade's Extruder Wiki Page too)

I actually hand-drilled the holes using the detached drill head from my lathe. My black PTFE (carbon filled?) is very soft and easy to drill and I used a brand new drill.

The holes should be drilled to 2.5mm, then you should insert the PTFE Insulator and drill a 2.5mm hole through both using the ABS part as guide. After the first hole is done insert a nail or second drill into the existing first hole to lock the teflon cylinder in place and prevent it from turning. After that use a M3 to thread-form the thread (one could also try to use a M3 tap drill (thread-cutter) and finish the mount, but thread-forming will do). The Teflon is very soft so it is very easy to thread-form. In the end the extruder should fit tightly.

However I doubt that this procedure can be repeated more than a second time on the same piece of ABS.

Edited 1 time(s). Last edit at 08/11/2011 02:22PM by katzlbt.

I print extruder parts with 100% fill so there should be no worry about the wall of the hole getting thin. It is on my todo list to make the holes bigger in my config file to save me having to drill them.

Yes PTFE is quite easy to drill but it tends to spring back so I think it is customary to drill a bit bigger when tapping it. The thread does not have to be very good because it is only to stop the bolts sliding out. On an older extruder design I used the pins out of pop head rivets. There is so much downwards force they didn't work loose even without a thread.

I have used PEEK hybrid barrels and they are a lot harder to drill than PTFE. the drill tends to wander sideways and not come out in quite the right place. It doesn't seem to matter though. They are not slippery like PTFE is, so a clamp design might work and be much easier to attach. I have an extruder with an aluminium clamp and that works fine. Not sure if plastic would though.

Good tip about inserting something in the first hole while drilling the second. That is is exactly what I did.

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[www.hydraraptor.blogspot.com]

My original machine uses the Wades extruder, with my Wildseyed Hot End pinched in using the 3mm screws. Don't really know who I bought the parts from to tell the truth, but even without drilling the PTFE, using the screws to clamp the hot end on worked fine, which was actually quite surprising at the time, considering that PTFE is so soft, and my hot end uses no other supports. I did re-drill the hole through the PTFE tube after mounting, because it did compress a bit the first time.