Need some threaded caps 3D printed

[Janger]

I'm just printing it anyway.

 

[kevin.decelles]

the design intensifies. @Janger employs a wrench-able facet. fascinating friday night stuff!

 

[YYCHM]

I'm just printing it anyway.

Ya.... OK. I'm not even sure it's 10TPI anymore LOL.

Been playing with bolting the rubber plunger to the cap. Initial water leak tests were promising. An O-Ring under the bolt head would probably synch it. Today the wife threw out an empty vitamin bottle and the lid (on the right) just fits the barrel. Certainly a candidate to be epoxied on.

Craig

 

[DPittman]

So I just did a sort of similar thing sort of....I wanted to reuse some aluminum containers for chainsaw gas but the plastic caps that came with them are not gas resistant. The caps have an odd ball thread that I can't reproduce on my lathe. (White cap in photo).
My solution was to cut off the lip on the can so I could slide an abs fitting over top. The abs fitting had to be bored out on lathe to the right diameter and then jb welded onto the can. Im happy with the results.

 

[RobinHood]

Who would have thought this would be an issue......

Ten attempts to thread this now and getting no where. The work piece keeps pulling out of the chuck mid thread pass. I've tried chucking it with both out-side and in-side jaws to no avail. Just too slick and flexible to grab properly.

Having worked with ABS (and other) soft plastic tubing, that is a common issue. As @Janger mentiones, a close fitting plug for the inside of the tube works wonders. Suitable candidates are steel, aluminum, another (harder) plastic or hard wood. I would have tried with the cap on the piece of pipe - that gives enough resistance to the jaws for something to grip onto.

Joe Pieczynski did a two part video a few weeks ago addressing deformation of plastic parts in lathe chucks.

 

[RobinHood]

Your carbide internal threading tool may also not be sharp enough. Super sharp HSS is the preferred tool for soft stuff.

 

[YYCHM]

Here is the cap John (@Janger ) printed for me....

The dimensions were spot on as was the TPI. The thread profile was another matter. I had to knock off the tops of threads before it would thread on. Once it was threading on a hydro test revealed it leaked (probably through the threads). Teflon tap reduced the leaking but didn't eliminate it. Silicon seal smeared through the threads and at the base did the trick. This is what I wanted to achieve, leak proof and not permanent.

Thanks John!!