"The bottom insert needs to be made. This would be a shape extruded up from the zero point to 15mm, then Boolean diffed out of the part (don't forget to delete the 2 solids in the cavity after this)"

Huh? You are talking about the 15mm tall "plug" that fills the bottom end, and contains the tapered hole? I think I get the Boolean, but what two solids in the cavity?

Nice job on the insert, but that's upside-down - the narrow end goes into the stepped and tapered hole that they call out, at 250C, and the ridges on the hot brass insert push melted plastic forward into the serrations and ridges as it slides in, for a really solid permanent embed. The hole needs to be wide end at the bottom, and shaped like the attachment. The 9mm figure was just a guess before I spotted the hole shape at McMaster.

Tapered Hole Diameter, mm
(A) 8.2
(B) 9.22
I'd put the narrow straight part of the stepped hole at about 2/3 of the way in, guessing from the sketch. The straight part of the hole needs to go all the way through the plug to the interior, of course.

Warm thanks once again, for your incredible work and sharing how you did it.

"""""""""Huh? You are talking about the 15mm tall "plug" that fills the bottom end, and contains the tapered hole? I think I get the Boolean, but what two solids in the cavity?"""""""

When you cut the "insert hole", the cavities will have little solids inside. It could be a bug with how the Boolean was performed, I'm not sure. Lets just finish it here so we don't get confused.

So, the tapered dims, fit to the insert look like this:





If these are set at the baseline, this leaves 2.3 mm before the cavity is reached.

Would you like to inset the tapered hole some? And, if we inset it, would you like the taper to continue out, so that the 9.22 starts at the inset value and the actual base opening is now larger? Or would you just like the opening to be 9.22, straight to the inset, then perform the taper?

Let me know and I'll finish off the plug hole

No, it can't be inset at all, because the fencer will screw the pommel/insert down onto the grip (and the shim washers) as hard as their hand can, so the insert has to be flush to protect the plastic from pressure that could break the insert loose. The fencers want the pommel/grip/bell-guard/blade clamped down as hard as they possibly can, so nothing comes loose under the impacts of vigorous fencing. (I also recommend a drop of Loc-Tite. On my first metal pommel design, fencers griped because I didn't include flats for a 3/4" wrench to tighten it.)

I set it flush when melting it in, by pressing the base of the pommel with still-hot insert down flat on a metal table. It's in there forever after the plastic cools and shrinks.

The straight portion at the top of the hole should just be extended the 2.3mm at same diameter, upward into the cavity, to allow the threaded tang to protrude into the cavity unsupported. Many of the threaded tangs will extend further in than 13mm, and need to do it without hitting anything and breaking plastic. The uppermost couple of mm of the 15mm tall "plug" is there to spread the stresses from the end of the brass insert into the cavity walls.

So far none of my prototypes have broken in use, even when using brittle PLA plastic, but I take my design guidelines from the Navy: Design it strong enough. Then make it three times stronger than that...

Ok Rick. this file should be it....

Just note that the base rim of the insert is 9.53 in diameter (the green), while the tapered plug cut was made at 9.22. But I guess you understand how this "melts" into place...

Let us know if you need anything more about this...

That is Perfect, and I cannot express my gratitude for your work!

:)

I can be proud I helped you.

I'll make a couple vids later regarding the start/beginning point of the process.

Well done Burr! great to see a real product life cycle unfolding on the forum.

Cheers

Thanks Danny! It's going to be great to see some guy "Perry" some poor chap with one of these!

I was stoked we got what he needed.

I think Rick was stuck with working in MoI because he is experienced with another app/workflow.

I'm going to make a couple other vids on it for him. Feel free to input on other methods or mistakes you see me make. This is NOT a paid venture (Ricks to kind to ask for "free" help).

Talk later.

Great job Burr!

- Michael

What a Great Forum. MOI's creator must be an incredibly nice guy to have spawned such a good group.

I'm now fine-tuning the printing, and will get this on the market this week!

Hope you'll post some photos of the printed results!

- Michael

..hey Rick... you have found just the right man to ask an help... :)
you're lucky !

Sure will - I'm in production now!

Just a quick update:

I attended a Junior Olympics Qualifier Fencing tournament in Portland over the weekend, hooked up with a well-known vendor, and he ordered 100 of the Melting pommels on the spot. After I sold him the 30 or so that I had in stock, I ran completely out of parts and plastic, so I've been frantically working on getting shim washers, brass inserts, and plastic since then.

I haven't shipped any yet, but will within 10 days or so, and will send Burr one as a memento and Thanks for his invaluable help.

That's cool Rick!

"""""""""I haven't shipped any yet, but will within 10 days or so, and will send Burr one """"""""""""

Be sure not to worry about it while your swamped.. Get all the orders filled first! It's not necessary, but THANKS!

Good luck.

Cool!
Burr you'll have to go on Ebay and find yourself a cheap foil for the pommel :)

En garde!

Yes! May have to make one in MoI first.

May stab myself in the foot though.... Perry, perry, demi plié?

And here's the image and the link (for any epee fencers out there). I FINALLY solved a 3D printing issue just this afternoon, and my production quality is now of commercial quality (about $150 of plastic later).

http://www.fencing.net/forums/thread73463.html

Looks great Rick, thanks for sharing the photo!

- Michael

Realized I never came back and thanked Rick. He sent me one of the finished pieces... They are very well made...

Thanks for the piece rick. It's on my desk... :)