PTT6.6 ST-INKY Mounting Hardware

This will be my first Purifi PTT6.5 build project. The plan is to make flush mount bolts to cleanup the lines of the frame/baffle area.

I have no clue whether they matter acoustically. I just find the standard cap screw, or whatever other standard fastener, to be clunky. If there really must be a reason, chalk it up to fabrication warmup exercises.

The goal is to have one completed by this Wed. but I'll give myself a week if it takes that long.

Oh, and it coincidentally looks like something I've seen elsewhere, but I can't quite put my finger on it...
 

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The ST- aka Steel INKY is now CU-INKY as I decided to use some tellurium copper scrap.

I got the easy part done. Before going further it will need a special fixture to hold the threaded ends so they can be liberated.

Ran into a small problem. Purifi has 5.1mm mounting holes listed on the spec. sheet. This is WRONG. Most of my mount holes physically measure to 4.84mm-4.9mm. So the ones I just made to 5mm do not even fit the hole. Will have to do another round, but not the end of the world. Or I can just open up the frame with a drill bit.
 

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i think you have OCD issue rite :D

i find on other purifi build, it should not be an issue for me using round head screw.

here is my subwoofer M6 screw where it's hard foam is also not rounded. only silver screw available on this gauge, smaller gauge can be found in black.

i even never had a thought to make it an issue to be solved, life is already complicated
 

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OCD on a diyAudio thread? Never happens, not even once- ROFL!

That is a sweet box, I assume those are dual PRs? Gonna need some ghost bolts for those puppies ;)


I decide to go with a longer shank steel version and had the first end mill casualty. Hopefully the last as I'm running low on the good ones. Also managed to get the side two fixture made, so hopefully I can get a set completed today.
 

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I went that route because of convenience. It would take more fixture work to start out with a round bar that is the approximate head diameter.

To really mass produce I suppose forging in the same way as regular bolts would be the most productive. Next best might be some version of spot welding, as you mentioned.

The main issue is with making the head because curvature is in three dimensions, so to be true to the frame lines you can't just come in from one direction and do a quick seeping profile cut. For this reason the material waste is less of an issue because the real expense is contouring the head surface due to far longer cycle times.

Ultimate would probably some flavor of metal injection molding.

If I personally had to make a ton of these, I would probably mill out the head circumference from round bar. Next place them on a jig in the shape of the driver frame (as many as will fit in that diameter), and turn them all to profile on a lathe in one quick shot. Finally attach threaded studs by welding, brazing, friction stir, or whatever.
 
I set a goal to get this made by tomorrow. I milled the tops but ran into an alignment problem where the shank was offset from the head.

Because I knew this was a possible issue I didn't bother with adding the "INKY" ghost face details. However, while deciding on a better fabrication method, a really crazy idea struck me that is much more interesting to pursue. So for know I'm going to consider this goal met on a technicality and table it for a later day.

At the very least I did clean up one profiled head and flame treat it to a nice light black color. So here is how that turned out....
 

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