I have no idea what you guys are talking about.
1. Stumac still sells everything you need
http://www.stewmac.com/shop/Fretting_suppl...Press_Caul.html
Separate inserts
http://www.stewmac.com/shop/Fretting_suppl...=1&xsr=4365
that full size insert kit for others who need everything
http://www.cncguitarparts.com/index.php?cPath=46
they also sell the Arbor Pres system still...So I am lost
I guess a separate Arbor Press would be cheaper but I understand you need to drill out the hole to fit the caul shaft. I think; I am not 100% positive as I bough the whole system to save on shipping costs since I did not have a HF where I lived at the time.
OK now that that is done. The Caul must pivot..No its not a feature it is a requirement.. If your neck is slightly cocked (I mean slightly) to one side the fret will not press in fully. The pivot point removes this risk and aligns the insert flush with the wire. As long as you align the center of the caul with the center of the neck it works well. There is no jig that I have or have seen that keeps the neck perfectly square to the arbor press caul, things move around. A fender style neck with a long support would work the best, but imagine trying to support an angled HS that is off to one side. In that case you are relying on the back of the neck. For anyone who does multiple designs there is no one solution. even the concave caul I use allows the neck to rotate.. remember you must support the neck under the caul or you risk snapping the neck..
Another feature of the SM Arbor press system is the Caul also rotates 360 deg. Look for the ring on the shaft. This allows a setscrew to hold the shaft so it does not drop out but can still rotate. Again feeding the neck through the arbor press it may not be straight lengthwise. So again the caul can rotate to meet the fret crown rather than you having to adjust the neck.
If you are gluing in your frets you have a limited amount of time to put on the glue align the fret tang in the slot and press in the fret. all of these features help align the insert and apply even pressure quickly.
If you haven't pressed in frets with this system then its simplicity and function may be lost on you
Making the Caul is the easy part. A rod of metal a block of aluminum and a table saw is all you need..OK a drill a tap and a few set screws and a pin to hold the rod.. Not really rocket science.
The inserts are another story. for the price its not worth making your own, even though some have done so (Saopbar?).