▪ The ‘titura’ (larger square which is the base of the ‘bayis’) may be made of a separate piece of leather than the main cube; however, it is desirable that it be of the same piece. (Ed: I think John Knowles wrote a book discussing this point! (Sorry!) Seriously, the way that one piece of leather is shaped and formed into so many different folds and with such straight edges and sharp corners, is truly remarkable!)
▪ The ‘ma’avarta’ (passageway for the strap) has the same rule as the ‘titura’ (see previous bullet).
▪ Before the ‘klafim’ (parchments) are inserted into the ‘batim’, they are wrapped in three layers: a piece of kosher-animal hair (yes, you read this correctly!), a blank piece of cloth or parchment, than another piece of hair.
▪ The ‘parshiyos’ (lit. sections, i.e. another way to refer to the ‘klafim’) are rolled from end to beginning, and inserted into the compartments standing straight up. The beginning edge of the ‘klaf’ should be closest to the front of the ‘bayis’, such that theoretically, if someone faced the tefillin-wearer and had x-ray vision, he would see the “opening” of the writing.
▪ A short piece of hair - customarily from a calf – is inserted through a hole in the ‘bayis shel rosh’, so that it sticks out just a bit. The hole is between the third and fourth compartments, and the hair points toward the first compartment. (Ed: I try to give you the what – not always successful with the why! I do know that this calf hair has something to do with reminding us of the Sin of the Golden Calf!)
▪ The ‘bayis shel rosh’ holds four different ‘klafim’, each with one ‘parsha’ written on it), while the ‘bayis shel yad’ holds one long ‘klaf’ with all four ‘parshiyos’ written on it. (Note: If a single ‘klaf’ was wanted to be used for the ‘shel rosh’, strings would have to be tied in between the ‘parshiyos’ to create a separation between them. Conversely, if four ‘klafim’ were wanted to be used for the ‘shel yad’, it is preferable that they be glued together first to form one continuous ‘klaf’.)