Tools of the Trade III - Double Edged Knife

Traditional Izmel - double-edged knife

Modern Innovation - the Double-Edged Scalpel

Tehillim (Psalms 149)

6Lofty praises of God in their throats and a double-edged sword in their hands,

ורוֹמְמוֹת אֵל בִּגְרוֹנָם וְחֶרֶב פִּיפִיּוֹת בְּיָדָם

What are we supposed to use to excise the foreskin?

שולחן ערוך יורה דעה הלכות מילה סימן רסד: סעיף ב

בכל מלין, ואפילו בצור ובזכוכית ובכל דבר הכורת, חוץ מבקרומית של קנה, לפי שקסמים נתזים ממנו ויבא לידי כרות שפכה. יז] ומצוה מן המובחר למול בברזל, בין בסכין בין במספרים, ונהגו למול בסכין. 

The Shulchan Arukh YD 264:2 says: We circumcise with anything: even a stone, glass, or anything that cuts. Except for a reed, because it has splinters with may cause damage [to an important tube]. It is an enhanced form of the mitzvah to do the circumcision with steel - whether with a knife or with scissors. But the custom is to use a knife. 

The Midrash attaches the above verse from Tehillim to the concept of Bris Milah, suggesting that the knife that should be used should be like a double edged sword. 

The problem with the more "traditional" knife is that it needs to be sharpened, and then sterilized. But the sterilization then makes the knife less sharp. So one is faced with the Catch-22 of wanting the knife to be as sharp as possible, and also wanting it to be sterile and still sharp.

As a result, the double edged scalpel was created in recent years, to maintain the Midrashic custom of a double edged sword, while at the same time allowing for a scalpel that is for one time use, that is sharpened in the best way (with a laser?) and sterilized. 

Many mohels (including I) use a single-edged and single-use scalpel blade because it removes the need to sharpen or sterilize (scalpel blades come that way) and it allows for the swiftest (and hopefully least painful) circumcision. I have seen mohels use a back-and-forth motion (shudder!) while really all that is needed is a smoothe incision.

Could I look into getting the double-edged scalpel? I suppose. But it's not necessary. At most it is a (likely kabbalistic) stringency. The main mitzvah is to have the foreskin removed.

[I've joked in the past that the need to have a double-edged scalpel is good for the mohel who can't otherwise see, and is not sure which side is the sharp one. Of course if the mohel can't see....]