Using Thicker End Mills

Thin end mills let you cut very small features (think slots) and waste less material when doing coarse cuts.  The downside is that they are weaker by i think the square of the change in diameter.  

I was cutting circles with 1/8" carbide end mills.  If you get the feed rate too high--snap and there it goes.  The 1/4" end mill seems pretty darn solid at every feed rate.

A while back, I bought some 3/16" end mills when I was still planning to cut my own setting circles.  (Before I discovered a website that lets you create them, download, and print them.)  The great difficulty was finding an endmill holder for the Sherline that holds 3/16" end mills.  Sherline sells one that is supposed to do so.  I ordered one from a retailer of their end mill holders and it was clear too big.  In retrospect, I wonder if that particular one was defective.   It makes no sense to make a holders that precludes centering the endmill right in the center.

In the meantime, I realized that while not quite as perfect from a runout standpoint, I can use a 3/16" endmill in a drill chuck also.  Even if less than perfect, it is probably good enough for my purpose.