Re: Machining

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "June Heidlebaugh" <rheidlebaugh-at-desertgate-dot-com> 

Gerry:  high speed steel drills are cheep and easy to sharpen. Carbide are
the best most expensive and hard to sharpen. Cobalt are in-between. The
coated cut well and can not be sharpened so your investment is lost as a
throw - away item.
    Robert   H
----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Wednesday, April 21, 2004 7:52 AM
Subject: Re: Machining


 > Original poster: "Gerry Reynolds" <gerryreynolds-at-earthlink-dot-net>
 >
 >
 > Hi All,
 >
 > So far in this thread, I've heard of four types of drill bits:
 >
 > 1. High speed steel
 > 2. Carbide
 > 3. Titanium Nitride
 > 4. Colbalt
 >
 > Could someone rank these as to hardness and cost and comment on
application.
 > Also, are there other bits to consider (not counting wood applications)?
 >
 > Gerry R
 >
 >