QUOTE(sam sam @ Jul 30 2012, 05:26 PM)
carbide is mainly for stainless steel this are slightly yellowish
bench drill just buy HSS they are meant to drill normal steel, make sure you buy the branded stuff which cheaper than the cheap hardware store stuff from china
If you buy from a screw shop or a proper machine shop then the bits are important stuff from NZ or UK, or even germany
a evacut brand new HSS drill takes 30 seconds to drill m4 hole on a 1.5mm Stainless steel. and about 2 minutes on a blunt bit to cut thru 1.5mm stainless steel.
most people are not aware that you are not suppose to use high rpm while drilling. RPM for most drill just set around 800rpm as its the most versatile for small bit. Too fast it would blunt the drill bit, there is a chart you can follow. As the bit diameter increases you are suppose to drill at a lower speed. High speed above 1000rpm is meant for small size like m2 and m1 where the speed dictates the acuracy
but what I learned are really different ...
HSS mostly can be used but they broke easily and would need to resharpen most of the time. We mostly use them since they are darn cheap
Carbide are much more stronger but yeah they cant handle impact but since I'm using a table drill ...less impact + high rpm does help cut aluminium faster ...
what make me weird is that I cut through 1.2mm 6061 T-6 in a matter of second ... I didn't bother counting ..m3 hole
I rechecked in case I'm wrong ...I found this
http://store.curiousinventor.com/guides/drill_speed/ suggested that 2000 rpm would be a good range to cut aluminium
QUOTE(shuhong90 @ Jul 30 2012, 05:29 PM)
LOL you guys. . . so much for a "drill" nevertheless your knowledges are very valuable to me who are really newbie when it comes to tooling =)
It good to learn something