how do you calculate the rpm needed to drill a 14mm diam hole in a piece of bronze?
Hi there, my son is doing his homework from a marine engineering course and I am totally out of my depth trying help him!! Does anyone know how to do this?
- SGT. DLv 61 decade agoFavorite Answer
Get yourself a copy of the "Machinerys Handbook" at the library and it will tell you all about calculating Metal cutting speeds and feeds.
- pwwatson8888Lv 51 decade ago
There are formulae for RPM and FEED RATES
you need to calculate the feed rate which is high speed slow feed related so you don't break the drill bit.
Cutting speeds for various materials
(Based on a plain High Speed Steel cutter)
Material type meters per min feet per min
Steel (tough) 15 - 18 50 - 60
Mild steel 30-38 100-125
Cast iron (medium) 18-24 60-80
Bronzes 24-45 80-150
Brass (soft) 45-60 150-200
Aluminum 75-105 250-350Source(s): http://en.wikipedia.org/wiki/Cutting_speed