View Full Version : Speeds and Feeds

08-04-2003, 03:10 PM
I'm a newbie (working in a shop, but not an apprentice yet) and am wondering if there is either a website, or a handbook that has all the speeds and feeds for milling, drilling, late turning etc, for all the different kinds of metals.

I know the basic forumula is CSx4/diameter of cutter, but would like a chart especially for drilling (well for all of them really).

Also does the rpm and feed depend on the size of cut your taking? (ie a .080 cut vs a .010 cut)

Any websites or books to reccomend would be helpful. Thanks!

G.A. Ewen
08-04-2003, 03:43 PM
Hi there, try "shopswarf" on your search engine.

08-04-2003, 05:27 PM

Here is the link to shopswarf.


08-05-2003, 05:55 PM
Cutting rates depend on the material and its brinell hardness as a rule. Harder, tougher materials will require slower cutting speeds (SFM - surface feet/minute)

Then you have:
DOC (Depth of cut)

Feedrate (normalliy inches per minute or ipm)

MRR (metal removal rate - normally in cubic inches per minute)

FPT (feed per tooth - in the home shop this is usually in the .ooo5-.oo6" range per tooth)

WOC (width of cut)

HP factor (normally the machinability rating of the material i.e, 12L14 = 1.0, Alunimum = 3.0)

To determine the amout of horsepower required you use MRR /HP factor = HP required

All of these are used to determine the optimum initial settings - although they frequently require "tweeking" under actual cutting conditions as edge condition of the tool must also be considered.

Another point to mention is that carbide tooling can/should be run about 4 times faster than you would use HSS cutting edges in general. Carbide works best when pushed as hard as possible and run dry (no coolant).

These formulae are in both "Machineries Handbook" and Modern Machine Shops "Handbook for the Metal Working Industries" and should be in any basic metal working book somewhere.

C. Tate
08-05-2003, 11:10 PM
Ditto Thrud. You can also get the data from the manufacturer of the cutting tool. Valenite for example gives away a handbook with all of the info you are looking for and it is small enough to fit in toolbox. If you can go to trade shows the reps are glad to help and give away tons of freebies.

08-06-2003, 10:24 PM
A couple other units of measurement for feed is IPR or inches per revolution and CL or chip load. CL is about the same as FPT. Thrud, you make a good point about these settings being starting points. There are so many factors that "horn in" when machining. Length of part vs. diameter of part. Spindle rigidity. Tool post/tool holder rigidity. And it goes on an on. I sometimes think that average annual rainfall in the back yard can influence feeds and speeds.

08-06-2003, 11:24 PM
I used 500 rpm as a rule of thumb for a 1/2"HSS drill in steel,when I started learning the trade,switch to a 1"drill and cut that in half,250 rpm,1/4"drill the other way,1,000.If in cast iron add about fifty rpm to each of those,aluminum double.
But these are just approximate,speeds and feeds will change with the wind,but so will you,It will take sometime but you will develop a "feel" for it.
Like said before lots of variables,tool grind is yet another,I find that some days everything cuts like s---,and then the next smooth as butter,stainless can be an evil b---- godess,and some days glide right through,all in all you basically just have to develop a sixth sense,its like eating food,until you taste it all you won't know what it should taste like http://bbs.homeshopmachinist.net//biggrin.gif