Machine Tool Speed Calculator & Machining  Notes 


I found this many years ago printed in Engineering In Miniature I have found it very useful and for beginners to model engineering a very welcome chart.

You just need you're  trusty 6 inch steel ruler or a like to find out what speed your lathe should run at, what speed your drill press should do to drill a hole, Or what speed the milling cutter should be doing on your miller.  If you click the top one, this is the chart you get in the PDF A4 printing. The chart below I have shown the example what is in the machining notes below for 3/4" brass

Machine Tool Speed Calculator& Machining Notes A4 printing    



Machining Notes

When using HSS tools, the correct machine speed is read on the centre scale when a straight line joins the points on other two scales. For example diameter brass requires a speed of 700 rpm.

When DRILLING Take the DIAMETER OF THE DRILL to determine the speed of the machine.

When TURNING take the DIAMETER OF THE TURNED SPIGOT to determine the speed of the lathe.

When MILLING  take the DIAMETER OF THE MILLING CUTTER to determine the spindle speed of the miller.

CARBIDE TIPPED CUTTING TOOLS only cut efficiently at high speeds. Increase the machine speed by 5 or times depending on the grade of tip and machining conditions- see below.

REDUCE THE SPEED of the machine when:

(a)  The depth of cut is large

(b) The work set up on the machine lacks rigidity

(c)  The machine or cutting tool lack rigidity

(d) Chatter occurs.

INCREASE THE SPEED slightly or light finishing cuts.

COUNTERSINKING should be done a low speed to achieve good results.

REAMING should be done at very low speed. Reduce the speed by 1/3 and use a cutting fluid.

KNURLING is a deforming operation rather than a cutting operation. A speed of 100 rpm should be found satisfactory. Cutting fluid is essential.