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Monten Pierre
09-21-2013, 12:01 PM
Hello,

can somebody help me,
i would engraving in a piece of brass a word in an oval, deep 0.3 mm.
Engraver bit is 60 and the tip is 0.2 mm.
How mutch deep every pass? How mutch every contour? What feed rate?

Many thanks.
Pierre

P.s.: sorry for the bad English langugage.

Mark Sipes
09-21-2013, 4:30 PM
by my conversion the tip is .007" (.2mm) or so and the brass is .012" (.3mm) thick I would take at least three passes. The first is an attempt to make sure the table and material are flat. the center oval will need to be taped down so it does not move or you will break your cutter/ruin the brass edge. place the brass on a sacrafice piece of plastic so you can cut through the metal and into the plastic. .005" (.1mm) per pass at full revolutions 15-20,000 rpm and .5" per sec (11-13mm) should be a good start point.

Monten Pierre
09-22-2013, 5:50 AM
Hello Mark,
thank you for your useful reply, i give it a try tommorow.

Pierre

Rodne Gold
09-22-2013, 6:19 AM
Rule of thumb is the max cut you can take is 1/2 the diameter of the cutter- in this case the tip. So as mark says you can take a 0.1mm cut per pass

For lettering , the rule of thumb is that the cutter tip needs to be 1/7th or less of the height of the letter
so your 0.2mm tip (which I think is way too fine) would be good for a 1.5mm letter or a little bigger - is the engraving so small?
If it's not , consider using a thicker tip as it will be less prone to breaking and you can do less passes

If it is engravers brass - you can do it without any lubricant. If not use a cutting lubricant to avoid burring , the problem with soft brass is that it clogs cutters , so if you have a cutter grinder grind the cutter with more back clearance for brass.