Drilling Cast Iron - Tormach CNC

Tormach on the web @ http://www.tormach.com

Overview:
This video reviews carbide spot drilling and HSS drilling in cast iron.

Material: 1.5" cast iron
Cutters: Carbide Spot Drill, HSS End Mill
Speed: 1000 RPM, 900 RPM
Feed: 1.7 IPM, 2 IPM
Machine: Tormach PCNC 1100

Background:
Traditional twist drill bits may tend to wander when started on an unprepared surface. Once a bit wanders offcourse it is difficult to bring it back on center. A technique called spot drilling, in which the center of a hole is started, frequently provides a starting point for the traditional twist drill.

Fixtures & Tooling:
The tool used in the first part of the movie was an insert carbide spot drill. In this case, we decided to use a spot drill to insure that the second tool we use does not wander off the drill mark. We used drill cycle G73 with a feed rate of 1.7 inches per minute.

The tool used in the second part of the movie was a traditional high speed drill bit with titanium coating(letter drill B). It was run at the slow speed of 56 surface feet per minute. This allows the bit to remain cool and last longer. We used drill cycle G73 with a feed rate of 2 inches per minute.

Cutting Process & Results:
Cast iron is a very easy material to cut, but it creates a lot of dust. It is important to have a vacuum handy to clean up the dust during the cutting process.
http://www.tormach.com/MfgDatabase/AN20110_DrillingCastIron.pdf


Key Words:
cast iron, spot drilling, HSS end mill, carbide spot drill, machining, milling techniques, CNC, Tormach

Category:

Science & Technology

Tags:

• Tormach
• CNC
• milling
• techniques
• cast
• iron
• spot
• drilling
• HSS
• end
• mill
• carbide
• drill
• machining

[kyle1058]

slow machining in my opinion.. very slow... why not throw in a solid carbide drill bit, use coolant, and run it FAST with no peck?

[2jzgtejza80]

@liaschinko

Listen the video again.

[soundspark]

@TheMathedis Also cast iron is often machined dry because it is porous and can easily absorb contaminents like oil or coolant. Also, the fine dusty chips can turn to a nasty sludge that clogs up your coolant system.

[TheMathedis]

@bestamerica some tools require different coolants and some tools don't even need coolants

[wa1523]

@bestamerica for the first drilling it's useless because it's tungstene , but for the HSS I would use some...

[bestamerica]

'

how come not use a cool oil mix with water on the drill

[RUSSSELLLLL]

I used to turn CA on an 84" VTL.. The sound brings back memories lol. Many long nights. Would it be faster drilling if you had coolant? we used coolant for the turning process of course. Nice video!

[liaschinko]

@SupermaxCNC

how you know that is Cast iron ?

[liaschinko]

it is foundry iron ?

[kuei1248]

Do you know what a "drill bit" is? A drill bit is a broken drill. But don't worry. At those feeds and speeds you will never end up with drill bits. BTW...why would anyone use a tin coated drill on cast iron? And why peck on a spot cycle?

[rick371]

sesh slow....unless u slowed the rapids down, and why not tap at same time...also useing a smaller stub drill at that size you do not need to centre drill...i could do this whole process and tap in 3 mins