[hscess]

I am extending the y axis on my G0704. I started out trying to cut the base with a HSS tin coated end mill at approx. 400 rpm. It didn't cut hardly anything and dulled quickly, so I tried M42 cobalt and it dulled easily as well. What end mill do I need for this job? Maybe coated carbide. Any input will greatly be appreciated.

[Fastest1]

I had no issues cutting the cast iron. Besides the dust it machined easily for me. Sorry

[109jb]

I used a 1/2" plain 4 flute HSS rougher at about 650 rpm and 5 IPM with no problem.

[GreatNorthGnome]

Lucky! You must have gotten one of those special edition "harden" bases lol. Its been a few years now so I can't remember what tools I used, but mine cut like butter. Carbide should cut through that no problem, could also try a roughing HSS em as well if you can find one.

[KriegKuts]

generally, once you break the skin, the underside layer is pretty easy to machine. With that being said, i machined it on my woodrouter... 4" extended reach endmill spinning at 8k rpm.. Lets just say I wont be using that endmill for anything. Ever.

[arizonavideo]

Did you use oil?

It really need to be dry cut. Cuts like butter.

[hscess]

After trashing the first HSS 3/4" roughing end mill dry, i went to a 1/2" M42 with WD40 and it didnt last either. I am going to buy an American made 3/4" coated carbide end mill Saturday. I hope this does it. I cut all kinds of steels with M42 and last a while. This cast iron is really tough. Maybe its the over seas end mills.

[109jb]

The 1/2" rougher I used I bought from Shars, so I'm sure it was imported. It was not coated, just plain HSS, and I machined it dry.

Are you feeding too slow? If you feed too slow in cast iron and let it rub, it will destroy just about any tool. Feeding too slow can be just as bad or worse than feeding too fast

[lcvette]

I agree with 109jb, to slow will burn tooling up from rubbing rather than cutting, if it's getting hot (changing color) feed it faster, also try a deeper cut if side milling, thin cuts can also heat the tooling by not having enough material to carry heat away.

Chris

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[lcvette]

After trashing the first HSS 3/4" roughing end mill dry, i went to a 1/2" M42 with WD40 and it didnt last either. I am going to buy an American made 3/4" coated carbide end mill Saturday. I hope this does it. I cut all kinds of steels with M42 and last a while. This cast iron is really tough. Maybe its the over seas end mills.

Did you have any success? I just did some machining on my lathe saddle for my conversion, I had to drill (0.159") and thread mill (10-32) holes for ball nut mounting.. I researched write a bit and the tool manufacturers recommendations scared the hell out of me.. for drilling they gave a 5000rpm spindle speed with a 10ipm z axis feed rate with a drill cycle. I was hesitant because I don't even drill aluminum like that.. But ultimately I said screw it and let her rip..I was amazed at how well it cut, zero issues and I had chips and not preferred meds being rejected from the hole. Drill bit didn't even show wear on the coating and was cool to the touch directly after.

For that milling they wanted 5000rpm and 30ipm.. With a tiny 10-32 multi point thread mill.. again I was nervous but since drilling went so smooth I again the caution to the wind and let her eat.. went splendidly!! No wear on the tool, dark coating still still remained and the threads looked fantastic albeit I oversized them to much but that was in the major diameter can programming not the cutting.. I am not sure what I was thinking but I had the major diameter set to .200 and it should have being maybe 0.191- 0.192"

I have to do some endmill work next and will be running it high and fast as well, the rubbing on cast iron build alot of heat and acts like gritty sandy compound that does the cutting edges, better to go fast I think unless the casting is scheduled garbage and filled with crap that shouldn't be in there. I feared that being I was machining a harbor freight 3 in 1 machine casting and it looked like crap, but it cut awesome. Just really messy. Next time I will didn't time covering everything to make clean up much simpler.

Here is a video of the thread milling, didn't get the drilling as I was to nervous and didn't want the camera as a distraction in case I needed to Tracy but after it did so well I set it up to capture the thread milling.. I made the threads in 3 cut depths as I've never done cat iron machining and didn't want to break a $100 tool, but I might try it in two next time especially since I don't need to cut the extra .010" I did on these.

You will notice a lone deep chamfer from a tool issue I had ( forgot I had replaced the tool and didn't enter the new tool length offset.. whoops..lol

I may drill the ball nut holes to accept 1/4-28 fasteners and re drill and thread so the fasteners aren't as lose as they are, friends how ambitious I get as these tighten down fine still..

Video below:

https://youtu.be/JQJxcF8mjlc

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