Small mill - reasonable expectations in steel?

You are right. That will teach me to respond while I'm elbow deep inside my espresso machine. So, rpm would be about 900 for a 1/2" end mill taking a 1/4" depth of axial cut.
 
I go lots slower and as it keeps the heat low.

If using carbide we go fast but sometimes we just toss in a HSS bit for something where the Cardiff will not fit and just go show and easy and the cut comes out fine and tool stays sharp.

Oil helps but a mister keeps chips clear.

You can try different speeds and vary your pressure to control how much material.

If auto feed then start slow and pay attention.

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Wow! Great input. thanks to all for taking the time to teach.

I misspoke in regards to the number of flutes, it was a 4 flute.
I was using an R8 mill holder. Everything was snugged up.

After posting I went back and checked on the gibs and they felt snug and the backlash on the X and Y felt reasonable.
So I pulled the mill and ran it across a stone and touched up the cutting edges. I remounted it and then tried it again on a different piece I was working on. It seems to cut better so I can't say what helped. DOC was more like 0.020" and it didn't feel like I was about the snap the end mill off.

The roughing end mill will be something I pick up very soon and I will go to a smaller size, probably 3/8".
I'll also slow the RPM down too.

thank you all.
 
If you pick up a rougher, go for the fine pitch for outside work. In general, a rougher will allow about 20% more speed and feed rate. I would also cut conventionally; your mill is probably not rigid enough to make climb cuts beyond a few thou.
 
As other have mentioned keep all gibs locked except the axis you are using. Make sure the quill is fully retracted. You are probably better off using a collet directly to hold the end mill to minimize the stick-out.

From looking at a picture of that machine the saddle is rather small so gib alignment is probably more critical. Check gibs for flatness and try bluing to see what the contact pattern is. It can be pretty rough from the factory. I spent a number of hours tuning the gibs on my machine, makes for a better experience.
 
I have the same mill and can take much deeper cuts than that. I do use solid carbide roughers and they work fantastic. One question, are you climb milling or conventional? That would make a big difference.
 
From a rigidity standpoint, I have a CNC G0704 that has taken cuts in steel far exceeding that. Here was the cutting data from a recent cut I did.

GARR Series VHM Endmill EDP# 49520
1/4x2" VHM HOG MILL *AlTiN

327 SFM (5000 rpm), 24 ipm, Total depth of 0.25" taken in (2) 0.125" passes. 0.83 motor HP required for cut, MMR = 0.75 in^3/m. Tool Stickout 0.38"

Talking less numbers, I've taken a 3/8" HSS roughing endmill through cast iron at full slot, 1" depth in 1 pass. The machine has the power and a moderate amount of rigidity, but you should have the gibs tight, the head locked, collet tight, endmill stick-out very short, vise tight, etc.
 
Also, that looks like run of the mill CRS, however if you accidentally got a really tough grade of steel, that could account for your issues.
 
Lots of good suggestions in this thread but no one seems to have asked how you are holding the work. Do you have a decent milling vise? Rigid and well-secured?

Craig
 
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