Newbie question on milling speed

Aris

Aris

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Hi all, with my limited experience on my lathe, I now want to expand into milling where I know nothing. After ruining a HSS end mill cutter, I just bought a 50mm Face End Mill Cutter with 4 carbide inserts and tried milling the bottom face of my AXA holder that sits too high on my toolpost. My initial results are no good, so after some googling I realize there are RPM, feeding and other parameters that need to be correct. I also found some 'formulas' but I cant can't make anything from them
Can someone please suggest the correct RPM and other parameters?
Thanks ahead for any help!
 
What size and type of mill do you have, and what is holding the work? What do you mean by "My initial results are no good"? What spindle speed were you using, and what depth of cut?
 
Do you have a milling machine or are you doing this operation on your lathe?
MS
 
Bob Korves said:
What size and type of mill do you have, and what is holding the work? What do you mean by "My initial results are no good"? What spindle speed were you using, and what depth of cut?
Click to expand...
Hi Bob, thanks so much for your immediate reply!
I will try to answer, even though being Greek, I'm not familiar with the terminology of the lathe and mill components, please excuse and correct any mistakes.
I have the Austrian classic Maximat Standard MQ3100 made by EMCO that I bought and have used the lathe for restoring classic cars. It is a combination lathe/mill (sorry I'm not allowed to attach pics yet) and both the lathe the mill take an MT2 shank and it can use a Draw Bar to hold the tools.
To mill the toolpost holder, I initially tried an End Mill, made of HSS, that has an MT2 sahnk, so I put it straight into the mill, and tried RPM's up to 520. It was jumping all over and I did manage to shave off about 1 millimeter after 3-4 passes, but the End Mill was very worn round at the edges. As to the Depth of cut I was trying each time to lower the mill by about 1/2 millimeter or maybe less, and as far as 'horizontal speed movement' I went very slow (here I have no idea of how to measure this....)
I guessed that the HSS end mill was too soft for the hard metal the holder ids made off, so I went ahead and bought the 50 mm Face Mill Cutter with the carbide inserts that I tried again up to 520 RPM and about the same 'Depth of Cut' and Horizontal movement. Even though I have the draw bar tight, all available tightening screws set to very tight, there is still jumping around.
Frankly I'm so newbie in milling that I cant describe how bad the results are, I only know that I'm WAY far from all the wonderful youtube milling videos I see!
Hope all this is not Greek to you!
 
Aris said:
Hi Bob, thanks so much for your immediate reply!
I will try to answer, even though being Greek, I'm not familiar with the terminology of the lathe and mill components, please excuse and correct any mistakes.
I have the Austrian classic Maximat Standard MQ3100 made by EMCO that I bought and have used the lathe for restoring classic cars. It is a combination lathe/mill (sorry I'm not allowed to attach pics yet) and both the lathe the mill take an MT2 shank and it can use a Draw Bar to hold the tools.
To mill the toolpost holder, I initially tried an End Mill, made of HSS, that has an MT2 sahnk, so I put it straight into the mill, and tried RPM's up to 520. It was jumping all over and I did manage to shave off about 1 millimeter after 3-4 passes, but the End Mill was very worn round at the edges. As to the Depth of cut I was trying each time to lower the mill by about 1/2 millimeter or maybe less, and as far as 'horizontal speed movement' I went very slow (here I have no idea of how to measure this....)
I guessed that the HSS end mill was too soft for the hard metal the holder ids made off, so I went ahead and bought the 50 mm Face Mill Cutter with the carbide inserts that I tried again up to 520 RPM and about the same 'Depth of Cut' and Horizontal movement. Even though I have the draw bar tight, all available tightening screws set to very tight, there is still jumping around.
Frankly I'm so newbie in milling that I cant describe how bad the results are, I only know that I'm WAY far from all the wonderful youtube milling videos I see!
Hope all this is not Greek to you!
Click to expand...
If the mill is jumping around, then it is not rigid enough for the cuts you are trying to make. Try shallower cuts, and it might help to take two of the inserts out of the face mill. Aris, your English is excellent, Greek is all Greek to me... ;)
 
I think you are running the spindle at too high a speed. On my mill, the lowest speed is 50 RPM and then it jumps up to 90 RPM. When I first read your post I thought that 520 rpm was too fast. I would first see how the mill cuts at 50 or 60 RPM and then go up to 90-100 RPM.
I agree with Bob, your combination Lathe/Mill is not rigid enough to run the mill cutter at the speed selected.
There are speed and feed calculators available on-line that are setup in metric.
 
Thank you all! Daft me I thought the higher the speed the better but it is the other way around ...... thanks also for the on-line calculator, the only thing I dont get is the SFM, surface speed per minute. How can this be applied on my lathe
 
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