Re: 795, 895 (etc) DC motors
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Hi Carl, I only used the 4 flute because Keith stated he used that.? The calculator is Machinist Toolbox.
? It tends to go for the absolute maximum surface speed which then generates a huge spindle RPM.? On my CNC mill I¡¯m limited to 3000 so I just cut back the surface speed until the RPM matches what I want to run the mill at. One of the nice parts is the depth of cut and axial cut. ? For example I¡¯m about to profile and cut this piece on my mill.? 
? I don¡¯t have the travel so I also have to flip it with alignment pins but since it¡¯s CNC doing the cutting I¡¯m never sure what depth per pass.? Hopefully this will work out and I¡¯ll start with half the feed rate and mist cooling. ? 
? ? ? John ?
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From: Carl [mailto:carl.blum@...]
Sent: September 2, 2024 4:54 AM
To: [email protected]; johnd@...
Subject: Re: [Unimat] 795, 895 (etc) DC motors? Hi Keith and John: In your chart I noticed you call for a four flute cutter. In my experience four flute cutters tend to pick up aluminum chips and weld them to the cutter, often with spray coolant. Cool calculator! Carl. On 9/2/2024 1:42 AM, John Dammeyer wrote: Hi Keith, You¡¯re good on the depth of cut at the max based on Machinist tool box.? ??I reduced the Surface speed down to 155 SFM to get the 5000 RPM you were using.? The max depth of cut is 0.04724¡± which is 1.2mm. ? I chose 6061-T6 as the generic aluminum scrap pieces.? Clearly you could go much faster than what you are doing but then the machine itself factors into that. John ? 
? ? On Sun, Sep 1, 2024 at 10:14 PM, John Dammeyer wrote: What¡¯s a normal cutting rate at 5000 RPM with a 3mm 4 flute cutter?? What depth of cut per pass?
I was only doing about 100 mm per minute, I would guess, and taking out about 1 mm. I also had 3 and 2 flute cutters, in case the metal tended to clog the 4 flute, but I've never used them. The whole machine is not so rigid that you can take heavy cuts, but I was cutting grooves with a 90¡ã pointed burr. That's fun at the point where the teeth are extremely fine and the cutting speed is low. I filled the groove with screen wash and it stopped it getting clogged. I was mainly machining anonymous chunks of aluminium. Apart from that I was setting it up as a precision saw using the cut-off discs from their little bench saw, chopping up small stainless tube, and other jobs like that. Some worked well on my SL, others on the mill. I even managed a few reasonably high precision operations on my big (compared to my other tool) pillar drill.
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