Speed and feeds from the supplier

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So, as I’ve mentioned elsewhere, I bought a couple of these, contacted the supplier to ask about speeds and feeds, and had a bit of a shock.

They’ve told me the following (which doesn’t relate in any way to the information provided for similar sized bits from the Carbide3D range and settings):

Tool diameter: 0.25"
Depth of Cut: 0.125"
Speed @ 18,000rpm

Hardwood: Feed rate @ 4000ipm, plunge rate @ 2000ipm,
Softwood: Feed rate @ 5000ipm, plunge rate @ 2500ipm
Plywood: Feed rate @ 6000ipm, plunge rate @ 3000ipm

Do the feed rates, and especially the plunge rates, seem a bit high?

Thank you

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You sure that it’s IPM rather than mm/min?

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Crap, of course they are!

Thanks @gmack, I’m pleased you passed the ‘deliberate mistake’ assessment :rofl:

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Oh, I was looking forward to the video of those feeding at 6000 IPM :wink:

I’ve used quite a few of the Rennie cutters, they’re pretty good in wood. I started from the standard Winston Moy Fusion 360 / Material Monday feeds and speeds for the Carbide 201 cutter and pushed from there using feed override in Carbide Motion to see what the machine / workpiece / finish quality would take.

It’s mostly going to depend on the width of cut you are taking as the Shapeoko is machine rigidity limited not cutter or power limited.

Did they give you an RPM for these cutters? (I just assumed 24k RPM was fine and went ahead with that)

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Sorry to let you down :rofl:

I asked for RPM and they said 18,000 would be fine (probably as these are a bit longer than normal?

I really only got them to hollow out box interiors as a precut, before smoothing them out, as straight end mills don’t seem to be ‘in vogue’. They’ll probably be OK for cutting out, too, I suppose?

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Ah right, 62mm flute, a bit long and wobbly, I have the 70mm upcut helix version and use it only when I have to and, yes, at lower RPM.

My suggestion, assuming you’re cutting wood, would be to keep the RPM up at 18k, keep the cutting feed speeds reasonably high 800mm/min or higher and then slowly increase the Depth of Cut until the noise and fear tell you enough is enough. You definitely don’t want these long cutters jamming up with chips in the cut so keeping them moving quickly to avoid re-cutting or heating on the long contact areas is generally a good move. I’ve not run my XXL much over 2,000mm/min cutting wood so I can’t really say much about those warp speeds but considering I normally see 5,000mm/min as a rapid let’s consider those as aspirational for us without industrial machines…

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