Sienci Labs
LongMill MK2.5 Feeds & Speeds Calculator
Starting feeds and speeds for the Sienci Labs LongMill MK2.5, with the numbers already adjusted for its spindle range and frame. Grab a starting point from the chart, then open the live calculator to watch the cut and fine-tune it for your exact bit.
Open the live calculator for the LongMill MK2.5Dialing in the LongMill MK2.5
Two things set the numbers on the LongMill MK2.5: how fast the Makita RT0701C spins, and how much the frame can take without chattering. It runs a working range of about 10,000 to 30,000 RPM, on acme lead screws (anti-backlash nuts). The LongMill MK2.5 has a solid frame for its class, so the depths below sit in a comfortable middle ground.
So for a 1/4" two-flute bit in softwood, a sensible starting point on the LongMill MK2.5 is around 17,000 RPM and 102 inches per minute, taking about 0.09375" per pass on a slot. The full chart below covers the materials you are most likely to cut. These are conservative starting points: always test on scrap and let your ears do the final tuning.
LongMill MK2.5 starting feeds and speeds
Two-flute bit, slotting cut (the toughest case for clearing chips). Feed in inches per minute, depth per pass in inches.
| Material | Bit | Spindle RPM | Feed rate | Depth / pass |
|---|---|---|---|---|
| Softwood | 1/8" | 25,000 | 100 ipm | 0.047" |
| 1/4" | 17,000 | 102 ipm | 0.094" | |
| Hardwood | 1/8" | 30,000 | 90 ipm | 0.023" |
| 1/4" | 20,000 | 100 ipm | 0.047" | |
| Plywood / MDF | 1/8" | 25,000 | 100 ipm | 0.047" |
| 1/4" | 17,000 | 102 ipm | 0.094" | |
| Acrylic | 1/8" | 25,000 | 100 ipm | 0.035" |
| 1/4" | 13,000 | 104 ipm | 0.070" | |
| HDPE / Plastics | 1/8" | 17,000 | 102 ipm | 0.035" |
| 1/4" | 10,000 | 100 ipm | 0.070" | |
| Aluminum | 1/8" | 30,000 | 60 ipm | 0.012" |
| 1/4" | 25,000 | 100 ipm | 0.023" |
Numbers are generated by our feeds and speeds calculator using the LongMill MK2.5's spindle range and a solid-frame rigidity factor. Aluminum needs a single flute plus lubricant. Always confirm your bit maker's chart and test on scrap.
Want to see it cut?
Open the interactive calculator loaded with the LongMill MK2.5. Change your bit and material, watch the cut run live, and hear the difference between a dialed-in cut and a bad one.
Open the LongMill MK2.5 calculatorLongMill MK2.5 feeds and speeds FAQ
What RPM should I run on a LongMill MK2.5?
For most wood with a 1/4" two-flute bit, 17,000 RPM is a good starting point on the LongMill MK2.5. Its working range is about 10,000 to 30,000 RPM. Go higher for smaller bits and finer detail, lower for big bits and heavy stock removal.
What feed rate should I use on a LongMill MK2.5 in hardwood?
Start around 100 inches per minute with a 1/4" two-flute bit in oak or maple on the LongMill MK2.5, at roughly 20,000 RPM. Listen to the cut and adjust: clean chips mean you are dialed in, fine dust means you are going too slow.
Can a LongMill MK2.5 cut aluminum?
Aluminum is a stretch for the LongMill MK2.5. Its frame is on the lighter side, so if you try it, use a single-flute bit, very shallow passes, lots of lubricant, and low expectations. It is happiest in wood and plastics.
LongMill MK2.5 full review
Specs, price, and what owners actually say.
CNC chip load chart
Feed-per-tooth for every bit and material.
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