I know questions on bits, feed rates, plunge rates, etc. come up a lot. I thought it would be good to try to consolidate everyone’s information on the topic rather than everyone having to search through countless different message threads.
To consolidate everything, I put together a google spreadsheet that is auto-populated from a google form. The form is used to somewhat limit and standardize responses and help people make easier comparisons. To add to the spreadsheet, click “ADD BIT” and you’ll be taken to the form. After submitting the form, the information should appear on the spreadsheet.
Please feel free to add any bits and feed rates that you’ve used and comments on your experiences with them. Hopefully, with enough responses, we’ll have a useful resource that we all can benefit from.
I believe the rule of thumb for step down is no greater than the diameter of the bit. The spreadsheet currently includes “plunge rate”, while that’s not exactly the same, I think it’s closely related.
I believe the rule of thumb for step down is no greater than the diameter of
the bit. The spreadsheet currently includes “plunge rate”, while that’s not
exactly the same, I think it’s closely related.
I’ve seen recommendations running from 1/2 bit diameter to 2x bit diameter. It’s
going to depend on so many things (how hard the material is, how stiff the
machine is, how fast you are moving, etc). Bar tends to do lots of very shallow
cuts.
We haven’t had a lot of testing going on with this.
IMHO, the thing to do is to do some testing and move towards being as aggressive
as you can be, until you either snap the bit or see the cut getting distorted
(on the maslow, this probably involves the sled tilting, not staying flat
against the workpiece)
The first one, quarter inch at 78.74 - 18,200 - 15.75. I added a note too, that I like the single flute better, I think it sounds better for some reason
for all new cnc users, my 2cents on this topic as an amatuer, is always run a few test cuts because your workpeice material and bit sharpness may change each job. so test everything, small samples before you go all in. you end up tweeking every setting based on your observation in closed loop. your own notes on what works will give you confidence over time. you got this
You like single flute better? I’m running the Maslow two flute and love that the feed rate is 2x. Assuming a single flute job is takes twice the time that a double flute would, what makes it worth the extra time in your opinion?
You have a point here, maybe I need to crank the feed rate higher and then Ill like the double flute better. For this speed though, I think the sound was off, I was seeing more dust instead of chips and I thought the tear out was worse. Hard stuff to quantify though. Maybe the double deserves another look for me.
That makes sense, it is pretty fast. Need to fix my machine first but so far a fresh Maslow two flute has been making nice chips at the feed rate you recommended in that google doc.
You like single flute better? I’m running the Maslow two flute and love that
the feed rate is 2x. Assuming a single flute job is takes twice the time that
a double flute would, what makes it worth the extra time in your opinion?
In general, the feed rate of a maslow is at the low end of the acceptable range
if you do the formal chipload (feeds and speeds) calculation, going with a
single flute bit makes it easier for the maslow to be in the recommended range.
I have never had to slow down the feed rate (or increase the RPM) due to a bit
that was sharp needing me to do so. I’m always trying to push the rpm down or
the feed rate up to have the bit cutting better.
Now, on a smaller bit, the chipload per flute will have to be much less, so you
may then need to change.
What feed rate do you usually run for each? I was doing ~40 IPM with a single and the recommended ~80 with the Maslow two flute bit. Both seemed to make nice chips. Both at maybe 1.8-2.0 speed on the DeWalt.
