Help on Bits/Feed Rates

Hi there,

I was wondering if anyone can recommend any guides on Bits and settings? I found some information here and there (like in the docs) but nothing where I can find all the information that I’m looking for in one spot.
Thankfully the sorotec bit set, which many of you recommended, came with recommended settings but only for the bits that were included in the set.

Does anybody know any guides that explains which kind of bit might be best for which material and application?
And do you know any guides with some general settings for each kind of bit?

Because currently I have three problems:

  1. I was trying to cut some ski base material (plastic) with the 1.5mm single flute using about 24.000rpm and 600mm/min feed speed but I couldn’t get any clean cuts. Which tool and settings would you recommend? I ended up cutting some MDF instead and using it as a template with an extractor knife.

  2. Is it a good idea to use a slot cutter like this one with the lowrider to cut out a shape out of some wooden planks?
    It is the only one I have right now which is long enough (25mm) to get through the wooden plank (22mm).

  3. And last but not least, which bit would you recommend for contouring/milling the top of of a wooden ski core?
    (I guess a wider tool would be better as there aren’t any islands/inlays and I’m only removing the top?)

I hope my post isn’t too much of a duplicate or spam but even with google or the search bar I couldn’t find anything helpful.

Those settings are to be taken with care. They are pretty optimistic. :smiley: Sorotec has got an App also that gives you some pointers, but it heavily depends on the build quality, size, router etc. That’s why there are no “definite” guides.

To get back to your problems:

  1. Depends heavily on the material. 24 000 might be way too fast, melting the plastic. There are missing a lot of details in your question.
  2. No, use this one Sorotec Online-Shop - Schaftfräser HOLZ, 6mm shaft, 6mm edge.

    It says 21mm, but you can cut a lot deeper, I cut 30mm with it.
  3. I am using the 16mm version of this one: Sorotec Online-Shop - Werkzeuge. You have to make sure your X/Y are properly trammed, otherwise it will leave ugly groves. Then it would be better to use the 6mm endmill from 2).

That´s not plastic :slight_smile: it´s uhmwpe
Don´t try milling it, there is a reason why Donek created Donek drag knife and why hobby builders use MDF templates in combination with an exacto knife.

There is no need to use such thick wood? How thick are you going to make your ski´s?
I rip cores out of wood planks with the size of ±15x15. My final cores are 2-3mm thick in the tip and 7-8mm in the middle as you still need to press it in a camber/rocker/hybrid shape.

Only reason I double the size of my core thickness is that it is really difficult to make a flat core as wood warps (you´re better of buying them, so you have a flat core, saves you a lot of pain and time).
So when you are done facing the bottom side, and start to profile, your maximum cutting depth will be <10mm.

I´m not sure if I get this, but use whatever you have (3 - 5mm) to contour the shape. For the profile though you´d want to use something thicker. Otherwise it will take ages.

Anyways, have fun building your shred sticks! If I could advise you, go for the vacuum infusion, more difficult but a much better job.


Or do what Olivier says because he seems to have actually cut a ski. :smiley:


I think you might get away with it (depending on the size of it ofcourse). The fibers of the fibreglass will level it out if it is a hair thick. Bottom side isn´t visible due to the thick uhmwpe that will be grinded before you hit the snow :slight_smile:

:smiley: how can I say this polite :slight_smile: I sell my own brand of boards and ski´s. But ofcourse that doesn´t make me the super expert in CNC.


@Olivier @Tokoloshe Thanks to both of you! This helped me quiet a lot :smiley:

Then I will buy the two bits from sorotec and continue cutting the base material by hand with a template.

The 22mm thick wood is for the press, not the core. The cores I bought are only 1.4cm thick and pretty flat already.

The Doneg drag knife might be something I might look into in the future if I decide to build more than 3 pairs that I’m currently building. So thanks for the tipp!

Yeah I meant the profile, my mistake.

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Do you have a website? I’d love to check out your work.

sure, check it out here there is still plenty of work on the site though… it is about time to stop doing things myself and hire talented people to do it instead (but I find it hard to find the ones that match my expectations) :slight_smile:

My bad! Thought the core was going to be that thick.
You´ll want to try and build your own cores in time as it isn´t that difficult. You can use the L2 if you do not have a planner to flatten them.

Wonder how your 3 pairs turned out. Any progress?

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Nice work. Looks pretty professional to me on my phone browser.

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thanks for the kind words. It took like ages to get there!