Hey yall,
I’m just starting my CNC adventure. I now have a functioning shapeoko 5 pro 4x4 with the 65 spindle. Also the starter bit that comes in the box and starter kit that has the starter bits.
Okay now for the questions, also I put this in on categorize because I had no clue where to put this.
Is there kind of a master list of resources for speeds and feeds on bits?
How to identify bits that are not purchased from carbide? I ie if I find some randomly on sale? And then how do is there some sort of chart that kind chart that gives me good rule of thumb on what to set that feeds and speeds at?
I would like to do acrylic etching that I can place the fake neon LED tubes into, Just shooting on bit for that?
I also am having trouble getting detail on some V carving, What bit do y’all suggest using to do the finer scroll work or graphics in wood?
Appreciate y’all’s feedback, I’m just climbing the steep curve of learning and figured I would try my hand and asking a community some questions.
Carbide Create (CC) comes with a list of bits that have speeds and feeds already assigned. Those are very conservative (means to conserve bits…), with experience one may change those. And will break some bits here and there. ALWAYS! listen to your machine.
Good sellers provide speeds and feeds with their bits, by far not all of them! Of course Carbide3d is one of them, https://idcwoodcraft.com is another, they also have a great database, even complete lists for carbide create to import to, also CICworkshop is one of them. A local one for me, located in Hudson NY, makes some bits, even on custom order (different lengths etc) when I call, their prices are not really cheap, but the router bits are probably meant for serious 24/7 steel work: https://dinosaw.com
Sometimes there are bits available on Amazon that provide speeds and feeds.
What one almost never gets (you hear, C3d guys?) is the chipload.
That is the parameter one needs to adjust speeds and feeds as correctly as possible. But when you hear what the machine tells you adjustment works well. Always produce chips, not dust. Avoid cutting HDF, that is mostly plastic, and wears the bits. Check for sharp cutting edges of your bits once in a while, I find a USB microscope for that purpose useful. What makes Dinosaw worth mentioning is that they re-sharpen bits, also saw blades.
There are a lot of chipload calculators, and techniques for calculating feeds and speeds — one which seems well-suited to the scale of tooling most folks use is:
Usual preface, I’m with PreciseBits so while I try to only post general information take everything I say with the understanding that I have a bias.
Short version is that there’s no “master list” or “universal feed and speed/chipload chart”. There are rules of thumb you can work within and ways of checking.
Without going too deep into the rabbit hole the problem is that you are trying to hit a minimum chipload for a tool’s geometry and the material combination. Basically to cut and not “rub” (using the cutter as glorified sandpaper). Within that you need to not exceeding the material, machine, or bit strength. e.g. a tool with more aggressive rake and smaller edge radius can cut with less force and take a smaller chipload (feed) without rubbing but has a weaker flute. Or a tool with higher helix (flute twist) can cause material failure at a lower chipload but provide more shear.
Those are also effected by things like runout which adds and subtracts from chipload (functional feed) in multi-flute tools. Or chip thinning which makes your chipload smaller. Then deflection machine and tool. Etc.
You can get way deep into all that but for starting out probably the best thing is to actual cut and experiment. As long as you are not riding the line on the limits of the machine or tooling the margins are big enough to absorb a lot of the above. Can you get better or more productive cuts implementing all that? Sure… But it can also paralyze you. So starting out I’d say stick to some manufacturers that you trust and can help you or have some guidance you can follow. After you get comfortable or run into an issue try to start implementing the other factors. The ebooks Will listed are probably a good start as they are already assuming for one of the variables (the machine). Although, personally I’d up the chipload on most of them.
On the bit side or more specifically address the “if I find some randomly on sale (tool)”. Be careful with that at the start. The identifying part is more complicated than I believe most think it is. Just having a say “1/4” 2-flute tool" COULD be fine. But if you are cutting plastic and it’s a metal cutter that is going to be frustrating at the very least. And probably not worth the amount you will save in money vs time and material.
V cutters are a whole other mess. In terms of getting details it’s limited by both the angle of the tool and the tip diameter. A lot of the time the latter isn’t even listed and the tip diameter plus runout is ultimately the minimum detail that can be produced. It’s hard to say where your issue is without more detail or examples though.
Hope that’s useful and not discouraging. If there’s something I can help with let me know.
