@Werner_Drasch
The largest problem with power hand tools is the bearings are in the plastic body housing. So no matter how good the bearings are, they’re held by plastic. It isn’t the greatest plastic known to Man either. I mean it is good enough for a hand tool, but it is not quite up to the rigors of machine use. Dremels were not built to run constantly for hours on end either, like CNC mills can demand. They simply were not designed with that kind of use in mind.
@Paul_Frederick 100% correct, some power tools even state their duty cycle or maximum run times. Reduced warranty time also if used professionally.
@Robert_Ritchie
I have seen tool warranties that are void if the tools are used in a professional capacity at all.
I can easily believe that seeing the build quality of some of these cheap tools.
@Marc_Schaefermeyer definitely agree with you! @Stephane_MARMELS I would suggest trying with what you have take it as far as you can. There’s lessons that you will learn that may change what you buy later. You might find that CNC is just want to get and later invest a lot more into it. Start cheap and its amazing what you can do! Just my 2 cents
There remains a lot to be said for starting out with a rotary tool then upgrading your machine’s spindle at a later date. You’re better off crashing a Dremel than a more valuable spindle.
might consider looking at a foredom rotary tool – reduces weight needed to be carried on the tool head, much less runout and if you use a smallish endmill(~1/8") as your cutter it works pretty smooth.
@festerND_NaN
I have a Foredom Model S. I do not think it would make a very good CNC spindle either. It is not a half bad bench tool though. It is better than the Dremel style rotary tools in many respects. I’ve a few of those too.
Some folks use certain pneumatic die grinders with limited success on CNC machines. That being economical is contingent on already owning a suitable air compressor though. As it takes quite a powerful AC to be able to supply continuous pressure, at volume.
By the time your electric bill arrives you might have been better off just getting a real spindle then too.
@Paul_Frederick for context of my suggestion, I’ve got a ‘real’ cnc mill(dynamechtronics DM2400), and have recently built a diy one –
the foredom spindle(model c, ebay sourced ~$30) has a TIR of around .004mm, I can’t measure the TIR on my DM2400 without buying a much more expensive dial test indicator than the one I’ve got.
In contrast, a good router has .005mm TIR, and a I usually see 0.1 to 0.2mm TIR with a Dremel. So the reason I recommend a foredom or equivalent for most DIY cnc mills is reasonable TIR for the quality of machine, low cost, and less weight on the tool head (reducing motor size/torque needed for the z-axis).
Why are you recommending against the foredom?
@festerND_NaN
While Foredom tools do come up used for a reasonable price, new they cost as much, or more than real spindles do. Foredom tools are NOT cheap! The kit I have retailed for over $300. Though like you, I purchased mine used. Run out alone is not the only criteria that a spindle must meet either.
One must compare apples to apples.
@Paul_Frederick Don’t forget my question… “So torque or speed? or does it depend on what you’re cutting?”… thought’s?
@Mat_Helm
You can have both torque, and speed at the same time, but you rarely ever need both simultaneously. Tooth geometry plays a more important role when it comes to what you are cutting too. Once your speed is correct, and you have enough power to drive the diameter tool you are using.
For optimal results all criteria needs to be met on cutting jobs. Which is a fact many easily lose sight of.
@Paul_Frederick Good info, But I was referring to a either or type thing with the air tool verses a router. from your previous comment…
@Mat_Helm
It is hard to classify the torque of all air tools collectively. I have a number of pneumatic die grinders, and they run the gamut, from extremely low torque, such as my Swiss iro hfs 100 turbine (80,000 RPM), all the way up to my CP 860, that is rated at 1 horsepower. Plus a pile of cheap Chinese air grinders, that fall somewhere in between.
@Paul_Frederick Well most of my air tools are of the low torque variety. At least all the one’s that would work with a CNC…
@Mat_Helm
Low torque is fine as long as you are using a small diameter bit at high speed. Say if someone was to try to isolation route circuit boards, then a pneumatic rotary tool would be ideal for them. Well, as ideal as that scenario allows. Chemical etching is a far superior process. Which is why the pros use it.
Have you seen the price of Dremel accessories? Some nice bits but those prices really insane $30.00 for a little carbide piece. I buy pro carbide for half that.
@Robert_Ritchie
What exactly is pro carbide? Is that a new grade? It is so hard to keep up with all of the carbide alloys I swear!