Dremel torque problem

In anticipation of possibly buying an X-carve I’ve been getting my feet wet with CNC by using a Shapeoko 2 at my local Makerspace. Initially I got some good results carving linoleum blocks but birch has proven somewhat problematic and I have some suspicion why; which I’m hoping someone might confirm.

Tonight, for example, I was trying to carve a design that consisted of just basic circles within circles. The product I wanted to end up with was a simple ceramic drink coaster and I was attempting to carve a “stamper” for the clay out of birch. So with a 1/8" straight, two-flute end mill the Shapeoko started cutting the first circle. But before it got even halfway around the circumference, the endmill bogged down and stopped in place and proceeded to drill right through the work piece into the wasteboard.

I’ve had this happen before when I was trying to carve some of the simple example projects from Inventables and I initially thought it might be because I was using the wrong end mills. But I’m pretty confident now that I’m using the right end mills and this time I suspect my problem is due to the Dremel simply not having enough torque to cut the birch at 30 in/minute. The Dremel speed dial is set to about 4 (that is, a little less than midrange).

So I’m wondering if my theory about the Dremel torque is correct? Or, if not, what else might be causing this particular problem?

What also concerns me is whether I’m going to encounter this same sort of problem if I buy an X-carve?


I’m not sure how much torque the Dremel has, but I’ve bogged mine down when trying to grind metal or use sanding drums. The fix for that is just to cut slow and shallow, experiment and find the right speed that doesn’t chatter or bog down but doesn’t go so slow that it dulls the bit and burns the wood.

You can purchase and install a hand router, like the Dewalt 611, in an X-Carve. I’m in the process of swapping my old low-power spindle for the 611, but all the reviews I’ve read on here have mentioned how it makes deep cuts at the speed of sound. It sounds like the limiting factor on the X-Carve, with the 611, may be the stepper motors. Unless you’re doing production work and using it all day, every day, the 611 and the NEMA 23 steppers should be able to take whatever you throw at them.

No need to reconsider buying the X-Carve based on what you see from the Dremel, just look at the different project videos and videos on YouTube that use hand routers instead of the 24V spindle.

With the 611 on the X-Carve, running the NEMA-23s, I can EASILY drive a quarter-inch two-flute through walnut at 60 inches per [strike]second[/strike] MINUTE on a quarter-inch deep pass. With the new X-Controller I’m testing out, I can likely be even more aggressive than that, I just haven’t tried it yet.

Trust me, there is absolutely NO comparison between the two. :slight_smile:

Let’s make it 60 inches per minute Dan. Someone will try 60 per second, X-Carve will become F16. :relieved:


yeah, 5 ft per second on an x-carve is something I wanted to see, it would be AWSOME!

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Holy kacheese, no kidding! Yeah, let’s go with per minute there. :stuck_out_tongue_winking_eye:

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I appreciate all the encouragement on the X-Carve guys. And I’m more inclined to buy one every day as I learn more. But I still really need to know if my problem with the Shapeoko was what i suspected it was. Have any of you encountered my particular problem before? And what solutions did you try?

Well, unless the bit was working its way out of the collet (possible) there was some kind of problem with the programming that caused an un-planned Z-move. A stalled spindle should just bog down, then probably break the bit as the steppers drive it while the bit is not turning.

I can’t say I’ve had any problem like that with the X-Carve, anyway, either with the old control unit or the new one. Mine has been dead-solid reliable, once I figured out the G28.1 thing. lol

I should add that, until I do save up enough to buy an X-carve, I’d still like to get some carvings out of the Shapeoko. So knowing if there’s a solution - other than just slowing the already slow Easel-generated carves down even further - would be appreciated.

Move slow, take shallow cuts, and make sure you have a proper mill fitted and well tightened. There’s nothing technically WRONG with the dremel for the use, it’s just very low powered.

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Maybe the Dremel doesn’t have even enough torque to break the bit when it bogs down? So instead it spirals into the birch and wasteboard?

It’s about material removal rate.

What bit are you using and what RPM are you running it at?

The formula to calculate your chipload is: Feedrate / (RPM x # of flutes).

Onsrud publishes a chart for different materials to look up the chip load.

You can then adjust your depth per pass.

It’s not about “fast or slow” it’s about setting up a chip load in the right scale.


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I was using a 1/8" two-flute, straight bit. I started at 30 inch per minute. Also tried 10 inch per minute. I have no idea what the RPM of the Dremel was except that I set its speed dial to a bit less than mid-range. The material was birch plywood.

Is it possible that too high a speed (RPM) would not allow the bit to eject the chips fast enough and thereby, due to increased friction, cause the bit to bog down?

Chip load is the thickness of the chips as they come off the bit.

0.005 chip load is chips of thickness 0.005"

So is this the chart you’re talking about Zach?


Ya pick a bit that is closest to the one you have.

You will need to look up the model numbers from that chart.

Found this on the Onsrud site at http://www.onsrud.com/xdoc/What-is-Chipload

What is Chipload?

For many people using wood materials in their homes or businesses, it is very important to be familiar with all the terms and tools used. The ability to do the job perfectly will be reduced otherwise, and the results will consequently not always be very satisfactory. Some people might be asking themselves, for example, “what is chipload, and why is it so important in the process of cutting edges?” When you are wondering, “what is chipload,” you must know that it represents the thickness of a chip being removed, and that a chip is usually part of the material being removed from the parts that being machined.

Other important terms used in this definition process are rotation speed and forward movement. These are related to the spindle, which is the tool that controls the size and thickness of the chip. The answer to “what is chipload” can be found by calculating the amount of material cut by one edge after one revolution of the cutter.

Furthermore, chipload is the same on multi flute cutters, with the only exception that the chip load is equally spread out over all of the flutes. What one must also know in order to correctly determine chip load is the fact that the cutting action produces heat, and that the heat has to be removed in order to avoid disturbing the whole process. One of the most effective ways of doing that is by removing it with the chip. This can only be done by maintaining correctly sized chips, which will eventually dissipate heat and produce a better finished edge.

Of course, having all the best results depends on what type of tools one is using, as well as the assumption that he or she has the necessary skills. One can only acquire those skills by staying up-to-date about the information that is available, and having a solid background on chip load and the factors that contribute to success of the process

I’ve purchased all my bits from Inventables so far. So I don’t suppose there’s any chance that Inventables might make a chart available which has the chip load data for the materials and bits you sell?


Chip Load = Feed Rate/(RPM x cutting edges)
Feed Rate = RPM x chip load x number of cutting edges
RPM = Feed Rate/(number of cutting edges x chip load)

Feed rate is in inches per minute