I’m looking around for a simple solution to control the speed on the DeWalt 660. I’m curious, I’ve seen some people use these kinds of dimmers that are cheap on amazon, intended for controlling DC motors. Looks great, but I’m wondering how folks are measuring the RPMs on the DeWalt, or if there are other solutions that would interface with a Rambo 1.4 to get full CNC control of the speed.
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Hi Jake, I like that question. I don’t think you can unless you have a way to calibrate the DeWalt with something like an Raspberry Pi or the like. There is a way but I think the easy solution is using the dimmer alone. I’m watching this thread because we have a lot of really intelligent people that probably have an answer to this. I want to know as well, otherwise, we have one speed and we must adjust the cutting depth to accomplish the same thing. Faster, less material removed, slower, more material removed properly because some materials don’t like high-speed cutting. Single flute bits are the best. some bits, like for aluminum are designed to throw material out and away from the bit to prevent welding or plugging the bit up. Let’s see what we get. Thanks for asking this.
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The dimmer you linked to is sold at Harbor Freight for less. It tends to get hot. Here’s an Instructable to make it run cooler. https://www.instructables.com/id/Harbor-Freight-Router-Speed-Control-Mod/ I’m searching for an RPM digital readout.
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There are a number of optical tachometers for the RC plane/drone market. Most are designed for 2 or 3 blade propellers and don’t have any serial output.
There is an incredibly relevant Instructable for building an optical tachometer for a CNC, and it should be possible to have an output from the Arduino control the dimmer.
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So is it safe to assume most people are just going fly by wire and giving their best guesses on RPM’s/adjusting to taste?
That’s a part of it and the "dimmer " is a part. I contacted a company that specializes in AC and DC motor calibration. The Dewalt 660 runs on 5 amp AC at 30,000 rpm. A DC controller won’t work. I’ll post what they send me in the morning when they open up the shop. If we are going to mill aluminum and other sensitive substrates we need to have total control. We need an accurate tach with a power reducer that can handle motor surges and AC amperage. We don’t need a fire or want to fry our router.
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There’s a thread around here in the hardware development section for making a pid controller for the dewalt.
https://shop.v1engineering.com/collections/miscellaneous/products/pid-development-kit
There’s a link to the thread on the store page.
Yes, Using my PID Barry linked or the Super PID is the only other option but very much not needed.
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I contacted a company about this and they suggested I contact Dewalt directly for an add-on part. Personally I think you’ll be fine with what we use as is. The dimmer will work if it handles AC but I think you can make enough changes in set up that it’s not needed.
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The item in the first post works for both ac and dc motors, says so in the description. I have one attached to a fan in the barn, low wasn’t low enough…
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Slowing the motor with a dimmer like that works well enough for most of our uses. Be aware that torque drops with the speed drop, so too slow means you might be able to stall the motor. Most of use use a mix of sound and cut quality to determine where the sweet spots are with different work material types. You should experiment and then just note the dial position when it seems to be working good. Remember also that the number of flutes on your bit makes big changes in best speed, the more flutes you have the slower you want to run the router.