Mar 212014

I am one of the sound people at the church I attend. Something that has always been an annoyance, though not really realizing that it was really bothering me, was that the dB meter we have is made of a very slick plastic. It is not so much the plastic that I disliked, it was that slick plastic is slippery. I would usually make some horrible looking thing… a stack of CD covers, batteries, board tape… to try to prop the thing up. But usually it would eventually slip and fall off the ledge above the sound board. Last Sunday, whilst fighting the battle of the slippage, it occurred to me, well… I could just make something to hold the thing. That’s exactly what I did. Everything I have made to cut out on the Shapeoko has been  2D objects. They are 3D in the sense that they are not flat and you can pick them up, but they are essentially extruded 2D objects. While the stand was to be more 3D, is would be made with 2D shapes.  I knew that I wanted the meter to sit at an angle for better visibility. I had the main idea laid out in Draftsight within a couple of hours (still learning the CAD thing, so it took a little longer than expected).

While this may seem completely obvious, I totally spaced on the idea that things which intersect in a pocket, at an angle, will be longer than things which intersect at a 90 degree angle. I get it (now). I had everything cut out and I started to dry assemble it when I realized my oversight. In order to make this work, I would have to get the piece spot on aligned on the Spapeoko, then extend the slot on the back, or, recut the whole top plate. I decided to try to get it aligned. While it was not a perfect alignment, it was pretty dang close for human accuracy. I am really happy with this as a first piece that had nothing to do with the building of, or accessory to the machine.

After seeing how this came together, I decided to make another one (though a little wider) for my phone with a few alterations to allow for audio plug and power USB.

 Posted by at 11:01 pm
Mar 182014

The next logical step (at least to me) was to get going on the dust shoe. While hand holding the vacuum works well, it is something that you have to keep a focus on throughout the whole milling job. Why? Because if you don’t, you will be met with a loud zzzshwap! when the end mill comes into contact with the vacuum hose. Not cool. Doesn’t do anything to the end mill, and actually did not hurt the job. It just scares the hell out of you.

The dust shoe will allow me to attach the vacuum directly to the cutting head (spindle). Meaning that the main force of the suction is always very close to where everything is happening.

 Posted by at 11:18 pm
Mar 162014

I finished this mod a couple of nights ago and have been testing it while working on my dust shoe. So far it seems to be making quite a lot of difference. I think that it intimidates the cutting material by having to look up at the menacing glare of the DeWalt. Also, being that the DeWalt is a moving, vibrating object, I have found that there are the added benefits of the upgrade making wonderfully unpredictable moves. I highly recommend this to any serious DW-660 user.

 Posted by at 10:51 pm
Mar 142014

Several years ago I made 22 absorptive panels for my edit suite at work. These let me control the number and amount of reflective surfaces in the room. This is great for accurate listening so the room does not color the mix. When we moved into our new building, all the edit suites received  new sound panels. Most of the panels were given to my church to try to fight some of the issues in our main room, but I also kept a few for myself. These have an NRC (Noise Reduction Coefficient) of 1. With these panels, most frequencies above about 400Hz are totally absorbed. While this is all well and great on paper, I wanted to do some rough testing of what I might really see as a reduction. These were very rough and fairly unscientific tests, so in theory, the end results will be even better than this. I did all testing at  1 meter from the sound source, which is 1. a very loud vacuum and 2. a very loud DeWalt DW660. The software is “Audio Tool” (clevar name) on an Android phone. I did some checking into the specs of the mic on the phone and it has a maximum sensitivity up to 90dB. So as the actual levels, they may be louder than what I am able to read, but it will get me close. To support my phone, I used a highly scientific bar stool with an even more scientific piece of wood sitting on top of it. I did not want the cushion of the stool to absorb the sound and give a false reading.

If I learned anything from Mythbusters (and science class years ago), you need a control. Here is a recording of the baseline room noise. These samples are roughly a minute in length. You can see that aside from my dog laying down and then dropping something a few seconds later. You can see some noise from the A/C as well. The base SPL is roughly 48dB.


I did not have any way to really hold the panels to test them with the DeWalt (again, this was not a completely scientific test, just trying to get a rough idea. There is a very solid tone just under 500Hz. This tapers off, then picks up again around 750Hz and stays strong up through around 7K. There is what looks like clipped level right around 6.5K, you can see a harmonic of this around 13k. About 2/3 of the way down the picture you can see the line under 500Hz swing off to the left. This is me shutting off the DeWalt.

I did not want to pull the Shapeoko off the table, and I am not yet ready to cut the panels down yet, so I shoved a panel behind the table, resting it on the window sill, shoved 2 other panels in along the sides, and held a panel in front of the table. Again, very scientific right? While the scream at 500Hz is still fairly present, the level is reduced for sure. But check out the what happened to the levels above 1K. This is crazy good to see. Near full reduction except for various frequencies between 3-5k. The 2 peaks around 6.28k (as shown) and 13k, while reduced still very present. This reading comes from what would be a horrible job of an installation of sound reduction material. When I get this actually enclosed, this may really do the trick.

Next up, I did a recording of the vacuum. This first image is with no noise reduction. You can see very high levels around 150Hz, with a second peak from roughly 1.7k – 6kHz. The Nexus phone mic is  reading is 88dB, so it is possible that it is louder. I may borrow the dB meter from work to retest with proper equipment. Being that the vaccum was not attached to the table, this was much easier to test. I made a little triangular room out of the panels and placed the last one on top (see the images below).

The first measurement was taken with the vacuum hose coming out of the front of the structure of panels. While things quieted down substantially this revealed how much air noise a vacuum makes by itself with air rushing through. Here you can still a strong presence around 150Hz, but no where near the levels they were before. From just below 1k to just above 2k you can see near full attenuation.


Lastly we have the vacuum with the hose moved to the back.  Being that there is no wooshing air noise directly in front of us, you can see an even greater reduction around 150Hz, and from roughly 600Hz and above there is a near full reduction.



 Posted by at 8:27 pm
Mar 122014

With proper cooling in place, I needed to respond to the needs of my wife… Get this $#!+ off of my kitchen table. Well, not her exact words, but I can read between the lines. Actually, she has been great about it all. I have been fretting about what and where my Shapeoko will live. I was initially thinking about putting having it in the garage. I live in south eastern US and I can see that 1. I will not want to work down in the garage during the heat of the summer. 2. Seeing that polar vortexes seem to like the south, and as you may have seen a little snow can bring the our City to a skreeeeching halt. I will not want to be in the garage for long periods of time. So… looks like it will be in my workshop.

If I am going to be in the workshop that means I need a table. I just finished cleaning off the air hockey table a couple of weeks ago, so that was off limits. Air hockey tables are a high gravity catch all for anything that does not seem to have some other place to live. Dangerous things really. I designed the table to be sort of a box on legs. I wanted a ceiling on it to support the drivers, control box, tools and so on.  It was designed to be long enough that I can grow the Shapeoko to 1 meter. Initially I will probably keep my laptop at the end of the table.

This was all originally supposed to sit on a couple of saw horses for the legs. After setting it up on the saw horses, the whole thing wobbled in an unsettling way. This is not exactly the sort of thing you want to be falling over mid milling job, so, I set off  to build legs that were a little more proper, not to mention structural.

Something that is being thought about (heavily) in the back of my mind is how loud the spindle (Dewalt DW660 router) and the vacuum are. They are each quite loud by themselves, but together they are a whole new monster. They are both running around 90 dB. Sound containment was also considered in the design. While I will not be able to eliminate the noise completely, I would like to knock it down to tolerable levels (without the need for hearing protection). So essentially the sides are built as a cage to house sound panels on the sides. I will also be building a sound panel box for the vacuum as well. Once built they should be able to slide into place. I played with some panels I currently have to test a couple of ideas. I will cover this in another post though.

 Posted by at 10:27 pm
Mar 032014

The next thing on my list was getting some air moving over the shield. While I understand that they will run hot and have become okay with the idea (sort of), I still want to take care of it. So I set off to cage the Arduino and shield and make a pseudo cooling stack sort of thing. I had some acrylic left over from another project years ago. While not a crazy hard project, this is my first venture into making something where all the parts really needed to line up. I designed this in a couple of hours in Draftsight. It probably would have gone faster if Game of Thrones was not on. I went through a time where I was buying all sorts of things from garage sales so my son and I could take them apart and grab the goodies inside. I am not sure what it came out of, but I had a 24V fan which I wired into the V-In on the shield. It moves a heck of a lot of air.

I cut’er out and put it all together. I was really pleased how close everything came out. Projects prior to the Shapeoko always ran the great possibility that come assembly time it may, or may not come together all together well. This was precise.


 Posted by at 10:26 pm