Chapter 2 - Tools
KRMx01 Upgrades and Addons
Dressing the KRMx01 Stand
I have lots of ideas about how I plan to finish the KRMx01 Stand. These include panels, trim, machinist drawers, breaker panel and some other stuff. This page will take some time to complete, but I will add sections to it as I get them done. Most likely, I will do some on the stand and then move to some other areas. Afterwards returning my attention to the stand. Anyway, I hope you check in once in a while and see what is happening to it. If you have any question, feel free to ask!
The State of the KRMx01 Stand Now
Here are some images showing what the machine stand looks like at this point. As you see, other than the computer rack with it's associated components, the stand is pretty bare. I have reached a point where I need to give the stand a little more attention. As more things are wired to the machine, it will make it difficult to cover the left side of the stand. As it stands I have the Monitor cable and power, router power and the stepper motor wires running to the rack. These wires will pass through the left side of the machine near the top back. So my first order of business is to fabricate the panel and any related parts the will go with it.
The Left Side Panel
First let's start with a good clear picture of what we have to work with. What you see here is the left side of the machine. All of the control wires and power for the external components of the machine will have to pass through this side. You can see the stepper motor wires passing through near the upper left corner. Hindsight they say is 20/20 and I have to agree. Having come this far knowing what I do now, I would have done a couple of things differently. First, I would have made my table from 2" square tubing. It would have provided me a means of connecting the rack components internally with the fasteners hidden. Second, I would have welded tabs onto the tubing to allow me to fasten the panels to it, keeping everything neat and tidy. However, this is what i have created and as a result, it is what I have to work with.
The approach I have decided to take is to mount the panel to the uprights behind the angle with some 10-24 screws, washers, lock washers and nuts. Additionally, I will leave an area in the upper left as a separate panel that will be attached to the main panel. This will allow me to remove the main side panel and leave the wiring intact.
Cutting the panel
I have attached a group of pictures of the panel that i have cut out for the machine. The first image is of a top to a central air unit. A friend of mine is in the business and was kind enough to donate this material to me. It is heavy gauge steel and I am hoping it will be heavy and rigid enough that it will not make a lot of vibration noise. The second image shows the panel I cut from the larger piece. I cut this with a cut off wheel in my cheap 4" angle grinder.
Cleaning things up a bit
With the panel cut out, I had a bit of a mess to clean up. The air conditioning panel that I used to cut this from had insulation glued to the underside. Pealing the insulation wasn't too bad of a job, but the glue that was used to stick it down was another story. These two images tell the story. There was gobs of glue holding down the insulation. I used my air-sander and went at it. This took me a while. My compressor is kind of small and i had to let it catch up several times.
Doing a Test Fit
With the glue sanded off it was time to make a test fit of the material. I noticed two things off the bat. First, the material bowed a little and second it was about a half inch too long. I had to flex the material to get it in place. Other than that, I felt like it would work fine. If you look at the image, you will see that the wires are tucked in the upper left corner. Now it's time to remove the panel and do something about the wires.
Wire Access and Bracing
In the first image you see the panel with the corner cut from it. I will use this little panel to mount my grommets in to pass the wires through. The other two pieces of metal will be spot welded to this little panel to give something for the large panels to rest against and fasten to. Finally, in the second picture, you see that I added a couple pieces of 3/4" aluminum angle to the panel to stiffen it up a bit and to take out the slight bow that I had.
Mounting the Panel
Here the panel has been fastened into place. I used 10-24 x 3/4" machine screws to fasten the panel. I placed a washer on the screw, inserted it then added another washer, lock washer and nut. The panel will stay here until the wire pass through panel has been completed and mounted. This was I know everything fits where it should. After all the fabrication and fitting is done, I will pull it all apart for a coat of paint.
The Wire Pass Through Panel
I thought I would try out my home made spot welder to spot weld some edges that I could attach to on the wire pass through panel. Recall that I made the side and pass through panel from 16 gauge steel. The first image show a spot weld in action. As Paris Hilton would say, "That's Hot!" The next image show the progress on the spot welds. Now I have to pass this along. I made this spot welder from an old microwave oven transformer, and for smaller gauge metal worked wonderful. With this thicker metal, I was unable to get enough penetration on the weld to make it usable. As a matter of fact, I broke them when drilling hole for the attachment bolts. So that brings us to the last photo. Here you see the pass through panel attached to the side panel. The four grommets you see are 50mm (2 inches). The holes were cut with a hole saw. Next, I need to remove all this from the machine, braze the nuts to the sheet metal, get it painted up add some edge trim. That comes next.
Finishing up the left side panel
More to come ...
The Monitor Stand
My great idea of using a rack mounted monitor turned out not to be such a great idea after all. Actually, I still like the idea very much, but it is just too close to the table to be very functional and I found myself folding it part way down when I went to zero the machine. Now, if they made one that would slide way out and swing to the side then everything would be great, but .... I digress.
So I thought how could I mount the monitor and still make it swivel and tilt. The answer was simple! Well simple after my friend Pastor John applied some grey matter to it with me in a brain storming session. The idea was settled on using a flange, a nipple, a coupling and part of the monitor itself. John was kind enough to fabricate the coupling and monitor base part. Thank you Brother John!
Here is a picture of the parts. These images are very similar with the exception of a couple of rotations in parts. The top right is the mounting flange. The bottom right is the coupler that has been cut down and the original monitor base welded to it and cut down. The center item is a pipe nipple and will serve to run the power and video cables through and elevate the monitor above the X-Axis stepper motor. The part on the left is the stand portion of the monitor. The square section attached to the monitor while the other end will attach to the plate that is welded to the nipple.
Painting the stand
Zachary was kind enough to clean the parts and paint them. In these three images you see the unpainted and painted parts, then in the final image Zachary has put them together so that you can see how the assembly goes.
Putting it all together
To attach the monitor stand to the side table a series of holes had to be drilled. The first image shows these holes. You have four mounting holes and a large hole in the center to pass the monitor's power and video cables through. The corner of the table is a little scraped up so it will receive some paint before the stand is mounted to it. The next image shows the stand attached and the Monitor attached to the stand. I have to give Zachary credit here. He done all the painting and assembly on this upgrade. Great work son!
Where to from here ...
This basically completes the Monitor Stand and Monitor upgrade. The only thing left to do is route the power and VGA cable for the monitor. That brings us to the next upgrade. Before we get carried away with running the PID or limit switches and other wire related projects, the left side of the machine table needs to be closed in and grommeted. As it stands, I will have to undo the wiring for the motors and then rewire them to get this piece in place. No sense in creating any more work than I already have for myself. Once the panel is in place and wired back up, I will take a pause on the upgrades to do some more cutting. I need to cut a couple of simple plaques that will be cast in aluminum as part of a grave marker for a couple of our pets. This is the project that caused the resurrection of the old JGRO CNC and the building of this one. They are important to my wife, and it is important for me to do it for her. So we will see you in the next upgrade, and then a new projects area for the KRMx01 CNC. Happy building!!!
Thought I woud post another picture of the monitor stand with it actually on. Zachary and I pulled the monitor / keyboard drawer from the rack and replaced it with a keyboard tray. This one works but I would like to find a better one that slide out a bit further than this one does. But you will get the idea nonetheless.
Fences and Clamps
Fences and clamps are a vital part of having a CNC Router. The fences allow you to reliably place stock for cutting and you need clamps to hold the stuff down. This little addon was part of the upgrade book for the KRMx01 and the clamps were part of the KRMx02 book. So no real details here but at least you will get an idea of what is going on.
Cutting the Fences
Squaring the Fences
Cutting Out Clamps
Next I cut some clamps to use on the clamping table. Your clamps should be router friendly in the event something goes wrong with your machine or code. These clamps are being made from some 1/2" plywood. This piece of material was clamped down using some scraps of lauan plywood. These clamps did not work well. They were not thick enough to really hold the material down and should have a groove on the end so that it prevents the material from sliding from the force of the cut. But they worked well enough to get these clamps cut. You should make lots of clamps in short, medium and long versions. You just cannot have too many. The book calls for some plastic knobs from a supplier. I didn't have these so just used nuts. I will use some wing nuts until I get a chance to find better hold down knobs. :-)
The Fences and Clamps in Use
Her are a couple of pictures of the fences and clamps in use. I hope you realize the value of these items to your CNC machine and decide to make some for your own. Thanks for reading about this add-on!
Adding the Dragon Cables
It didn't take much running of the machine with the cables hung from the ceiling by rubber bands to realize that something had to be done. Especially after you broke a rubber band or two. Fortunately that never happened while it was running, but I did go to my shop a couple of times to find the wires laying about on top of the machine.
Cutting the dragon cable parts were pretty simple and Michael explains hot to set up and cut in his book, so I will not bore you with that. I started with the X-Axis dragon cable and put it together. Now these are to be cut from hard board and the stuff I had was slick on one side and rough on the other. I think it is meant to glue down to a work bench or work table top. I had to sand the rough side a bit to get the parts to slide into the cut out slots. I put the cable together and, well...., I think something isn't quite right. If you click on the picture you will see that the dragon cable looks a bit like a rocker bottom. Not exactly what I was expecting, but fixable none the less. I had a couple of options. I could sand the parts or modify the G-Code. Since I only plan on making two of these and one was already cut out, I figured sanding the parts would be simpler. I sanded the edges of the inside link until it would allow the link to lay flat with the outer link. Additionally, I nipped the inside corners of the cross pieces that slid in the slots to allow them to sit fully flush with the outside pieces. Also, I took the time to tap the screw holes to make installing the screws a bit easier.
This next image shows the dragon cables after they have been assembled. Notice they lay nice and flat now! The shorter one in the front is for the X-Axis and the longer one in the back is for the Y-Axis.
The next five images show the X-Axis dragon cable as it is getting installed. I forgot to relieve the holes on my angle bracket to 3/8" before I painted it. I put it in the vice to drill it and the paint didn't hold up well. I should have protected it better. I will have to touch the part up. The raw metal is a bit glaring.
With the X-Axis dragon cable installed next came the Y-Axis. These images show the mounting hardware and the Y-Axis dragon cable installed. One thing that I must point out is that the 3" bolt that attached the chain to the carriage was too long. I think I substituted a 2-1/2" bolt here.
Dragon Cables Installed
Finally both Dragon Cables are installed on the machine and the motor wires are run through them. This is MUCH nicer than the wires hanging from the ceiling. I should have done this sooner. As I use the machine, I see things that I should have done sooner but didn't, or things I have done that I should have done differently. For example, I should have made a side cover for the machine table before running all these cable because now I will need to disconnect them and re-run them after the side panel is made and installed. Another idea I had was to use a rack mount monitor for the machine. This ended up being a bad idea as it really interferes with the operation of the machine. So my solution will be a monitor stand and that will be the next upgrade I post. Also, I will try to post a video of the machine running and the Dragon Cables in motion and add to this page.
Dragon Cables in Action
Air Exchanger and Brushes
Since doing a little cutting on the KRMx01 and having a lot more to do just to finish the dragon cables, I thought it would be a good idea to try to combat some of the dust created by the process.
The Air Exchanger
Kronos robotics sells an air exchanger that, while allowing the cooling air generated by the router to cool the bearings, directs the air away from the router so that it isn't blowing the dust around. This little add-on coupled with a brush of the right length will allow you to capture 99% of the dust generated according to the creator Michael Simpson. Pictured to the left is the exchanger I purchased from Kronos Robotics for my Hitachi Router. Sorry about the picture, there is some dust on it since I have been cutting with it.
Parts Needed for the Shrouds and Brushes
Pictured to the left is all the stuff needed to make a shroud and brush assembly for the air exchanger. If you buy the exchanger, Michael has the drawings, G-Code and assembly instructions available for this project on his website at kronosrobotics.com. Here you see the shroud pieces that I have already cut out on my machine, the craft foam (the parts are sitting on), the screws, lock washers and nuts.
Cutting the Plastic Shroud Pieces
Cutting the upper and lower shroud pieces turned out to be something of a challenge. The default feed in the G-Code is 50 IPM and Mr. Simpson suggests running the router at about 10,000 RPM. So I set my Hitachi router to about the third way mark on the speed control and let it fly. The job seemed to be okay at first but as it went along, I started noticing a little melting of the plastic. I tried changing the speed of the router up but was not really sure if I was having an effect or not. The image to the left shows the parts that I cut and if you look close you will see little divots here and there where the plastic melted. Now in fairness to Mr. Simpson, he told me when asking a question about what plastic do I need to buy for the limit switches, that the Home Depot / Lowes acrylic plastic did not machine well. I think though, that with the combination of bit, speed and feed that this stuff should be millable. When I have the SuperPID installed, I plan on doing a little experimenting to see if I can produce better plastic parts. After all, I will need a couple more sets of these shrouds.
Making the Brushes
The brushes are made from strips of craft foam. This stuff can be purchased at Walmart and other stores. It is cheap and very easy to work with. I started by measuring and cutting the little bristles with an Exacto knife. Then I quit measuring them and just started cutting them with an Exacto knife and a straight edge. Finally, I decided it was so tedious that I just grabbed a pair of scissors and just cut them to about an 1/8 inch wide. Let me restate that, cutting these things out kinda sucks, it is slow business, even just eye balling it and using scissors to cut them. If I wasn't so cheap, maybe it would be better to just order them from Kronos Robotics and save yourself the headache. On the upside, I did get a chance to catch up on some news while doing it. Anyway, here they are, three short brushed cut and ready to be glued to the shroud.
Assembling the Shroud
Tapping the plastic and assembling was pretty straight forward. The only part I was unsure of was the bottom piece of the shroud. I was not sure if it was supposed to be tapped or the screws just force threaded into it. I clamped the two pieces and tapped them through. The first image shows the completed shroud and the second with the shroud attached to the air exchanger.
Gluing the Brushes
What can you say about gluing the brushes on? Actually my son Zachary was nice enough to glue the brushes on the shroud while I had lunch. Thanks Zach. The image on the left shows the completed brush assembly and the one on the right shows it attached to the air exchanger.
Putting it all together
Here you see the air exchanger attached to the router and in the next two images the brush is attached. Now to cut some stuff and see how much the dust and debris is reduced. Thanks for reading this page!