Information pertaining to my building of a 3 axis CNC routing machine
I said I would post this about a month ago, but then I got going on the next machine… yes another one… it is really just a revision of this one, but there are some significant changes. I should be posting about it later today.
Anyways, here is my first cut video for the black and yellow beast:
So in the build up to the first run I decided I needed to attach a vacuum and get the wiring out of harms way. To solve the first issue I decided to build a dust shoe that would clamp to the bottom of the router. Since I am not skilled in 3D modeling yet, I decided to build a cardboard model of the shoe using old boxes and scissors, it was crud but effective in my opinion.
Wow, six months since I last posted something, not sure what happen there. I guess between work, family, home improvement, and critter control (bats in the attic vents) the time just whizzed by, kind of depressing… But no I am not dead yet, and neither is the new build, in fact it should have its maiden flight in the next week if I don’t break something again.
I left off in the last post with having just cut some new parts to replace one that I broke while running some tests… well after sanding, priming and painting those… I was unable to fit everything thing together due not pre-fitting the pipes before I started assembly, it was too tight and I split the pieces trying to pull it apart… there is no photographic evidence, but it wasn’t pretty when I was done with the rubber mallet. Re-cut the parts, drill, sand, prime paint… and I split both of pieces clamping down the z axis pipes… not happy. At this point I went back to the previous version of the parts, I did not sand anything, but did prime and paint, and I had no issues with the assembly, of course the parts are rough looking, but it is together.
So the next step was to mount the router. I purchased a Rigid R2400 back in January, but looking at the router and the machine, I realized I had been thinking about the Dewalt DW660 when I design the mounting plate. The DW660 is a much longer tool than the R2400, so I could not use all 4 holes that I had planned for mounting the router. I ended up cutting a simple clamping mount out of some Trex decking I had left over from re-cutting the lead nut carriers, I think it came out well and it seems plenty solid.
For the most part is has been too cold to work on the machine for the last month or so, so I have not made a lot of progress, and I managed to crack part of the Z axis while testing the machine.
First the good stuff:
I decided to mount the power supply and electronics in a cheap storage container, which is exactly what I did with my last machine. I used an x-acto knife instead of a drill this time, and did not any issues with the plastic cracking like I did last time. However using the x-acto knife to drill this many holes by hand did lead to a couple of good sized blisters, there is a better way I am sure. This part is pretty much done with the exception of a toggle switch on the power supply AC so I can turn it off without unplugging it.
…
I was having some issues with the lead nut carriers splitting when I bolted them down, so I decided to try cutting these parts from the Trex composite decking. The piece I bought was 1.125in thick, 5.5 in wide, and 8ft long for about $18, I cut it with the same 2 flute end mill I have been using with MDF, and I think they came out well.
Given that the part is now wider and contains a mix of saw dust and plastic, I am pretty sure I will not have the splitting issues.
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I got a little time last Wednesday to work on the machine, so I went ahead and built the table top. It consists of of a 59.5 inch x 24 inch sheet of 3/4 MDF that has (3) 56.5 inch sections of .75 Inch EMT conduit attached to the bottom for support. The conduit is attached by (5) .25 inch x 2 inch screws spaced 13 inches from each other that are counter sunk into the table. The table is attached to the machine using 6 more of the .25 inch by 2 inch screws that attach to 3 cross dowels in each end of the machine. Nothing too exciting, but its another step down.
Jordan Sipsip left a comment which among other things asked if I had noticed any sagging of the rails. I really had not noticed any issues with the rails flexing under the weight of the gantry, but I decided to do a quick test. I stacked a number of pieces of wood under the center of the longest rail so that they were almost/barely touching the rail.
I then moved the gantry to the edge of the stack and attempted to remove the top most piece of wood… it slid out without any binding at all. While not very scientific, I think this demonstrates the minimal flexing issues I have observed up to this point, and bodes well for the future.
…Well thanks to the vacation, holidays, and the drop in temperature it has been about two months since I have done any appreciable work on the machine, but I had a productive day yesterday and thought I would post an update.
I have completed all of the lead nuts and carriers, bearing blocks, and added a support to the bottom of the Y axis to firm things up.
OK, so here we go again.
A running theme in my building process is budget, I am always trying to build adequate parts myself instead of buying them. This has two goals, 1) Save money, 2) Learn how to create the parts I need so I can replace them as needed, and build more for future machines. This week’s project was couplings, specifically I needed four 1/4″ to 1/2″ couplings. I am modeling my attempt after this: DIY Coupling, and my own prior experience with using 1/4″ brass sleeve bearings for my first machine.
I decided to try and find some aluminum tubes that would fit the 1/2″ acme rod and 1/4″ motors shaft that would also nest inside each other. I found what I was looking for at OnlineMetals.com, and order the following:
0.75″ OD x 0.125″ WALL x 0.5″ ID 6061 T6 TUBE
0.5″ OD x 0.125″ WALL x 0.25″ ID 6061 T6 TUBE
They arrived in a week, I opened the box, took out the tubes and… the 1/2″ OD tube did not fit inside the 1/2″ ID tube… <*despair*> …If I only had one of they little metal lathes I could fix the problem. I have a drill press, and some 1/4″ nuts and bolts, instant vertical lathe, game on.
…I finally got back into the garage to work on the yellow and black beast again and I was able to create the first of four DIY 1/2″-10 ACME lead nuts.
You can find lead nuts starting at ~$7 on ebay, anti-backlash lead nuts from ~$16 from dumpstercnc, and up from places such as roton and other places geared towards commercial customers. I was looking for a cheap solution that I could make myself, and decided to try using some nylon spacers you can find for about 60 cents each at Lowes and Home depot. This did involve buying an 1/2″-10 AMCE Tap, these are not cheap, the best deal I found was on amazon for $35. I could have just bought a cheap set of 4 off of ebay for $28, but I am hoping this will allow me to create them myself and save money on future machines.
