Dirks 4x8 CNC Router Build

[dirktheeng]

All,

Started making my limit switch setup using the Pogo Pins. I think this will work very well and be very accurate. Plus it's super cheap. I think I can build the whole system for under $25 and maintain sub 0.001", have great temperature stability, and be stable over time. It is essentially the same kind of switch we use to zero the tool (direct electrical contact).

Check it out:

[dirktheeng]

All,

I got one of the limit switches put together today and tested it out. It works good and is pretty hearty. I purposely crashed the mill to see if it would break and it didn't. I have to to a repeatability study yet, but I think it will do very very well. I turned the kernel speed up to get Mach 3 to respond more quickly and that really helped get the axis stopped when I crashed it. I think I am going to switch the bracket around so that it zero's when the single bumper is compressed a little to protect the homing switch a bit more.

Anyhow, here's the test:

[dirktheeng]

All,

Today my dad and I finished up the homing/limit switches. I have to say that I would challenge anybody to come up with a more precise homing system for less money than I spent. I have about $15 of materials into the system and ended up with a very good homing system (not counting the extra that I had in the system because I couldn't buy a small enough quantity). The only thing to be mindful of is heavy dusting. I don't have that problem if my dust shoe and dust collector are working correctly. I don't even get the smell of wood dust (which is a good way to test for very small, invisible wood dust) when I run the system with mdf with a smallish bit.

Anyhow, I did a repeatability study and basically my dial indicator is not accurate enough to really assess the homing error. That means that it is in the sub 0.00025" region.

Check it out:



I also got the gantry squared up and it has about the same precision (which is expected), but my setup for measuring that is a bit shaky. I need a way to lock the spindle a bit better. Anybody have any suggestions?

[canadianavenger]

you might consider using a gold plated contact pad for the pogo pins to mate with to ensure long-term operation. The aluminum of your frame will oxidize over time, and aluminum oxide is non-conductive [it's actually quite an effective insulator]. As a result your limit switches may stop working or become intermittent over time.

[dirktheeng]

you might consider using a gold plated contact pad for the pogo pins to mate with to ensure long-term operation. The aluminum of your frame will oxidize over time, and aluminum oxide is non-conductive [it's actually quite an effective insulator]. As a result your limit switches may stop working or become intermittent over time.

I'll keep an eye on that. I haven't noticed a problem with it yet with any aluminum part that isn't anodized. The oxide film tends to only be a few nanometers thick and self heals. Under normal atmospheric conditions, it will usually never get thicker than that. It also forms within the first few seconds that fresh aluminum is exposed. In that kind of thickness, even a high resistivity material, like aluminum oxide, doesn't account for much loss. If it gets too thick it can be a problem. The anodized finish is nothing more than a thick aluminum oxide. That kind of finish can prevent electrical current from flowing. At worst, I could take a bit of 3000 sand paper to the face and clean it up.

I could also put a stainless bolt in there too. That would be a lot cheaper.

[dirktheeng]

All,

Today my dad and I worked on making a few shop jigs for us to use. We made a bowl gouge sharpening jig and a bunch of push sticks for our saws and such. I tried my hand at double sided machining and it didn't go so well. I used pins for alignment and somehow I got my pin gcode mixed in with my cutout gcode and I ended up machining stainless steel... I was actually surprised that the bit didn't break up as soon as it touched the steel... it actually cut about half an inch of the 3/8" pin away before the bit broke.

I think I should make some plastic locating pins instead of steel ones or use wood dowels so I reduce the risk of breaking bits this way again. I try so hard to be vigilant about how I set stuff up, but I made a lot of mistakes today... some were rookie stuff others were just stupid oversites. I'm going to make a check list to go through every time I start to mill something.

[dirktheeng]

All,

I started my own website: http://www.21stcenturywoodworking.com

The website is dedicated to tips, tricks, techniques and projects for cnc woodworking. I will host project files as I go though and make them and step by step instructional videos.

Here's a sample:



I'd like to invite all of you over to the website and would ask that you register when you get there. Registration is free and will allow you to get access to the Project Downloads page.

Also, if you register, you will get notifications of new content and downloads as they become available. I am going to try to post a new project every couple weeks.

[dirktheeng]

The z touch plate is all set up. Check out the video:



Come to http://www.21stCenturyWoodworking.com to get the project files and the machine setup instructions and macro's.

[dirktheeng]

Saw a video about traditional inlay banding manufacture on youtube by AppJourneyman. Thought you guys would like to see!