CNC Routers

[ktm_2000]

Hi All,

Its the middle of winter and I've got time to research stuff so I've been thinking about ways to improve my projects and get more accurate and professional cuts. It seems like there are quite a few consumer grade CNC routers out there and I've convinced myself that I want one.

Of course I am up for punishment and I was thinking of putting together one DIY as there are tons of kit pieces as well as videos and forums on how to put it all together.

Here's some project ideas I was thinking of:
Dash panel for Bertram - inset display screens
Clear Acrylic Cover panel for Livewell
Wooden engraved Name Plate for my Bertram
To make small hatches out of starboard to go under the gunnels of Bertram
To make fairly large panel out of starboard to enclose under the dash of the doghouse
non-boat - Single piece MDF Cabinent Doors for a group of Cabinets I built a few years ago with random sizes to fit into places
Dovetail joint Draws for cabinets
Fabrication of small shop jigs
"jig" made out of acrylic to scan film negatives with my mirrorless camera

Most of the items I am thinking about are fairly small other than the dash 12"x36" and under doghouse dash enclosure, What I would like to figure out is what size to make?

I am thinking in line with this guy's build but maybe purchase more of the components like the z axis rather than build myself and build the gantry out of aluminum extrusion.


Does anyone here have any experience with these machines?

[Rawleigh]

If you can make it fit a full 4x8 sheet without being too expensive you would probably be happier than a partial sheet.

[Tony Meola]

That would be cool, but my wife would have me committed.

[ktm_2000]

I don't do anything the easy way - and this involves more machine skills to build, a skillset which I am definitely lacking in

I've got @3 weeks to get it to come together before its full time boat, boat and more boat.

rough outline - alum C channel extrusion, linear rail bearings on top, it is sized 1m x 1m.
https://photos.app.goo.gl/jPesG8uf1KCY4Xaa6

I'm figuring out the bolt hole patterns for the bearings which the gantry rides on, I don't have the right size screws to put it together but the holes matched up fine, I can stack the other side and duplicate this piece fairly easily. This will also be the same pattern for part of the Z up/down axis.
https://photos.app.goo.gl/KYBQ7ip3UDaqg2he7

[Rawleigh]

Very cool! I look forward to following this build. Looks like McMaster Carr will be your friend!

[ktm_2000]

I am no machinst but I learn fast and have been watching an old timer machinist on youtube demonstrating techniques on how to drill accurate holes. So I bought a dial height gauge and a scribe and it came in today and I started making plates for the z axis of the cnc router. I didn't put all the bearings on the linear rails but just enough to see how things fit. I've left the panels long for right now and as I figure out how everything will come together I will cut them to size.

The Gantry is sitting on the side rails, z axis is in up position. I haven't made the side gantry plates yet as I have a lot to figure out
https://photos.app.goo.gl/rDYpiXBSMQorCkEd7

z axis in the down position. All the holes for the rails were drilled and tapped
https://photos.app.goo.gl/sb1LkJHU3jPjKHMY7

[Rawleigh]

Good job! Tubalcain is a retired shop teacher who has great videos teaching machining techniques.

[ktm_2000]

That's the guy who's videos I've been watching

Any way - - I got somewhat frustrated at my lack of skills as even following his videos and purchasing a new caliper and dial height gauge I was doing something wrong and the holes were not matching up perfectly - I only put 3/4 bolts through bearing, lower area had the back side piece to install 6 bolts and only 3 lined up correctly - I don't have any slack in the bolt holes and the ones that are off aren't by much so drilling the holes 1 size bigger would get me there.
https://photos.app.goo.gl/CJaaZd8szvxXdtdQ7

I did get the gantry setup and did a quick demo with a drill
https://photos.app.goo.gl/oBmCnY1kCcgjWxri7


In cruising through craigslist I noticed a person in town selling a Chinese 6040 router for very short $ so I called the guy and went and got it.
https://photos.app.goo.gl/CMZcqcSwEvpzzond6

The person selling the cnc had bought it, did a bunch of projects and wanted a better setup so he used the CNC to mill up the aluminum plates to make a better CNC and he sold it off to me. I think I am going to do the same path, one nice thing is that I could swap the parts over to my build to test as well as the overall cost was less than what it would have cost for the stepper motors, spindle and a few other parts he gave me.

learning new stuff - I built up a PC with LinuxCNC last night and as soon as I get the right parallel cable I should be able to start tuning the parameters and making a cut.

[Rawleigh]

Well that certainly saved a lot of time! Probably frustration too! With your computer knowledge CAD should be a breeze! Keep me updated on your journey.

[ktm_2000]

I was able to make some sawdust today

a view of the setup - the guy gave me his table too
https://photos.app.goo.gl/tt31yLEEds84H8Pu9

a view of the cut out piece
https://photos.app.goo.gl/XgorqFFTLE8jTyMt8

I've got a lot to learn in this topic, I have a bunch of drawings in google sketchup that need to be converted into gcode (machine language) and I will be learning what software will do that CAM work

now the fun stuff of finding engineering drawings of the Suzuki engine gauge as well as the B&G electronics and starting to draw out a dash panel, I also want to track down a Bertram logo so I can see if I can engrave that into some parts such as hatch doors

I'm sure I've got quite a bit to figure out the feed rate and speeds to run the cnc for different materials and will mess up quite a bit as I learn but this is fun stuff to me.

[Rawleigh]

Nice! Keep us posted!

[ktm_2000]

Rawleigh,

I've made a bunch of small parts and learning as I go, I subscribe to the crawl, walk, run approach and right now I am still crawling.

making a 5 switch panel instead of 6 - messed up the cam portion as most of the holes I had the router cut the outside instead of inside
https://photos.app.goo.gl/m84jKndUWa6wmkBd7

a 2nd attempt - there is still a small semi circle on the bottom so I think I cut the outside wrong
https://photos.app.goo.gl/ZYh7Err3YMduTtkh7

dust collection cart top - nothing earth shattering but 2 very precise holes. I did mess up on this one too but was able to recover, the front hole for the 5 gallon bucket I measured the bottom and added 1/2" to account for flare but that wasn't enough. Nice part was that I was able to redesign in the software to make the circle larger, get the board setup in the right spot again and recut.
https://photos.app.goo.gl/qp1oxQmJjWDK4Ldo6

I've made a bunch of signs with my kids, nieces and nephews names, those are coming out good and fairly straight forward to make. There is an art to what fonts look good

overall I am learning pretty slow when it comes to building the drawings in autodesk 360 fusion along with the CAM portion, I struggle with cutting out portions out of a solid and on the CAM side figuring out cut paths and what tool is best for the job. Right now my challenge to learn is to figure out how to cut small holes for M4 screws into aluminum and not break 1/16" bits

[Rawleigh]

How about just making a dimple with a center drill on the CNC and then finishing it on the drill press?

[Rawleigh]

Have you used it any more on your project??

[ktm_2000]

Rawleigh,

I have not used it on the Bertram Project lately, been somewhat swamped with work so any free time I get, I'm focusing on getting all the sanding and fairing of the cockpit done. I think when I get the areas gelcoated and I start on adding finishing touches and will pick that up again.

[Rawleigh]

I understand being overwhelmed! I look forward to an update when you get back to it.

[Carl]

and what tool is best for the job. Right now my challenge to learn is to figure out how to cut small holes for M4 screws into aluminum and not break 1/16" bits

The best tool is a #30 drill (.1285 dia), tap it to complete. I'd start with a spot drill for location going a tad bit deeper to add a chamfer slightly larger than the major diameter, taps like chamfers to start, plus chamfer looks good and you don't get that first raised thread.

A drill, yep that super simple old-fashioned drill is still one of the most efficient ways of removing material quickly with precision at a decent finish. Do not overlook the obvious.

Trying to interpolate a .130 hole with a 1/16" endmill to any substantial depth is painfully slow. Even slower if you do not have coolant or air flushing the chips out of the way...chips that do not get out of the tool path are recut and that Is Not Good. You program a chip load of say .0003 per flute at .03 depth of cut which the tool can handle. Now If only "one" of those chips gets in the tool path, the tool is cutting the intended .0003 Plus the chip thickness at .0003 doubling the amount the tool flute has to cut, that can pop the tool...now get multiple chips being recut it's even worse.

Then it also looks like you are cutting plastic which has its own issues as some of it is abrasive polishing the sharpness off the tools making them run hotter leading to material welding onto the flutes. Once that happens your no longer cutting but rubbing leading to a poped tool.

Also, the heat leaves the cut in the chips...chips not being evacuated creates more heat...see above. Small slender tools are problematic for that reason...no room to evacuate chips, chips get recut, heat builds up...drill when you can.

Now if you feel the need to interpolate the hole as you have a CNC, I'd say drill the hole then a finish pass to size.

[ktm_2000]

Carl,

I did similar to what you recommended to make some side plates out of 1/4" lexan for a friend who was making a Rasberry PI server. He did the case itself on a 3d printer then He got a file for the sides of the cases and I used multiple tool passes to cut it out. I used double sided tape to hold down the piece of material, did a 1st pass with a starter drill went down .2mm just to get the V where the holes needed to be drilled and then I drilled out the holes and then put screws to hold down the part to my waste board. I then changed tools and cut the rest out with a 1/8" straight cut bit. my pattern has been to put a mark on the center of one side of a piece, and setup the starting point for a pattern off of that, if I need multiple passes, I can go back to that side point so everything lines up.

way more work to figure it all out than if he just bought the parts off ebay for $10, once setup I could make a bunch if I wanted.

This is really my learning, you can do a lot of prototype stuff, to get fairly high precision, you have to put a bunch of effort into a part.