Here is a photo of my friends tabletop CNC machine he built.

He is quite a craftsman! Attached files

 

very nice

 

That's sweet, looks like it could make some parts out of fiberboard pretty easily! Do you have any idea how much it costs to build a machine like this?

 

He has not worked up a bill of materials as yet but at one point I think he told me that he thought it should be around $300 for the oak, stainless steel rods, bearings and such.

He uses nothing but top grade materials, so I expect you could make it for less if you were tight for cash.

He has said I could come over to his place and build one for myself, but I really don't have the space to put another CNC machine as much as I would like to have one.

I watched the progress as his table evolved. It was not a simple task although he makes it look simple.

He went from plans on paper napkins to a fully working machine in about 2 maybe 3 weeks and this included putting together a controller board with a power supply he designed. All of the stepper motors for this machine as well as two other mills he has mechanised have interchangeable connectors.

He has rigged up 2 controllers so far, one using the easy cnc board, and another using the probotix single driver boards and he runs everything from his laptop using two smooth steppers. I think his original plan was to have one controller for all three machines but has now decided to make individual controllers for each.

His big mill uses 482oz/in steppers and the table top router you see in the photo uses the 166 oz/in steppers I posted from MPJA.

He is an inspiration to me. I hope that he will join in the forum discussions and post his own words and information about his designs.

 

News Flash!

The incessant rains here in Florida have brought the Oak tabletop router to a standstill!

It seems that the oak took in some moisture and swelled up causing all of the axis to bind!

Version MK II of the table top router is now in progress.

Out with the oak, in with the new (aluminum)... Attached files

 

Did you guys know that 8020.net regularly sells their mis-cut and odd-length extrusion pieces on eBay, at a considerable price cut? Just search for "8020" on eBay and smile!

 

Larry,
Thanks for the kind words!

The oak machine was a test of how to make a CNC machine. I wanted to CNC a couple of mini mills I had, and when I saw Larry's PhlatPrinter, it all got out of hand quickly!

Stainless rods, bushings, stepper motors, controllers, wiring, napkin designs quickly found their way into my shop, and the fun was on...

I was just getting to carve out some wood on the cnc router, and made a few test items to get used to it when I found one of the axes (Y) wouldn't move. I had to drive one of the guide rods out with a hammer. It normally just slides right in. The other axes were ok.

So... back to the drawing board.
I'm dropping the bushings and going with full bearing carriages and rails. This should eliminate the friction caused by a bearing setup, and not increase the cost by much at all.
I found the picture of the mill Larry posted, and decided on the T-slot Aluminum as a great CNC Erector Set! You could make it as big (or small, Larry! you might have room for one after all!) as you needed.

I did see the garage sale on ebay for the series 10 and 15 stock, but the individual shipping prices quickly made it quite expensive. I believe I found a supplier that will cut it to length to order for very good prices.

I'll post the build here if folks are interested, as well as the dimensions/suppliers/parts/whatever.

And to think it all started with "The PhlatPrinter looks cool. I should start gathering the steppers and drive parts..."

John

 

Crash,

$3k should be more than enough (famous last words). I too tried to absorb all the data from the various CNC forums. The electronics (for me) is the easiest part. The real decision was the type of bearings/bushings to use for the carriages. I initially went with ground stainless 3/4 in bar with bronze bushings. It did work, but way too much friction.
I finally found a full ball bearing carriage system running on 1/4" cold rolled plate that looks like it will support whatever you throw at it without breaking the bank.
I'm gathering test amount of materials to build an x and y axis using the aluminum extrusions. I'll post the configurations once the stuff starts arriving at the house and I start assembling it.
I'll post the dimensions and all the parts sources that I use, as well as alternatives I considered (and why I didn't use them).
I should begin posting some info in about a week or so.
Too many projects, not enough time!

John

 

I've used 8020 before to build stuff at work and it's awesome. I design everything in CAD first and then send 8020 cut, tap and bore specs and the 8020 would arrive at my door all pre-cut, tapped and drilled, all I would have to do is assemble the parts. And it only costs a little more to have them cut the parts for you. This coupled with the free design service Dorsal mentioned makes 8020 a pretty good deal in my opinion.

 

Crash,
Just a couple thoughts..

Joes machine looks great, super design, BUT it is a hybrid. Alum/steel is stronger than MDF...

The 8020 extruded series 15 parts would easily support a 3 x 4 or a 4 x 4 size easily. One of the mods I'm looking to do on the plans I listed above is to build a 4 x 4 table. The extrusions will allow extending the width or lenght easily, without having to build a whole new machine. The steel rails add considerable rigidity all the way up to almost 6-8 feet, wher you would run into screw whip at fast screw speeds. (it would probably also take a long time to move the carriage over the length of the table, but that's to be expected with a table this big).

As for steppers/driver board, I have the EasyCNC, HobbyCNC, Probotix and GeckoDrive controllers in my shop, and for a machine this size, the EasyCNC should have no problem if you use a 425 size stepper rated at under 2.5A (they do get pricey at this size/amp rating).
Remember, most of the bipolar controllers (with the exception of the Gecko, this is a cadillac of controllers) are limited to around 3A max. The HobbyCNC controller is UniPolar, and the stepper ratings will be reduced accordingly. The real concern is the power supply. So far I'm not having any problems missing steps or exceeding current on my 10A supply. I have not run any measurements on if I am exceeding current limits from the supply when driving all axis's simultaneously though.

Just some comments...
John

 

Crash,

Drop me a line at johnbernard810@comcast.net, and we'll exchange skype/video numbers. I have video in the office and the shop, so we can do a video con call...

You are right about doing it right once. Building something that doesn't fit your needs to save a couple of bucks just costs twice as much in the end to re-do it to what you wanted in the first place (ask me how I know, as I do this time and time again...).
John

 

As a follow-up to the previous, I have pulled the trigger and am committed (should be committed?) to the build. I ordered all the carriages, the Z and Y steel rail, the Z plate, a porter cable router mount from K2, a couple of bearing blocks, etc. I already have some ACME screws, antibacklash nuts, steppers, drivers, etc. laying around. My thoughts were to build a working Z axis to get used to the material and design, and go from there. At this point, I don't know if it would be cheaper to get a cut kit from FLA, or piece build it to my specs. If you want a 4 x 4 table, you pretty much need to build it yourself, as I believe their kit is 3 x 4. Regardless, it seems like the parts will run less that $1500, but we'll see.

John

 

Crash,

Sounds good. I see you're in Texas (I'm in FL). I get some of my stuff from DumpsterCNC in your state...

As a side note, a 4 x 4 machine is big enough to use the table to support at least a couple of PhlatPrinter MK II's when you're not using the router!!!

Thought... set up a safe zone on the router table to run both machines at once? Sick?

 

I received my order from Fine Line Automation of drive rails, carriages, z-axis plate, a couple bearing blocks, a couple 8020 motor mounts, and various other pieces to see how an 8020 aluminum extrusion machine would go together.

All I can say is I wish I had used these parts instead of screwing around with bars and bushings. The rail and extrusion system seems strong enough to support a fully loaded cement truck!

I put together the Z axis and had it moving in about an hour. It is very smooth and seems to have almost no drag compared to my original rail system.



I gathered together some spare parts and put together a Y axis (the screw is short only because that's what I had laying around). I use screws that have the ends turned down for bearings, and then one end is further turned down to 1/4 for a motor coupling. This makes for a very simple drive interface as can be seen in the photo of the x and y axis.


I can't say enough about an 8020 aluminum extrusion based machine. Solid as a rock, goes together quickly as the rails, carriages, bearing blocks are drilled for easy assembly, like a giant erector set.
As I have a lot of components, I'm going to order the parts piecemeal, or have a custom parts bundle put together. I believe this is an option at FLA, as they seem very open to putting together a package based on your specific needs, as well as having some pre-configured packages.

I am making some cusom bearing blocks just to support the configuration I already have, but the beauty is the ability to easily customize to fit your needs.

Just thought I'd drop a line to show what the original wood machin morphed into. I'll post some additional progress once my next order comes in.

This is my controller with a built in smoothstepper.
Attached files

 

I love it!!! See what I started! LOL

 

Crash: Look at K2CNC for a router mount. That what I'm using for my Porter Cable trim router, and it fit great. http://www.k2cnc.com/shop/products.asp?cat=31

Flash: We're going to have to hurt you!

Hybrid machine while I'm ordering parts:

Bolted my 8020 Y and Z axis to my original oak machine. Here is where you can feel the difference between the FLA rails, CNCRouterParts Carriages, and the solid feel of the 8020 extrusions. Yes, it actually works, but it was more for fun than doing any work with it....


Attached files