In response to Matt -- the motor I stalled was the router itself (the high speed cutting motor), not one of the steppers. As I mentioned, I had a bit wander out, and it started to gouge the material. It was too much for the weeny motor to handle.

I haven't yet noticed dropped steps or accumulated error, but I do keep the belts tight and don't try to accelerate the steppers faster than they can handle. That being said, it's early yet. The Nema23's I got are 270 oz-inch, 200 steps/rev, 3 amp. I'm running them at 75% power. Plenty strong, any more than that and the machine would start to tear itself apart if it jammed.

I'll post the gantry and side plates in DXF by tomorrow, thanks for asking. I will also post a few other custom parts that may be useful. I cut these out of aluminum on a CNC plasma table, then post-machined for accurate holes.

Mark, thanks as always for the encouragement. Means a lot to know there are folks like yourself who have "been there" and are willing to lend an ear!

The router mount (with hose clamps) is really rigid, that puppy's not going to move. It was nice that the particular router has a true cylindrical shape, fits into the middle groove of the V-Groove, keeps it aligned. The (4) brackets are plasma cut and bent up, one-screw mount to the extrusion with a Tee nut. I cut the straps into two pieces, looped the cut ends through the brackets, then back on themselves. I also cut off excess length and put electrical tape over the cut end, it's pretty sharp:



For those who may be interested, the belt tensioner is similar in concept to strap tighteners that have been used on backpacks and etc for years. The belt exits from the chassis through a hole I milled into the support plate, once around the slots, and then I tuck a short end back into the chassis, locks on itself that way. The screw tip has been ground into a dull point, fits into the head of the nearby screw (to keep it in place). Here are better photos, one is a screen shot from SW (minus hardware and belt):



Also, thought I'd post a photo of the "drag chain" that I used on the carriage (there are two more under the chassis). I've not used them before, I really like them for keeping the wires out of harm's way. Also, I used Cat6 24 awg cable for the step motors, with like-colored wires paralleled (4x2) for greater current capacity:



Thanks for the leads on the 3mm belts/pulleys (and router bits). I will probably pick up some of the 3mm stuff soon, glad you're adding it to the store. I'll email you separately (as promised) with parts feedback and a few other items you may consider for the store.

Be well
N

DXF, IGS and STEP format files are now in the "Files" area for download. They're in one zip file. Enjoy!

We need video! Because other then Kram you have your machine the furthest along!

Neil was kind enough to publish the DXF, IGES, STP formats. These are the closest thing to universal formats that exist. Most CAD programs can ingest either format with out any of the following work arounds.

I played with eDrawings a bit and discovered that there is a work around - to use it to output files from his original models which you can then measure or modify. I posted over in the tutorials section:

http://www.openbuilds.com/threads/solidworks-edrawings-viewer-to-sketchup.351/

I posted this info with the hope that it may benefit anyone looking to work with these files with only freely available software. It's a little bit of work but it can be done.

Then you can generate files you can use to get CNC cut.

Glad you were able to read the files.

Looks like the version you used of the Side Plate is from an earlier rev, or you removed the "hog holes" that I put in to reduce weight. With 1/4" aluminum plate, the extra material is not needed for suitable stiffness.

The dimensions in your Sketchup drawing look good -- overall 14.7" x 8" for the Side Plate and 6.75" x 7.5" for the Gantry Carriage Plate. The height of the Side Plate is derived from my specific bed, which is thicker for the vacuum table. As Mark mentions in one of his videos, it's best to keep the routing location as close as possible (vertically) to the z-axis support wheels. In other words, if you plan to use a thinner bed, you may want to decrease the Side Plate height and thus lower the wheels.

Important: the hole diameters in my models were selected to allow post-machining for bearings, threading, screw clearance and such. If anyone plans to make a Frog, I urge you to adjust the hole specs for your specific process. You can check out the purpose of each hole by looking at the final assembly. Sorry, most of the hardware is not included in the models -- if you have questions, let me know and I'll respond asap. Also, you may be able to figure it out from the photos, which I plan to supplement soon.

I will also post a video of the thing in action. I'm not running it at full speed yet, need to get some sharp bits!

Neil

P.S. I have done some preliminary testing of the vacuum table. As long as I cover all unused holes (with plastic sheeting) it works really well!

Mark - Sure I would be glad to - Posted in tutorials..

Neil - I do like the vacuume table concept and seeing the under slung motors I am thinking that one option is to replicate the mounting hole patten for the crossbeam so that it could be mounted in a high or lower position depending on the bed in use.

Neil - Thanks so much for posting your files!

I am working up things from your side plate files for my own build. I am doing this in SketchUP and will share them if anyone is interested. I like the concept leaving some material under the gantry next to your motor mounts just in case I ever want to connect the plates with additional extrusions to better box the gantry assembly. These cross braces Could also be used to drive the gantry with ACME screws under the bed if someone wanted to go that way. I have not priced out the ACME screws vs belt & pinion drive parts yet.



I also took Mark's comments in to account and figured I'd add a second set of Y axis mounting holes in the side plates so that it's possible to choose a high or low location for the gantry extrusion based on what style of spoil board or bed is chosen for a build.

Looks great Matt, can't wait to see how the design evolves under your care! I also have thought about using a leadscrew rather than belt on the y-axis, but for now the belt is performing quite nicely.

I'll post videos soon of both routing operations and the Donek Drag Knife (a cool tool!). No surprise, with a sharp router bit I can cut really fast and still maintain accuracy.

Also the vacuum table has not disappointed, amazing how firmly it holds parts! I've ordered a standalone 3-stage vacuum (http://www.centralvacuummotor.com/Lighthouse/LH6765-13.JPG) for the table, should arrive soon. Word on the street is that Shop-Vacs have a nasty habit of bursting into flames when you restrict airflow for a prolonged run.

I'm also building a dust shoe, I'm drowning in sawdust. Here's my starting point: http://www.instructables.com/id/More-stable-dust-collection-boot-for-CNC-routers/

If it's of interest, here's the super cheap 4-axis driver I'm using. It's gotten LOTS of bad press, but so far it's behaved really well, no errors or problems at all: http://www.ebay.com/itm/4-Axis-CNC-...458?pt=LH_DefaultDomain_0&hash=item2c797b8642

Enjoy!
Neil

Neil, we need pictures, or video!

For dust shoes, you should check out this thread here. I just finished the first prototype for my dust shoe, its in that thread under nlancaster, and page 6.

DOH!

http://www.cnczone.com/forums/diy_cnc_router_table_machines/127975-show_dust_boot_pick-_shoe.html

Where?
Fixed, Thanks!

Updated my post with the link! Swear I pasted it in!!

Here's a short video showing some of the features of The Frog, hope you can see it ok:

Nice, looking great Neil. I'm interested in any details you can provide on the z axis rack and pinion setup. How did you attach the rack? Bolt completely through the extrusion? Once attached, how did you tension the pinion against it? Lastly, you said you are using cat5 to run the stepper power, are you using stranded line? Or do you think that the cable chain will protect against breaking solid copper lines?
Thanks!

Glad you like the machine, thanks

The rack is attached to 1/8" flat plate (threaded holes), which is in turn attached to the extrusion via Tee-nuts and screws. It's pretty easy to slide closer or further away to adjust gear engagement, then locked in place. I haven't observed any shifting. If you download the models I posted you may be able to see the details.

For motor cabling I used Cat6 stranded 24AWG, forming 4 pairs of 2 conductors each. I don't expect to have breakage problems. I did solder tin the ends where it attaches to the driver box. The RJ45 connectors are clean and easy.

Neet!

Thanks Nick

Also, cool thread on the dust shoe, definitely gonna grab some ideas from that one!

Thanks Robert, I'm still figuring out the best ways to use the vacuum table, so far the results are promising.

Hadn't seen Podz before (newbie!), they look like a nice solution, very flexible. Keep us informed as you progress please.

BTW my wife is a quilter, she uses a porous stiffener called "Peltex" in some of her projects. What I've found is that a layer of Peltex (search for it on Google) between the vacuum table and the workpiece allows me to cut all the way through the piece into the Peltex, thus avoiding marring the table surface. The vacuum hold-down is not affected.

I have found that the dust shoe has largely eliminated dust getting into the tracks, glad I added that. Notice the two neodymium magnets -- I have holes for 4 but that was WAY too strong. I'm re-doing the brush soon, it's a balancing act between too-stiff and not stiff enough. Also, I've added some new comments over in the build description area, plus a photo of a new vacuum motor and my first 3d contouring project. Onward!

Hey, thanks

looking good. How loud is that vacuum for the table?

Hard to be precise. It's not as loud as a shopvac, mostly due to the muffler.

Anyway, the router is quite loud so I wear Peltor earmuffs when I'm working.

you think that little router is loud? My big CNC router uses a 2.25hp router. you can hear it next door.

Earmuffs, required CNC accessory.

Yikes!