First CNC Build- Joe's

[louieatienza]

I agree the table saw does seem to have the most accidents connected to it, and I think you're right, because it is the most common tool in the shop. I think its a little ironic that it's also the most difficult to make safe. I don't know a shop rat thats comfortable using a table saw with guards for the same reason I don't like it, they block my view of the blade, and where my hands are in relation to said blade. I've never had the pleasure of using one of those instant stop things, but I might love it if I actually triggered one, that being said I don't know if I would want to get behind a saw that had actually seen one triggered, bearings?
Anyway in the interest of karma, as this is my build thread, and I'd like to keep the vibe good ( I know I first brought up the accidents, sorry!).
Did I mention that its very satisfying just moving the the darn carriage back and forth? And I think I ran through two battery charges on my drill just running the Z axis up and down!
On a slightly more relevent note most probably have not noticed that my gantry sides are thicker than normal. I read a lot about the gantry needing a little extra bracing so I decided to make mine from two layers of 3/4" mdf. With the gantry assembled in trial mode, just finger tight it seems very rigid, I'm debating whether I need the extra threaded rod lower in the gantry which seems pretty standard now, I can't really see how it would help, and as I said things seem pretty rigid, any thoughts?

I'vev seen quite a few of these builds, where additional support on the gantry uprights were added later so doubling that up was a good idea. Of course things that seem pretty ridgid now in a static state can be different when things are moving, accelerating, and decelerating.

[Ohioflyer]

I'm sure your right, I'll probably put in the penetrations just to be on the safe side. I suppose what I was wondering is if the gantry sides were deflecting while the side/torsion box joints remained rigid (in which case my sides should resist this more). Or of the whole gantry frame was moving like a paralellogram, ie: the joints were moving as well as the sides deflecting (in which case my mod won't do any good). In either case I'm still not seeing how adding more horizontals will help. Wouldn't they have to be braced at an angle to prevent flex?

[TrickyCNC]

My Dad was chopping up rough wood for the fire two weeks ago, the wood caught and he ended up with two fingers less

he has been warned (nagged) by his wife many times, but wouldn't listen.... you gotta take care with sharp spinny things !!!

[Ohioflyer]

Well, time for my nightly update,
I'm in the middle of painting the upper and lower torsion boxes and gantry sides with the hammer paint. The torsion boxes only have one coat of primer, but this stuff seemed to go on so thick last time I figured one coat would probably work. I few thing I just learned. This stuff has some sort of heavy duty solvent in it, something that dissolves itself. So if like me you use the same old paint tray DON't! I got around to the second coat and the earlier layer of dried paint had flaked off onto my new stuff, so when I rolled on the new coat I got TONS of flakes in it. Also today at my local hardware store they did not have the foam rollers, so I got some napp ones. I like using them much better, they hold the paint better and lay down a nicer pattern, that is until the second coat. This stuff is meant to get its second coat before the first is fully dry, as such the rollers experience a lot of tack on that second coat, bad with a nappy roller. So now I have a torsion box side full of paint flakes, and a gantry side full of roller napp.
Also I tried to assemble the x axis bearing adjuster. I had the parts already made from HDPE, just needed to be drilled and tapped. So I set up my various jigs and stop blocks and started drilling...and forgot to lock the drill press table down. Soooo my alignment is terrible, and I don't have any more HDPE, will order more tonight, that is if I can manage to make a web browser work. I guess its been one of those days.

Well onto the questions:
What are people doing for AC spindle power? I was going to wire a handi box onto my z axis carriage, but the more I think about it the more I think I would like a little more elegant solution.
Also I got to thinking about limit switches and emergency stops. I plan to have two emergency stops, one on either side if the machine ( so when I get to close and it grabs me by my dirty hippie hair I'll have recourse) and I got to thinking, the limit switches won't nessisarily stop the spindle, so I thought it would be a good idea to put a relay or contactor in line with the limit switches to control AC power? And as for the emergency stop goes I suppose I need a DPST button, one pole for AC power and one for DC power to the stepper drivers?
I got to thinking about the resonance issues I'm sure to face. My steppers (425oz) from Keling have rear spindles so I'm thinking about dampers. Was it you Carveone, or maybe the Bamboo build thread that had the wood dampers with weights located around the perimeter. I remember the authur said it worked better than the Castor solution, thought I might check it out a little closer, but have not been able to find the thread again, a point there would be greatly appreciated if anyone remembers.

[Ohioflyer]

OK,

That was last nights post. That crack about getting a web browser to work? guess I spoke too soon. Actually my internet went down, happens all the time here, the only time I don't mind is when it drops some nice powder for skiing, so last night was a mystery.
Anyway today went a lot better that yesterday, I fished out my x axis pipes out to turn down and realized that when I bought them they only had two that looked good, so tomorrow I have to run to town and get a few more, maybe I'll I'll get some aluminum tube while I'm at it as I've had no luck with the brass. The two I did today turned out pretty nice. As my x axis is 6' and these pipes are bigger than the y pipes I had to turn them much slower than before, so doing only two at a time is fine with me. I can only run sandpaper over a spinning pipe for so many hours before it gets old.

The other job I completed was finishing the glue-up on my table. I cant remember if I mentioned earlier that 1/4" mdf does not exist in my town in 4'x8' sheets. At the time I discovered this I thought " no problem, I'll just dado some 1/2" mdf to match the box structure of my table". If you are building by hand like I am I want to offer a little advice, do not ever ever ever, ever ever ever...ever do this. resize your bulkheads to compensate for the 1/2" mdf. This is asking too much of hand tools in the front yard, regardless of how much time you take. With my extended table I have something like 48 lapped dado joints per side. There were discrepancies. Hours of eating mdf dust got me there, things still feel pretty tight, but we'll see what kind of deflection I get when everything dries. I'll be happy if it comes out flat and sturdy. I think my "seating" operation" for the pipes is going to get a good workout here. In any case it will certainly be good enough to cut out parts for another table down the line.
Despite these troubles it has been a good day, I believe this is the last large glue job left. The rest of this project is finish, not fab I believe. Thats a good milestone. There are still bearing blocks and things to make, but its small stuff. Lots of tweeking I'm sure, and of course more painting, I hate paint. so it goes...
Will try to get some pics up

[ger21]

Home Depot should be able to special order 1/4" MDF sheets for you.

I think my dampers are the only ones I've seen made of wood? You can find them in the damper thread.

For power to my router, I bought some flexible power wire from McMaster Carr to run from my control box all the way to the router, through the e-chain.

[louieatienza]

You might be able to get 1/4" white melamine at Home Depot. Sometimes it has an MDF core, sometimes it has Masonite. They usually have 2' x 4' pieces of different thicknesses...

As for paint, it helps to use tray sleeves, they're pennies each, and yo can just throw them out after; no paint lifting and no cleaning. If you're waiting to do a second coat, put the tray and roller in a plastic bag, remove as much air as you can, and tie the bag or fold it under. This way the paint won't dry right away and it will be fresh for the second coat. also, if you're using a smaller roller (or have the paint in a larger bucket) you could simply just leave the roller sleeve in the paint can or bucket before sealing it. For brushes, get an old coffee can, make a small slit on the plastic lid, and push the handle through. Put enough paint in the can to cover the bristles...

[Ohioflyer]

Lets see, today I managed to prep and paint the main table. Doesent sound like much but I had to move the table to its final location. The extra hands I lined up for that disappeared as well, that thing is rather heavy. Have not checked deflection yet but it seems very rigid. I laid a straight edge on the top and it looked pretty flat, no low spots as far as I can tell, on the top anyway. The bottom side has a slight wiggle to it but I can live with that. I went ahead and seated the side rails, both sides top and bottom seem parallel to each other reasonably. We'll see how the gantry slides roll I guess. I didn't manage to make it to HD to get the last Two X axis rails, tomorrow.
My HD has 1/4" mdf in 2'/4' size only. I don't like special orders from the big boxes (used to work for one) its not worth the trouble. despite my dadoing I 'm sure I saved time. The only white melamine stuff they have near me is 3/16"
I do like that coffee can Idea, might save a brush cleaning. That being said the afor-mentioned paint problems do not bother me that much, they suck yes but this is a tool, I might fix them if I feel ambitious, but maybe not. I admit that I am not a finish guy...at all. I can make some bleeping nice things in wood, and ruin them with the finish. I kid you not my most prized piece of personal furniture I varnished for TEN months, continuously. Anyway I hate finishing.
I had not planned on dedicating my router completely to the cnc. I'm sure I'll want to use it separately from time to time, so I thought I would have to mount a plug on the gantry somewhere for it. Also as I have several routers, I thought I would make several adapter rings so I could use whichever seemed the most appropriate for the job, hence my power question. Does anyone have any Ideas on the relay? If this thing ever reaches a cutout switch point does the spindle keep cutting?
I apologize if I am missing something. I don't know where to look for the damper thread. I've done damper searches, but I cannot find thread, again if I'm typing with thumbs I apologize.
Is E-Chain drag chain?

I thought it would be handy to be able to disconnect the electronics ( machine) from the computer, my local radio shack has a few plug connectors styles (molex) and they are very pricey. I've searched digikey and mouser for these and I must be calling them by the wrong name, I'm sure they exist but I cannot find them. I would like to have a one plug solution ( not amphonol ) something like a motherboard power connection, with the stackable 4-pins if nessisary.

[Ohioflyer]

Pics

[TrickyCNC]

real nice work there !

nice view too ! where abouts are you ?
Any chance of a better pic

[TrickyCNC]

nice view too ! where abouts are you ?

Doh!!! ... I guess the clue is in your user name !
Still.. a pic would be good

[ger21]

Typing "damper" in the Google search bar in the upper right takes you right to it.
http://www.cnczone.com/forums/steppe...er_damper.html