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Build Log

Some assembly completed

posted Jun 25, 2016, 7:54 PM by Daniel Taylor

I assembled things enough to check squareness... and it looks pretty good. At least as far as I can tell without actually machining some hard material.

That said, I may or may not have broken one of my stepper drivers. Due to a wiring issue, I blew up one of the current-sense resistors (it's 0.056 ohms, so I don't know what else it would be). On the up side, I can replace that pretty easily (and DigiKey will get parts here in a couple days for a reasonable fee). On the down side, it's one more thing to do.

Next step is probably trying to wire up a 240Vac outlet. I don't have one of those here, and definitely need one before I can cut anything.

So... mechanical good, electrical still needs work. And actually the mechanical does as well (adding in two more bracing pieces on the bottom, tapping the holes in the table, putting all the screws in the Y axis rails, etc.), but it's enough to try cutting things.

Some assembly required

posted Jun 22, 2016, 8:38 PM by Daniel Taylor   [ updated Jun 25, 2016, 7:55 PM ]

I think that's the last of the parts that need to be made. A few still need some more or less minor fitting/rework, but overall it's just assembly at this point. Plus pesky details like electronics and limit switches...

Anyway, the pictures:

The back piece needs the hole for the coupling enlarged so the clamping screw doesn't catch on it, but otherwise seems to fit well. The corner supports look good.

The table also fits well somehow- I'm still amazed when that happens, despite CAD and building things via CNC. The holes/countersinks line up perfectly for the ballnut mount and linear bearings. It just needs the edges cleaned up (not technically required, except for maybe the edge by the stepper), several holes drilled (all those black X marks), and every single bloody hole tapped. Preferably actually perpendicular to the plane, unlike most of my tapping jobs...

In short: I'm super excited! So close...

X axis (mostly) assembled

posted Jun 21, 2016, 8:27 PM by Daniel Taylor

Not terribly new, but all put together:

Everything fits together really well, and it moves smoothly. I don't think there's much more I can ask for.

Nothing else today was terribly picturesque- mostly just marking hole locations for the cross braces on the under side of the base. It's probably overly-optimistic, but I'm hoping to get the final few pieces machined tomorrow. Then drilling out some holes to allow things to fit better (namely the side plates), and I'm well on my way to being able to hook up some electronics.

Not as complete as it looks

posted Jun 20, 2016, 8:07 PM by Daniel Taylor   [ updated Jun 21, 2016, 11:25 AM ]

I got enough pieces done enough that I wanted to stick things more or less together. Here's the result:

The "full assembly" there isn't quite as close to complete as it looks. The gantry is held on by only a few screws, since they don't entirely line up. Not sure what's crooked, but something sure is. The sides are also only loosely held. The rails need a couple more holes tapped/screws put in. And so on.

Still, only some 4 pieces left to machine (well, 6 pieces, but 4 of them are half-done, so I'll call it 4). Plus fitting, of course, which probably means drilling out some holes to accommodate my crooked tapping, and hitting some crooked gantry supports with the belt sander.

The only really "new" thing to be seen (aside from things being assembled) is the channel cut on the table. That should allow the ballnut to move without grating on the bottom.

10 holes/hour

posted Jun 19, 2016, 8:42 PM by Daniel Taylor

Or thereabouts. Seems a little unreasonable when put in those terms, but that also included machining edges, aligning everything (multiple times), and more. On the up side, the base is more or less done! Mostly what's left is to machine the channel in the middle so the ballnut has some clearance. That didn't get done today because the chunk of metal is warped, and I'd rather like that area to be planar with the rest of it. Anyway, the idea is that the linear rails and the supports on the bottom should hold it pretty flat.

(Also pictured are the new ginormous linear rails. They could probably use a little grease, but otherwise seem fantastic)

Quick update

posted Jun 9, 2016, 8:32 PM by Daniel Taylor

It's late, so I'll just say that the edge pieces for my mill are done-ish (and post a picture of dubious quality). They just need holes tapped. I'm pretty pleased with how they turned out, especially given how many different times I had to clamp/unclamp the part. Miraculously enough, the relevant corner is about as square as I can measure- no play I can see with a machinists square. Yay!

Also, the X axis is more or less assembled. The Z mounting plate and leadscrew even fit on there, and seem to line up nicely. I'm always amazed when parts actually fit together.

Z axis assembled

posted Jun 2, 2016, 7:14 PM by Daniel Taylor

There's a big step- the Z axis is fully(ish) assembled! At least all the hard parts (ie, the ballscrew is secured and going through the carriage). I made a small mistake, and need to drill a hole up top so I can tighten the coupling onto the leadscrew, but that's not terribly difficult nor requiring precision. There leadscrew also isn't quite centered in the axis, so I need to machine out the mounting holes for the stepper plate a bit so it can float into the right position. Again, no big deal.

Overall I'm happy. The plate to attach it to the X axis is "done"- all the holes are cut, the relevant surfaces machined flat, and the cutout for the leadscrew mounting block has been made. All that needs to be done on it is to cut it down to the right size- it currently has an extra ~inch on one side...

Z axis almost done

posted May 28, 2016, 5:18 PM by Daniel Taylor   [ updated Jun 2, 2016, 7:16 PM ]

After screwing up a couple things, the Z axis is mostly done. I got the front milled flat to accept the new spindle adapter place, a hole bored through it for the leadscrew, and a cutout (plus mounting holes) for the ballnut. Oh, and a place for the bearing beneath it, of course. One little piece needs to be fabbed yet (a bearing clamp for the top side of the leadscrew), and some holes need to be tapped, but otherwise it's basically set.

A couple things really went wrong when doing this work. First, the cutout for the ballnut was too big- I screwed up the gcode offsets. Anyway, that meant that the six mounting holes for the ballnut couldn't be drilled. So... with some help and the use of a press, a new chunk of metal was machined to size and pressed in the hole. Then I drilled the holes, and machined the ballnut cavity to the proper size. There shouldn't be a lot of force on those screws (the flange is at the bottom of the carriage), so I think it's all good.

Speaking of the ballnut... that had to be reversed on the ballscrew. Now, I know there are ball bearings in there, so I was being smart, and turned a piece that would fit on the end of the ballscrew to keep the balls inside while I twisted the nut off. That... didn't work. Somehow the balls got out of their tracks anyway. Fortunately they were covered in grease, and many tedious minutes later I had them stuck back in the right place

Anyway, things are still coming together- now I just need to tap a bunch of holes, and machine some giant plates for the main structure of the machine. And then probably spend far too long re-aligning things to get them as close to square as possible.

Z axis mount

posted May 26, 2016, 3:03 PM by Daniel Taylor

One more piece- this time the mounting plate to attach the Z axis to the X axis rails. It came out... hopefully OK. The part shifted a bit while trying to elongate the holes on the lower right. And of course I screwed up the gcode and forgot to drill the other holes (leftmost) before that. I think I got it realigned (ie, they should be square to the rest of the holes), but who knows. At least the rightmost holes are non-critical. I was hoping the left holes would be a good alignment reference, but it's not the end of the world if I need to drill one of them out a hair. I'd rather not, but that's the way it goes.

Fortunately everything else came out well enough. The edges need to be trimmed a bit, and there's a pocket on the back that still needs to be cut, but it's getting there.

New parts: gantry, leadscrew axial shims, and Z axis stepper mount

posted May 23, 2016, 2:46 PM by Daniel Taylor

A whole batch of new parts. The big one (literally and metaphorically) is the gantry. It's been squared up to the right length and had holes drilled (and tapped). More on that in a bit.

The second-largest part is the plate that the Z axis stepper sits on. And the little parts are shims to go on the leadscrews. The bearings I got are shorter than the non-threaded portion of the leadscrews, so in order to clamp down on them, I need a shim in there. That's what all the little round things are. Strictly speaking, I really have no reason to need to do anything to the ends of the leadscrews, since they're going to be held in place by the bearings (which will be clamped at either end, so the leadscrew can't slide anywhere). It's more a matter of principle... And I already got the (oddly-sized) nuts for it, so I might as well.

Back to the drilled/tapped holes on the gantry... evidently an M5-0.9 tap is a thing, and I have one (the "normal" M5 thread is M5-0.8). As far as I can tell, it was only ever used on some pre-1972 cars. And when I went to the hardware store and asked for a normal M5 tap, that's what I got. I'm really no sure why they even had one in the first place, and I probably should have double-checked the taps before I left, since the guy fishing them out for me didn't seem terribly with it.

Long story short, those holes will need to be drilled out, and I'll just stick nuts on the back side. Fortunately I can do that with these holes, and haven't tapped any other M5 holes yet. Which is really good, since most of those are blind, and I really couldn't recover from having the wrong threads in them. M5-0.9 screws are nearly impossible to find, and stupidly expensive (like $2/screw), so that's not really an option.

Anyway, it's progress, with some frustration. On the up side, I think there's only somewhere in the mid-teens of parts left to machine...

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