CNC Build, Day 8 – Axes, baby!

Posted on August 11, 2010 by jimbo

With the “first critical measurement” in the bag, my way forward was clear tonight. First thing, cut the Y-axis pieces to the correct length. Then, lay out all the measurements. By the way, the Y-table pieces have the most drill holes of any part of the machine; the main piece has 14 cross-dowel holes (and their attendant 1/4″ holes), plus 10 counterbored holes (which means 20 passes through the drill). That’s a lot of measuring and laying out and drill bit changes and &c.

Before I started cutting on the Y-axis, though, I had to get one piece of busywork out of the way. I measured, cut, and drilled the X-table rails, and got them installed on the X-table. The X-table is complete. w00t!

After I had prepared the X-table to receive the gantry, I went to work getting the gantry installed. First, I went to work on the gantry bottom (a relatively simple 6 cross dowels and 2 holes for the X-transmission nut). Once that was in place, I was able to attach the Y-gantry sides (which have been complete for a few days now, waiting for “critical measurement #1″), and suddenly, I had some moving parts! The U-shaped Y-axis was rolling along the X-table rails. I did a little dance of joy at this point.

I admit that I had some frustration getting the cross dowels to hook up with my drilled holes. I really do suck at hand drilling. But I eventually got them installed, and I got *lots* of practice doing cross doweling on the Y-table. But I am skipping ahead.

I then started in on the Y-table, first drilling the 1/4” holes that connect the two pieces (with the pieces clamped), then disconnecting the pieces, drilling the “second set” of cross dowel holes (I had pre-drilled one end of the piece previously), then going back through and counterboring all the 1/4″ holes. I tried to attach the Y-table pieces together, and after thrashing about trying to figure out which screws go where, I realized that I needed to counterbore more deeply. So 20 more counterbores to get them to the right depth. It went together pretty easily after that.

I decided to test-fit the Y-table with just a few 1/4″ holes connecting to the cross dowels. I had a lot of these to get through (10 in all to connect the Y-gantry sides to the Y-table), and I didn’t want to have to drill them all twice (or more). So I very (!) carefully drilled just one or two holes on each end of the Y-table, then installed them to check the fit. I think I finally got my hand drilling mojo. Out of the 10 holes, I only had to re-drill 2 of them. Very nice. That went together sort of rough, but I got it done and all of a sudden, I had a full Y-gantry rolling back and forth.

It was at this point (or a little earlier) that I realized that the X-table is narrower at one end than the other. The gantry gets really loose on the rails and looks like it’s going to fall off at one end, but is nice and tight at the other. After worrying and thrashing around this for awhile, I decided to shim one of the X-rails to make the gantry tight all they way down the X-axis. I will likely have to tweak this a bit. But I am learning how to solve problems with this rig. Building it all by hand really gets me a level of understanding about how it all works that would have taken a few years with a commercially-bought machine.

With the Y-table in place, I was just a hop, skip, and a jump from being able to make “critical measurement #2”, the Y-table width. All I needed to do was to cut the Y-table rails to size, and clamp parts C&D in place. Both operations went a lot faster the second time around, and I was able to easily get “critical measurement #2″, 10-1/16”. Strangely enough, this is the exact measurement from the plans. With all my “off by a 16th here” and “measure to the 8th” there, my Y-table is somehow exactly on-spec.

So I’m ready to cut out the Z-axis “table” and “gantry bottom” tomorrow. I even have the length already set up.

I may have the structure done tomorrow night. I’m really, really close with the “major” parts. I have to get the Z-axis assembled (which secretly consists of a Z-axis and a “router axis”), then cut the leadscrews to length, get the motor mounts cut out and installed, and I’m done!

Then it’s on to electronics and PC software setup. I found an ancient PC with a parallel port that’s running XP. If I get some time, I will start cleaning off the HDD and get Mach3, CamBam, and … erm… can’t remember what CAD program I was going to use… I should make sure Eagle is on there, too.

It feels like I’m in a progress cascade at the moment. With X- and Y-axes both up and running to some extent, the “pile of parts” is really starting to look like a CNC machine. It’s so cool!

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CNC Build, Day 7 – First critical measurement

Posted on August 10, 2010 by jimbo

The parts arrived today (both the electronics, on time, and the hardware, 3 days late). Life’s good!

In anticipation of having BRAs, I borrowed 4 pipe clamps from my friend John (thank you!) on the way home.

I spent the time before dinner building out BRAs and fondling the rest of the goods. Those motors are gigantic.

The Y-axis BRAs had some untapped holes, so I pulled out the 5/16-18 tap and banged those out. I checked all 3 sets of parts that needed BRAs, and it turned out that because of the way the bearings are mounted, the C & D parts (the Z-gantry sides, which hold the Y-axis BRAs) needed more drilling. There was no measurement for where to put the tiedown holes, so I arbitrarily chose to put them 1″ in from each edge. It needs at least 1 1/2″ to clear the bearings. No biggie. I banged those out, and mounted all 6 BRAs and all 6 leadscrew bearings. 1 1/8″ is a perfect size for those.

I then tackled the “tough” problem for the night, getting the “critical measurement” on the X-axis, upon which the length of the Y-gantry bottom and Y-table depend. It took all 4 pipe clamps, 2 Da Kine rack straps (love those things), and 2 levels to get it all together. Kristi came and helped for part of it, too, when I lost one of the X-rails (oh, I cut the 1″ rail for the X-axis, too; miter box worked great for that). The critical measurement is 26 1/16″. This is 10/16″ shorter than the plans call for, but that’s to be expected, since I carved away a bunch of the edge on day 1 while trying to even things up. I need a table saw. I marked the Y-dependent pieces and clamped them together. I’ll cut them tomorrow night while the kids are awake. I probably could have gotten away with it tonight, but I didn’t feel like testing the sleepers.

With the measurement done, I decided to see what I could do about progressing the build some more. I attached the X-table legs, and suddenly I had a CNC table sitting around. It’s cool! I installed the X-axis leadscrew temporarily. It works fine. I will know for sure once I get the X-axis transmission nut installed, which attaches to the Y-gantry bottom.

With the legs on, I decided to continue where I left off last night, which was cutting the motor mounts. Let me take this opportunity to say that I did not do well, here. 🙂 I ended up cutting the central hole slightly off center, which means that there are only certain orientations in which the holes all line up. sigh. So I spent the next 2 hours fiddling around with motor mounts, trying to get a motor attached so I could see if I’d gotten things right. In the end, I got it to work (and without re-drilling anything), but seriously. Measure twice, cut once.

Right before stopping, I decided to measure and drill the new BRA mount holes for parts C&D. That went fine. Then as I was mounting up the BRAs, I realized that I was provided angle-headed bolts instead of pan-headed bolts to mount the BRAs (which is a better idea, in my humble). In the book, they show angle-headed bolts used for attaching the table together, and pan-head for the BRAs. In this kit, the angle-headed bolts are for BRAs, and the table halves are held together with hex head bolts.

I am of two minds about this. First, I don’t feel like counterboring all those bolt heads when I’ve already got the table together. On the other hand, I am not happy about how the edges of the table are not coming together, so I may want to reinforce the connection by making more attachment points, and what do you know, I have some extra bolts for that now (I provided my own angle-headed bolts and nuts to attach the halves).

Also, with the BRAs attached (they take 28 nuts and bolts all by themselves), I am almost out of the 1/4″ nuts provided with the kit. I suggested to PHD that this was going to be the case, since the kit has ~100 bolts, but only ~80 nuts/cross dowels. I will keep track of the parts I add to the kit in order to complete it, and will send him a list. I can think of 10 1/4″ nuts that I’m going to need to provide off the top of my head, and I feel like there will be more. No biggie. Just want to help the next guy who buys the kit.

I got so many new toys today that I am overwhelmed with trying to think about each of them. I spent the most time playing with bearings and the motor.

The X-table is so close to finished I can taste it. I just need to drill the rails and the mounting holes for the rails, and I’m done until the Y-gantry is up, at which point I can mount the leadscrew.

To be done presently:
– cut the Y-gantry parts to size.
– measure and drill the Y-gantry parts and get them mounted
– build out another motor mount and test-fit it to the Y-gantry
– cut and mount the Y-axis rail, so I can take the next “critical measurement” (which I will be able to do with bar clamps on-hand)

I know that my tone of upcoming work has changed somewhat. That’s because having parts makes all the difference. Now I’m on a roll.

How far can I get before I have to go to Washington? At the rate I’m going, and if I can do the last few saw cuts I need to do when I need to do them, I could be close to fully complete. I might need to boot up a PC and see if I can start getting Windows installed. It occurs to me that I need to have a machine with a working parallel port with me. I hope I can get something done with a laptop, but I am not confident. Also, I need a straight-through DB25 cable, which is apparently not like a printer cable. hm. Maybe a trip to Fry’s just to be certain.

Anyway, if I pack up the CNC and take it with me, I can certainly complete it with 2 weeks off while I’m in WA. I need to start a packing list for the CNC. I would need:
– the machine
– the electronics
– a PC with Windows (or a recent version of Linux) and a parallel port (+monitor+keyboard+mouse if it’s a desktop).
– some clamps
– a spare piece of wood or two
– a parallel cable (buy a couple of DB25 ends at Fry’s — gender?)
– a bunch of extra wire (Ethernet should be fine)
– some resistors (wattage? accuracy? value?)

It would be best to test the electronics in a “dry run” before taking it all up there, but having a voltmeter, small toolkit, carpenter’s square, power drill could be useful.

Get all the cuts done.
Get all the holes drilled.
Get a PC running.
Test the various parallel cables for usefulness.

At that point, I think it’s ready to transport. And no need for a lot of the heavy tools (drill press, saw, etc).
But worry about deadlines later. Just keep working. This is a good pace.

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CNC Build, Day 6 – two showers

Posted on August 8, 2010 by jimbo

I got a lot of work done today, despite being at a “stopping point”.

I started the day by chamfering the remaining 3 edges of the X-table.
Then I reset the chamfer bit, and chamfered the Y-“table”.
I was going to cut out and do the same to the Z-“table”, but ran into a roadblock.

I spent a bunch of time scratching my head, figuring out how to cut up the “primals” into parts.

While I was mulling it over, I rooted through the observatory and dug up all the 1/4-20 hardware I had lying around. I had just enough bolts to bolt the two halves of the X-table together. Nifty.

Then, before dinner, I pulled out the chop saw and cut:
– Parts C & D, the “Z-Gantry Sides”
– Parts W & X, the “Router Gantry Sides”
– Parts G,H,I, & J, 4 of the 6 motor mounts
– Part E, the X-axis transmission nut

I also realized that of the 3 primals I have left, two of them have enough meat on them to consolidate some of the parts, and in particular, all of the Y-axis “dependent” parts are on one primal, and all of the Z-axis “dependent” parts are on another one, and all are set up such that I can cut the length all at the same time, so they will be perfectly the same length. w00t!

I showered before dinner; I was covered in sawdust after routing and sawing all morning and afternoon.

Once the kids were in bed, I started laying out measurements on the parts I’d cut. I ran into some “bugs” in the plans. Nothing I missed catching before taking things to the drill, but there was a lot of second-guessing and re-checking involved.

In particular, bugs that I found are:
– The axis bearing counterbore + 2 holes to attach the motor mount have a variety of widths in the plans. They are shown on 4 different parts (the X-table leg, the Y-gantry side, the Z-gantry side, and the motor mount), and they simply don’t all agree. I ended up lining things up against parts I’d already cut out (luckily, the two that *do* agree are the two I’d cut already), and that worked.
– The BRA hold down points have different spacing on various parts on which they occur (The Y-gantry side, Z-gantry side, and Router gantry side). I checked several places, and even laid some 3/4″ rail in between some 1/4-20 screws on the Y-gantry sides, and changed everything around to match that.
– There is not a comprehensive set of correct measurements for the Z-gantry sides. This is a well-documented problem, but even the “best” version, the one from the forum, has the BRA mounted in a different way than the “normal” plans, so there was some fancy “to the 32nd” math that had to happen before I could get that laid out.

I have decided that I really, really suck at hand drilling. I tried a couple more of the “this will go into a cross dowel” holes today, and frankly, I can’t get it done right. I will have to re-drill them. sigh. I see some J-B Weld in my future.

Anyway, once I had everything laid out for the drill press, things went pretty quick. I banged out all the 1/4″, 7/16″, and axis bearing holes I had to get done. My big pile of parts is down to some partly-drilled motor mounts (I am going to wait until the motors get here tomorrow before I drill those), and the X-axis transmission nut, which somehow escaped my notice while I was measuring.

I have now completed:
– Y-gantry sides
– Z-gantry sides
– Router gantry sides
– X-table legs

Partially completed:
– X-table (I still need to drill the holes for the angle, but I am worried about the warping of the table, so I might add some more through bolts)
– motor mounts (need the coupling hole and the 4 motor holes drilled and counterbored)
– X-axis transmission nut (needs to be measured and drilled)

Dependent:
– Y-table, both parts, and gantry bottom (dependent on width of X-table)
– Z-table and “gantry bottom” (3 parts total) (dependent on width of Y-table)
– Router-table and “gantry back” (3 parts total) (dependent on width of Z-table)

En route (all expected Monday):
– hardware kit (can’t wait for BRAs, bearings, cross dowels, and couplings!)
– electronics kit (yummy)

Now I have to shower again before bed. Sawdust, baby.

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CNC build, day 5 – things to do while waiting for parts

Posted on August 7, 2010 by jimbo

OK, it’s not like I have nothing that can be done while I’m waiting for the parts to arrive. I just have to go off-script a little and find stuff later in the build that is independent. So I went through the rest of the book, and here’s what I came up with.

The following parts are independent of custom measurements:
– Part E, The X-axis gantry bottom nut (where the X-transmission nut sits), pp 115
– Parts C and D, the “Z-gantry sides” (“Y-axis bearing supports”), pp 138 (but note that you want to use the cut plans from the forum)
– Parts W and X, the “Router gantry sides” (“Z-axis bearing supports”), pp 162

The rest of the pieces are dependent in one way or another on something custom, either the width of the X-table (for the Y-gantry pieces), or the width of the Y “table” (for the Z-gantry pieces), or the width of the Z “table” (for the router base).

I have been thinking about redesigning the Z-axis. It’s a poor compromise between wanting to allow a larger router, but not really being wide enough to do so. It occurs to me that this might be a use for a DUP! Hmm.

OK, off to cut-and-drill some more parts. All of the remaining parts will require a chop saw to extract them from their primals.

…on second thought, I think I’m taking the night off. I’m tired.

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CNC build – update

Posted on August 7, 2010 by jimbo

The hardware did not show up today. Very irritating.

I decided to bite the bullet and buy a “laminate trimmer” router to be the main cutting blade of the CNC machine. It’s lighter than my “big” router, and narrower, too. In theory, I could make a new Z-axis that took advantage of this, gaining me another inch or two of cutting on the edges.

I also picked up a couple of cross dowels and some 1/4-20 hardware so I can test-fit some of this stuff together.

No sawdust yet today, but I imagine it will happen at some point later.

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CNC Build, day #4 – a stopping point

Posted on August 7, 2010 by jimbo

I had another productive night on the CNC build.

I measured and drilled 4 decently complicated parts. Luckily, they came as two sets of pairs, so I only had to drill one set of holes on each. I have a feeling that there will be a lot of paired parts in this build.

I started with the X-table feet. Eight 1/4″ holes each (6 to attach to the table, 2 to attach to the motor mounts), plus a very nifty 3/4″ through with 1-1/8″ counterbore. Setting up to do the counterbore on the second piece was interesting; flip the part, then put the 3/4″ bit back in to get it lined back up (with the drill off), then clamp the piece down, swap bits, and voila, a perfectly centered counterbore. Nice.

With the X-table feet out of the way, I’m essentially done with the X-axis for now. There is a little more drilling on the table itself, but I am holding off. More on that in a bit.

I moved on to the Y-axis. Generally speaking, Y is probably the most complex axis as far as being large enough to be heavy, so needing lots of bolts to hold it together, so there are several large parts that have just a ton of holes in them.

The first pieces to be done are the Y-Gantry sides. These are the big vertical pieces on the sides of the machine, and they are mirror images of each other. There are sixteen (yes, 16) 1/4″ holes in each gantry side; 5 to attach to the Y-axis rail, 3 to attach to the gantry bottom, 6 to hold down the BRA, and 2 for the motor mount. It occurs to me that one of the sides won’t have a motor mount. OTOH, maybe I will decide I want to switch sides for some reason. I’ll have motor mount holes ready to go if I need them.

I spent a lot of time on the drill press today. I am beginning to understand why people have a lot of clamps. I really could use some small, maybe 3″ or 6″ clamps, because there is a lot of wrestling with the clamps to keep stuff from moving around, yet not hitting the drill bed. sigh.

The four pieces look really awesome. I am really hitting my stride I think with being able to get everything kind of accurate. As the axes get smaller, the pieces get smaller, and the tolerances get tighter. I’m hoping that I’m getting everything accurate enough.

Which brings me to my next point, and the reason for the title of this post.

The next 2 pieces that need to get cut are the two that attach to the gantry sides. But the *length* of those pieces depends entirely upon how wide the final X-table is. And since I have no way to check that until the hardware gets here. I need cross dowels before I can attach the feet or rail to the X-table, and I need a Bearing Rail Assembly (BRA) before I can see how far apart the gantry sides will be. Both of those things are in the hardware kit that I ordered on Monday, but didn’t get shipped until Wednesday afternoon when I complained. They were sent Wednesday night (I didn’t get the ship notice until Thursday) USPS Priority. If I am lucky, the kit will be in tomorrow’s mail, and this post will have been premature.

But if the kit is not in tomorrow’s mail, I have to wait to cut anything else until it gets here. I am going to start poring over the book, to see if there are any parts “downstream” of here that don’t depend upon those custom measurements (there’s another set of custom measurements coming up, too). And I can chamfer the rest of the X-table and also the Y-rail (and maybe even the Z-rail, who knows?), and drill the rest of the holes in the X-table. I can keep myself in “busy work” for the weekend. But if the gear shows up, I can make a lot of progress, since I can bolt things together and start confirming that I’m doing the cuts and drills right.

Really good progress tonight. I just hope I can keep it up tomorrow.

On the immediate todo list:
X:
– drill holes in the X-table for the feet
– drill holes in the X-table for the rails
– cut the rails, drill holes in each end
– chamfer the other 3 edges
Y:
– chamfer the rail
– I guess I can pre-emptively drill one end of the gantry bottom and Y-rail, waiting for the measurements on the other end.
– decide whether I can clamp the Y-rail reinforcement

Other:
– see if there are any non-dependent pieces that can be worked on
– vacuum up the dust in the garage. It’s starting to get a little intense.

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CNC build, day 3 – on a serious roll now

Posted on August 6, 2010 by jimbo

I had a couple more holes to punch with the drill press on the X-table before I could really move on. The 7/16″ holes for the cross dowels for the rails needed to be measured out and punched in. I picked up the kids form daycare today, so I came home 1/2 hour early and banged out the 4 holes. I left everything sitting, just in case I forgot anything. Once the kids were in bed, I went back out and looked things over. Yep, done with the drill press on the X-table.

Rather than drill a bunch of manual holes in the edges of the X-table, I decided to move on to cutting out some of the other pieces, since I can’t really do anything else until that happens. So I measured and laid out the circular saw cuts on both boards, then started in with the circular saw. It’s been awhile since I did any cutting with one of those, so it took a little while to get set up. And the first thing I found out was that the blade is shot. Luckily, we had a spare sitting around. With the new blade, things started going pretty smoothly. I need to figure out how to deal with the “part that falls off” when I finish a cut, but other than that, all was well.

With only a few small mistakes, I now have a pile of parts waiting to be drilled, a pile of “primals” (boards that contain multiple smaller parts that still need to be cut out), and a 2’x2′ piece of extra plywood, in case I decide that I absolutely need to re-cut anything. The so-called primals are all small enough to be cut apart using the chop saw, which makes my life ever so much easier. By the end, I was decently good at getting consistent cuts out of the circular saw; I knew whether a particular cut was going to require me to construct a fence (the 2′ level does a great job at this, by the way), or whether I could use the little fence-guide-thingy that came with the saw, which is awesome if you have to cut out two of the exact same size part in a row. I am particularly proud of my X-table “feet” pieces, which came out exactly the same size. Another “win” moment was when I was able to cut away a bad chunk of wood that was less than 1/2″ wide, by skillful use of the fence-guide-thingy.

This is a lot of words to say that at the beginning of the evening, I had 4 plywood boards, two of them clamped together with a couple of holes drilled in them. By the end of the evening, I had a pile of CNC parts, waiting to be processed and installed.

Tomorrow, I will start putting together the X-table legs, then the gantry sides. If I can get all that drilled tomorrow, then I am simply waiting for the hardware kit to arrive (it shipped today, after I wrote a note to the seller to ask for status) so that I can build the X-axis BRAs and make my first “custom measurement” to cut a couple of key pieces of the Y-axis to size.

Things that I may have to be worried about:
– The X-table boards are not flat, and when unclamped, the edges and corners pull away from each other. I may have to add more connection bolts, or maybe it will come together when I bolt on the legs.
– I am uncertain how I am going to get the legs to line up properly with the table, since some of the holes are not lined up right. I may end up redrilling them and epoxying if necessary.
– The gantry sides are not the same width. I made a really bad cut (first cut with the circular saw) and one of them is about 1/4″ narrower. I don’t think it’s a big deal, in fact I think that most of the holes are drilled with the gantry sides clamped to each other, so that should be fine. But there you go.
– The most visible piece on the whole kit, the Y-axis rail, has a big ding on it. I am hoping that chamfering will help. The gantry bottom has a ding, too, but that rides under the table so is usually invisible.

The hardware kit is underway via USPS Priority from Houston, so it might be here on Saturday, which would rock.
The electronics kit is underway via UPS from Chicago, scheduled for Monday. I’m in no hurry, there. Unless something dramatic changes, I won’t be ready for electronics yet by Monday.

I have all the pieces and parts in place or underway. Now I just have a couple hundred holes to drill and some assembly required, and I will be CNCing!

Good progress today.

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CNC build, day 2 – Righting the ship

Posted on August 5, 2010 by jimbo

Progress, thy name is “Drill Press”.

After several frustratingly inaccurate drill holes from last night, I knew that my hand drill accuracy was not going to be sufficient to complete this job. Seeing my frustration, my ever-accomodating wife (may the sun always smile upon her) told me to go get one.

I checked craigslist. If you live in/near Fremont and need a serious drill press, there’s one on there for $140 that your grandkids will use in their wood- or metal-shops. The problem is that, being a floor-standing model, it weighs… well, a lot. This is not something you want to wrestle out to the backyard for a little sawdust-making-in-the-sun.

So I checked Home Depot (and Lowe’s, Sears, OSH,…) and found a 12″ (which really means 6″, but don’t get me started) Ryobi benchtop drill press, weighing in at a svelte 92lb., and for which I paid $169 + tax. w00t!

Let me start by saying that this is the right size drill press for me. 92 pounds is no joke to lug around. And 6″ is exactly the amount of room I need in order to do this build (the cuts on the table bed are all 6″ from the edge — hmm (: ).

Some assembly required. That was pretty fun, as you’d imagine. Like any “real” shop tool, part of the installation instructions call for whacking the brand new tool with a mallet (I am not making this up). That’s how you install the chuck and arbor into the spindle. Seriously. It was totally cool! (:

Once I got the rig put together, Kristi cut the first hole with the new drill. I forbade her to whack it with a bottle of champagne. That’s just too much. BTW, the unit has an RPM readout and a pair of lasers that tell you where the cut is going! schwing. The RPM readout is a little over the top, but the lasers are so awesome I could cry. You want to be at the other end of a big chunk of plywood and figure out whether the bit is going into those pencil lines you just drew? It’s a beautiful thing.

I spent some time trying to figure out how to position the drill bit in the world such that I could put some wood near it (again, something that’s trickier than you think when the drill bit in question weighs more than both your kids put together). I ended up with the drill standing on the router table (finally that thing comes in handy (: ), standing on a sturdy wooden platform (the boxes that the Chinese tiles came in are really burly!), and with the sawhorses at their lowest adjustment, and with a shim here and there, I could get the plywood level.

Note that this would not be a problem for most regular sizes of wood, but the router table consists of two quarter-sheets of 3/4″ plywood, a chunk 2’x4’x1.5″, weighing about 50#, which is OK, since it’s also a little awkwardly large, too. Oh, and the holes I’m drilling are the ones that will be bolting them together, so they are still clamped with 4 or 5 clamps around the perimeter. It was a joy to wrestle that stupid thing around. I look forward to unclamping it as soon as it’s all drilled.

Now that I was set up, I started with correcting the erroneous 7/16″ through-holes from last night.

And this is the moment where I go a little dewy-eyed.

In a word, wow. Drilling with a drill press is dead simple. Set up the wood, set up the bit, fire up the machine, and wham. Straight hole. Just like that. Move the wood to the next hole, fire up the machine, wham. That one’s straight now too. In about 5 minutes, I’d fixed all 3 bad holes from last night.

So I measured and drilled the 7/16″ holes at the other end of the table.

And I counterbored all 4 of the remaining holes for through-bolting the table together. I even had to switch from “end-on” (drilling the 2′ side) to “side-on” (drilling the 4′ side). Easy.

I finished up, then remembered that I still have four more 7/16″ holes to drill (to hold on the X-axis rails), so I can’t unclamp yet, nor am I going to move the drill yet.

I spent a little time thinking about whether I could figure out how to drill into the edges of the plywood. So far, I haven’t come up with a method that will work, given the geometry of the problem. In particular, I am a little worried about how to secure the base of the drill while I do crazy contortions with the drill head. I might wait until John C gets back in town, then go and drill those holes on his floor-mount drill press. Or I could just use a hand drill.

Or not. (:

I made great progress on the X-table. The “big” pieces are within reach of being complete. To be done:
– four more 7/16″ through holes
– six 1/4″ holes on the end (to attach the legs)
– four 1/4″ holes on the edges (to attach the rails)
– chamfer 3 more edges (that will be a nightmare of setup)
– cut and drill the rail
– attach the rail

and that’s it! Then I can do some stuff that actually requires a saw, cutting the legs.

Once I finish the table, all of the other pieces of the kit are small enough to simply clamp to the drill press to cut. And I think that a majority of them can be cut on the chop saw, once they are carved away from the main sheet of ply.

I just counted it up, and I have 10 cuts to do with the circular saw (because I don’t have a table saw), and the rest devolves into chop saw cuts. There are 24 pieces that need to be cut out, so being able to bang them out on a saw by just lining up and cutting is going to make life very easy. The 10 circular saw cuts will produce 7 atomic pieces, and 4 “primal cuts” that will get broken up by the chop saw.

I’m excited. I really feel like I’m underway!

Not having to worry about drilling is really a load off my mind. Thank you, drill press!

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CNC Build Day #1 – making sawdust

Posted on August 3, 2010 by jimbo

Now that I have all the wood onsite and more or less marked, and a jig to help me drill straight, I decided to start in on the build.

In the videos, PH-D (the author of the book and owner of buildyourCNC.com) starts with the Z-axis. There are lots of little parts and he can show off his miter box skills.

In the book, however, he starts with the X-axis. Essentially, take a guy who’s pretty green and hasn’t picked up tools in awhile, and start him on cutting the largest pieces of wood in the build.

I’m not sure this is the wisest place to start.

I understand that once the X-table is built, you can start taking critical measurements that help the rest of the build. Honestly, it probably *is* the right place to start, if the builder is a skilled woodworker. But I have messed up several times already, and I worry about how much I can get done before the hardware gets here so I can test-fit some of these holes I’ve been making.

Among things I need to remember:
– If you are going to counterbore a hole, make sure to use a pilot hole first!
– The router doesn’t like chewing off large chunks of plywood at a time.
– The chamfer bit has a “straight” part that needs avoiding.
– Try out the new jig on a test piece of wood first.
– I need a drill press. Drilling straight holes is not as easy as advertised.
– Routers are loud and can only be run until the kids go to bed. Get routing done early.
– sawdust goes everywhere. Do routing outside. Drilling and sawing are not as bad, but do those outside, too.

Here’s what was done tonight. Whether it’s “progress” or not remains to be seen.

one edge of 4 is chamfered (ran out of time before bedtime).
6 holes are drilled through the two table pieces, two of them are counterbored and have 1 1/4″ taper-head screws in them. In theory I could un-clamp the table halves from each other. Oh, the halves are clamped. With all 4 edges even. Speaking of which, the table is now 1/8″ narrower than it used to be, since I had to route one edge to get it flush, and… well… I haven’t used a router in awhile and I messed it up. By the time I got it more or less OK, I’d eaten away some serious wood. sigh.

I have the holes drilled in one end of the table that will eventually hold the table leg on. That’s six 1/4″ holes and three 7/16″ holes that intersect pairs of them. I don’t know if it’s the jig or my drilling, but the holes are … not quite right. It will be interesting to see whether I can salvage this, but I’m not drilling anymore until I get my hands on some cross dowels.

I’ve made progress I hope. At least, there are holes. and I cleaned up some sawdust off the floor. I may have ruined two nice pieces of plywood, but I have 2 more.

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CNC – It’s on

Posted on August 3, 2010 by jimbo

After a weekend of hard labor in the garage, I’ve cleared enough space to get started on the CNC project.

Today, I ordered the electronics package from KelingInc:
Gecko G540
3x 425oz-in stepper motors
48v/7.3A power supply
E-stop switch

and I decided to waste some $ on the parts kit from BuildYourCNC, since it contains all the hard-to-find parts and who wants to go chasing down a dozen different sizes of nuts n bolts?

I also picked up 4 quarter-sheets of 3/4″ Oak Ply and 9′ of 1/2″-13 threaded rod.

The only outstanding purchases that need to be made are a drill bit or two and the angle aluminum for the rails.

I spent the evening marking the parts out on the wood, and trying to figure out what hardware I was going to need to attach them, when I gave up in disgust and put in the parts order with BYCNC.

I did make a little sawdust tonight, too; I built myself a drilling jig so that all these 1/4-20 to cross-dowel connections will be spot-on. It looks like it will work pretty well, but I can’t call it “complete” until I drill the cross-dowel hole (did I mention that I still need to pick up a 7/16″ drill bit? 🙂 ).

I have a good feeling that a lot of parts will start to show up just as Kristi is out of town, so I can furiously start creating sawdust this weekend.

…which is not to say I won’t be working it after work this week, too. 🙂

If all goes perfectly, I might have a CNC machine that needs to fit in the trailer!

In short, the CNC quest has begun.

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