Rails are cut to height now. I really wish I'd used my steelmax for the rough cut (.1" higher than needed). The grinder with cutting disk worked great... until it was through in some places, not in others. Then it would grab the edge and yank itself into the slot (and almost out of my grip :mad:).

I wasn't about to change my process after doing three rails (and screw up the fourth one!), so I just forged onwards.

Ah well, that stage is done. On to grinding the angles tomorrow!

I made some modifications to the skate for grinding the angles. The exposed disk had me worried... 1 second of inattention and I'd be visiting the hospital :eek:.

I saw the photos of the laser-cut parts with the built-in guard, and figured I'd just weld something quickly to approximate that design.

I cut a 10" piece from the off-cuts of the rails, made a few relief cuts to be able to bend it, and welded it to the bottom part of the skate. Then I used a cutting disk to remove the connecting part from the old piece. End result: easier to change the disk, and much safer to hold :).

Nicely done Melissa! Your moving along nicely!

Yeah, I see Instructables like this every day... Step 1. Weld some stuff onto your hand tools...

grinding rails
 

Started on grinding the rails today. The first rail is done. After glazing one disk very quickly, I opted to use a sanding disk backed up with the grinding disk. The trick is to make 4 cuts in the abrasive disk (around the centre hole), to help it conform to the dish shape. Next, press it into that shape with a vise. Then, it was actually possible to spin on the centre retaining nut on the grinder.

Here's a fun animated gif of me grinding the V (click for the bigger version) :):

http://i1109.photobucket.com/albums/..._rail_anim.gif

Charlie Chaplin, colourized and with safety gear. Do they make bowler hats with built-in face shields?

Finished grinding the second rail tonight. Here's a couple of photos of the v-wheel sitting on the rail. The grind was done with a 36-grit sanding disk mounted on top of a normal 1/4" grinding disk.

Also pictured is my magnetic sweeper, which is probably the most useful tool I've purchased for this build. It's just magical how it clears the floor, all without using the vacuum cleaner! :)

magnetic sweeper! Great idea....

Looks kinda fuzzy! :)

and how do you clean the magnetic sweeper ?:)

Heat it past the curie point??

Well done Melissa ;)

Oh, that's easy! You use an even BIGGER magnet! :D

(just kidding, there's a handle on top to retract the magnets inside the aluminum body)

(In case anyone's wondering, any resemblances between that sign, and the piece of equipment that got Paul Lauterbur his Nobel Prize, and the scrapping of said equipment, are purely coincidental. Although that magnet could have easily lifted an entire Mechmate.)

A new milestone: dead grinder!
 

I reached a new milestone on my mechmate today -- a dead grinder :o.

I think I let out some of the magic smoke yesterday, when it was running rather hot. It ran OK this afternoon, then started making a awful rattling sound. It appears that part of the magnet assembly has come loose inside the body.

Ah well, good thing I bought a 2-pack of grinders on sale :) so I can just swap grinders on the skate, and finish the last rail.

...yep, that's about par if you push the little grinders to hard. Once the lamination inside gets to hot, the metal parts fall apart.

The part of the DIY experience is usually killing at least one tool along the process. :)

Melissa mentioned dozens of pounds of steel shavings, perhaps worth reclaiming a few bucks on at his nearby recycler. Do they need to be turned into briquets first, with specialized tools like http://www.ars-inc.com/ ? Just curious if other builders (well, shavers) have tried this.

Main beam end-plates welded
 

Today I cut the main beams to length, now that the rail grinding is done. I also beveled the ends, and welded on the end plates.

For a moment I thought about holding the plate in place with one hand while tack-welding with the other... and then decided that clamps were a better idea :).

Question - main beam angles?
 

I checked my main beams with two squares, to see if the top and bottom faces (as when they're on the MechMate) are coplanar. They're not :mad:.

If you look at the C channel on end, the points of the C are too close together. The angle appears to be about 3 degrees.

I'm now at the stage of cutting and welding the legs, so this would be the time to fix it. I figure if I tweak the angle a bit where the beam meets the leg, then I can have the top face of both beams coplanar. This will help with the rail and rack alignment.

The bottom face will be off a bit, but it won't matter that much. I'm welding the cross bearers for the spoilboard, so a gap of 2mm or 3mm will be easily bridged.

Any thoughts or suggestions?

Clever two-stage clampology!

Why is it I get the feeling Camille is helping with this build? :)

Heh. I think he's encouraging me along so he gets to play with the MechMate the next time he visits :D. He's certainly not lifting any steel from 700 miles away! ;)

(for those unaware, Camille is my brother)

Only fair, Melissa helps me at a similar distance with aeromodeling and other bricolage!

First parts painted
 

I just finished welding the end plates on the legs, and cutting the foot plates (my laser kit predates the laser-cut plates).

It's currently -10°C outside, and hovering around 0°C in my workshop, so I had to get creative for the paint to dry. There's a 500W heater hiding in the foam "oven". The steel is around 23°C right now, which is enough to get the paint to dry. I just painted the bottoms of the table legs, as the rest will be painted once the sides are welded together.

That stable of sawhorses remains useful. On Dancer, on Prancer,...?

I like those pyramids...handy little things.

Painter pyramids
http://www.painterspyramid.com/ handy things

First Side Welded
 

The first side of the table is now welded. I used a whole bunch of wood blocks to shim the legs and lower longitudinals to the correct height, before tack-welding. I was more concerned with coplanar than level, so the legs are in line with the main beams (when standing vertically).

One "oops" on this stage: I knew I had to be careful about which end had the 100mm offset for the spoilboard. I carefully measured and welded. And once I had welded enough that I couldn't go back, realized that I got it backwards from the orientation I wanted :mad:. It is nice and accurate, though! So... once I've welded both sides, they'll get placed on moving dollies and be rotated around the other way.

...and I can't wait to see how that 5100mm long table looks standing up!
I certain you will get plenty of thanks from that gantry crane.

Great work.
Thanks for sharing.

Sean

Table goes 3D!
 

Well, upside-down 3D, but 3D nonetheless :).

The clamped 2x4's are to keep things in position, and to keep the sides from falling on me :eek:. The sides are positioned to within about 5mm of where they need to be.

Next up is cutting and tack-welding the cross braces. They'll be bolted in temporarily, so I can invert the table one side at a time. I did NOT want to weld the whole thing upside down, and have to lift 500 lbs eight feet in the air.

BTW, I'm really happy with how rigid the sides are. With the beams resting on blocks at the ends, the middle needs to be shimmed to within 1mm tolerance, otherwise the middle blocks are completely loose. All those braces are there for a reason!

Why not 500 lbs 8 ft up? Movie stunts do that kind of thing all the time!

8 ft is about the vertical hoist limit of my crane (beam is 10' high, chain hoist takes a bit over a foot of vertical). Plus, the chain hoist would require me to be almost directly below the object being hoisted. With that much potential energy... no thanks. I'll do it the slow and predictable way :).

Some recent progress photos: clamping the cross rails which will join the two sides of the table, prior to welding. I just about ran out of clamps. The good news is that nothing wiggled, and I didn't need to grind and re-weld any of these parts.

Next, what it looks like welded, but still upside-down:

With that completed, the table was disassembled and placed aside, while work progresses on the gantry. First drilling the gantry tubes, and then the Y-rails, for the mounting bolts and proxys.

Between the friction of turning all those shavings and the raw heat of a 6 kW welder, you'd think that boots mitts and toque wouldn't be needed for long in the workshop!

Thanks for the photos.

Great Progress Melissa. Keep going and posting
wish you all the best

Gantry welded
 

Good progress today, finished clamping and squaring the gantry (for the third time, after being reminded to smooth the edges of the laser-cut parts before welding). The beams are clamped to my table saw.

With welding finished, I actually had to use the crane to lower the gantry to the ground. I haven't weighed it, but it's seriously heavy, even without the rails or Y-car.

Up next is welding the Y-car, and then the table gets put together right-side-up.

Y-Car Welded
 

With Camille helping, I got the y-car clamped and square, sitting on the table saw. We ended up using a block of wood inside the car to keep the end plates exactly vertical. Also, the bends were a little bit off, so the large bar clamps are to bring the corners together for welding.

I'll work on grinding the welds a bit later. Tomorrow, it's full steam ahead to get the table standing.

Yep. That looks about right. :)