I'm using 4x8 sheets across the width of the table, cut to 1900mm [74.8"].

They'll be joined with biscuits, and glued with PL Premium construction adhesive. I'm confident that the glue joint will be stronger than the MDF.

That's why so many sheets... the table is a bit more than four sheets long.

...staggering the joints on the top layer?

Of course. The 4' section from 0,0 will be in the top layer, to make resurfacing easier. I expect that not all areas of the spoilboard will wear away equally quickly.

Here's a shopcam photo of the painted MechMate.

The drop sheet has been rolled up, as I need to drill 96 holes from underneath to mount the support board. The wheels on my mechanic's creeper would not do well on the plastic.

Once all the holes are drilled, I'll roll out the drop sheet and close the tent once more, to glue the parts of the spoilboard together. The glue needs 20C to dry properly, and it's still hovering around 5C in the workshop.

Melissa,
Great work. It's fun as always to be here from almost the beginning and see 70+ machines built. Only one other machine equals your in size and length and it was used to cut aluminum boat hulls.

Can I ask what your intentions are to use such a large platform for cutting?

Sean

Sean,

my intentions were to build a large machine once because I had the space available :). I didn't want to find myself wishing the table was a bit longer, after the fact.

It's such a common predicament in boat ownership that it has a name: "two-foot-itis" :D. Wishing your boat was two feet longer.

As for cutting... right now I'm looking at stitch&glue plywood boat kits, as well as folded horn subwoofers. Beyond that, who knows. I've also got a lead at the local lumberyard. Apparently carpenters in my area are looking for someone with a CNC router. All good prospects!

BTW, I'm already happy I went wider than the "usual" 48" cutting width. Baltic Birch (which I use for speaker cabinets) comes as 5' x 5' sheets. It would be silly to have to cut them with a circular saw, just to fit them on the MechMate!

Melissa

...All reasons why I built my first table as a 5' x 10' table...then wished I made it for 5' x 12' sheets!

You might find yourself doing some custom work where you can dedicate one end of the table for vacuum or special duty purpose fixture work and keep the general area clear.



Thanks for the reply.
Best on the rest of the build.

Work starts on the spoilboard:

Melissa, looking good, Ahhh Princess Auto, I love that store. :)
For you US guys, Harbor Freight is the same thing. :)

Coming along nicely, bolting it down will be fun :) Keep working at it, its one heck of a machine to use!
have you seen delftship, its free and exports dxf files just your size
Tim

Tim, delftship sounds cool -- particularly that Melissa doesn't need to second-guess their translations to English.

Heath, them's fightin' words! Comparing The Princess to Harbor Fright is like comparing Tim Horton's to Starbucks. Don't do that if there's Canadians within earshot that you can't outrun.

(Oh yeah, Melissa, serious milestone reached there, moving from metal to wood at last.)

Camille,
Not comparing, just giving the closest reference I could think of. :) Maybe Princess should go to the US too! Although it would probably be nice to have a HF close to me just over the border. :eek::cool:

Did I mention the table is long? :)

Support board (5 pieces!) slotted for biscuits, and all holes drilled. Next up is recessing the holes with a forstner bit, and installing it permanently with glue between all sections.

That's enough biscuit-joinery to prevent Quebec from leaving Confederation.

Looks like a MechMate runway !!!

Aircraft carrier

OK that's 3 in a row... Melissa, when you crack a bottle of bubbly on the prow, please christen her the H.M.S. Hyperbole.

Two more photos of the table top, with bolts temporarily installed:

Aw, now I gotta chime in too ... Since you've got the spikes in place, how about telling us which cities are at the ends of your rail lines?

Nice looking table, BTW.

How do you drill a recess with a forstner bit, when there's no wood left to guide the point? Answer: add some wood around the outside :). Here we go.

I made six guide blocks from off-cuts of the spoilboard. Each was drilled with a forstner bit on the drill press, all the way through. Top view:
Attachment 11457

Bottom view: note the beveled edge (we'll get to that in a minute)
Attachment 11458

The guideblock is placed over the hole, and visually centered:
Attachment 11459

And then I used a brad nailer to drive two 1-1/4" 18ga brads through into the spoilboard, to hold the guideblock in place:
Attachment 11460

I need a drill collar, but that doesn't work very well when the bit is this large! So the collar gets larger:
Attachment 11461

When the collar touches the small piece of wood, the drill is deep enough:
Attachment 11462

And what it looks like when it comes out:
Attachment 11463

Now to remove the temporary guideblock. I use my renovator's bar (like a crowbar, but it's much nicer to the wood). This is why there's a bevel on the bottom edge -- easier to pry it up.
Attachment 11464

Here is the newly recessed hole, with the guideblock:
Attachment 11465

Checking the bolt for depth. I didn't want to press it in yet, as the boards still need to come out to be glued.
Attachment 11466

Even with six blocks, they need to be re-used 16 times, so I need to remove the brads. They're too thin to hammer out, and you can't pull on the point, so I use vise grip pliers and my renovator's bar:
Attachment 11467

Here is the removed brad:
Attachment 11468

Easy! Only 95 left to go :eek:.

I just eyeballed mine!, one heck of a job. Once you resurface your going to have to seal it all, I used water based polyurethane. Worked great

Melissa, give double sided tape a try instead of the brads.

Too late, all that drilling is done now.

Besides, I wanted something that would be strong to sideways forces, but weak vertically. The brads worked like a charm.

Top layer of the spoilboard is ready to be glued in place.

I filled the bolt holes with "bondo" polyester filler. The top sheets will also be joined with biscuits, though I'm using regular white glue for this layer.
Attachment 11496

The biggest challenge was where to put the four sheets I needed. They had to be inside the tent to be warm, and off the table for glue application, but the tent isn't big enough for sawhorses at either end of the table...

OK, looks like we're going up instead :).
Attachment 11497
Attachment 11498

Did you use "bondo" before tightening the screws?

My idea, after suffering some loosening with time, was to tighten the screws first and then pour in a thin resin. That resin is meant to soak into the porous MDF around the screw head, especially into cracks that may have formed while the heads bit into the wood. It makes for a "harder" bond between screw and board, over a slighty bigger area than just the screw itself.

I used bondo after tightening the screws.

I did opt to use lockwashers, so there's some spring tension that will hopefully keep things snug. If it really becomes a problem later, I can always put on a new spoilboard. We'll see, I guess.

It would be messy, but to really spread the load beyond the screw heads, adhere the lower half of the spoilboard to the full length of each crossbearer (or even just a one-foot bead near each bolt). Sure, it's gluing onto paint, but the bond isn't strongly stressed, and down there nobody will see how ugly it is. Wait 'til Canadia warms up and the tent comes down, and then sacrifice a tube of PL Premium to the cause.

At last, assembly starts. The spoilboard is done, the tent is gone, and the rails are in place! :)

Well done so far. Looks like a A380 could land there.:p

well done Melissa. You almost there :)

Good job! Almost... Almost... :)

Motors Turning!
 

Moving right along... I've got the essential bits of wiring hooked up, and the motors turn under mach3 control. I still need to do more wiring (for the pushbuttons, e-stop and proxies) but I'm really happy that it works so far!

This will all be much neater when it gets installed into the control box :).

simply beautiful your machine .. thanks for illustrate the tricks
construction .. Gonzalo greetings.


I seem to see in the photos that you have used flexible leveling legs, so I thing this legs will give you unwanted vibrations problems on the machine.

Each foot has a screw thread, with bolts and lockwashers. The foot itself is rubber, but very hard rubber, harder than an automobile tire tread. Its resonant frequency is probably higher than the table's. I bet that the feet are stiffer than the table itself.

Kobus, on final approach a hundred metres directly above this MM you'll find no mere A380s. We snapped this pic ten paces from the front door. (Google Earth Brighton Ontario, head east 10 km, and you'll see why.)

Now that is BEEEG!!

Introducing Brighton International MechMate Airport: :D
Attachment 11536
Attachment 11537
Attachment 11538
Attachment 11539

A few more, farther down the runway:
Attachment 11540
Attachment 11541
Attachment 11542

And taxiing:
Attachment 11544
Attachment 11543