[fretman_2]

Nice...will double as a sweet billiards table when you're not CNC'ing!

[Biggs427]

Will you laminate phenolic to hold your rails as you did with the Z axis?

How will you make rails on both side leveled on the same plane?

Great to see this project active again!

[ger21]

I don't have a really good picture, but yes, I already have the side rails mostly finished. They are 3 layers of 3/4" plywood with phenolic mounting pads already machined.
However, After I made them, I decided that I'd be using helical rack and pinion, so I need to add some phenolic pads for the gear racks.
My plan is to first mount the linear rails. Then, I'll make a router sled that mounts to the linear rails, so that I'll be able to machine the parallel mounting surface for the gear racks.

I have my baltic birch for the table, and am hoping to build it this weekend.
I've been doing a lot of work in Fusion 360 to make sure all the holes and T Nuts are in the right places.
Here's a rendering. I think I'm going to make a change to the legs, after seeing the entire machine in 3D.

[ger21]

How will you make rails on both side leveled on the same plane?

The top of the Torsion box will have an overhang on it, and I'll be clamping the plywood rails tightly to the underside of the top when I bolt them on to the sides of the box. Since the phenolic mounting surfaces are parallel with the plywood edges, they'll be parallel to the top.

I'm planning on assembling the torsion box on the vacuum table of our big router, so it will be as flat as possible.

[ger21]

Here's a rendering of the X axis rails and rack and pinion.

[peteeng]

Hi Gerry - Where's the grease drip on the nipple? Peter

[ger21]

Today I was able to cut and assemble my torsion box table. I now have a big box in my garage taking up space, which hopefully gives me some incentive to get working on this thing.
My goal here was to make this as thick as possible, and get it out of four 4x8 sheets. With two sheets for the top and bottom, that left two sheets for all of the ribs.

The top and bottom skins are 1/2" baltic birch. The outer sides and ends are 3/4" baltic birch. I wanted these stronger, as the main frame rails will bolt to the sides, and I'll be mounting a vertical clamping fixture to the end. The sides and ends have T-Nuts for the bolts. After pounding them in, I added some hot melt glue to make sure they didn't rattle loose on the drive home.

After cutting the sides and ends from the 3/4" sheet, I had enough left to cut all but two of the short ribs. Those two, plus all of the long ribs, are cut from the last sheet of 1/2" baltic birch.

I had never intended to build a torsion box, and originally planned on a bolt together wood frame. I need to be able to take this apart, as I'll probably be moving in the next year or two.
I had some serious concerns about being able to mount the side rails perfectly parallel and coplaner. In the end, the torsion box made a lot more sense, as I could build it very accurately.

In order to get it as accurate as possible, All the parts were CNC cut. Almost 400 holes were drilled for screws and T-nuts. 80 nuts and 300+ screws.

All the ribs are in dados, to make sure I have a consistent thickness. Since everything is cut on a vacuum table, all the dadoes are offset the exact same amount from the outer faces. And thickness deviations in the plywood end up on the inside of the box.
Since the location of the two side rails is critical, I made those dados a snug fit. All the interior dados are rather loose, to make assembly easier. All the short ribs are a snug fit between the sides, forcing the sides to the outside of the dados., giving me two parallel mounting surfaces.

Once everything was cut, I started assembling all the ribs to the top panel. I used the vacuum table to hold the panel flat, hanging it over just enough to attach each rib, moving the panel each time. The ribs themselves do a pretty good job of keeping the panel straight, and when all the ribs are installed, it's pretty stiff with only one face attached. But you can still lift one corner by itself, adding a twist to the entire panel.
The vacuum table was used to suck the top panel perfectly flat while the bottom panel was attached. After flipping it over, I slid a 6ft level around, and it's dead flat in every direction.
I added a couple holes in the bottom in case I add a vacuum table down the road, so I don't have to cut holes from underneath at a later time.

The top panel overhangs about 2" on each side, and will be screwed into the 2-1/4" thick side rails.

On top of the torsion box will be two layers of 3/4" MDF, bolted into the T nuts in the torsion box. The MDF will overhang the linear rails, hopefully helping to keep them clean. The current plan will be to have a grid of T-nuts in the spoilboard, similar to my current machine. I plan on using some vacuum pods for working holding, with a small Gast pump I picked up a few years ago. If I end up in a bigger shop with more power, I'll then think about adding a full 4x8 vacuum table.


I need to get some paint on this in the next week or two, and then I'll start building the legs, and figuring out how to make room for this thing.

[nlancaster]

Glad to see some progress! Been watching this thread since it started!

[pupdogg]

Hi Gerry, I might have 1x 400W servo w/ DYN2 drive for you (sorry not 2). I'm currently using it on my Z-axis but plan on changing it out for a 750W with DYN4 drive...just personal preference. The only catch is that you might have to send the DYN2 servo drive to get repaired as it keeps shorting out for unknown reasons. Michael from DMM did confirm that they can fix it no problem. Send me a PM if you're interested as I'm in MI as well.

[ger21]

Thanks, but I'm using DYN4 drives.

[pupdogg]

Sure thing. I thought I seen 400W motors in the mix and figured you could at least use the motor if anything. Gotcha though!

[ger21]

The motors are different for Dyn2 (60V) and DYN4 (200V) drives.

[pupdogg]

Since the DYN2 gave up, I have the motor running with a DYN4 drive...no issues. DMM helped me set that up since I had a spare DYN4 laying around and it was much faster than the service turn-around on the DYN2 drive. I’ll have to check the specs for difference tho...I sure didn’t notice any.

[peteeng]

Hi Gerry - Hows the box painting going? Peter

[ger21]

I've been on vacation for the last week, so nothing has happened yet.

[RobsonKoch]

I would like to make a router with 2 spindles

[heavyweather]

I guess I missed the part where you dropped the roller pinion drive? Is the Y axis still servo belt?

[ger21]

X and Y are going to be helical rack and pinion now.

[ger21]

Quick update.

After a few years, I finally got around to sealing the X axis beams with epoxy. But, it was in preparation for a lengthy delay.


We bought a new house on the lake. (Pending inspection and other details)

So I'm packing up all the parts I have, as well as the rest of my garage shop.

Bad news? I need to downsize. Garage is a little smaller, but storage is at a premium, so I'll need to dedicate a portion to that. But the upside to that is I'm throwing away 20 years of clutter. Garage is also full time heated and air conditioned. It'll need an electrical upgrade, though.

Good news is that after this summer, I should have a lot more free time. No more fall yard work, and no more (well, minimal) house projects.

So I'm hoping to have the garage updated by the fall, and be able to work on this straight through until completion.

[nlancaster]

Gerry, Good luck, but you need to finish this machine this year. Otherwise it will have been 10 years since you started! LOL