MDF or ply for JGRO router?

[carlnpa]

I hate to work with MDF and have had humidity problems with it expanding (never to shrink back) also. Any reason not to substitute a good 3/4 ply marine/oak/maple? I have all the electronics rounded up, so am ready to start building. Thanks

[buscht]

I built a machine with Baltic Birch plywood and have been very happy with it.

[CNCadmin]

I also have built a wood router with shop grade birch.

[carlnpa]

Thanks for the input, I will use a quality plywood for this first machine.

[ger21]

If you're going to get something like Birch from Home Depot, spend the little extra and go with Baltic Birch, if you can get it.

[carlnpa]

My local store had pine maple and oak. Really nice grain in both hardwoods. I went with the oak as the sheets were much heavier. I finished the board from Hobbycnc last night. Will start cutting the ply today.

[carlnpa]

One 4x8 sheet of ply has provided all the parts (less some bed and brace support material) to build the machine to the plans. There is not much left over. It took about 5 hours of steady work. Due to the weight I used a circular saw and set up clamped guides to cut the larger pieces. Used a table saw when the pieces got smaller. I'll keep posting if there is any interest. Thank you JGRO.
Merry Christmas

[gmfoster]

Please Do

Keep posting.

[carlnpa]

Total plywood 1 sheet 4x8 3/4 in., 4x4 1/2 in.
Worked seven steady hours today on the router.
Finished four large adjustment blocks - changed the design some, hopefully picture attached. Recessed and set with epoxy the hex nut for adjustment block. Will likely be using 1-1/4-20 bolts all the way around to allow second jam nut. There isn't enough space with the 1 inch bolt.
Partial finish the eight small adjustment blocks - all the holes cut.
Completed support-motor side, support bearing side. I ran these assemblies through the table saw to square up as initial cut was with a guided circular saw. Next one I would leave these a bit long to allow finish cut.
Base support structure and bed support completed, design chage again, I'll take a picture later. Much less bracing complexity, if more is needed I'll add later.
Will be using 1/2 acme rod with home brew preload assembly. Enco has this on sale for $7/6 foot, nuts for $0.99 till mid Jan 05. Measured .003/.004 backlash at a number of points, not great but consistent.
Dave at Hobbycnc was kind enough to send a replacement resistor (I soldered in the right place for a 4 axis board, mine is three, I coudn't remove so left it in) so the board is done.

[Hobbiest]

Sounds like you have already completed all of the blocks, but if not, you really only need two adjustment blocks per axis (actually, one is all you really need to get the two axis' parralell, but two does make it easier). How are you planning your connections between pieces? It seems as if drilled and tapped holes wouldn't work as well as they do in MDF. lookin good.

[carlnpa]

Worked three hours today. Made progress on the gantry and cutting bed. The plywood allows the use of self tapping deck type screws, instead of drill and tap that would work poorly in the ply. I am using a poly glue on edges with 1-5/8 screws, it goes fast and the screw pulls the pieces tight together. In places where a split would be unacceptable a small pilot hole is drilled first. The glue makes these joints permanent, without glue disassembly would be possible. I plan to through bolt the bed and base to allow these parts to be removed and grow if needed in the future.
I am using galvanized pipe as it is much smoother than black finish gas pipe, it costs a little more though.

[carlnpa]

Worked five steady hours today on the bearings. The x and z are done and the y just needs the guide spacers milled. I hope I understand how the alignment works with these. I set up a jig and drilled holes to be spot on per the final alignment under the free router plans thread. Hopefully they can never get out of alignment this way. My HF 44991 mill dug into a 1/2x0.520 y linear guide spacer and broke the nylon gear. These went much slower than I had envisioned.