5' x 5' CNC Router Build

Well good news from the ebay seller, they said they'd ship me some replacements. After looking closer, both temp sensors had wires pulled out of them. I think the one good flow indicator would still work, but has a chip out of it.

I got the spoil boards bolted on today. I need to run a fly cutter over the top and take a skim coat as there is about 1/16" dip towards the front side that was causing some issues. I have recessed all the mounting bolts (after this pic). I'll need to do the flattening in two passes since the gantry can't reach the section in the back. I'll shift the top layer to the left and forward to hit everything.
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I ran the surfacing job on the spoil board last night using a 2" fly cutter, man what a mess, I dont think the dust boot was catching a thing. I did have it about 1/4" off the table, mostly to keep the brushed from getting into the blade, so time for a new boot design.
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The first section was about 45" x 45", then shifted the top board over an forward to finish.
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The rear was a lot further off than I originally thought. Took almost a 1/4" by the time it reached that back right corner. I'll have to try to figure out where it's off some day and maybe cut/re-weld to level things out. Most of it seems to be in the last raised table support. or the rear cross brace may be up too high. I guess it may be possible the leg is adjusted too high too, either way, I'l figure it out.
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This will do for now. Most of my work will probably be up on fixtures or "sub" spoil boards that I can screw work into and bolt down them down to this board.
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Once I finished, I opened that rear shop door and blew the place out with the 110 mph yard blower. :D
Couple of thoughts,

  1. Maybe you could shim the bottom spoil board to flatness?
    Maybe just chuck up a small piece of round stock in the spindel and move it to the high point, then go around and shim up the bottom spoil board?

  2. Wonder if your machine would support auto leveling?
    Pretty sure my board/firmware supports it similar to the 3d printer. would be a little more work to do the measuring.
    I know for doing circuit boards that feature is available.
Thanks Leo. I've had a lot of years of thinking about this build and still have a few things I'd change, but isn't going to be my last build either. ;)

Thanks Brent, I think the board is ok now that it's been surfaced. Hopefully it's just an adjustment issue. Putting a level on it shows it was mostly dead on, but over 6' it's pretty hard to know that the bubble is in the exact same position as it was on the other end of the table, so could be a very slight twist in the leveling. or may just be something pulled/pushed on a final weld. I don't think Mach3 has any auto leveling features, but something to consider on future updates to look for.
Facing the spoilboard IS the best way to do it. That is the most common method I have ever heard.
I don't find that to be unusual at all.

Often times we will face the top of the material as well to ensure a flat surface to engrave onto.

Even in machining. Grinders will grind the mag chuck often to ensure a flat surface.
I wish I had seen your top before I did mine.. I think it looks great. I'll may do something similar in the future. Maybe next year when I change out the 8 inrisers on the gantry for some 13" so I can get back to the full travel on the Z axis right now the most I can get is a little over 5 inches and that's with a 3/4 table.

Looks interesting
This is the original build, back in 2007, but I've scaled these to 90% an want to try out of just plywood, so laminating 4 pieces for the width, rather than 2.

I'm not sure I'll stick with the 90% scale. I started these files when I was still using the old cnc and didn't have the length for the full size for the rockers, even at 90% they were being tiled to fit on the table.
Well I was hoping to be further along on the rotary by now, but one of my two timing pulleys went MIA in shipping. After having no luck getting it here I ordered a couple of others. Of course since then I've realized that the bore diameter wasn't going to be of the right size for the lathe head shaft.

One of the replacements arrived today and after some research it seems the same pulley is used for 3mm bore up to 20mm, so what's a guy with a metal lathe to do? ;)
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I started with opening up the bore to 1/2", then 9/16"
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My largest 1/2" shaft drill bit is stepped up 5/8"
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From there I took a 10mm boring bar and opened up until I crept up on 20.05mm, the size of the original pulley opening.
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It slipped on nice and snug, I tightened down the set screws with some blue locktite, and added the jamb nuts.
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The belt should arrive tomorrow and then I can start doing some layout of the metal for the bed and figuring out the motor mount.
So bonus points for using the metal lathe, but pretty sure you could have just 'winged it on a drill press, lol.
I'm playing around with the rotary bed in sketchup. My thought has been to make the rotary expandable by using smaller square tubing inside of larger square tubing, where the head stock can be pulled out away from the bed a few feet I'll probably need an adjustable support/leveling leg to go with it, but something like this is what I'm thinking.
Well, After much consideration. I think I'm going to just stationary the rotary on the material I have for now.

I have some smaller square tubing that may work, but there's a gap most of the way around, not leaving things quite squared up, even in the shortest position. I can get stock that is made for "telescoping" but it's about 4 to 5 times more expensive than regular square tubing.

I can also think of a dozen ways to shim and square up the telescoping of what I've got on hand, but for no more than I'll use it in the extended layout I don't think it's worth doing, at least for now.
I got my belt today for the rotary, so was able to mock up the bed. the first layout was to support the rails on the very outside cross beams.
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This looked ok, but once I got the height I wanted and added the 6" chuck, I was losing about 4" of workable space on the spindle.
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My rails are the same length as my machine, so the next option was to cantilever the tail stock end over the next to last cross member. This actually looks to be a better option as if a heavy piece was on the rotary, there may have been some flex in the bed rails with no support in the mid section. The tail stock is also a couple of inches shorter than the head stock, so I'll have a just enough room to slide in a section of bed over it should I need the wider space.
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This put the chuck completely outside of the working area of the gantry by about 1/4". It also allows me some room to mount the motor below the head stock. I'll have the maximum amount of working area, which is 48" with some room for the center on the tail stock end.
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My other project is the dust boot re-design. I 3d printed this piece, which was scaled to fit my shop vac hose.
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Rather than sucking the dust from the side of the spindle
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I'll enlarge the hole in the top of the printed piece to allow more pass-through of the spindle shaft and collect it at that area. My boot will be re-cut to use some 3" brush in an 8" diameter around the spindle, which should give a bit more flexibility to the brush and they will be far enough away from the bits to keep them from being in the way.
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Since the original bed for the mini lathe tail stock was about 1/2" thick and I'm putting it on 1 1/2" square stock, the locking mechanism needed extending. Just going with threaded coupling and some threaded rod, which showed up yesterday.
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I also was able to cannibalize the broken temperature sensors/displays and get one working of the two. The seller is shipping me new ones to replace these, but hated to see them go to waste if I could make them work.
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There's still a big chip in the flow indicator, but hopefully it's not leaking and hopefully the temp sensor reads correctly, it's got some dings in the sensor wire.
Been hammered with work and a few other projects. I did get all the parts cut and the mounts welded up for the rotary. I've got it mocked up for welding the rails on. I've got one issue to resolve with the locking mechanism for the tailstock. I may just weld a couple more plates to the mounts to give me the clearance I need. I need to make sure that won't take it too high though.