Looking Good.

getting there ! There must be a summer filled with new MM's coming up. :D Mine looks roughly the same minus paint and with different a Z.

I like your coffee table also

I keep mine filled with stuff too, it keeps the dust from settling on the spoil board. I like the red! You are really close to making dust.

That is a sharp looking machine ... and since you are the racedirector a nice checkered flag decal on the machine would look good and be appropriate since you are about to cross over the finish line.:)

Why did not I think of this excuse :cool:

Thanks guys, appreciate the comments. John, I just love the excuse re the spoilboard :)

Bit of a setback yesterday. Went to check the fitting of my racks on the X and found the rails are canted over as the PFC top is definitely not parallel or flat across the whole 75mm span. Had to work today so nothing done about it but it seems I will need to shim them flat like John did with his. There may be another way if my tests are successful. I thought about buying some 75x6 square edged flat and screwing that to the top of the PFC taking advantage of what flat surface there is on the top. That would give me a flat surface to bolt the angle onto. I have to pull both rails off and do some better measurements to get a better idea of the task at hand so no decisions just yet.

Jacked up the gantry and put it on axle stands then removed the rails. Measuring a large, heavy, straight steel tube across both beams I deduced it needs .80 mm packing under the outer edge of the rails. The tops of the PFC are infact flat, it is a slight cant in the PFC which is causing grief. Tomorrow (too much wine right now!) I will try and remove the cant on the PFC, if I can't I will try the ole coke can spacer trick to get the rails flat.

Sorry to hear about the extra bit of work on your rails, angles are always tough to shim. One option I have seen is to use plastic body filler (bondo). Skim coat the low spots then drag a straight edge across both rails. Perfectly flat. Good Luck.

The car body filler like John described is a very good solution.
I allows for you to "screed" the to top edges like a concrete poured driveway.
I had similar issues too on my #5. But, since I was a bolt together frame, I was able to add shims to the end gates that make up the base table and adjust the "TOE" of the table like a car alignment by rotating the bottom of the beams in my shortening the spanning member on the bottom chord of the end gate.

Like this.

\----/
/----\

Until my two top planes were flat to each other.

Good luck
Sean

John, that is a brilliant idea. Will go grab some filler tomorrow and give it a go. We have a holiday weekend here in Aus so a day or so of drying should see me putting things back together by Monday. I'll report back how things go :)

Edit: Sean, just saw your post after I replied to John. I too have a bolted base and will probably try your solution first. The only possible downside of this method is that my holes for the cross members may not be in the right place once done but I will try and cater for that as I go. I originally had the beams bolted to the legs but decided to weld them instead, I am regretting that now.

The cross bearer table holes are the pivot....They should work perfectly. Or maybe have to upsize from 13mm to 14mm to accommodate the drift angle.

I had the legs welded to my sides too.....just the end gates and cross bearer bolted.

Good luck.
Sean

Of course, silly me. Time to clear things from under the beasty (4 sheets of 18mm MDF) and get unbolting in the morning. Thanks for the good luck, I'll need it :)

Well, I must have got the worst possible pieces of PFC in Sydney because PFC they are not. After a discussion with my wife I have decided to fully weld the base giving me a chance to perfectly match the base cross beams and ladder sections to the horrible state of the PFC. Due to its shape the base ladder sections will pretty much be parallelograms just so I can get the tops of my PFC flat. I went out and bought some new 50x50 box for the task and am now setting things up ready to go. I'll spend a bit of time welding up all the holes that will be left first and then get cutting. The only down side is that I will need wheels now and if need to move it I will need a car trailer or flatbed tow truck.

These things are definitely sent to try us but I want my machine to be the best I can get it.

Cheers

Bruce I am not so sure I understand what you are experiencing. If it is the C channel is not flat from side X to side B and it tips one way or the other. I used set screws at each bolt down location of the X rail and B rail to fix it. You can see it on my thread here

Hi Pete

The PFC I got here seems to have both short faces more than 90 degrees from the large face. If I put a square hard up against the "bottom" of the channel both legs are canted inwards so if I sit it flat on one of the legs the whole section leans inward. I was seriously considering finding better channel or going with an I beam instead but my finances argued otherwise. Besides, what the heck would I do with 2 3m pieces of non PFC channel :)

Your solution seems like a brilliant one, just checked out the post. Mine would be closer to the angle if I had not done anything with my machine meaning the C channel top was sloping to left if looking at the end at 0,0. At this point I have both tops flat in relation to each other, checked by placing my 2m level across them and not seeing daylight/torch light under the edges sitting on top of the channel. This has translated to a 7mm difference in width between the top of the legs and the bottom. Based on this I don't hold much faith in being able to pull it apart and put it back together without alot of grief so welding is my next best solution.

Understood

Do you ever have those times where you can only see the worst possible scenario and then move towards fixing that only to figure out there was an easier way? Well guess what I have done?

I spent yesterday and today pulling the machine entirely apart and resetting things up for the (to me) mammoth task of remaking the base ladders joining the sides together. I pulled the base spoilboard off and drilled the end holes in the cross beams bigger to allow adjustment. I bought more steel to make all the changes including a 75x50x4mm length to clamp to the tops of the beams to keep them flat, all up another $120.00 worth of steel.

I have just returned from the garage after sitting there staring at the mess and realising that I could do it a far easier way. There are only a total of 6 welds per main beam and it would simply be a case of grinding those welds off to reset the beams only. I will bolt the old ladders back in, square up the lower section and then reposition the main beams, complete with the tops nice and flat for the angle, and weld them back on again. Instead of the fix taking all day and probably tomorrow I can have the machine all ready to go sooner including touching up all the paint I have barked off in the process.

Sometimes pushing the desired result inhibits clear thinking. I am glad you found a solution.

Well, my revised method has worked, ground/cut the welds off the leg/beam combo and resituated the beams. I actually have them back in the original bolt positions that I started with (!!) and the tops are now firmly held flat with 2 beams of 75x50x4 box section. I have put the bolts back in and will now tack weld the beams back onto to the legs.

I also squared everything up again and now have it square within 0.5mm. Coffee break right now and then off to tack weld, clean and repaint the missing paint bits.

Are you edging ever closer to the end?

Getting there Pete. I painted the touch up areas with a brush and it turned out a better finish than the parts that were rollered. So my wife bought another can of paint and I plan to repaint the base with a brush each night over this week so it can dry while I am work. Then this weekend will be a mammoth effort to put things back together to at least get me back to where I was a week ago. Purely aesthetics I know but if it doesn't work at least it will look good :)

Best to do it now, once you get it running you won't want to go back and do touch ups.

I second John's take, once it started to move, you'll be too busy making wood dust :D
*ps, don't worry about the looks, when it works, looks becomes insignificant... :p

Hey Bruce
You're CNC is looking great!
Lovely work fulla, making dust very soon going by the rate you build!!
Red is good!
Cheers
Bazza

I haven't been idle, just quiet. The machine is pretty much back to what it was in the earlier photo minus the base spoilboard. I went on to the control box and had a few dramas with my safety circuit but that got all sorted today so I continued on with all the wiring. A little closer to making things move but far but still far enough away not to get too excited about it :)

Bit of a setback, I managed to blow up my PDMX 122 by doing something I shouldn't have. Same incident also took out the power supply on the PC so you can guess what I did.

I have an email into PDMX to get a price for shipping a PDMX-126 to Aus and will send my 122 back to them for repair. If it is fixable I will use it as a spare. Along with the 126 I will also be adding an ethernet smoothstepper to the mix, might as well while I am *still* doing my control panel.

Sorry to here about the setback, I feel your pain. Lightning took my 126 and the entire PC, I too have thought about a smooth stepper.

It will be a nice control panel though...

PMDX just paid for, will be back in action in about 2 weeks. Will try and get the rest of the machine done by then. Will test a few things with another BOB I have to have it ready for the inclusion of the 126 & smoothstepper

Back to Mechmate mode after a few distractions.... question of Z motor and the gas strut. I have just connected all the wires together on the motor to check I have the right poles. This "locks" up the shaft making it hard to turn, as it should. I attached the motor spring to the Z motor and then pushed the Z down wanting to see if the motor could hold the Z in a set position just like when I turn the power off on the machine. The gas strut however just dragged the Z back up to full top travel.

This is where the question comes in. Am I correct to assume that what I have done with regards to the motor wiring would be the same if it was connected to the control box but powered off, like when I switch the machine off at the end of the day? Have I buggered up the purchase of the gas strut by buying one that is too strong or can I not determine that until I have all the wiring complete.... as per the previous statement?

I am nowhere near actually needing this in a panic but would just like to confirm the actual purpose of the gas strut in relation to holding the Z up at the end of the day in case I need to buy another lessor charged one....

When I power off my machine, the Z does not retract, it stays wherever it is when powered off.
My first strut was a higher rating, and would retract my Z to top of travel when powered off.
Hope this answers your question.

Like Darren stated, Gas strut should hold the z stable or pull it up when there is no power to the machine. I would say error on the side of "slightly" stronger strut, you can always add weight if needed.
Mark

Same as above; powered off, Z stays in place. Your test seems reasonable. Key question: Is the Z at full weight (spindle or router installed)?

Without my spindle (or dust foot, for that matter), mine would drift upwards too.

Bruce, if it is a gradual rise and there is not any gear reduction (direct drive), I would not worry about it. If the Z stepper has a reduction of 4:1 or higher and it is a very slow rise, I would not be concerned. Unless your steppers are under 400 in-oz I would be surprised if there is a problem. If you are still concerned, you can write a quick program and repeat it 1500 to 2000 times. Use a dial indicator to read the bottom position at the start, simulate resistance of material using a spring (either compression underneath or extension above) to engage during that last 30 mm of travel. Run the program, check the distance again and see if it looses steps.

We use 1100 in-oz Nema 34 steppers to hold and adjust position cranks on 45 ton pill presses where I work. There is a lot of back force exerted back to the stepper and they hold just fine.

As for the position of my Z, it stays in place. I did make a M code to retract the to the top position just like at a tool change and added the call to the end of the post processor code in Aspire. That way when the program completes, the Z always retracts. This will serve 2 purposes, 1. I don't have to remember to retract it so the spring does not weaken, 2. it always the shaft to stay almost fully retracted so the oil stays over seal with the shaft retracted to stop corrosion of the shaft that will weaken the seal.

My dust foot is separate from my spindle so the weight is only the the spindle and Z assembly.

Thanks guys. It looks like I bought the wrong one. After Brad mentioned the spindle, I put that on and it made no difference, the Z shoots back up like nothing was there. My motors are 640oz-in and are wired bipolar parallel, also will be initially running direct drive before making my own 3:1 or 4:1 gearboxes.

I'll grab a set of bathroom scales (we don't actually own any!) and weigh the Z complete to get a better idea of the strut needed or maybe I can get this one recharged instead to a lesser value.

..or add ballast to the z to balance it.
I did that so I could interchange my spindle with my router without affecting the gas strut.

Hi Sean

I think I would need a small child strapped on there to slow the damn thing down. I tried to do a video with my phone but it was already at the top by the time I pushed record :)

lol.....that's funny.

How about a couple of Koala's, they would look good on the mast,
or are they a protected species ?.

The gas strut that I got was far too strong.
I used a spring instead.
It is slightly stronger than the motor but from a safety point of view I feel that it is better for the Z to retract if there is a loss of power.
Power cuts and current spikes are not uncommon here.
Better than having a rotating cutter drop into the work or the table.:)