I have been trying to keep busy on this project just to make sure I get it finished. Now you are giving me incentive to finish quickly.

I will have to fight the urge to put aside precision for speed of building.

I too have electrical work that needs to be done. I think I have all of the parts needed. I have been doing the easier mechanical work first.

I have also been thinking of how to do the V-block Flatting of the rails or at least to see the highs and lows. I think a 12" long block would be minimum. Just need to prevent tilting side to side while sliding down the rail.

Don't worry about polishing the rail. The Hardened VEE roller will do it in about a month of use!

I am more interested in checking for waviness in the rail as a result of changes in the depth of the bevel. If I stain the bevels (marking pen) on the rail and slide a 12" v block along it, I may find out it is fine. Just need to know, kind of anal that way.

Or. . . I can hurry up and finish the build and do the fine tuning later.

John,
I see your point.
The taught piano wire and shim technique with feeler gauge does a wonderful job too.

Sean

I need to be careful that I am not trying to create unnecessary precision. The vertical precision would only be necessary within the area that I am doing 3d work. Over the entire length of the table I would be doing 2D work and vertical precision doesn't matter as much. I may have just talked myself out of going down this rabbit hole of precision.

I also found that in using the machine....30 thousands of an inch 5 feet away doesn't really translate to anything when the material you are cutting moves that much with the humidity. If this was an IRON giant and milling billet metal, different story...but the MM is a routing type machine that this precision is achievable, but not always noticed.

(quick story....I ran over a shop rag while cutting multiple sheets of the same parts - never noticed a difference!)

Good luck!

Sean

The problem with trying to determine the accuracy is finding an accurate reference point, line or plane to begin with.

I too hate the fact that I can't spend full days on it, usually 1 day in the weekend and one night during the week. I think I am about a full week of work away from first cut, but due this restraint it will be more then a month before I reach that point I am afraid.


Accuracy of rails:
I totally understand the motivation to just let them be at 80 grit, and I agree the metal machine will move more then the rails in the heat/cold, but for me it makes sense as for sure it won't make the machine worse and does actually not eat a lot of time. I used a metal v block and some sandpaper and just run it the entire length it actually easily polishes the rail quite quickly. I did a test with some 120 grit in 5 minutes for one rail.
Dunno of I will take it as far as 400 right now ... but 240 I will, my estimate is it will only cost me about an hour for all 4* rails, based on my test, and it will take out any imperfections. * ( my Z has linears)

Small price to pay on my total build time, or even compared to grinding time, and it gives me ease of mind for the future.
For example if I shim it it, it won't settle any different after some use because of the small imperfection in the rails are settling.
This V-block will also come handy in the future to get small nicks out of the rails or shave of the burrs of the rails that occured to some folks after running it in, or simply cleaning them up.

Fox, You worried too much, no evil will creep back if you leave the rails as it is. Just skip the polishing, you got more important stuff to tackle :D
U gotta have faith... ;)

Finished boring the spindle mounts I picked up from surplus. Need to trim the base and add some mounting holes.

Looks good. While you have everything unmounted you might want to drill and tap some extra holes for attaching other items to spindle mount later.

Very nice work.
That thing looks like it could crush your spndle.

Nice mount and fabrication...the only downside I see theres no substantial bolt trough possible with that little flange ? you will have to tap it to mount it ? It's easy to strip the soft alu...

Ps1. I indeed added some extra M6 and m5 bolt holes to my spindle mount, which I can use to simple add square metal pieces of sheet to, which can be modified at will, with holes etc for laser, air, etc without destroying my beautifull mount, plus ... they allow for magnetic feet of the mist cooling etc to be attached (spindle mount is made of aluminium).

Ps2. I indeed worry too much, sometimes a good habit, sometimes bad.

It is a little hefty. I want to remove some material but it's more difficult to do on the outside.
The hold down will be either Counter bore from the inside of the mount and bolt through the Z plate or drill for inserts on the back and bolt through the Z-plate into the mount.
Thanks for the suggestion on drilling accessory holes, never though of it.

I quit messing with the spindle mount and installed the painted Gantry, rails and Y-Car.

Installed the Z-Axis and Motor.
Pulled in wires.
Moved the controller to the table so I couldn't ignore it any more.

Looking real nice John, I nominate you for the next serial number as you are advancing more than me at the moment :) You'll be making that lovely clean machine all dusty in no time.

More motivation to get through the control penal. :D

Don't be intimidated by the control penal wiring, think about it this way, all the terminals are labeled, you just have to connect the right terminals together with wires.
If you had done your kitchen table project, it will be a piece of cake.

Bruce,
It looks promising but you never know what is lurking around the next corner.

Ken,
The plan is to make this my Kitchen Table. I'll keep the pinions away from the racks until the bugs are stomped out.

ok, 2 pieces of cakes :P

Started getting things wired with the transformer. Then on to the input of the Geckos. Then the latching circuit with 24V E-Stop.
Before I could power up I needed to change one of my welder outlets from 250V to 250V/125V. My Controller needs a neutral for the 125V stuff.
Disconnected the Power Supply output to protect the Geckos while I played with the Power On latch and E-Stop circuit.
Power On latch and 24V E-Stop circuit worked. Measured the no load voltage at the output of the Power Supply (48.4V)

Took a break from wiring back to motor mounting.
Cut some Teflon washers. 1/16"(1.6mm) and 1/18" (3.2mm) thick.
Holding the bolts in place with Push Nuts. Cut flats on the end for tightening the lock nut.

Like the push nut idea. I will have to use that on my machine.

I put a dab of epoxy on the countersink area and had the slot cut in end of bolt.
All great solutions shown here to make it a bit easier for that low clearance bolt requirement.

Installed the X-Motors
 

Mounted the X-Motors and was able connect one to a terminal board.

did you really weld your stepper hole shut to avoid the standard 'put a sticker on your hole' comment ? DRASTIC dude :eek:

That looks like a split ring on second guess, so i guess they are supplied that way by the factory (the picture was not too big)
Ps. good progress. I am connecting my motors with a Neutrik plug, other then that ... very similar build (stage) !

Factory supplied.
I wanted to use a plug and socket but had the terminals available. Nothing dangling. The yellow cable will pass thru a square EMI suppressor. I'll mount the square suppressor and use it as a cable support for that side.

See figure C

http://www.mouser.com/catalog/catalogusd/646/1184.pdf

I hide all connections inside a junction box where the E-stop is mounted.
Looks nicer too.

Ken,
Good thought, I may wait until I mount the E-Stop Boxes before I finish terminating the motor wires. I also need to install relays for the proximity sensors in the E-Stop box.

Trimmed the spindle mounts and plan on cutting the ears down and counter boring for 1/4-20 socket head screws closer in.

Better to not use relays for prox sensors.
It will work but they have 'random' delays, making it less accurate.
Use a simple optocoupler (4N27 for instance), and a resistor instead.

Like the idea of an optical connector. I have been using a Winford RLP104 relay panel mounted in the y car for over two years now with no trouble at all.
Just information.

Al

For the record, relays will not cause any problems if you choose to use them, many have... They will work. But ... if you are after repetability, they are not as reliable/accurate as optocouplers ( the moment off switching is randomly delayed ( but we are talking miliseconds here ). And optocouplers really divide both circuits in terms of power, so they are 100% failproof isolation, relays not.

An optocoupler cost mere cents, so it's actually even cheaper.

John, you can built this on a piece of pcd for less then a dollar.
I added an 3mm led on the board (between the sensor and the resistor) to have a indicator ( my prox also have an intergrated led but these are buried inside the machine)
It's very simply.
Use the 24 volt specs (since you already have 24 volt e-stop), and choose the circuit that matches your sensor (PNP or NPN)

If you want you can also buy optocouplers with more inputs and outputs os you only need one opto coupler. I choose seperate optocouplers (cuase they are deadcheap) and mounted the optocouplers in feet, so they are easily replaced if I blow them by accident, but this is not likely so hardly neccesary.

http://www.planet-cnc.com/faq/proximity/proximity.png

Fox,
When I saw that the opto chip wanted 1.5 volts I went looking for solid state relays and found these.

Input 3-32V DC Output 4A 200V DC 4 Pin PCB Solid State Relay HHG1D-0/032F-20

Now that I see the resistor is figured out for me and they can be so small I may switch back.

Fox,
Just to make sure I'm clear on this.
Nothing connected to pins 3 and 6 on the 4n27.
Wire the collectors (pin 5) of the 4N427 together and connect to the limit on Bob.
Current limiting resistor on the input (pin 1)
Pin 2 returns to the proximity switch. - correction
Pin 4 connects to ground on Bob. - correction

Fox, very interesting, thanks for the circuits. Just a question. ... what would it look like connecting the opto's in series for connection to 1 pin in the bob?

It should also be shown that it can be wired this way for a regular switch

http://www.planet-cnc.com/faq/proximity/switch.png

4N27 diagram from datasheet

1)pin3 (NC) and PIN6(BASE) can be left floating indeed.
The rest -> combine image below of the pinout with description and my first image above, and you should be able to do the 'math' (compare the images) so resistor to leg 1 etc etc. ;-)
I have separate inputs for my proxy so will wire all separate.
If you have one input, you can combine them wired in series. You want o have your X1 and X2 wired seperately to be able to autosquare your gantry for example.

Kids words:
The proxi needs power to function, and it put's out a signal that switches on the led inside the optocoupler, which in turn triggers the output side of the optocoupler to switch.
An optocoupler is nothing more then you pushing on the button of your flashlight so you can send a signal with the flashlight to your neigbour, who then pushes a button for you, that opens your gate.
That button he pushed can actually be used to control anything low voltage (like your bob inputs) directly, and your bob can use it to communicate with the software which can control big things.
And because you never had to put an extension cord to your neighbour, to signal him, you can't electrocute him, which is nice, cause he's you neighbor, and you might need him in the future....

In other words .... that lame ass 2 dollar flashlight you built, saves you from from frying your expensive BOB by accident.

http://www.wvshare.com/img/pinout/4N25-28_35-37.jpg

Ps1. I use Eding CPU5b, which switches to ground and has multiple limit inputs.
ps2. all images just sourced from the WWW, not my work, but checked to be correct.

Edit to post #194

Pin 2 returns to the proximity switch.
Pin 4 connects to ground on Bob.

Inching along. Details are getting in the way of progress.
Installed the Z and Y motors. Needed to extend the flats on the pinion shafts of all motors to line up with the set screws.
Painted and assembled the E-Stop boxes.
Received the Solid State Relays (SSRs) from Amazon for the Proximity sensors. The 4N27 chips will be here by the end of the week as an alternate.
Pulled out the computer and installed 60 windows updates, dual parallel printer board, Mach3 and V-Carve Pro software.
Plugged in the Bob with power to make sure that the computer could see the status.

Need to complete wiring from the motors to the Geckos before I can continue with software testing. Still need to get a bearing for the Y Car Idler. I'll see if the local HW store has one on the way home tonight.