IMO it looks better when the x-rails are flush with the outside of the beam. Also, there is no overhanging metal to hook your shirt into as you walk around!!!

Clayton

Aesthetics are one thing...steel yield is another.
One of the reason's for the "under length" C channel is due to steel availability length.
Gerald had plenty of forethought in getting one machines main beams out of 1 standard length of 8" channel. If the beams were longer to completely support the angle, or not cut at an angle - it would require you to purchase more steel. The overhanging rail section is within the structural needs of the machine - thus a sound choice.

The "little overhanging" for those on the budget conscious machine, save about 250.00-400.00 for not having to purchase more steel for the sides.

...my little 2 cents worth today!

I agree completely.

If you choose to use channel, you accept the overhang as you should not cut into the channel to eliminate the overhang. It would compromise the channel.

If you elect to go with the I-beam, it would be OK to remove a a small amount of steel from the outer edge.

Clayton

I used I beams as well. I orginally intended to put the rack under the (supposedly :()parallel flange of the I beam.... for aesthetics plus it saved me some width ( very limited room around the BIG machine ).

After finding out the flange was tapered instead of parallel :eek: I also partly cut the flanges back ( it's only a portion not the entire flange width), since my gantry was already cut and welded. But in hindsight I would recommend to cut it back anyway ... or let it overhang like the original with the C beam, mounting the rack on the rail is more accurate.

Either option is fine, as long as your mathematics add up. As stated my motivation for less width and aesthetics led me to the first option. Do mind you have to be comfotable that every deviation from Gerald's plans (obviously) requires more input/planning ( equals work ) from the builder.

Your choice...:D

If your top flanges weren't parallel then your "I" beam was what in the industry is referred to as a "S" shape..."I" beams with parallel flanges are known as "W" shapes...clear as mud right :-)
I've been in structural steel design for 20+ years...doesn't mean I know how to make a Mechmate out of it, but I do know steel :-)

The extra inch or so of width by overhanging the x-rails isn't a deal breaker, so I'm gonna go that route...gotta figure up the extra width to keep my cut width what I need...

Hotrolled 200 mm I-beam still is only so-so in terms of dead-on dimensions ( it can vary in mm not in tenths of a mm - look up the norms), so even if you get your hands on the W beam I would still recommend; cut out the flange or extended like the orginal plans so you can mount the rack on the rail, like Gerald intended.

Think about it, if you are shimming the rails because your beam is uneven, then your rack will not be parallel with the rail when it's mounted under the I beam flange. It's not a lucky coincedence, Gerald has designed it the way he has, he thinks about that stuff ;)

It's all relative of course ( the pinion is spring loaded and allows for a wobble + the tape cushions ).

if one is bothered by the less then 1" (25mm) overhang of the rail, surely one would be impossible to accept the motors overhanging.
I'm not bothered by both or any overhang of any sort in the original MM design.

Agree with both the above posts...gonna overhang the angle and mount the rack under the angle instead of the flange. Fox is correct on the hot-rolled steel tolerances. The AISC (American institute of steel construction) allows rolling mills +1/8 -0 in flange width on a W-section...tolerance might vary in other parts of the world.

One is also bothered by the motors, so much in fact one came up with a cunning plan to have the motors pointing inwards from his gearboxes, so the motors are running under the flange ( handy thing that I beam :D)

Structure modeled, ready to get to building
 

Got the machine structure modeled and data to the steel shop. Everything you see will come to me as a ready to weld/bolt package. All plates with holes, beam flanges with holes, everything cut to exact length.

According to the 3d steel modeling program I use, that is 2209 lbs of steel right there...Believe this will be a "solid" table...

Picture here....

Cutting area will be 12'-6 x 4'-6...to get the length I needed I am basically running this thing within a couple feet of the building walls on 3 sides...will have just enough room to slip around it to sweep and check on the machine. Because of that problem, I have arranged the bracing to allow 4'x8' sheets to slip between the legs on the near side to a storage rack on the bottom. All loading will be over the rail :( unless a roll up door is raised and then can come from the end...don't like that, but that is the option I have...(you know the saying, when you have lemons, you make lemonade...)

Ready to get going!!! Should have a laser kit coming from Metalhead in the next few days and this steel package will be 2 weeks out...soooooo time to figure out the electrics and get a kitchen table project going.

Rock-n-Roll! Will you remove materials over the rail too? You may have to come up with something to slip over the rail for protection.

I thought about that...my rails are gonna be ground rails...was thinking the rails are definitely not gonna get hurt by plywood/MDF but the ply/MDF could get gouged some. wonder if I could find something like those plastic U-channel things that ice skaters put on their blades when they come off the ice?

I was thinking something like that too. The other issue would be rail alignment. I'd think you need to keep from smacking it around, so what ever it is really has to guard against that as well.

As long as you are not throwing the wood, it will not be hurt. I have to side load my machine only as I have a wall that is inconveniently in the way of the loading section of the Mechmate. The hardened V-rails I actually use to help slide the wood onto the spoilboard. I have never seen any damage to the wood as of yet.

Good to know...and high five to another "space challenged" Mechmater ;-)

...I made some rail caps by ripping a dado in the center of a 2x4 for each rail to keep everything safe when loading over the rail or just parking the machine at night.

People in my shop had a tendency to use the rails as a place to drop hard heavy things from the forklift when driving around. The 2x made a nice cover.

Nice idea...like it.

If you are referring to the spoilboard distance from the floor, I would recommend a little lower than your hip joint height (two inches below). This allows for easier reach from the open ends of the bedway. The reason I say this is because if you are 6'6" a bed that is 26" from the floor if working at it all day is a back pain but a bed that is 36" and you are 4'8" will cause discomfort also. You best comfort zone is around your naval for standing work on a workbench but the machine is not a workbench however you seem to want be able to use it as one also. So you need to form the build based on your needs.

Know what you mean...no such thing as one size fits all. Good info.

Spindle vs. router
 

Okay, looking for the pros and cons. Is a stupid long story...but end of it is this, I already have a 2.2 KW chinese spindle with the matching HuanYang (sp) VFD sitting in a box waiting to be installed on something. I use a Hitachi M12VC on the little plywood CNC I have now...it has been bulletproof and about as complicated as an anvil. It isn't horribly loud, but supposedly the spindle is quieter. In this Mechmate I am going to setup the router/spindle to be controlled by MACH 3 (it isn't on the current machine). In trying to get my head around all the electrics, I completely see how this works for the router but the whole spindle with chinese instructions has me banging my forehead on the table. Am considering just getting rid of the thing and sticking with a router.

Give me an opinion...

If you have one of these spindles and know of a decent tutorial on setting it up wiring-wise I would be much appreciative of a pointer. Have spent some time on CNCZone, which is like trying to read the original chinese instructions...aggravating at best.

I guess I really want to know if there is enough "benefit" from the spindle to justify the learning curve to set the thing up...I seem to see plenty of MechMates with a simple store-bought router...

I've not got my machine going yet, but have set up my VFD/2.2kw spindle for trial run and testing. I can tell you that it operates much much quieter (until tool starts cutting the materials) than any router I've ever encountered (almost whisper quiet (depending on how well you could hear before)). The 2.2kw spindle operates all speed ranges at a true 3hp while the hand routers rated at 3.25hp (peak)are really operate just over 2hp. WAY worth the headache imho.

The spindle could be wired as simple as a standard 3 wire run set up....start, stop and enable.
The speed and direction of rotation could be preset on VFD front panel. Once you get into cutting a lot of the same thing, you go months without changing the spindle speed.

I personally used both on my machine. Both worked fine, but the router was a PC 1758 and incredibly loud. The spindle I had to check and see if it was on! Love the spindle...

Okay, I'm convinced...quiet is good, hp is ALWAYS good. Sooooo next point to ponder would be where's a good tutorial for hooking up the thing. The VFD is complete Greek to me...you can't even call me a beginner. I understand why Gerald wanted people to read and learn instead of giving out a bill of materials and a step by step how to guide...I've learned a ton already working thru my personal wiring diagram...heck I might not even let the magic smoke out, but I'm finding nothing of educational value about the HuanYang VFD. I have searched CNCZone and have found countless mentions of the VFD and have read till I'm cross-eyed but have yet to find much in the way of "knowledge"...:o

I remember seeing a post somewhere about one guy that put a 'warning light' on his CNC machine to denote the spindle being powered on because of it being basically silent until it starts cutting.

If you do a search on youtube you will find several videos on using the HuanYang VFD. I bought the same type of setup. I have not tested it yet, but I am not concerned about getting it working when I am ready to install it.

Will check youtube. Didn't even think of that one... ;-)

Jack, That sounds like a good idea.

Power supply and proxies
 

Am trying to get my head around several things, electric-wise, and want a clarification. When using the SI12-C2 NPN NO H proxy sensors, the spec sheet says they will work with 10-30VDC...if you power them from the start with 12V and then each additional sensor causes a little voltage drop...you very likely get below the 10V minimum before the circuit is completed (leading to a iffy situation, function-wise, if I have got my head around this)...so best idea is to power the circuit with 24V to begin with...and with the PMDX 126 and its ability to handle 24V into its inputs you have no worries of harming the BOB and no need to add relays/etc. Does this sound right?

Second question would be about the power supply. The Antek units have a main voltage that comes off the coil, but different versions also have a couple of lower voltage taps as well. I seem to remember reading of a 48V model with a 12V and 5V hookup as well. I can't this one mentioned on their site...does anyone know a location for it?

If I am understanding the proxy circuit right it would seem that I would also need something to supply 24V as well...is there one power supply that will handle this as well?

The Antek unit your referring to is here:
http://www.antekinc.com/power-supplies/

When you look at the chart you will need to work out the math for your PS current needs.

The part number should look like this PS-xN XX XX
The first is the Wattage size of the PS
The second is the 1st alternate tap you want (24V, 12V or 5V)
The third is the 2nd alternate tap you want (12v or 5V)

For instance, my machine used a 600 Watt, 56 Volt with a 12V tap and 5v tap.
Thus PS-6R56N12R5 (I know the new website shows a slightly different part number scheme...but close for demonstration)

Make sense?

When I bought my power supply, they did not have the add on low voltage supplies in stock. I decided to just use DIN mounted 24V power supply for the proximity sensors. I have also purchased a 5V DIN.

I also purchased a seperate DIN rail powersupply, cause Antek burned down at the time and shipping woudl kill me anyway. So I built my own toroid powersupply for the drives and used seperate Din powersupply for the prox and controller board.
I can recommend the brand Meanwell. They cost me about the same as a stepdown regulator ) would but with the advantadge of the isolation and they boost a V ok led and signal output ( not that you need it, but )

Great info guys...finally had an "ah-ha" moment on the power supply sizing...Will go with the 48V main with 12 + 5 V secondary taps, and just get the DIN mounted 24V PS for the proxy sensor circuit. Should start having presents from the UPS man start showing up on the doorstep soon :-)
New guys take note...if you keep reading this electrical stuff, it actually starts to make sense...imagine that.

I know that feeling ;-)

One tip: properly write down the dececisons you make and their motivation, as the conclusions to any calculations on these electrics... now that they are obvious. File them with your plans. What seems logical now, can give you headaches in a few years time when you need to repair/reroute something. If it's on paper it will take minutes, otherwhise hours to find in that grey mass ( especially when deviating from the plans/common methods). Those WTFWDIDT* moments aint funny when you have a deadline.





*(What The F*ck Why Did I Do That ?)

Have actually already started that :-) I realized a few years ago that if I HAVE to remember something it better be written down. I have a 11x17 printer...I have been printing the wiring diagrams, large format, and drawing sketches and doing the calcs long hand...documentation it's a good thing :-)

Well, no longer planning...actually building
 

Well, after off and on planning and parts buying, I finally attacked metal. Decided to get the part I've been dreading the worst out of the way first...the electrical stuff. The metal work is kinda fun to me...the electric stuff is an alien language. Gonna post a few pictures of my kitchen table project then ask a question or 2.

(Did a quick pattern layout in CAD of the PMDX boards, Smoothstepper and various other items to locate holes.)
http://www.kilocharlie.us/MechMate/Pictures/1sm.jpg

(Thin layer of spray glue on the back of the plot and stick it to the removable panel from the box...center punch the holes)
http://www.kilocharlie.us/MechMate/Pictures/2sm.jpg

(Drill all the holes appropriate sizes)
http://www.kilocharlie.us/MechMate/Pictures/3sm.jpg


http://www.kilocharlie.us/MechMate/Pictures/4sm.jpg

(Coat of color on the box...sorry this MechMate is gonna be safety red...cheaper than the Ferrari shade I had in mind)
http://www.kilocharlie.us/MechMate/Pictures/5sm.jpg

(Mount everything on the panel)
http://www.kilocharlie.us/MechMate/Pictures/6sm.jpg

(Outputs from the contactor wired to a test light to test the main power circuit...everything clicks on and off with the door mounted switch, and the test circuit with the Emergency Stop button pops the contactor off just like planned...so far the magic smoke has been kept inside)
http://www.kilocharlie.us/MechMate/Pictures/7sm.jpg

Looking good !!!
No smoke is a good thing !!

G203V resistor...What size?
 

Am using KL34H280-45-8A motors...wiring them UNIPOLAR. The spec sheet with the motors shows them pulling 4.5A wired unipolar. The silk-screened chart on the body of the G203V's says 62K @ 4A and 120k @ 5A...so split the difference? 91K +/-?
Looking for opinions.

loose bulb
 

Can't remember the model number, but is the common switch used from FactoryMation...the bulb doesn't appear to have anyway to lock into the holder other than friction...is this normal? Any significant bump makes the bulb lose contact and I assume the vibration of the machine will certainly make it jostle loose in no time. Does this sound normal?

http://www.kilocharlie.us/MechMate/P...Light_bulb.jpg

doesn't sound normal to me.

I'll take it apart and get a good close up picture off it...I'm wondering if the holder might be a defective unit...