Joe's 2006 in Boise ID

[Jay C]

The www.use-emco.com order is also attached below. It's also the same as what was listed in the Joe’s thread, except that I added the aluminum angle, two 48” pieces @ $10 each. I never ran across that size locally.

BTW, it's use-enco.com not emco

[gacrwell]

BTW, it's use-enco.com not emco

Oh gosh, I wonder who I ordered from then? Be funny if I got a truckload of flower pots or something... But thanks, I seem to have a mental block about that enco-emco thing.

I'll have pics of the motor/controller/ps when I get them spinning. I still have to d/l and install some driver s/w.

Gary

[gacrwell]

Finally did find a place that sells shielded multi-conductor cable by-the-foot, that looks good for limit switch connections: www.altex.com

I actually ordered the 4-conductor, rs-232 cable, shielded. Specifically: http://www.altex.com/product_info.ph...oducts_id=1620

At 0.18/foot it's about the cheapest they've got, and I figure many of the switch connections can be ganged in the same cable (rather than run a single 2-cond cable back to the controller for each switch). It bothers me a bit now that I notice the description doesn't specifically state that it's stranded - guess I'll find out.

As ever, the shipping cost makes it a not-so-great deal. I'll report on the quality/suitability of the stuff when it shows up.

Gary

[bp092]

Sounds good Gary, bolt depot rocks, it's a small business and they are very helpfull and personal.. plus everything is sep. bagged and labeled neatly. It's the cheapest way to go, HD Is a waste of time, they don't even sell larger full thread bolts anymore. Also anyone that used BD be sure to up your quantities to full 100 boxes sometimes. I believe I posted the pic in joes thread, but I did the math on a few and it's actually cheaper to buy a box then sep. in the higher quantities, plus then you have extras .

[gacrwell]

... Also anyone that used BD be sure to up your quantities to full 100 boxes sometimes.....

Yep, I see I should have done that with the #835 1/4-20 x 2; $7 vs $4 would have been worth getting 3x as many - useful size too.

On all of this stuff you could save a ton if you could share with a local partner(s) who was also doing a build, to save on shipping and bulk discounts.

Gary

[gacrwell]

ON CONNECTORS:

I was really surprised when I started reading on CNCZone, that there apparently isn't a common motor connector type in use. Everyone just gets to hunt down whatever fits that they can afford. I guess DIN connectors are used pretty often, but few seem to admit it; whenever DIN is mentioned, someone pops up saying that they aren't really for high current and the quality is poor. Some mention D-subs, but I dislike those even when I have to use them on PC ports. So, apparently like everyone before me, I started my connector search. Apologies in advance for the length, I just rambled on.

The first consideration is going to be the motor and controller you're using. My controller is unipolar, so that means at least 5 wires. I've got 8-wire motors, but two wires of each pair of coils are common, so they can be served by six wires in the cable. The common points of the two coil pairs could also be connected together, requiring only 5 wires, but that puts all the return current in one wire and I don't think that's a good idea; so six wires. The wires coming out of the motor are 22AWG, for a 3A, 23-size motor. While 22 gauge would probably work, those wires weren't intended to run the 10 feet or so back to the controller, and, I might like to upgrade the motors in the future, so I think a larger gauge for the cable is prudent. When I was searching for cable, 20 gauge seemed pretty uncommon (odd wire gauges are right out), so 18AWG seemed like a good choice. The cable I finally bought (at a pretty good price) looks huge: the outer jacket is 0.425" in diameter. I doubt that any 6-wire, 18 gauge is ever going to be much smaller.

I'm assuming that it's desirable to put a socket on the cabinet housing the controller, and a connector pair at the motor. They don't absolutely have to be the same style of connector, but if they are, it allows the motor to be plugged directly into the controller for testing, without an intervening cable. So a panel mount version of the chosen connector is a pretty stiff requirement.

So those considerations and other needs define my connector requirements:

• readily available from multiple sources, and in stock.
• 6 circuit, (7, 8, or 9 is acceptable)
• 18-22AWG
• 5-12A/pin
• durable, >100 mating cycles desired
• selection of genders and mounting styles
• >0.425" cable entry (>10mm)
• positive latching
• polarized
• fully shrouded pins
• reasonable cost

Circular Connectors:

• Any Amphenol connectors are too expensive.
• Switchcraft ENC styles are priced on the high side, but include everything; connector, pins, cable shroud; but don't accept a cable dia over 6.5mm.
• AMP CPC: Similar to the Switchcraft ENC and probably about the same price after adding up all the parts, but they don't accept a cable over 0.3". (On both the ENC and CPC, it may be possible to hack up the shroud to fit the cable, or just leave it off.)
• And that's about it; everything else I've found is way too expensive.

Besides the expense, the major difference between circular and rectangular connectors is durability: When it is specified, it's usually listed as some number of mating cycles (before it goes out of spec for contact resistance). The circular connectors I've looked at report cycles in the range of 200-600. That's what you're paying for. The much less expensive rectangular connectors, when they report a durability figure, are in the range of 20-50. You're going to have to ask yourself realistically how often you expect to be cycling the connectors - maybe rectangular connectors will be unsuitable, or perhaps the expense of circular connectors is unnecessary - depends on what you're doin'.

Anyway, I didn't find any circular connectors that would fit, that I could afford. So on to the open-type rectangular connectors. But first:

• A word on connector pin current: When a connector mentions maximum current, that's the maximum continuous current per pin, that produces an acceptable temperature rise, on that single pin. When connector pins are placed in a common shell, even if they are electrically isolated, they will heat mutually, attaining the temperature limit much quicker. A 6-pin connector, that is rated at 10A/pin will not carry a total of 60 Amps; 20 may be the practical limit.
• Another word on connector pin current: Parallel pin current ratings are not additive. That is, two 3A pins ganged in parallel will not reliably carry 6A. Small variations in contact resistance can unbalance the current in shared pins dramatically, causing one pin to carry more than its rated current. It's common practice to derate the current spec with pins in parallel. The more pins in parallel, the greater the derating per pin. 2 pins, derate by 20%; 3 pins, derate by 30%; four pins, derate by 35%. Those values are approximate, from memory. But, in general, you don't gain anything in current capacity by ganging smaller pins, that isn't better served by a single correctly sized pin.
• A word on connector pins: On most of these connectors the contact pins are purchased separately and inserted into the connector housing after the wire is crimped onto the pin. Pin prices vary from about 10 to over 70 cents per pin. With 6 pins/connector, the pin prices often outweigh the cost of the connector shell. The less expensive pins are usually tin, tin-lead, brass, or phosphor-bronze. Mid-cost are gold flash, and the most expensive are some variety of thicker gold. First rule: don't mix pin types. Mate tin-to-tin, or gold-to-gold etc. Second, if you are going to mate-dismate the connectors more than a few times, don't bother with gold flash - it'll be worn off after a couple of cycles.
• And also, when crimping wires into connector pins, do -not- tin stranded wire.

Rectangular Connectors: The overall cable diameter doesn't matter with rectangular connectors, because there's no cable shroud or
strain relief - this is not a good thing, but it's what you're pretty much stuck with in the realm of rectangular connectors.

• Molex Micro-Fit - doesn't take wire sizes larger than 20AWG
• Molex Mini-Fit Sr - doesn't take wire sizes smaller than 14AWG
• Molex Mini-Fit Jr - I've used MFJ's in dozens of applications, and never had a problem. However those applications were usually inside boxes, and didn't involve repeated connection cycles. They are inexpensive, ubiquitous, and available in the widest variety of styles. But most people don't seem to like them; they sometimes have problems with pin retention, and they can be difficult to unmate sometimes.
• Molex MX150L - I've never seen these in the flesh, but they look neat in the catalog. More expensive than other rectangular connectors, but the connection interface is sealed - more like circular connectors. Unfortunately they are cable-to-cable free hanging only; no panel mount version.
• Molex MLX 0.084" - really plain, super cheap. They'd probably work. No option for gold pins.
• Molex Standard 0.062" & 0.093" - friction latch only, wouldn't trust 'em.
• AMP Commercial MATE-N-LOK - These are another fairly vanilla rectangular connector except for one thing. I distinctly recall seeing one a few years ago and fiddling with the dual latch that is on the 6, 8 and 10 circuit dual row (not matrix) style of this connector. I was impressed with how positive and easy to operate the latch was. Pins are available in a wide range of AWG sizes and contact finishes. The shells are cheap, total cost depends on how much you want to spend on pins. Free-hanging or panel (they call it motor) mount; and a vertical pcb header too.

Surplus/other connectors: Good luck, you might find a gem. The only drawback is that you might find it impossible to get more of the same in the future, should the need arise. I've mentioned before, HUBBARD CNC COMPONENTS, on ebay. They have four and six pin connector sets, that are inexpensive and look really good in the picture. 18AWG, 20A/pin, positive latching. I don't recognize the specific model/manufacturer - this worries me about future availability, and, no apparent panel mount version.

I may inquire about the Hubbard, but for the moment I'm considering the MATE-N-LOK. I also might think about the AMP CPC without the cable shroud. I'd appreciate any comments or other ideas and suggestions.

Gary

[David Da Costa]

You seem to have ruled out no connector and just connecting straight to the controller which is what I ended up doing after trying DIN connectors.

I think the reality is once all tested you are unlikely to want to disconnect the motors from the controller very often and when you do it is not to much work to just disconnect the cables from the terminal blocks.

David

David

[jspencer]

Hey Gary, did you get the switches yet and if so are they any good?

James

[gacrwell]

Progress – 4 weeks in

• The Bolt Depot order arrived.
• The USE-ENCO order arrived with the acme rods, Lovejoys and aluminum angle.
• The 6-conductor 18AWG cable that I got on ebay arrived.
• The shielded 4-conductor 28AWG cable from altex.com arrived.
• The micro switches that I got on ebay arrived.
• At this point the FedEx and UPS guys are really wondering what’s going on.

Other than the kit from Joe, and maybe some connectors, that should be everything that’s coming by mail. All that should be left to buy are the gas pipes, some allthread, the ¼" skins for the table, and whatever I’m going to paint it with.

Both of the cable types I got look excellent and I think the price/foot was good, though in both cases I’ve probably got 3x what I’ll need for this build. I haven’t got the cable routing planned out, but I think the 4-conductor will work out well – that’ll give 2 wires for a limit switch loop and 2 for the home switch per axis.

The micro switches look good; smaller than I expected, but that shouldn’t be a problem. I got a set of them over to James tonight so he should be giving them a try long before I can. I see the same guy has another lot of 50 on ebay now: http://cgi.ebay.com/Micro-switches-with-Roller-Lever-switch-250V-5A-50ea_W0QQitemZ230102715590QQcategoryZ50916QQssPage NameZWDVWQQrdZ1QQcmdZViewItem If that link doesn’t work, the seller’s name is pm-sam. Starting bid is $20.50, buy-it-now for $30, shipping is $7.50. They come with a little 2-pin 100 mil, latching connector installed on the 20” wire leads – might be able to use that.

I didn’t get to do much of anything this week, ‘cause I had an online class I had to finish or else I’d have to eat the tuition. But that’s finished now. I actually did just make my very first cut on the aluminum angle, with my old wobbly radial arm saw. On the third try, I think I did get it figured out, and made a nice cut. It’s too late to continue annoying the neighbours tonight, so I’ll get out there bright and early tomorrow to finish cutting.

I finally did download and install Mach3, and fiddled with it a bit. I need to install it on a different PC, then I’ll try the motors and controller. I also did a bit more on the schematic for the vCNC controller; just a few details to fill in – I’ll attach it.

I never did find the cabinet that I was planning to put the power supply and controller in, but while looking I ran across another cabinet that I’d totally forgotten about. It’s probably even better than the one I was thinking of. It’s an old S-100 computer chassis that someone gave me. I’ll get pics of it later. The neat part about it is that after I strip out the backplane and old linear power supply, it will still have a fused power input plug and power switch that I can wire into my switching supply. It has a fan too.

I was sure I had an old solid-state relay module here somewhere that I was going to use for the spindle control, but it hasn't turned up yet. Might have to find something else.

Gary

[gacrwell]

OMG, just got an email from DHL that a BFP is on the way.

Gary

[joecnc2006]

OMG, just got an email from DHL that a BFP is on the way.

Gary

yea, they already took it and on its way. Sorry it was a few days late, I cut these out in my spare time.

Joe

[bp092]

yea, they already took it and on its way. Sorry it was a few days late, I cut these out in my spare time.

Joe

you have spare time? where can I find such a thing? my machine has been running every night since I started cutting

[gacrwell]

Progress - 5 weeks

• The kit has shipped, and I expect it'll show up sometime next week.
• Cut all the aluminimum angle bearing slides to length
• Drilled the 6" slides

The angle cut very well on my old radial arm saw. I haven't used it in years, but somewhere along the way I must have bought it a new blade. The cuts got better the more I did, so I guess the blade was getting sharper. It also worked extrordinarily well for cutting the notches. I was able to dress up and deburr the cuts on a little disk/belt sander.

For the holes, I measured, scribed, centerpunched, and then drilled most carefully. A small Harbor Frieght drill press for that, and some really nice pilot-tip bits that went thru it like butter; no wander, not a hint of snagging. But. I can't see worth a darn, and no depth perception to boot. It was really difficult to set the pilot point on the punch point, so I'm not too happy with the placement accuracy of the bearing holes.

I've only drilled the 6" pieces, so I test mounted the bearings, and set out to measure just how misaligned the bearings would be. See the pics. I set the bearing angle piece flat, set the drill rod in it, and measured the vertical displacement of the rod above the table, about a foot from the end of the bearing, then zeroed the calipers, flipped the bearing 180, and measured the difference at the same spot. Then, with a left-over piece of angle held alongside the bearing, I measured the horizontal displacement the same way. [Flipping the bearing piece and looking at the difference instead of measuring each end insures that I'm measuring error from the bearing, and not my warped table.] These were the results:

• bearing #1 190mil vertical
• bearing #1 88mil horizontal
• bearing #2 43mil vertical
• bearing #2 36mil horizontal

This is the effective misalignment over about 2 feet of run. I'm pretty happy with the second one but the first bothers me. So I'm wondering - is this a bad thing? Has anyone else tried such measurements?

After some thought, I realize that the only really critical dimension on the bearing holes is the 0.433" offset from the corner - minor longitudinal variation won't affect the alignment at all. So when I drill the rest, I'll clamp the drill press vice onto the table to set the 0.433 distance identically for all drills - even if I miss the distance a bit, it's more important that they all be identical. If they come out better, I'll probably re-do the 6".

BTW, I'm sure someone must have noted it before, but I thought I'd mention it again; on the .pdf R-2 instructions, the line on page 6:
"Each 7-1/2" bearing slides uses (4) 5 /16"x1" bolts, (8) 51/6" nuts and (8) 5/16" lock washers (one nut and one lock washer between the bearing and angle alumn.)" ... can't be right. 1" bolts aren't long enough - I'm sure that must be 1-1/2", and I think that's reflected correctly in the bolt parts list earlier in the document.

I've done some more on the vCNC schematic. The 'miracle' box is smaller now. Looking at Triac switches to include as relays & deciding what I want to do for terminal blocks/connectors.

And about connectors, while DIN are discouraged for motor cables, Mini-DIN look perfect for limit/home switch cables.

Pics are also of the old S-100 PC chassis that I'll use to house the power supply and controller. Latching, hinged top; power switch is in the upper left corner of the front panel; even has folding handles on the sides. Just remove the card cage, old linear power supply, and take care of the ferret infestation, and it'll be ready to go.

The spiffy yellow bearings in the first pic are the ones that came free with the >$30 vxb order. I don't know if they're 'better' than the others or not, but they do seem to turn more freely - I thought the Z axis would be a good place for them.

Gary

[gacrwell]

Here's a shot of the switches I picked up on ebay. They're just over 3/4" of an inch long. I don't know that they won't work, but I would have preferred something that at least looks more robust. The terminals are too small to take faston lugs; wires will have to be soldered. And, it looks like they will need 2-56 screws for mounting. It's already wired with a 20" lead and connector, but I don't know yet if it's wired NC or NO - would be easy to change - the other terminal is there. jspencer has some of them to try on his machine - haven't heard yet how that's worked out.

I'd mentioned earlier that there was another set of 50 on ebay but someone picked them up with the Buy-it-now. But, I see that the same seller has put out another bundle of 50: http://cgi.ebay.com/Micro-switches-w...QQcmdZViewItem
He may have hundreds/thousands of them.

Gary

[bp092]

lol, your ferret might get a nice shock if he decides to find his way back in there while you're machining something

For the switches most have writing on one side or it's molded in there. Typically one will go on the side, and then the two on the bottom are NO and NC. You can test it with a circuit meter if you're still unsure, just by clicking them until you find which one you want. IE: closing the switch makes a complete circuit, or it doesn't.

I actually broke 2 on my z before I set them up because I wasn't paying close attention. They were smaller like yours anyways. I would get something a little beefey, otherwise they are a pain to mount, especially in mdf. Yours are prewired though, kind of a plus. I wired mine and used the same clips that david used, crimp on connectors. They slid over the prongs pretty good but came out after a little while. Had to affix them later on.

[jspencer]

... but I don't know yet if it's wired NC or NO - would be easy to change - the other terminal is there. jspencer has some of them to try on his machine - haven't heard yet how that's worked out.

I haven't got the wire to hook them up yet. Maybe this week if I am lucky. They are NO as they are wired right now, if you swap the two terminals that are close to each other they will be NC. I'm still trying to figure out the best way to mount them. May need to get some aluminum or sheet metal and make some mounts that way I can use machine screws on the switch and wood screws on the MDF.

You'll be posting mill progress pictures before too long.

[gacrwell]

My daughter just called and said somebody delivered a box of giant puzzle pieces!

Gary

[bp092]

I'm assuming that's your kit . Welcome to the club, just rent a forklift on the way home to bring it in, it weighs a ton!

[joecnc2006]

My daughter just called and said somebody delivered a box of giant puzzle pieces!

Gary

LOL, Watchout for my popcorn ninjas as someone called them.....

Joe

[bp092]

haha, I didn't have the luxury of fighting off mine but I hear they make a mess, by the time I got home from work all my parts were unpacked in my garage.