4th axis progress

  1. The Troyke rotary table is mounted on the table
  2. It is connected to the mill via flexible watertight conduit
  3. Inside the conduit, there is a proper cable with six shielded pairs for signals, plus two power conductors.
  4. I set up the servo amplifier to work in torque mode, full torque
  5. The servo amp is connected to PPMC and EMC
  6. The amp gets power
  7. When commanded by EMC2, the amp sets a given torque (in other words, maintains given current).
  8. The table spins per torque given. Not very fast as they go, but acceptable. I would say 10 RPM just to make a guess.

What remains to be done is

1) wire the resolver to the resolver converter, and resolver converter to PPMC. I hope to avoid surprises. 2) Add a bunch of statements to EMC2 config to reflect the nature of the 4th axis. 3) Add a home switch to the rotary table.

I could not accomplish task 1, because I ordered small bullet connectors and they still have not arrived (&^%!). I want the connection to be disconnectable.

Reply to
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I'm sure you've already found a solution.

DoN Nichols and others helped set me up with a D-sub pin crimper and D-sub connectors. They are just the ticket for multiconductor cables with wire smaller than #18 gauge. I used them all over on my Matsuura refit project.


Reply to
Karl Townsend

Karl, can you expound on this a little please? What sort of crimper is that? I think that I would like that sort of thing too.

Reply to

read this thread, especially Don Nichols, "DB connectors, karl townsend, RCM":

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Ask if you have more queries


Reply to
Karl Townsend

When you first posted asking about connectors for this project, I posted the crimper you want, and some eBay auctions that were currently selling that. The crimper you want is the 90312-1 by AMP, and a current auction number with a good example (including photos showing tha the pin nest is still present on this one) is: 300510920648

Hmm ... it appears to the the *only* one on eBay at the moment.

I also closed the previous post with a suggestion that this time you *keep* the crimper, because you will have other projects for it, instead of selling it as soon as you are done, as you did with the hydraulic crimper I pointed you to.

You'll need to go to Mouser, or Digi-Key or Newark or someone similar and buy the connector bodies (they are the D series, like DB-25 for RS-232) with crimp pins. You'll also need to buy some pins. There are two wire size ranges (indicated on the actual pins by a tiny dot of red or blue paint), and of course both male and female pins. You'll also want to get the pin insertion/extraction tool -- especially if you wind up needing to move already crimped pins to other pin holes.

Enjoy, DoN.

Reply to
DoN. Nichols

Don, first of all, I resolved my immediate issue by mounting the terminal block insidethe enclosure that is mounted onthe rotary table.

But I think that I will do very well if I have a complete D-sub cable making ability.

So read on.

I bought it. Thanks

Yep, it was a mistake, although I have a big mechanical crimper.

Do you know what that tool looks like? In some categories, there is so much stuff on digikey that I am lost.

I have a little file where I write stuff down that is project related, so I will write down digikey part numbers for pins and connectors.

BTW I have two nice AMP crimpers for their 0.1" and 0.2" connectors.

Thank you!

Reply to

Ignoramus12953 fired this volley in news:IM6dnV-nLvocibTQnZ2dnUVZ snipped-for-privacy@giganews.com:

Ig (and Don, diagonally), you can - with proper strain reliefs - also use solder-cup connectors. Soldered connections aren't appropriate where vibration will disturb the wire/solder interface (fatiguing the joint, and eventually breaking the wire), but those D-sub connectors CAN be properly strain-relieved such that vibration will not affect the terminations. They sell strain-relief shells in a number of configurations. Additionally, the shells can be flooded with RTV after being debugged and certified working properly. The appropriate shell type is the sort cast in a complete "cup" shell with a screw-actuated "slider" at the wire entry that pinches the wire tightly, as opposed to the "clamshell" style hoods which only shield, but do not strain relieve the connections.

If you use solder-cup connections, you can buy pre-made D-sub connectors with all 9 or 25 pins already in place, and just use the ones you need.

Don't rule that out as a *very* inexpensive alternative to what you're proposing.


Reply to
Lloyd E. Sponenburgh

Lloyd, for now, I used a tightly spaced terminal block from McMaster and I hope that I am set (though I was not able to finish today to the point of being able to test, maybe later).

For the future, though, I think that it is great to have the ability to make D-sub connectors right, quickly and relatively inexpensively (per each connector).

Reply to
[ ... ]


Great! It is a very good tool for the flag type crimp pins. (There is another style which is for the machined pins (hollow cylinder which is crimped (indented) from four directions at once -- but those pins are significantly more expensive.

Yes -- for un-insulated terminals, IIRC.

I'm having trouble finding it too -- Mouser, Digi-Key, and Newark. All the search strings seem to fail.

Here is an eBay auction for a Radio Shack version in the UK:

# 130458979630

Note that normally the two halves (red and white) are snapped together. And this one looks a little shorter than the AMP one. (Beware, in your searches in the catalogs, the name AMP has been replaced with Tyco or Tyco Electronics. (They apparently absorbed AMP some time ago.)

Newark -- a sample pin: 90F3568

Their insertion/extraction tool -- which looks different from what I have: 90F1401

O.K. This takes you to a catalog page with their insertion tool, their crimper, shells, and pins:

Well -- above you have the link for them in Newark. It will give you a starting point, including the manufacturer's part numbers.

Great! They do make really nice tools

Enjoy, DoN.

Reply to
DoN. Nichols

I normally use digikey but poor and high cost on these items. I had good success at mouser

tool 601-40-9865 hi density dsub stuff

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NOTE: Hi density pins are smaller (.75mm vs. 1mm) and closer space, no large wire AFAIK. Normally use regular dsubs. The mouser search tool brings you right to the connector you want but it doesn't work well for the contacts. Click the catalog page on this item (currently

1298) for a large listing of various contacts.

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Reply to
Karl Townsend

FWIW, the Harbor Freight hydraulic wire crimper is quite nice, especially on sale / coupon in the $50 range. The dies it uses are quite simple, so you can easily make your own custom dies as needed.

Reply to
Pete C.

Yes. The problem with crimpers is that there is an immense number of combinations of terminals, wires, and crimper dies, and one never has the right stuff, except for those few things that one makes enough of to be worth collecting a correct set.

It's hard to beat solder cup terminals for one-off projects. I will mention that with high-density solder-cup terminals, the easiest way to do the soldering is to use resistance soldering, which allows one to solder one wire without melting the insulation on the next wire over, without needing much care.

When everything was inspected, the connector backshell was filled with polysulfide rubber and allowed to cure overnight, thus potting the solder joints and gluing the wire insulation to the connector body.

I first met this approach at RCA in the late 1960s, when working on flight equipment that was literally going to the Moon, and therefore had to survive the vibration of a Saturn V launch. If it's good enough for NASA, one assumes that it's good enough for RCM uses.

Functional resistance soldering stations pop up on the used market for pennies on the dollar.

Joe Gwinn

Reply to
Joseph Gwinn

The tool for sub-D terminals is available at those Shack stores, if the store still stocks much in the way of parts.

The red color is the same for aviation terminal tools for the same size of terminals, easy to remember if one is familiar with electronic component/resistor color coding.. red (2) is for size 20 terminals.

As mentioned in an earlier thread, there are two different terminal types (and connector bodies) for sub-D connectors.. stamped-sheet brass formed into the shape of mating M/F terminals, which have the dual flag tabs, and the other type is the machined-from round stock into the mating M/F terminals (much more expensive terminals and crimper).

The formed brass sheet type terminals are common commercial-quality terminals, found in many D-type computer cables (but also many other applications). These terminals are cheap to produce, and easily implemented with the proper industrial assembly machines.

The machined type terminals are high-reliability types, which are far less common in consumer goods.

Both of these types of terminals are extremely labor intensive and very costly, compared to soldering. Soldering is permanent and prone to less fabrication-related failures than crimping, whether one is familiar with crimping or not (assuming that one is capable of learning how to solder properly).

The vibration aspect keeps getting mentioned, and is definitely not much of a significant issue with home shop machines. If the sub-D cable connector is installed with a connector shell, then the soldered connection is already essentially immune to vibration issues, as the shell will dampen cable vibration. If various cables are so loosely installed that they're free to shake (or be pulled on), then any failures are a result of poor installation.. free-hanging connections swinging in the wind are destined to fail anyway.

The fact that military/aviation connectors are fabricated with methods to guard against failures is obvious. Home shop machines will not drop out of the sky if a connection fails. Rarely will injury or deaths occur if communications are lost between a control and a motion device (troops and intel analogy).

Looking at the conditions that exist under the hood of a car, compared to a stationary machine in a workshop, there are few similarities. Yet, many connections in engine compartments aren't high-reliability, or environmentally sealed connections.. and they generally hold up for many years/decades. Many home shop machines will may even be modified/upgraded or sold within a couple of years.

I understand the practicality and efficiency of doing something well, and this is often the primary issue with most things I do. Aerospace certified connections on a mill or other shop machine aren't practical from any perspective.

Most RCMers will make electrical/signal connections better than taping twisted wires, and there are countless interconnection products commonly available (many more than in previous decades), but carrying simple wire connections into the area of industrial machine manufacturing isn't practical. No one here is attempting to build more reliable machines than Bridgeport or Boeing, for the sake of building a reputation of a company manufacturing highly reliable machines.

In most cases, soldered and insulated (shrinktubed) connections, properly secured to a stationary surface, are just as reliable as any connector of any cost.. practical, inexpensive, easy and effective.. wire markers optional. When the wiring requires changes, cut and repeat.. caution for any tighter-than-a-frog's-ass types, this requires wasting a few inches of solder and a small amount of shrinktubing.

When circuits need interconnection devices, and many don't, solder the wires to the connector contacts (install connector shell or insulate well), and secure the cables nearby.. the results are more reliable than many engine compartment connections.

Many times, the situation is matching a connector to an existing connector (low voltage signal connections). If the existing connector doesn't need to be disconnected regularly, then soldering wires to the device eliminates the need for the connector. To disconnect, apply heat, remove. This will work fine if the device is your own stuff, doesn't affect warranty issues, resale value, or safety issues.

Reply to

For those who have used transformers (including modified microwave oven transformers) for other projects, making a resistance soldering station shouldn't be difficult. Essentially, the xfmr secondary is only a few turns of heavy conductor, and the primary winding is controlled with a simple (slow) duty cycle control circuit.

Making a suitable handpiece isn't extremely difficult, the concept is two electrically insulated contacts that can easily reach between the solder cups of (many types) of connectors. A tweezer-type handpiece is the typical style for this type of soldering, and some thermal resistant insulating material is best for the grips.

Since the output of a properly utilized xfmr will be very low AC voltage (only about 3VAC), and properly isolated from the AC line voltage, resistance soldering is very safe and efficient.

The contact arms(?) of the tweezer handpiece are typically heavy gage stainless steel wire, as it generally resists common lead solders, and doesn't require constant cleaning to remove heavy surface oxidation.

The principle is that the solder connection will heat more rapidly than the air-cooled SS arms do, enabling the solder to flow freely without heating the arms up to soldering temps. The tips of the arms are typically smaller in cross-section than the arms, making the most concentrated heat at the solder terminal, and less heat in the arms.

As far as securing the wires in a connector shell, a glob of hot-melt glue is probably as effective as filling the shell with something else, and fairly easily removed if needed. Potting the soldered connections isn't practical for sub-D connectors (or many others) since the mechanical connection of many connectors isn't sealed anyway.

As far as advantages to using solder cup-type connectors, there are rarely any reasons not to. If home shop machines are vibrating within the range of destroying soldered connections any time soon, it's probably dangerous to be near them.

Got a powerful ultrasonic cleaner? Please, let us know the results.

Reply to

Hmm ... note that the normal insertion/removal tools from AMP for these (DB-25 sized) pins in the old days (pre TYCO) was two colored. A red end contained the insertion tool -- a C-shaped tube of probably bronze. The white end contained the extraction tool. It is a spring steel (normal metal color), and while not fully cylindrical, it is almost completely so. There is a very thin slot opposite the open end, terminating in a small hole to stop stress cracks from forming. This one is sprung open and slid over the wire before passing down into the connector body to depress the locking tabs on the pin to allow it to be removed. The red end has AMPs molded part number (91087-2), and the white end has a stamped number M81969 -- probably a Mil-Spec inventory number, along with a partial date /1-02.

Another which I use interchangeably with the above is quite similar -- except for the lack of any part numbers, molded or stamped, and slight difference in the shape of the plastic body (D cross-section instead of square).

And both can be used interchangeably in the connector bodies.

Of course. Did you hear anyone suggesting that these be used in the project in question?

Interstingly, Ma Bell used to consider soldered joints to be temporary, and wire-wrapped joints to be permanent. (And wire-wrapped joints, like crimped joints, require special tooling.)

Depends on the machine. My Nichols Horizontal mill, with 6" conventional milling cutters makes a lot of noise and vibration under certain circumstances. Granted, it is not a CNC machine, so if a joint fails, the spindle motor stops -- nothing else. :-)

Depending on the frequency of the vibration. It can be tuned to the wire length to cause a lot of vibration between the point of support and the point of connection.

Of course.

I would consider CNC machines (which is what this discussion is about) to have some potential for injury or death -- especially if they use servo motors. If one of the tach feedback wires parts, the motor will suddenly speed up to maximum speed in one direction or the other. This can be *very* fast compared to a stepper driven axis, and given the leverage of ball screws, can apply a lot of force to a human pinned between the table and some adjacent machine -- or between the spindle and the workpiece.

Yes -- but the frequency range of the vibrations is well known, and unsupported wire lengths which would be most subject to those vibrations are normally avoided.

This can be an argument for crimped pin connectors -- it is easier to move a connection to a different pin there.

Yes -- it can be done with soldering -- but every time you unsolder and move the wire, you do more heat damage to the insulation, ignoring the wicking of solder up into the wires, since you want to ignore vibration failures anyway. And some connectors -- the ones with white nylon bodies -- tend to be quite sensitive to the heat of repeated unsoldering and resoldering of pins.

Nobody was suggesting Aerospace certified connections -- e.g. the machined pins. The stamped pins are fine for this application -- even better than in automotive use where spilled battery electrolyte, or salt filled road splashing can get into the thin slots present in formed pins and lead to corrosion -- not a problem in a typical home machine shop.

[ ... ]

The project which started this discussion -- a rotary table being CNC equipped for a mill -- is one which would not be installed on the mill full time, so a connector does make sense here.

As for soldering the connections -- a lot of us are getting older, and connectors are getting denser and denser. A three row Subminiature-D connector (e.g. the typical VGA connector) requires good vision and practiced skill to solder those pins without resulting in solder blobs connecting adjacent pins, or soldering iron damage to the insulation of the wires in question. And not all HSMs are experienced electronic solderers. It is for these that the crimp pins are the easier way to work. If you get a wire connected to the wrong pin in the middle row of a well populated three-row connector -- with crimp pins, you reach for the extraction/insertion tool, pop it out, and put it where it belongs. With soldered pins -- you are likely to have to unsolder several wires blocking access to the one needing change -- with the increased chance of reconnecting *these* to the wrong pins.

And with printed circuit boards -- even the good glass-epoxy ones -- each removal and resoldering increases the chances of floating the pad away from the board -- or damaging nearby plated through connections. If the board is an old phenolic PC board, the chances of floating a pad free are vastly greater. They really were *not* made for maintenance. :-)

And is insufficiently dense to provide problems for the skill level and vision of the person doing the work.

I've got good glasses, and a stereo zoom microscope for really dense things. I've done repairs to boards with the high density surface mount chips using these (and some 20 Ga wire wrapped around the tip of a small soldering iron to make an even smaller tip at need). I still prefer crimp connections for many things.

Enjoy, DoN.

Reply to
DoN. Nichols

First of all, ask Ig if he has even been discussing an electrical disconnect for the rotary table.. not that I've seen.

What I've seen was his discussions wrt connections inside the housing on the RT.

He hasn't mentioned what, if any, connector is now, or is intended to be used to disconnect the RT when not in use.. AFAICT. Of course, a sealed, reliable connector would be handy to have for the RT.. maybe he can get three weeks of comments for that BIG problem.

I wouldn't recommend a sub-D connector for a RT connection cable for use on a milling machine, in fact, I believe that I mentioned a mil-spec-type sealed connector for that type of use in a previous discssion of the same RT.

That's why I suggested solder and shrinktubing for the internal RT connections, instead of ordering ~$30 worth of connector and pins to make a simple internal connection.

Why would he present a question with such a simple, easy solution?.. becuause he nearly always does. And folks respond, over and over again.

You seem to hint around at saying I'm including comments in replies that don't address the exact issues at hand. Most of my comments aren't specifically targeted at the OP or their present situation/problem/imagined, non-problem. The comments are generally written wrt relative shop issues.. motors, wiring, crimpers etc. Most times, I don't care if the OP, or anyone else, already knows the information I present, instead, the info may be of help to others in different situations. I typically don't reply to questions that have already been answered in detail.

I add comments to posts because the comments are about various shop related issues. I'm not going to preface comments with: Oh, this isn't about this exact issue, but .. so, if the comment doesn't apply exactly, then disregard it. I also don't use smileys.. this isn't kindergarten (or AOL where you might piss someone off without intending to offend), and I couldn't give a FRA about conventions, otherwise I wouldn't top post. Have fun scrolling thru others' posts, even though the quoted comments are days old, previously read clutter, but don't make waves.

I've put in my half-century, and then some. I'm about the same age as others here in RCM and yourself, DoN. My eyes probably aren't any better than yours, maybe worse. When I can't get by using a magnifier lamp, I'll stop doing the small stuff. I won't spend hours looking thru a magnifier, and I doubt that many would enjoy doing that. Hand crimping flagged terminals also requires good vision to get the terminal placed in the correct position before, during, and after the crimp process. Soldering also requires good vision, but so do most things.

Removing locked crimped terminals to relocate them still stresses the wire(s) by making several bends near the terminal, so relocating removable terminals is not a perfect solution either.

Moving crimped terminals of the sub-D type (and others) risks collapsing/bending the locking tabs which hold them in the connector body, and without removing the connector shell, there is no way to absolutely know that the terminal didn't get shoved back into the shell during connection, other than X-ray. So, others too, can imagine various failure modes that could possibly occur.

If the connectors have soft insulators/fillers that melt away during normal soldering, buy better grades of connectors and/or practice soldering more often. My trick for soldering connector terminals in soft materials is to connect the connector to a mating connector, to keep the terminal in perfect alignment (from walking around).. it also cools quickly. I've reused solder-type sub-D connectors of only average quality often enough to know this generally isn't a problem. In my experience, moving a wire around on a soldered connector isn't a problem.. it would be on an F-18, but not on average terra-bound stuff.

Soldering, as I said days ago, would Easily solve the Internal connection issues presented.. cheaply, and reliably.

For individuals that can't tell the difference between a good or bad soldering connection, they should get someone that knows how to solder well to help them learn. There are going to be those that have poor success with crimping too, until it's practiced enough to get it right every time.

Properly soldered wire-to-wire connections are already environmentally sealed/airtight.. until the solder or wire is eroded away by strong contaminants/chemicals. Soldered connections are also vibration resistant if secured properly. Anyone can severely bend copper wiring until it work hardens and breaks.. but most home shop machine wiring rarely has to endure that much stress in at least several years, but in all probability, many years.

Like I said in another post.. if a home shop machine vibration is within the extremes needed to make connections fail within a short time, the machine is probably not safe to be around.

Interconnection terminals rely on friction or slight spring pressure to make a good connection. Improper handling of interconnect terminals can damage the actual contact surfaces and/or tension of the terminals.

There are always more reliable connectors and methods to do almost anything.. and in some cases, they matter, but in many cases they don't.

The only "issue" here is Ig. He can be offered a simple solution, and insist that it's not good enough, not what he was looking for, on 'n on, blah, blah.

Most other people would have figured out the simple problem, and not even presented the question.

Reply to

--FWIW I'm not a huge fan of bullet connectors; there are some neat insulated male spade connectors that have a boot that covers the tang, going over the outside of an insulated female spade connector; you might want to try those...

Reply to

Don, thanks a lot! The crimper arrived today.

Just one more question: on that Newark page

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The left column is for high density HDP-22 connectors and the right column is for HDP-20 connectors.

Which of those fit the crimper 300510920648 that I bought on ebay?

I am guessing right column for HDP-20, but I want to be sure.

i >> >

Reply to

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Would it be prohibitively expensive to buy one of each, and see which one fits?

Good Luck! Rich

Reply to
Rich Grise


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Certainly the HDP-20 for the connectors with two rows of pins (or the DD-50 three-row ones). But the crimper seems to work well enough on the HDP-22 ones as well. Note that the HDP-22 pins are all listed for 28-22 ga, instead of two groupings -- 24-20 and 28-24. Both series seem to be for insulation diameter up to 0.040", and (IIRC) the major diameter of the back body of the pin (as distinguished from the actual pin diameter) is the same so the crimper's nest will work with both.

I'm not sure which crimper I would use for the 26-22 size range (a few of the HDP-20 pins are marked that), but I have the 24-20 and the

28-24 size pins.

The HDP-22 pins are for connectors like the VGA connectors (15 pins in a DE-sized shell, instead of the usual 9 pins for that shell.

So -- unless you need more pins for a given size (and have or plan to get the appropriate shells), stick with the HDP-20 pins.

Note that you can sometimes buy the pins in reels (and they cost less that way), but these are for automated machines which snip the pin off a continuous back strip of metal as they are crimped. And you have to buy rolls of 20,000 pins -- nice for production, but a bit much for a hobby worker. :-) $0.04 per pin sounds nice, until you discover that you've just ordered an $800.00 reel of pins. (I've gotten reels of pins, via surplus paths, for quite reasonable prices, but it is a pain to have to snip each pin free of the backing strap. (And no -- I'm not going to get one of the industrial machines to crimp them. :-)

Enjoy, DoN.

Reply to
DoN. Nichols

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