drive pin on R8 collets

I recently bought a used rockwell mill. There is no drive pin in the spindle that is suppose to engage with the R8 collet. My other mills
do have drive pins. Is this a problem that I need to fix?? I seem to remember this question before and it might be ok??
thanks chuck
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Mixed reviews on that subject. Personally, I'd fix it, but there are some that go out of their way to remove it. It's nice to know that the collet isn't going to spin on you when you tighten the draw bar, which is it's real intended purpose, not to drive the cutting tool, although I have no doubt that it also helps in that department. In all my years on the machines I've never run a mill without one, nor have I ever busted one, although the shank of one of my boring heads is a little buggered up from one from a crash many years ago. I guess you might say it's a personal judgment call.
Harold
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On Wed, 30 Jun 2004 11:34:54 -0700, Harold & Susan Vordos wrote:

I noticed that a mill I was using in one "high end shop" had had the indexing pin removed and asked the shop foreman about it. He told me that it was really there for indexing of the collet to keep it from turning when tighting or loosening the drawbar, but they'd pulled them from all of the mills after someone engaged the drawbar and started tightening it before the collet was indexed into the pin slot. The pin was soft enough to shear off, but they had the devil of a time getting the collet out without causing more damage.
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Harold sez:
"I guess you might say it's a personal judgment call."
Yeah, Harold and a good call it is. The original designers had good reason to include the pin and it should be left in. IMO, those that rant about the pin not being really necessary are just looking for an excuse to justify their sloppy procedures.
Bob Swinney

some
collet
real
doubt
machines
the
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reason
the
That's more or less that to which I was alluding, Bob, but there are those that feel their decisions are just as valid as mine.
I'm anal enough that I tend to jump through all the hoops when I'm on the machines. I wipe out the spindle and wipe off the collet, then hit both with a blast of air before assembling. I also am heads up enough to avoid engaging the drawbar before the collet is properly seated in the spindle. I'm the kind of guy that always wipes down the ways and oils the machine before beginning work, and then I stop during the day and repeat. The oil on my ways is ALWAYS fresh, never dirty. I tend to preach that concept, but not many appreciate being told, so I don't do it any longer. Hopefully those that didn't do it have learned to do so now. It's very important to the longevity of ways and screws.
The one benefit of not having the indexing pin, and I don't take advantage of it, is that if you use something like a Sjogren collet head (I do) and do considerable heavy work, you tend to get a definite wear pattern from the collet. If the collet had the ability to fit randomly, that would not occur. To me, that is not enough of a reason to remove the indexing pin.
Harold
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On Wed, 30 Jun 2004 20:35:46 -0500, "Robert Swinney"

snip
I think that is a pretty unfair statement. A persons desire to have or not have the index pin is certainly not a reflection of the quality of their work proceedures by any means. Its akin to saying those that use a China made tool to make an item will produce an item that is inferior to an item made with an American made machine. Simply not true as to an index pin in or out reflects on work proceedures or quality of work produced. Visit my website: http://www.frugalmachinist.com Opinions expressed are those of my wifes, I had no input whatsoever. Remove "nospam" from email addy.
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wrote:

reason
about the

justify
snip----
When you've spent as much time working in commercial shops as I have, you'll come to understand exactly what he mean. To the man, those that cut corners, be it in processes or how they approach machine tools, tend to be not great machinists. The problem is that when they're surrounded by people like themselves, there's no one to make them look as bad as they are. Those with the greatest skills and ability deal with the field of machining in a totally different way. If you've ever worked with someone that has that level of skill, you'd know and understand it quite well. They stand out. I've yet to see it any different, and I've been on machines since the late 50's commercially. The very idea that a feature of a machine is eliminated because a worker is incompetent (what else would you call it?) and screws up a machine because they're either in too much of a hurry to do it right, or don't know enough to do so, is a perfect example of sloppy procedure, regardless of the reason. Sorry, I agree with Bob. It does reflect on the work that is produced.
Harold
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On Thu, 1 Jul 2004 11:24:09 -0700, "Harold & Susan Vordos"

Well its your opinion and your entitled to it, but I still dissagree. Visit my website: http://www.frugalmachinist.com Opinions expressed are those of my wifes, I had no input whatsoever. Remove "nospam" from email addy.
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some
collet
real
doubt
machines
the
judgment
Chuckle!
I'd question just how "high end" the shop was when they pull tricks like that. My opinion? They should have replaced the guy that screwed up, not removed the indexing pins from all the machines. But I digress. I think it's a personal call, as I've stated, but anyone that worked for me that made that call wouldn't be working for me at the end of the day. I, by far, prefer to have those that have enough skill and talent to not screw up instead of altering machines so they can't do so. To me, it's a sign of a fine craftsman when he can operate equipment properly.
Harold
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On Wed, 30 Jun 2004 22:15:18 -0700, Harold & Susan Vordos wrote:

Have you ever used a machine with a power drawbar? On the ones most of their mills were fitted with when you tripped the handle it took about 0.5 seconds to fully tighten the drawbar. I presume some one was changing the collet and just tripped the handle a bit sooner than they meant to.
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not
No, I have not, but under that circumstance I can see how it could happen to anyone. There was no mention of a power draw bar originally. If that be the case, I stand corrected. Still, with just a *little* care, it could be avoided!
I'm from the old school where everything that was done on a machine was done by the operator. Skill level is what sorted out those that could from those that could not. I can see that CNC has changed all that.
Harold
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On Thu, 01 Jul 2004 11:28:13 -0700, Harold & Susan Vordos wrote:

My mistake, I should have mentioned that all of their mills had power drawbars. I agree that in the absence of same that anyone abusing a machine by pulling a collet past the index pin should be fired on the spot for total incompetence.

I don't think that CNC can really be blamed on the decline in skill levels. The blame lies partly with the education system. How many schools do you know of that still offer any training in "hand arts"?
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like
up,
0.5
the
happen to

be
could be

That does make a significant difference. Sounds like you have to have all your ducks in a row when you "push the button". I can see how a guy could be deep in thought and do so prematurely.

I fully agree with the lack of training, in part because the educational system (in all its wisdom) has made the decision that we no longer need that type of training. Before moving from Utah I shared in the good fortune that came from schools selling out by attending a few auctions, at which I bought a lot of nice equipment to augment my shop for use in retirement. For the most part, I would not have been able to otherwise acquire the stuff.
I contend that guys coming up on CNC machines must know totally different things than guys do that run manual machines. My age group has a nice mix of both talents, so it's not as obvious that the manual skills are absent in general. I'm of the opinion that younger guys coming up generally don't know how to do the manual work, which is skill intensive, at least for a predictable outcome. I've always said anyone can make chips, but it takes considerable talent and experience to make good parts, and do it reliably and efficiently. That doesn't come without considerable effort.
I don't mean to demean those that run the CNC's, just point out that the skills involved are not the same. An outstanding CNC operator, one that can do his own programming, is likely as skilled as many of the old time guys were that were considered the cream of the crop, but the run of the mill operator may not have any machining skills at all, yet still do good work, thanks to the machine and the programming skills of others. Sadly, the skills that were required to be considered a machinist are getting lost in the shuffle from manual to CNC. Even tooling departments are using CNC these days. I guess the only thing to consider is how important is it? Seems no one is making buggy whips any longer, and we get by nicely without them. It's just a little hard to consider yourself outdated and useless. Can't tell you how pleased I am to be retired, where it makes no difference any longer. I think I'd be hard pressed to hold a job in today's market.
Harold
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On Sat, 03 Jul 2004 17:56:09 -0700, Harold & Susan Vordos wrote:

I think that's completely accurate. From what I've read what training that still survives is oriented to CNC processes rather than the manual skills that used to be taught. While I've never had any formal training, and this sort of thing is just a hobby, I did have the good fortune to spend a good bit of time with what was arguably a couple of "master toolmakers" back in the 70's. I was a physics major working part time in a physics research facility and had a number of occasions to have to have things built in the machine shop. I learned a lot about how to design things from those guys (and how not to design things as well).
The shop had an old beat up mill and lathe that could be used, with permission from the guy that ran the shop. After he was satisfied that you weren't going the break the machine or injure yourself or anyone near you could use the tools. Having had lots of experience, he did require that one of the machinists inspect your setup before power could be applied. After I while I had learned quite a bit and, surprisingly, my skills had progressed to the point that the old tools had become a limiting factor (although I didn't have the experience to realize it at the time).
One day when I was struggling to cut some fine threads on an adapter ring for some camera gear (a home project) the head guy walked by, saw what I was doing and "took my project away". He took into "his area", set the part up in a EE Monarch and had me finish it there. I remarked on how easy that was and how well the part came out and he said, halfway jokingly, that if I could make a true 1" cube from mild steel with nothing but hand tools he'd let me use the EE or one of the new Bridgeports. I suspect he figured I try, find out hard it was to do, and give up on it. What he didn't realize that "having had a taste" I was highly motivated to learn how to do it just to be able to get my hands on good tools again.
It took over a month and I blew the first one. The angles were correct and the sides flat to less than a half, but one dimension was 0.998" instead of 1.000" and another was 0.999". So I made another, correctly this time having learned how to do it from the first one. I showed him the finished part, which he duly inspected and declared to be satisfactory. After that I could use, unsupervised any tool in the shop that wasn't being used for a shop project. He later told me that he'd been required to do that years before as a part of his formal machinist schooling. Apparently it was a "standard test" at that time.
I don't think they teach those sort of "hand arts" skills now. And for the most part they probably aren't required for a CNC process.
The same can be said for a number of other things. Back in the seventies the computer courses I took started with assembly programming and worked up to high-level languages (Fortran & Cobal at the time). We're talking punch cards and "submit the job today, find out if it worked tomorrow". One learned a lot about how computers worked and consequently how to right good code, the first time. Now they plunk these kids down in from of a windows box and "teach" them programming using Visual C++ in a Gui only environment. While those kids do learn to program they usually don't have any idea of what "is under the hood" in that process (Makefiles, compile steps & options, or linking and libraries) and know next to nothing about the internal workings of the CPU.
--
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snip-----

That point is one that is difficult to explain to fans of rusty machines. I see many defend buying old rusted hulks, especially when they can be cleaned up and made operational without too much trouble. The "rebuild" usually includes a wonderful paint job. Unfortunately, paint does nothing to make a machine tool work well, and the portions that are critical often get the rust removed and nothing more. That is where experience comes into play. Unless one knows what can be reasonably expected from a machine tool, it is most difficult to say with certainty that the tool is working properly. Many just assume that it is difficult to hold a thou, that it has nothing to do with any given machine. For those with experience, though, it takes little to no time to point a finger at the cause for given difficulties. It's a good step forward when you can finally ascertain that it is the machine, not you, that has a problem. While it's true that a good machinist can do reasonably good work on most any machine, it isn't cost effective, especially when the risk of scrap increases.

snip-----
Talk about dedication! Congratulations of the accomplishment. You paid a small price to have the use of nice machines. I'd have done the same thing had I been in a like situation.
I've never had to pass that test (the 1" cube), and was more than fortunate to have been assigned to an EE that was but one year old, on which I learned the fine art of thread chasing, along with other lathe operations. I started in the trade having owned a small lathe and having taken some machine shop classes in high school. It was interesting to note that in school I was on top of the class, yet when I was hired it became apparent to not only me, but my supervisors, that I knew almost nothing about machining.
There were times when I chased threads for an entire week, then on to other parts. I guess what prompted me to get serious about quality was the fact that everything we produced received 100% inspection (defense work), even between operations, so good money wasn't thrown after bad. I was fortunate to have had a supervisor that took a personal interest in me and my progress. He patiently talked to me and lead me along, teaching me the right and wrong ways to do things, and encouraging me to shoot for quality. I was told that if I learned to do things in an acceptable manner, that speed would come automatically. It was true.

Yeah, that was my point, too. In a way, I guess it's no loss, but I can't help but wonder if the day won't come that we have regrets. My training was job specific, so I didn't have to jump through the hoops the way apprentices did in the "old days". I managed to run a shop, subcontracting, for the most part, from the industry from which I came. It treated me well, and I closed the doors voluntarily. I could have kept busy endlessly. Still, my skills alone would not have been enough to compete. Without CNC training, not many can do so today. I guess that, in part, helps explain why the classes have been dropped. What disturbs me is that we wouldn't be able to respond as easily in a national emergency as we once could, not when we depend on foreign nations for the majority of our manufacturing, and few are learning the skills, be they CNC or manual.

That is the part about CNC operators that troubles me. I realize that they turn out the work, but without the computer, often they can't. They may be well trained to do what they do, but in many cases they don't really understand the workings. For example, can they sharpen tools? Of necessity, CNC operations dictate almost exclusive use of inserts. I don't have a problem with the fact, but those that train on and operate such machines are very likely to never have a grip on cutting tool geometry, and couldn't hand grind a tool if their life depended on it. If a CNC operator thinks it's a simple step to go from the computer to a manual machine, they're in for one hell of a shock. Again, anyone can make chips, but when it comes to stepping off dimensions for drilling, or cutting a window, it can be a dreadful experience when done for the first time. My hat's off to guys like you that have taken the bull by the horns and learned the things that constitute one being worthy of having the title "machinist", even though to be one doesn't command much respect.
Harold
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On Mon, 05 Jul 2004 01:35:10 -0700, Harold & Susan Vordos wrote:

Absolutely correct in all respects. While I've developed the skills (on a hobby basis for the most part) to be able to resurrect an old machine with lots wear, it's not something that I'd want to invest the time in again. When I get the shop space to re-acquire metal working tools I'll get new unless I can find an awesome deal on a GOOD used machine. And if I do find a used one I'm going to have to have "hands on time under power" before I'll plunk down the coin. At least I've had enough experience to know if the machine is in decent shape and won't require a large investment in time to restore it to good condition.

Thanks... In addition to the manual skills one has to learn to do that I suspect that the most valuable one is learning to work carefully and be patient. Too many times folks get in too much of a hurry and quality suffers.

It's really these old guys that have been doing this sort of work since tools were steam powered that are some of the best teachers. Just about anything you can think of they've done. And they've probably found all the ways not to do it as well as what works.

I have little doubt that will happen. Consider industries like ship building. With the fewer yards every year we're loosing the years & years of experience that's necessary to build ships well. At some point all the "old guys" may be gone and with them all that knowledge. And that's not something you can "learn from a book".
I get a kick out of watching the show about Craig Boddington's (SP?) shop and the guy that's "older than dirt" that can work magic with metal. There's fewer & fewer of those guys around every year what with production moving off-shore and the increasing reliance on CNC. I'd love to have the opportunity to just be able to stand around and watch that guy work...

Yep...
Yeah, that, in a sideways sort of way, was what I was talking about. Those guy's might be a gee whiz at programming and setting up a CNC machine, but if you really only needed one part it would cost a fortune compared to a manual process by a good machinist. And, by and large, I suspect that the CNC guys couldn't do it if the job had any complexity (needing jigs, careful planning, etc).
If you have the time learning the old skills can be immensely rewarding. And this is true of any "hand arts" skill set and isn't confined to metalworking. And, suprise, suprise, the fastest and best way to learn those is to hook up with one of the "old geezers" that did it that way for years. While it is unlikely that one will ever make any money with those skills the self satisfaction one gets is well worth the investment in time.
--
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Lots of guys don't use 'em. My BP didn't have one when I got it, but I replaced it.
Grant
Charles A. Sherwood wrote:

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