Van Norman #12 makes chips!

Absolutely -- and one of the charms of this group is that there are many professionals who gladly cross the divide.
And also many professionals who can address the interest and concerns of the hobbyist and give them the benefits of their experience without sounding the slightest bit patronizing.
If I tried that on my 12" lathe I'd lose a knuckle or two. And if I tried to stall my geared down little mill, then I'd be a prime Darwin award candidate.
I don't know about that. I've used lots of Jeweler's and watchmakers lathes that can be stalled with one's pinky. Hardly useless at all. Not much for hogging metal off with 1/2" cuts, I admit -- but then some of the professionals also work in the small.
I was talking about my little #4 Burke, or was I? What is appropriate for small mills (whether used by hobbyist or professionals) is unlikely to be appropriate for big mills -- I assume that most people would recognize that. Come to think of it, all the big-mill arbors I've ever seen had keyways.
I guess that it is really "big" versus "small." as contrasted to "hobbyist" versus so-called "professional." And it really isn't one versus the other but that of recognizing that what is useful and appropriate in one domain is marginal or even dangerous in another. If someone were talking about speed and suggested that they would really like to push their lathe up to 8,000 or so rpm -- that's why I've been looking around for a really small lathe at a bargain price -- A reader of this newsgroup would have to be very obtuse or very ignorant to think that I was suggesting that for use on a 36" monster used for turning ship shafts. On a similar note, often I see postings about the quality of this or that tool -- a quick-change tool post, for example. The one doing production work would be foolish not to buy the top-quality (e.g., Aloris) toolpost if he expected it to last more than a year -- while most home shop enthusiast will be quite satisfied, for a lifetime of use, with a Phase II or even a cheaper knock-off. I stand by my comments regarding the advantages of keyless arbors on small horizontal mills -- but in view of the litigiousness we sometime see, I advise that you not try this on your 45" x 256" horizontal mill with the 3" arbor swinging those 12" cutters.
Boris

Actually, when I'm turning really small stuff, such as 1/2" long belaying pin or sheave about 1/8" diameter, I often just partially engage the clutch on my 12" lathe so I can control the cut better. I let the collet chuck slip through my hands for the last few turns .. thereby stalling the lathe. Of course I could avoid all that hand fiddling and slipping if I opted for a CNC setup on a Prazi -- which might be appropriate for production work.
Boris

That's not a fair comparrison, but proves the point I made. Machine size and application dictate different terms and requirements. Yeah, I can see your position. Your comments are driving home all the more the vast difference in what home shop guys do and what industry does. I see no right or wrong here, but more an indication of the creativity of those that have machines not well suited to the work at hand, and methods used to get around given problems. I'm sure you can understand that those working in the trade for gain would likely not work that way, if for no other reason, economics.
You're fortunate you don't own a Sag 12 Graziano for your lathe, given your preferred method of operation. I've owned mine for over 35 years and have almost no complaints with the machine. I have often made reference to it as the poor man's Monarch EE. They're that good! However, the idea of playing clutch games with them is not an option. These machines have electro-magnetic clutches so you are either in or out. There is no feathering. What those of us that have years of experience do is rely on our skills to get in and out of cuts at the right time. Mostly it works!
Do you want to share something with us here? Sounds like you're working on miniature sailing ships. Do you have any pics we could see?
Harold

My time running both Van Normans and K&T exposed no such device. I even worked in machine repair for over a year and don't recall anything like that in making repairs. I have far less time on Cincinnati mills, so I can't speak for them. I think such a device might be counter-productive in a way, though. At what point would you have a feed disengage? What would constitute a reasonable load?
The nearest I can come to such a device is the longitudinal feed on my Graziano. They have what might be termed reaction type clutches that are adjustable for the amount of pressure needed to cause them to disengage. That permits feeding to positive stops without damaging anything. I'm not familiar a similar type of device on horizontal mills, however.
Harold

I can think of the feed clutches that hardinge built into their lathes, for one. The feed for the UM milling machine goes in through at worm drive at the table, and there is a peculiar trip setup that latches on to the feedscrew. The trip obviously will bump the feed off, but it sort of seemed like a large force on the leadscrew would do so also.
This is pure conjecture on my part, because I've never had that unit apart, ever. I took it off the machine when I transported it to my shop, and re-assembled it when I got it there - with the idea in mind of dismantling it and cleaning it up 'someday.' Ah, someday.
Jim
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I'm proud to say that although I can usually get the quality work I need, my speed is glacial compared to a working stiff doing it in a production shop. Based on piece work rates, I'd probably clock in at $1.00 an hour. I do know both sides of the aisle though -- since I worked for many years as a jewelry craftsman.
Slipping the clutch is not my "prefered way of operating." It is a useful trick for turning small, delicate parts on a too-big lathe.
There's that patronizing stuff again? I don't have a foot brake on the lathe.
Actually, the largest size disparity I ever faced in working a lathe was when I was an instrumentation technician (career #2) at Columbia Presbyterian Medical Center. I had to machine a small canula (tube) about 1/2cm diameter and 3cm long, thin wall, out of nylon-- with some precise inside and outside tapers on the ends. I had been there several months and the professionals in the hospital machine shop decided it was time I was initiated. I went to the lathe I usually used, a 9" Sears/Atlas -- but as I got there, one of the machinists jumped in front of me and said that he was going to use it -- and the pros had priority -- always. Okay, I went to the 12" Clausing and the same thing -- ditto the 15" Monarch. There were only two lathes left in the shop. The 24" x 18 foot bed and the 36" x 40 foot bed lathe -- you know which one I was directed to. These monsters had been installed in the basement of the hospital because the architect figured it was cheaper to build the machinery (lathes) required to repair the huge cooling and air circulating fan shafts than to provide doors, cranes and lifts to get the shafts out and transported to a distant shop. Of course, the wrong chuck was in place -- two hours of sweating with the overhead crane, lift blocks, and other big gear and I have a useful chuck in the headstock -- actually, a chuck in a chuck in a chuck -- all of which had to be indicated in because they would only let me use four jaws -- similar nonsense for the tailstock center and the tool holder -- but before I could start I had to oil the monster. On this lathe, the operator sat in a saddle that was on the end of the cross slide. The actual machining was scary -- imagine a 24" 4 jaw chuck rotating at 250 rpm a few inches from your head. I'm surprised that the saddle didn't have a relief tube. When I finished the job, I had another hour of work with the overhead crane and all the rest to restore the monster to where it had been before I started -- and after that, I was considered initiated. So you see, I have some experience with dealing with machining small things on a big lathe. Actually, the momentum of the monster was such that the machine was tricky and it took a considerable amount of anticipatory skill to disengage the drives -- which is why I did all the machining using the compound set at 90 degrees or the correct angle for the required taper. I don't think that slipping the clutch or braking the chuck driven by a 50hp motor by hand would have worked -- at least I was in a hospital so had something gone wrong with my amateurish machining practices, expert restorative surgical would have been conveniently at hand.
Boris ------------------------------------- Boris Beizer Ph.D. Seminars and Consulting 1232 Glenbrook Road on Software Testing and Huntingdon Valley, PA 19006 Quality Assurance
TEL: 215-572-5580 FAX: 215-886-0144 Email snipped-for-privacy@sprintmail.com
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Not miniature --scale 1:16, 1:48, 1:50 like that. "Miniature: is really small -- e.g., 1:400 with models under 6" long.
I'll have to do some and send them to the drop box. When I get around to it.
Boris

I've occasionally run into that effect.
My response is immediate, right from stock, every time - it is: "screw you, I'll take it home and do it in my own shop."
The last time that happened, it was a *lovely* 60 degree sunny fall day, and told my boss that there was a jam-up in the shop, and I would be peforming the required machining at home. Transported back and forth via motorbike!
Jim
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We run both keyed and unkeyed arbors on our mills at work, depending on the machine. Our standard horizontal Van Normans and Brown & Sharpe arbors are keyed. Our Burke and Nichols mills are not. These two latter type mills have pneumatic table feeds with Hydro-check control devices to set feed. They are set up for repetitive production cuts. If one of our, Hmmmm, how should I say it?, "questionably qualified hourly rate operators" forgets to turn on the spindle before hitting the feed control button, the mill table with part will just glide forward and jam against the cutter, usually with no damage. Pneumatics gives us fast production rates using a person with little or no skill to "feed" the machine parts which number into the tens of thousands. More qualified operators are used on the more dangerous hefty mills. These mills will hurt your ass. One inch wide stagger tooth cutters buried in a piece of stock will keep you on your toes. As far as release clutches on feed drives, I had an inattentive operator a few years ago break the main casting on a Van Norman 22 by putting the upfeed lever in gear instead of the horizontal, then pulling the rapid traverse lever. It lifted the top right off the mill, breaking the main casting in the process. Drove the cutter through the stock till the arbor bottomed, then kept going. Needless to say, he seeked other employment. That's also the difference between using machine operators, versus machinists. Skill, pay, awareness, and machine damage.
RJ

Ouch. That's pretty amazing, that the feed could actually rip the top off the machine. I would maintain that this would be an *excellent* place to put a shear pin, or at least some kind of clutch. To prevent self-disassembly and all.
Jim
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Interesting report, Jim. I'd like to hear what more you learn when you finally get to the "someday" part. :-). Meantime, what you describe resembles that which is (was) used by Graziano. I have to admit it's a nice feature, one that I occasionally rely on. It's nice to be able to feed up to a shoulder and have the feed kick out when rough turning a steel item and the chips are coming off near red heat. On my machine, a positive stop or just a reverse pull on the carriage hand wheel will disengage the feed..
Harold

I rest my case! :-)
Harold

You'd be well served to not confuse those of us that came up in the trade running manual machines and with broad experiences with machine operators that push buttons and load chucks. We are not interchangeable. The key here is to know and understand machining techniques well enough to run the work at hand in a timely fashion, without supervision, with repeatable and acceptable results, and be capable of making setups. Those qualifications usually sorts them out.
Which means you may be very good at doing fine work, just not fast. Fast comes with experience. There are no shortcuts to getting there, which was the hardest lesson I had to learn in my apprenticeship.
While I have never worked as a jeweler, I worked closely with them for years as a refiner of precious metals, the hobby that finally liberated me from the shop. My job was to reclaim their waste material and as a rule I dealt directly with the benchmen, not the owners of the store, assuming they were not one and the same person. Aside from having to work efficiently and make a profit, I saw few, if any, parallels between the two industries. Bottom line is you do understand that those that do something as a vocation tend towards having work habits that are, in many cases, far removed from the habits of those that may choose a given field as a hobby. As a result, they tend towards being far more productive hour to hour, a necessity if they intend to keep their job. I think that's what I've been trying to point out.
I've never used it, and I've produced items so small that a couple hundred of the assemblies could be held in the palm of one hand. I guess it's all in what you learn and how you apply it.
I have no problem with how you get where you are going, especially if your chosen method yields good results. I simply choose to work differently, if for no other reason, because I can. Rarely do I find starting or stopping the spindle as an aid to anything aside from controlling chatter under strange circumstances. I tend to manipulate the cutting tool instead, leaving the spindle running at my chosen speed. That's fact, and I can't see why you would take exception to the statement. I couldn't help but notice that you conveniently left out the :-) I had included in my post. Huh? I must be a bit slow here. Am I to understand that your statements are to be considered as something I'm to read and accept at face value, no offense intended, nor accepted, but if I happen to make mention of my methods of working that I'm patronizing? You're troubled by my statement, said with a smile, that those of us that are experienced work differently? That troubles you? Come on, Boris, surely you're better than that. If you're waiting for me to apologize for having mastered my chosen trade, for having the ability to do as I say, we're never going to get off first base. If I wasn't able to work that way, I'd not have been able to have done the work I did for years. Why my abilities should be offensive to you is not something I can understand.
If I'm having a conversation with you and you tell me something about your methods of dealing with particular problems in your field of expertise, I think you might be pleasantly surprised to find that I would be listening to you, not making judgments about you looking down your nose at me. Maybe you and I come from different backgrounds. Dunno. Could it be that you just resent hearing anything from someone that has made a living at running machines? Is this conversation supposed to be limited to those that "play" (not for gain) on machines?
I don't use having a brake or not having one as a reason to work as I do, by the way, but if it makes a difference to you, my lathe doesn't have one. That doesn't prevent me from pulling a tool out in the middle of a cut, such as chasing a coarse thread up to a shoulder. Like I said previously, mostly it works. :-) (And sometimes it doesn't!) :-)
snip----- It's nice to hear you enjoyed success. Most any fool can make a part on the best of machines, it's the guy with talent that can do it with the worst, or under the worst conditions. They are the guys that generally succeed in working in job shops dealing with high end work. Rarely does a job shop have the perfect machine for each job.
Like you, I've spent time on large lathes, but don't prefer to run them. My interests and talent lie in small work The largest lathe I've run would be the 48" sliding gap bed LeBlond, plus a gap bed 40" (or 42") DSG. It's been a long time, can't recall the exact size of the DSG. All too well do I know about the large chucks and face plates whizzing past your ear.
Thanks, I'd be pleased to see anything you're willing to post. I'd also welcome anything you might like to send directly to me. I have a keen interest in old muzzle loading cannon, which I imagine might work in nicely with what you're doing. Any comments?
Harold

Interesting. The arbors made by Nichols for my Nichols are certainly keyed, though some others are not.
O.K. My Nichols has both lever feed and leadscrew (optional, depending on the task). I don't have one of the pneumatic feed ones. so I tend to prefer the keyed arbors for most things, so I can lean into the feed lever to optimize cutting rate.
However, for the gang of slitting saws (for slitting the heads of a special run of screws), I have those on a keyless arbor. I don't expect that it is possible to drive those hard enough to make them slip. They would break long before I got there.
Enjoy, DoN.

I can see damage only if someone runs an endmill holder into a vice. And that at a good clip. If there is belt slippage - it would slip. If geared tight - gear breakage. I tend to think the spindle as a tough part of a mill. After all, it holds back and turns the cutter all of the time.
Martin
Boris Beizer wrote:

Can't speak in general, but the Van Norman #12 (where this thread started) does _not_ have an overload device on the feed. The 1/4 HP feed motor drives the feed gearbox thru a silent chain with a reduction of about 4:1. Then the 12 speed gearbox reduces it some more. From there a shaft with U-joints drives a worm in the saddle, the worm turns a worm gear (more reduction), and that is clutched to the leadscrew thru a set of dog clutches engaged by the feed lever. There is a small angle on the teeth of the clutches, so they _might_ tend to pop out of engagement at very high loads, but I certainly wouldn't count on it. That feed system has some serious push!
And the #12 is _not_ a very large machine. 9x36 table, 1800 lbs. It is smaller than a Bridgeport. But it's not a benchtop machine.
I know there are other machines, from some very good makers like Hardinge, that don't use keys. That's fine... I'm not about to question the folks at Hardinge. But the machine in question is a #12 Van Norman. The stock arbors for a #12 _do_ have keyways.
The manual for the #12 specifically points out that the feed and spindle are interlocked to prevent the feed from running unless the spindle is turning. They are well aware of the risk of damage from power feeding into a stopped cutter.
When I bought my #12, it had damage to the feed mechanism. Some genuis had taken it apart and reinstalled the angular contact ball bearings on the lead screw with both facing the same direction. I'm sure it worked for a while, but eventually during a heavy cut the feed pressure was too much and the bearings "popped" out of their races (force was being applied in the weak direction). The bearings are in a sturdy part of the main table casting on the left end of the screw. The right end is supported by a cast iron bracket with a bronze bushing in it. When the bearings popped, the screw moved about 1/2" to the left, breaking the right hand casting. That gives you a feel for the kind of push the feed system can deliver.
By the way, the spindle drive on the #12 is also all geared, except for twin vee-belts from motor to gearbox input shaft. So even though it's small, it has _lots_ of torque, probably as much or more than a Bridgeport in "back gear" (low range). The lowest speed from the 9-speed box is 70 RPM.
John Kasunich

On the UM hardinge, the feeds are belt-drive off the spindle, so there is literally no way to get the feeds going without the spindle turning.
Jim
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I was slab milling a chunk of HRS last weekend. The helical slab mill pulled the work piece out of the vise, taking a MUCH bigger bite than it was supposed to, and jammed the machine. It broke off a couple flutes from the cutter, started the belts smoking, and moved the vise 2" down the table before I got it shut off. Good tnuts, paper under the vise, the whole works. Im not sure if I should pull that key out or not...
This from a "little" Clausing 8540 horizontal mill in back gear.
Now there is also more than normal backlash in the lead screw...so I dont know if I pulled the guts out of the nut or not.
I reran the job on the shaper. Worked much easier..
Gunner
"As my father told me long ago, the objective is not to convince someone with your arguments but to provide the arguments with which he later convinces himself." David Friedman

=8-O
Yikes. This has also been my experience too, even with a small one hp motor on the hardinge, it is pretty easy to rip stuff out of the vise. I've found that I need to be equally careful about workholding as I am about cutter speed and feedrate selections.
Jim
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snip------
I hope you had the good sense to not be climb milling! How long was this thing struggling with the cut, allowing so much movement of the vise?
Don't know where you learned about paper under the vise, or what you expect it to do for you, but I wouldn't use it. If you keep your mill table in fine fettle by the occasional draw filing, and keep the base of your vise clean, without clamping it on chips, the paper serves no other purpose than to behave as a bearing. I've worked in the shop for almost my entire life and I've never seen anyone put anything under a vise, and that includes some of the finest tool & die makers to have worked in the area where I grew up, which had an extensive missile and aircraft industry (Hercules, Thiokol, Sperry (Univac), Litton Guidance).
I've run enough in the way of large horizontal mills to have a firm understanding of the significance of keys, proper speeds and feeds. There's been some pretty compelling reports here to help others understand the same things I do. Yours is certainly no exception, in spite of the fact that it pertains to a smaller mill. A few things are coming into focus. For the most part, machine tools are built to be run by skilled and talented people. They rarely have little features that help keep you out of trouble. Slip clutches for overloads, for example. If machines are equipped with such devices, while they may act to prevent damage, they are generally a feature to aid in running the machine, not to prevent damage. That would be a coincidental benefit. The clutch assembly I mentioned on my Graziano is a perfect example. It is intended to act as a stop mechanism for ending power feed, not to behave as a safety.
John Kasunich has presented two (well written) examples of damage done to machines by fools or otherwise inexperienced people. The message should be clear. One should be well trained before running these machines. There are no features that forgive ignorance. When you place people on machines that don't understand their capabilities, mistakes will be made, some of them very costly.
Harold