How Come Lathes Don't Have Mill-Type Feeds?

[BadDog]

If you haven't noticed the difference facing, by hand or with power feed, than I can only assume you haven't faced any larger diameters. Somewhere above 1" or so in common LC steel, you see a rather distinct difference. And my first lathe didn't have power cross feeds. Perhaps your hands are far steadier than mine, but even using the double hand hand-off I could never get consistent finishes like I get with power feed. And doing something like parting, where the feed rate and chip load are very important to success, when I had to do it by hand, you could feel a rather large difference in load as things progressed. If that were a mill style feed, that chip load would be changing.

Will it work? Of course. Would it be better than hand feeding, almost certainly. But my problem was with your statements which I took to effectively mean "why do we need those complicated gears, this would be much better except for threading". So most of my posts was just my thoughts on the matter, but my closing comments really capture my answer. To repeat, if there were not REALLY good reasons why that is far less than optimal, you can bet that either the high-end or low-end (depending on details) market would be doing it. And with the exception of a few outliers like Hardinge (who did it specifically to allow controlled and consistent variable feed where it mattered, not just a disconnected power feed), it simply wasn't/isn't done.

[BadDog]

Oh, and with reference to the mill, I do it just like you do. And the same on the lathe, I rarely calculate anything anymore (unless things are just wrong and I'm trying to figure out what I screwed up). But mill loads are very different from lathe, and finishes are not even close to what is expected from lathe work.

And Franks machine, based on the Hardinge, is far from a budget machine. Those DC drives are also FAR from a mill power feed adapted to an axis. I'm pretty sure the DC controllers are load sensitive, maintaining the rate under varying load (like sensorless vector VFD, etc). Mill feeds have no such niceties, and only attempt to maintain rate with varying load through massive torque multiplication, and even at that I've seen mine change rate based on load.

Also, look at the huge amount of effort expended on the ELS project. If it were generally "better than using the gears", again, I would expect it to have been adopted and marketed, but to my knowledge no commercial product ever existed to pursue that technology.

Again, I'm sure it will work and will be better than hand feed (I've already said I can't maintain consistent feed by hand). And I've even done it myself to good effect in the form of a variable speed (gear reduction) drill motor on the compound. My problem is with the theory that it would make a good replacement for the normal coupled gear feeds.

[SteveHGraham]

It is true that I don't face stuff much over 2".

[Hopefuldave]

And some mills have lathe type feeds...

Particularly industrial mills from the pre-CNC era, a good machinist would.set the feed in thou" per spindle revolution, calculated from chip per.tooth and.number of cutter teeth, and usually get it right first time without having to adjust it on the fly - it worked.well for 80 years, works well now.
"mill type" basically seems (in this thread anyway) to mean DC motor feeds a la Bridgeport, but they're not industrial mills, more job-shop, and.the power feeds are an afterthought, not designed in.

[ctwo]

K&T have hydraulic feeds?

[Hopefuldave]

Recent K&T, the older ones. (2H, 2CH, 3H etc.) were geared, same with most from about 1890 until the late 50s, Deckel, Thiel, Maho, Cincinnati etc. - Particularly horizontal and universal metal munchers! If you were lucky you got lever changes, but a lot had 'pick off' gears like a changewheel lathe, fiddly but it worked...

[BadDog]

Yum, would love to have a nice 2CH universal, maybe a 2D to go with it...

[Harold_V]

And some mills have lathe type feeds...

Particularly industrial mills from the pre-CNC era, a good machinist would.set the feed in thou" per spindle revolution, calculated from chip per.tooth and.number of cutter teeth, and usually get it right first time without having to adjust it on the fly - it worked.well for 80 years, works well now.
"mill type" basically seems (in this thread anyway) to mean DC motor feeds a la Bridgeport, but they're not industrial mills, more job-shop, and.the power feeds are an afterthought, not designed in.

I operated several of the pre 1960 K&T mills in my early years, both horizontal and vertical, all mechanical, no hydraulics. As has been stated by Hopefuldave, feed was selected by a rotary handle on the left side of the saddle, with indexing at 180° intervals. Each half turn of the handle progressively increased or decreased the feed rate, depending on the direction of rotation. Rate was designated as fractions of an inch or greater. Speed could be selected on the fly.
I also operated Van Norman and Cincinnati mills, as well as the odd Brown & Sharpe. It is safe to say that the K&T was the best of all of them. Magnificent machines, capable of moving metal at horrifying rates.

Harold

[Richard_W]

And some mills have lathe type feeds...

Particularly industrial mills from the pre-CNC era, a good machinist would.set the feed in thou" per spindle revolution, calculated from chip per.tooth and.number of cutter teeth, and usually get it right first time without having to adjust it on the fly - it worked.well for 80 years, works well now.
"mill type" basically seems (in this thread anyway) to mean DC motor feeds a la Bridgeport, but they're not industrial mills, more job-shop, and.the power feeds are an afterthought, not designed in.

I operated several of the pre 1960 K&T mills in my early years, both horizontal and vertical, all mechanical, no hydraulics. As has been stated by Hopefuldave, feed was selected by a rotary handle on the left side of the saddle, with indexing at 180° intervals. Each half turn of the handle progressively increased or decreased the feed rate, depending on the direction of rotation. Rate was designated as fractions of an inch or greater. Speed could be selected on the fly.
I also operated Van Norman and Cincinnati mills, as well as the odd Brown & Sharpe. It is safe to say that the K&T was the best of all of them. Magnificent machines, capable of moving metal at horrifying rates.

Harold

Is it possible that you are thinking of the dial feed selector would set in motion the hydro shift to change the gears. Mechanical gears is are the ones I remember, they just shifted with hydraulics.

Richard W.

[Jaxian]

My No.4 Cincinnati horizontal is an old industrial type. Specifically they called them dial type. As the IPM was set not feed per revolution. The primary reason for IPM and not Feed Per Rev like a lathe is by and large mills had to contend with one extra issue that lathes usually don't. That being the number of teeth/cutters on each tool.

For my Cincinnati I have from single point flycutters to a 10" 20 insert face mill. Obviously your feed rate would be enormously different for the two different tools, even getting into allowing for hp needed and such. All of which can be found on the side of the Dial type machines.

For most lathes, even industrial ones they tended to predominantly use single point cutters. They also tended to be in a size range, not wildly different like a mill where I can go from a .015 2 flute end mill to a 20 insert 10" face mill.

So as was noted above, heavy duty machines where like lathes in that they had geared feeds that where set in increments. Mine are hydraulically shifted even though gear driven. Which is kind of fun...as long as it doesn't break.

I must admit when trying to use RPM/Feed/DOC calculators it's a little confusing since the mill ones aren't Feed Per Rev and are IPM instead.

My electric Servo drive ones on my Lagun used to drive me crazy because I like to have a ballpark to start at when doing settings and it was just numbered 0-9. I measured mine and with my leadscrews it turns out I was getting about 5 IPM out of every increment starting with 1 at 1 and topping out at 40 IPM at the fastest setting on the dial.

Here is a picture of the 'Dial' on mine you can see the RPM on the outer dial and the IPM feed on the farther one (they move independently). Inside you can just see the little built in calculator to determine ballpark starting points. Nice to have it right there on the side of the machine.

All that said it goes without saying all modern CNC lathes have electrically driven servos for feeds as do CNC mills. So mostly this is talking about old stuff. Can't get into old Monarch 13EE with Constant Drive system for facing and stuff. That was state of the art stuff so definitely not typical.

[Harold_V]

Is it possible that you are thinking of the dial feed selector would set in motion the hydro shift to change the gears. Mechanical gears is are the ones I remember, they just shifted with hydraulics.

Richard W.

Hmmm. Now that you suggest that, sure, that may be how it worked. I was never involved in a tear-down, so I never saw the workings of the feed selector. I just assumed the rotation of the handle selected gears, much the same way a quick change does on a lathe. In any case, I really liked how it was changed. Very convenient and easy.

Harold

[Harold_V]

Mine are hydraulically shifted even though gear driven. Which is kind of fun...as long as it doesn't break.

Oh, yeah! There was a #4 vertical Cincinnati at Sperry, years ago. As you alluded, they shift hydraulically, and with the vertical, there's a huge gear in the head that is involved in selecting high or low range. On more than one occasion, it shifted while in use, of its own choosing. Gears really hate that! Our head repairman finally isolated the problem and made the necessary repair, but each incident was rather costly. They're a rather impressive machine, size-wise!

Harold