ADA: Ask Doc Anything!

[DocsMachine]

How useful would this lathe be for non industrial stuff.? Its an American Tool Works unit, 16" swing, 76" bed ,single phase

-My common answer is that any lathe is better than no lathe. There was a time not all that long ago that I'd have killed and helped hide the body for such a machine. My first lathe was a Grizzly 9x20, and after that a Logan-Made Powermatic. That latter one had a spindle speed that might have achieved 600 RPM, downhill with a tail wind, and had no screwcutting or quickchange gearbox. Nonetheless, I still made some pretty decent parts on it.

On the pro side, it's a screwcutting lathe, power cross and traverse, and has apparently plenty of accessories including what might be three chucks (or two and a faceplate) a steady rest, tools and toolholders, etc. The ways don't look too worn, it doesn't appear to have been beat to death, and appears to be ready-to-go functional. (With a good cleaning and oiling.)

On the con side, it's got plain bearings and a cobbled belt drive, which will limit the top speed. Probably to less than 500 RPM. This is not a fatal flaw, of course, but is a limitation. Possibly worst of all, it probably has a now-obsolete spindle thread, meaning to adapt any other chuck will mean having to make ones' own backing plate. It may also have what is today considered an absurdly small spindle bore, like 3/4", though it could have as big as an inch. It's not impossible it has no hole through the spindle at all, but I think that's "new" enough- relatively speaking, of course - that's probably not the case.

If it's not too expensive, you have the room for it, and are willing to work around the limitations (and no better machine is available) I'd say grab it. ATW was well-regarded, later developing the nigh-legendary Pacemakers, possibly the epitome of American-made manual lathes.

If you DO get it, several things to keep in mind: There's no chip or drip tray, and machines like that [i]live[i] in oil. As I said in an earlier post in this thread, you can't over-oil a machine like that- at least, not 'til you start noticing your socks are getting squishy. The common trick is to find a sheetmetal guy or HVAC shop and have a pan made up, big enough the legs can just sit in it. That'll catch the drips, chips and other gunk, and keep from staining your floor.

The spindle especially needs to be constantly oiled- keep oil in the glass- and use the correct oil. Any oil is better than no oil, but the right stuff is best of all. It's been a while since I looked into plain-bearing oils, and such is not my forte`, so you'd want to do a little research.

Apart from that, keep the ways clean, oil the bejeebers out of it, and pick up a copy of South Bend's How To Run A Lathe. Have fun!

Doc.

[Target]

How useful would this lathe be for non industrial stuff.? Its an American Tool Works unit, 16" swing, 76" bed ,single phase

[BrickHaus]

I just stumbled on te duke build thread on Docs website. Yeah, I may sell a kidney when you start dropping those.

[Siress]

Whats the proper terminology - if I need an oring groove cut into a cylindrical object, are you milling or machining the groove?

You didn't ask me, but in the set of all things 'machining' exists both 'milling' and 'turning'. As such, 'machining' is the most correct answer between the two options. It also covers others methods of cutting o-ring glands that you didn't mention. (e.g. sinker EDMing) I say glands because they have particular features that grooves do not necessarily have.

And I want to share the absurdity I have to live with - but not to be a smartarse to Doc: what if it's a lathe with live tooling and I've got my flywheel cutter in the chuck holding a grooving tool just right while the part is spinning in one of the live tool holders.. What then, eh? other than carbide fragments everywhere...

[DocsMachine]

Whats the proper terminology - if I need an oring groove cut into a cylindrical object, are you milling or machining the groove?

-Well, if the part is in a lathe, it's turning, if it's in a mill, it's milling- arguably circular interpolation milling.

As Xe notes, most often it's just called "grooving". You'll find parting tools these days listed as grooving and parting tools.

Doc.

[XEMON]

Neither ... You're grooving ...

[Jordan]

Whats the proper terminology - if I need an oring groove cut into a cylindrical object, are you milling or machining the groove?

[DocsMachine]

Is there data to support these claims of optimization or do you think it's just something someone chose long ago and it has stuck through time?

-There's reams of data. One of the first books written on the subject was published in 1888. Check eBay for "twist drill book"- at the moment there's fifty-five listings; most are catalogs and reference books, but more than a few are theory and application.

I know that for a high volume production application I had insight into, the steel cutting carbide drills all had a 140deg tip angle. And I know that for precision drilling in plastics, I've seen drills with crazy small tip angles; they looked like ice picks.

-Certainly! There's a hundred or more types of tip profile. Brad point, spade bit, split point, core drill...

Keep in mind that 118-120 was settled on as a sort of "all around" tip, which is why you most commonly find it on most consumer-grade bits. But if you're doing production, or have a specialty job, there's a ton of other tips and styles. A shallower angle is better for hard materials, a steeper angle is better for soft materials. Some materials, like Brass and Delrin, want a minimal rake, others, like copper, want a high, sharp rake. Abrasive materials like fiberglass board wants something in between.

You can get zero-angle drills- effectively an endmill end- if your machine is rigid enough for it, and you have a pilot hole. You can get 45 or even 60 degree drills for fast cutting in softer materials.

118-120 is considered the best compromise for general use, not necessarily the Absolute Best for all applications under all conditions.

Doc.

[Siress]

Is there data to support these claims of optimization or do you think it's just something someone chose long ago and it has stuck through time? I know that for a high volume production application I had insight into, the steel cutting carbide drills all had a 140deg tip angle. And I know that for precision drilling in plastics, I've seen drills with crazy small tip angles; they looked like ice picks.

[DocsMachine]

How or why did 118deg become the defacto standard drill tip angle?

-That'd actually take a pretty involved answer. People have written entire books about just drill-point technology, believe it or not.

To try and boil it down a little, it's a combination of things. First off, the drill point has to have some angle, to help it self-center. A flat-faced drill would wander all over the place. The steeper the angle, the better the drill centers itself.

BUT... the steeper the angle, the longer the cutting faces, and thus the heavier the cut it takes per revolution. No big in aluminum or plastic, but that starts being a concern in mild and alloy steels.

There's also the rake angle- the steeper the tip angle, the sharper the rake gets, and thus the weaker the cutting edge. It chips and wears easier, and generally doesn't last as long.

Also, too sharp and the chip itself doesn't want to clear as well- it's pushed more toward the center of the drill, and less out the flutes.

Keeping in mind that all of this doesn't matter too much to Harry Homeowner who's just drilling a hole in a stud to hang a picture, but matters a LOT to the production shop having to drill 20,000 holes a day in 4140 steel. Most of this stuff has been determined, often empirically, over the last century and a half since the twist drill was invented. And basically, 118 to 120 degrees has been settled on as a general "all purpose" bit for most situations.

It works adequately in a wide range of materials the average user is going to encounter (mild steel, hardwood, aluminum, brass, plastic, etc.) and gives the best average between self-centering, edge durability, and so on.

Doc.

[DocsMachine]

Anyway, I'm going to noodle on it and will send you an email with the full list. Are you taking new work right now or still finishing the backlog?

-At the moment, I'm hoping hard to get my benches cleared by the end of the month. I only have a few jobs outstanding, though one is a pretty full reconstruction that's been kind of hangin' fire for a bit.

I'm not stopping accepting work, but I have been suggesting the heavy-mod/heavy-rebuild stuff hold off a bit, until I can clear out the ones already on the table.

Doc.

[Siress]

How or why did 118deg become the defacto standard drill tip angle?

[dartamon]

Anyway, I'm going to noodle on it and will send you an email with the full list. Are you taking new work right now or still finishing the backlog?

[dartamon]

Nah, I'd say a trigger job and a reactive trigger is about as far I'd go - the original Raptor "saber" grip frame is too distinctive to get rid of. Electro conversion is going a little far. Reactive trigger would be fun because there is a ton of space in the part of the grip frame that sits inside the body to route pneumatics from the valve.

[DocsMachine]

So it sounds like I don't have any particularly wild ideas for it. Would you care to throw some out?

-"Wild" means different things to different markers.

There's a TON of things you can do something like an Autococker. There's not that many things you can do to an LV1.

There was a lot that could be done to a Rainmaker, in part because it was such a complex, yet cobbled design. There's not that much that can be done to a Raptor- partly because there's not much aftermarket support, and partly because there's not much that will do any real good. I could make you a new valve, for example, but I doubt it'd make any real difference to performance or reliability. I could also make you a volumizer- as long as you understand it would be mainly cosmetic, and would do little for performance.

Truly wild ideas? If it were mine, I'd fit a match-anodized aluminum grip frame. I'd start by trying to fit something like an old Benchmark 'Mag frame or something, and if that didn't work, I'd cut my own.

If you really want to get hairy, it wouldn't take much to convert it to an electropneumatic rammer, like an Ego or Etek. The Intimidator was originally designed off a Spyder body, in part because Bob got stuck with a ton of extrusion for Millennium bodies- we'd have to make some custom components, but it's certainly doable.

But at what point are we jacking up the radiator cap and rolling a new car under it?

Doc.