ADA: Ask Doc Anything!

[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.

[dartamon]

The Monsoon is mine, I hunted after it for 8 years. Dave Brisco, who built it, also used to have a Raptor with hand painted flames.

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

[DocsMachine]

The vertical feedneck has a hole drilled through it to reduce blowback, so it needs to be replaced - I think better bolt timing/length can get rid of the blowback issue.

-You're always going to have some blowback in a blowback. The only exceptions are for things like the VM or Golden Eagle, whose hammers are so big the whole cycle is slowed down. We can lose the vent if you're going to go with a modern force-fed loader, but I'd recommend keeping it if you'r ejust going to use an agitator.

I have a BE Eagleworks/Jacko barrel that I'd like to Freakify for this.

-Easily done. I wound up with a binful of those years ago. Rethreaded most of them for other guns, Freaked just about all of them- since the bore is like .693".

The regulator will be a MaxFlo coupled with the BE expansion chamber as a foregrip.

-Max Flow, yes, expansion chamber, no. Well, let's say I wouldn't recommend it, anyway. Won't do you any good, other than slightly reducing your per-tank shot count. Personally, I tend to prefer the old KAPP gas-thrus. If one can't be found, I can make one.

Bonus points if you can recess a gauge into the bottom of the expansion chamber.

-That would indeed be cool, and yes, I think it can be done, but just about any generation of the Max Flows up to the screw-ins had a built-in port for output pressure.

The grip frame should be the double trigger pot metal, but maybe reworked/polished up to look better.

-Easily done. But pot metal tarnishes rapidly, especially in contact with a sweaty hand. The frame would have to be painted, Cerakoted or plated.

The Monsoon (in the second picture) has a nickel plated pot metal frame and an anodized trigger.

-I haven't seen the Monsoon in years. Is that your photo? Is it still around?

Folks used to also put a cocker rear rod onto the striker and a custom beaver-tail to make it rear-cocking.

-Easily done.

Then custom milling and anno.

-Also easily done.

If you really want to get wild, make it mech full-auto the way ME262 designed it 20 years ago. A ram (air cylinder) coupled with a needle valve and a quick exhaust to slow down the cyclic rate. You could even fit it all inside the top rear plug and make it selectable by turning it (selecting different sized exhaust hole). But that may be too much without getting CNC involved.

-It's not something requiring of CNC, but that kind of setup tends to be pretty finicky. The kind of thing that works great in the shop or the backyard, but can be troublesome out on the actual field.

Other options: It can be remachined to take Autococker barrels, we could make a new ASA, even one of the classic 15 degree ones the Automag and Autococker guys were once to fond of (or, alternatively, angle it a few degrees back to match the main grip angle) and there's always things like custom grip slabs. I also have a laser, so adding a name, slogan or signature after it's done, is also possible.

Doc.

[dartamon]

There's plenty we can do, but you gotta understand, it's kind of an open-ended question. It's like "what can I do to this car?" Well, are you going to drag race it? Mud-bog it? Autocross?

In the case of a paintball gun, are you looking only for maximum performance? The best consistency, accuracy and efficiency? Are you looking for a wild showpiece that looks as good as it plays? Are you looking for a major reconfiguration, like an electro conversion?

Repeating my last answer: Bolt, definitely, maybe a better detent; we fit it for an Empire style feed neck, and a Freak back.

After that? If you wanted to give it a swing, we could try one of those low-recoil valves, add some body milling and have it custom annoed, and if you really want to get wild, replace the pot-metal grip frame with milled aluminum.

Throw a midrange-pressure inline reg on there and do some tuning for consistency. If you have a choice of rail or ASA, if that needs a T-slot or dovetail, that can be added too.

I need at least a little guidance. My idea of cool and radical might not be your idea of cool and radical. I mean, I might wind up trying to fit a Gamma Core engine in there.

Doc.

Wild showpiece is definitely the right direction, staying mechanical. So here is the pic of the VRaptor. The vertical feedneck has a hole drilled through it to reduce blowback, so it needs to be replaced - I think better bolt timing/length can get rid of the blowback issue. I agree on the detent. I have a BE Eagleworks/Jacko barrel that I'd like to Freakify for this. The regulator will be a MaxFlo coupled with the BE expansion chamber as a foregrip. Bonus points if you can recess a gauge into the bottom of the expansion chamber. The grip frame should be the double trigger pot metal, but maybe reworked/polished up to look better. The Monsoon (in the second picture) has a nickel plated pot metal frame and an anodized trigger.

Folks used to also put a cocker rear rod onto the striker and a custom beaver-tail to make it rear-cocking. It makes sense since there are no slide slots on this body. Only the top-cocking slot.

Then custom milling and anno.

If you really want to get wild, make it mech full-auto the way ME262 designed it 20 years ago. A ram (air cylinder) coupled with a needle valve and a quick exhaust to slow down the cyclic rate. You could even fit it all inside the top rear plug and make it selectable by turning it (selecting different sized exhaust hole). But that may be too much without getting CNC involved.

[DocsMachine]

My Victory had a good sounding set of pipes on it. It wasn’t obnoxious[...]

-That's the key, right there. Totally unmuffled pipes are obnoxious. Tuned pipes and a sweet rumble, that's cool. I don't in the least mind- and often love the sound of- a well done exhaust system. But I hate obnoxiously loud ones.

The car example is the same as the difference between a set of straight pipes with maybe something like glasspacks- which borders on the obnoxious, but on a good V8 isn't too bad- and the rusted-out exhaust under some big eighties' battle-barge. That's obnoxious.

One of my neighbors has a Corvette (70's) with some kind of "lobulated" pipes- sort of a pair of long baffled glasspacks, as I understand it? Even though it's just a small-block, that sounds cool.

Doc.