5/8dia 1.125 deep hole in Al strategy

I have a low precision production part in aluminum. Currently I am doing a helical bore with a 1/2" EM which takes forever. Would plunge milling with a 5/8 or drilling with a 5/8 S&D drill be better options.

6k max rpm
15hp
11k# box way machine.

Even just a halfway decent cobalt jobber drill will make short work of your feature. If you want to get fancy the aluminum-specific ones are nice.

is your machine set up to do hammer drilling?

Standard end mill clearance is not that good for plunge. With having a good sharpening shop to have it made to center cutting and with 10* primary clearance.

On one of my old dinosaurs with shitty coolant I've drilled about 3 million holes like that. I like a screw machine length drill with a flat ground on the side stuffed in a setscrew holder. About 2000 RPM and feed it until the load meter hits 100% or the part rips off the table and back off a smidge. Should be easily able to hit 80+ IPM feed. Chips should be real heavy and broken. No peck, just ram it.

^^^^I love this guy. And have hacked more than a few "handweldon" flats on SML bits. Just do it like a boss.

5/8" x 1.125" is less than 2xD.

That's deep?

I wish she'd say that.

Agfrvf said:

I have a low precision production part in aluminum. Currently I am doing a helical bore with a 1/2" EM which takes forever. Would plunge milling with a 5/8 or drilling with a 5/8 S&D drill be better options.

6k max rpm
15hp
11k# box way machine.

Click to expand...

First off, Agfrvf this is not really about you. From what I've seen you're not alone in your ideas. Yes the S&D drill is your best option. Bright finish. Glad to see you eventually thought of it.

Some times I wonder if I'm the narrow thinking one. That or I'm in a parallel universe with different rules. I mean for the life of me, if I had a basic, low tolerance production job in any material come in and it needed a 5/8 X 1 1/8" hole through it, the last thing in the world I would think to do is helical mill it out. Plunge milling it out would be even further removed from my conscious thought. Actually that thought doesn't exist. Anything but a drill of some sort would not enter my mind... at all.

I think my main beef here is, who is teaching this stuff? In this situation, where does the idea of helical milling or plunging it out come from? The internet? Youtube? I pray they're not teaching this in Vo-Tech schools. (Some of us remember those, right?) Don't get me wrong. Helical bore milling has its place. Though from my perspective it doesn't here.

I get it... you got a one-off and have never bought a 5'8 drill? Sure go for it. But at least first start with that 1/2 drill I know everyone has.

Flabbergasted. That's the word that surrounds me right now.

It's only the beauty of Garwood's idea that is relieving my pain for the moment.

I'm with Larry. OP if you have Sawzall you could do that too. Or just get a pet Beaver. Or Brad point wood Drill.

R

13engines said:

First off, Agfrvf this is not really about you. From what I've seen you're not alone in your ideas. Yes the S&D drill is your best option. Bright finish. Glad to see you eventually thought of it.

Some times I wonder if I'm the narrow thinking one. That or I'm in a parallel universe with different rules. I mean for the life of me, if I had a basic, low tolerance production job in any material come in and it needed a 5/8 X 1 1/8" hole through it, the last thing in the world I would think to do is helical mill it out. Plunge milling it out would be even further removed from my conscious thought. Actually that thought doesn't exist. Anything but a drill of some sort would not enter my mind... at all.

I think my main beef here is, who is teaching this stuff? In this situation, where does the idea of helical milling or plunging it out come from? The internet? Youtube? I pray they're not teaching this in Vo-Tech schools. (Some of us remember those, right?) Don't get me wrong. Helical bore milling has its place. Though from my perspective it doesn't here.

I get it... you got a one-off and have never bought a 5'8 drill? Sure go for it. But at least first start with that 1/2 drill I know everyone has.

Flabbergasted. That's the word that surrounds me right now.

It's only the beauty of Garwood's idea that is relieving my pain for the moment.

Click to expand...

Helical can be entertaining. .750 2 flute, 1.5 dia hole, 10000 rpm and I forget feed rate. What I do remember is wet chips flying up and over the enclosure and landing on the floor, or my head. Enclosure is about 7' to top I think. Push green button, walk away. And wear a hat.

If you're doing a lot of holes, get an alu specific drill from somebody like OSG, SGS, Fullerton, or Allied. If the OSG Mega Muscle can run 200 ipm in steel, what do you think a 3 flute drill could do in aluminum??