Best 9/16" drill bit for AL castings

Long Tom · Oct 1, 2017

Howdy folks!

Got a new customer feeding me aluminum castings to machine several hundred at a time. Each casting gets (4) 9/16" through-holes about 3/4" deep, so the quantity of holes is ~ 1000/batch and about 750 inches of aluminum drilled.

I drill in one pass using the power downfeed on my knee mill and with A9 fluid. Has been working "fine" but I'm just guessin' theres a better bit to use than the black-oxide standard bit I'm using... something with aluminum-specific geometry, perhaps, along the lines of the wonderful Alu-Power end mills? Is there a better fluid than A9?

And finally, my big Taiwanese mill isn't noticeably complaining, but am I asking too much to downfeed so many 9/16" holes? This is ongoing work so I need sustainable methodologies.

Thanks guys.

Newman109 · Oct 1, 2017

Long Tom said:
And finally, my big Taiwanese mill isn't noticeably complaining, but am I asking too much to downfeed so many 9/16" holes? This is ongoing work so I need sustainable methodologies.

Thanks guys.

I also have a big Taiwanese Mill (Webb 4 VH) and, like the Bridgeports after which they are copied, the manual says that nothing larger than a 3/8 hole should be drilled using the downfeed.

The reason for this is that the downfeed mechanism is rather weak. I say this from personal experience since when I got mine, there was a dead spot in the down and up feed motion. This was traced to missing teeth on the bevel gears that transmit motion downward from the worm gear cradle that engages the down feed.

After disassembling the head replacing those two gears, I resolved that use fo the down feed would be limited to 3/8" or smaller on drills and mostly for boring, which is very easy on them. Apparently the previous owner was Bubba, who likes big holes.

If I drill something larger than 3/8" I simply use the hand lever and feed by hand.

Sorry, I don' t know the answer regarding the best drill for aluminum.

Larry Dickman · Oct 1, 2017

well, so the title of your thread is "What is the best drill" For that I would recommend an MA Ford 3fl twister.

Since the title should have read, "What is the best drill for drilling by hand on a piece of shit", I would just go with a cobalt stub.

Long Tom · Oct 1, 2017

Larry Dickman said:
well, so the title of your thread is "What is the best drill" For that I would recommend an MA Ford 3fl twister.

Since the title should have read, "What is the best drill for drilling by hand on a piece of shit", I would just go with a cobalt stub.

Aren't the MA Ford bits for really hard materials?

I'm drilling by hand on a piece of shit? Do tell.

Long Tom · Oct 1, 2017

Newman109 said:
I also have a big Taiwanese Mill (Webb 4 VH) and, like the Bridgeports after which they are copied, the manual says that nothing larger than a 3/8 hole should be drilled using the downfeed.

The reason for this is that the downfeed mechanism is rather weak. I say this from personal experience since when I got mine, there was a dead spot in the down and up feed motion. This was traced to missing teeth on the bevel gears that transmit motion downward from the worm gear cradle that engages the down feed.

After disassembling the head replacing those two gears, I resolved that use fo the down feed would be limited to 3/8" or smaller on drills and mostly for boring, which is very easy on them. Apparently the previous owner was Bubba, who likes big holes.

If I drill something larger than 3/8" I simply use the hand lever and feed by hand.

Sorry, I don' t know the answer regarding the best drill for aluminum.

3/8" in steel is probably about the same machining pressures as 9/16" in aluminum.... that said I suppose I could RTFM for my mill!

Newman109 · Oct 1, 2017

Long Tom said:
Aren't the MA Ford bits for really hard materials?

I'm drilling by hand on a piece of shit? Do tell.

Don't let the inane remark from one of the thread title Nazis bother you. I understood your title perfectly well and it is also correct with regard to the Site rules.

Keep smiling. :popcorn:

Limy Sami · Oct 1, 2017

Larry Dickman said:
well, so the title of your thread is "What is the best drill" For that I would recommend an MA Ford 3fl twister.

Since the title should have read, "What is the best drill for drilling by hand on a piece of shit", I would just go with a cobalt stub.

Okay big shot, what would you drill the OPs castings with?

litlerob1 · Oct 1, 2017

Long Tom said:
Aren't the MA Ford bits for really hard materials?

I'm drilling by hand on a piece of shit? Do tell.

The Twister drills aren't for "hard materials" they are for round holes and great chip evacuation, with high feed (if you have the spindle speed). The straight flute drills that MA Ford makes are awesome for hard materials though.

You said your self that it was a Taiwanese machine, and you were drilling by hand. If the instructions are nothing bigger than 3/8", that is not exactly high end.

R

Limy Sami · Oct 1, 2017

litlerob1 said:
You said your self that it was a Taiwanese machine, and you were drilling by hand. If the instructions are nothing bigger than 3/8", that is not exactly high end.

R

Just because it's not ''high end'', doesn't necessarily make it a POS

Newman109 · Oct 1, 2017

litlerob1 said:
You said your self that it was a Taiwanese machine, and you were drilling by hand. If the instructions are nothing bigger than 3/8", that is not exactly high end.

R

The 3/8" recommendation originally comes from the Bridgeport manual. Page 2.3. Item b. of the 2J2 manual.

DDoug · Oct 1, 2017

Do you need the mill for postioning ?

If not, I would suggest a change to a simple drill press
with power feed, or a Snow automatic drill.

Either one should be $500-750, and allow you to deburr the last casting, while this one drills.

With a Snow, you could easily add a commander multiple drill head to do all 4 at one time.

Larry Dickman · Oct 1, 2017

Sorry Long Tom, I didn't mean to insult your machine, it's just that you ask for the best drill for the job, but you don't have a machine capable of using it.

MA Ford makes a variety of drills for different materials. The 3 flute twisters for aluminum are amazing. Easily feed at 100 ipm and get a perfect hole with no centering or pecking. Only drawback to them, you can't take it easy. If you slow them down, your hole will come out like shit.

As far as your Taiwanese machine, like I said, a cobalt stub is probably your best bet. And, fwiw, I've said on this forum plenty of time that I would take a Webb over a BP any day of the week. (and also, FWIW, if I had to drill 1000's of holes by hand on a BP, I would also refer to it as a POS)

I would also set up to drip feed regular coolant, and shit can the A9

MattiJ · Oct 1, 2017

What grade of aluminium? High silicon content alu is quite abrasive on tools.

Black oxide coating is far from good on aluminium.
I'd try something more shiny and polished like Dormer A002 or shorter Dormer A920 (you can probably find roughly same drill under Union Butterfield brand in US)

litlerob1 · Oct 1, 2017

Limy Sami said:
Just because it's not ''high end'', doesn't necessarily make it a POS

I didn't call it a POS did I?

I just pointed out the facts that were posted. (I do drill a lot bigger than 3/8" on my 1 HP Lagun though.)

Limy Sami · Oct 1, 2017

litlerob1 said:
I didn't call it a POS did I?

I just pointed out the facts that were posted. (I do drill a lot bigger than 3/8" on my 1 HP Lagun though.)

No you didn't, .......I was merely making a point.

DanielG · Oct 1, 2017

I've become a big fan of the YG-1 drills for general purpose use. They've served me well in steel and aluminum. They run well and are inexpensive.

They don't have a 9/16" screw-machine length HSS drill, but they do have 14.25mm (.5610") if the tolerance on the hole will allow that.

Long Tom · Oct 1, 2017

Thanks everyone.

There's been a bit of mixup here... I'm not the guy who said anything about 3/8" maximums, etc. My machine is considerably bigger than a "Bridgeport" @ 3 HP and multiples of the weight. I haven't yet checked the manual. It's been a good mill. I make more profit in one batch of these castings than I paid for the mill.... I love the thing!

I don't know what grade of aluminum... they are castings that have been Heat-treated and judging by the chips there's some variability in the material anyway... they also get a bunch of material removed on the lathe and I just did about 300 of them with the same sharp CCMT insert and it's still cutting cleanly so I doubt it's abrasive.

I do need the mill for positioning. While doing this batch (my second) I tried to come up with fixturing that would eliminate that, but I'm not seeing it... plus cycle time through the fixturing is critical and any ideas I DID have were gonna take more time to fixture/remove than my bolt-and-locating-pins fixture uses.

Side note: fixturing castings is... interesting!

I came up with a fixture that takes all 3 different parts, has 3 different positions on the mill, also moves to the lathe where it goes into a 12" 4-jaw... it's working great but does require that I am able to position the part under the mill spindle with precision.

Long Tom · Oct 1, 2017

OP here again. One thing I should likely do is invest in a drill bit sharpener. I think having the bit be SHARP would be to my advantage, in aluminum at least, yes? I can freehand a bit on my grinder a couple times but then the geometry starts to get away from me. Anyway.

Limy Sami · Oct 1, 2017

DanielG said:
I've become a big fan of the YG-1 drills for general purpose use. They've served me well in steel and aluminum. They run well and are inexpensive.

They don't have a 9/16" screw-machine length HSS drill, but they do have 14.25mm (.5610") if the tolerance on the hole will allow that.

2nd that, YG-1 drills have been nothing but good for me, their cobalt worm pattern for alu are superb HSS & PM Drills for Non-Ferrous ......and like Daniel G said, are not expensive.

Cutting data for them here https://www.cutwel.co.uk/FileDepository/PDFs/ProductId - 18641/DL510 Cutting Data.pdf

DDoug · Oct 1, 2017

A picture or drawing would be nice, I think a cheap/simple/quick fixture could be made up.

Best 9/16" drill bit for AL castings

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