Drilling 1.625 8xD w/118 point?

[djstedman]

So I got a project thrown at me that were not really setup for .. but it has to get done one way or another.. and i'm not allowed to send it out (not my call), so here is what I have to do..

 

I have a vertical machine (no horizontal available) with the standard through spindle coolant (not high pressure), I need to drill a 1.625 hole 13 inches deep (with a 118 drill point) in 6061 Aluminum

 

Currently my main problem is even finding a drill with the proper geometry.. so far the only drill I have found is a Allied Spade drill which has the reach but comes standard with a 132Deg tip.. also in aluminum they suggest to have a coolant flow of 70Gallons per minute..  (I highly doubt I have that much flow)

 

I was wondering if anyone knows if they (Allied) will make custom drill points at different angles..  or if anyone has any other suggestions for different tooling brands or options.

 

If need be I can always drill with the 132 point and then perhaps find an old monster twist drill that's got a 118point on it to cut the drillpoint for the part geometry .. I would prefer however to cut once and be done with it if at all possible.. although I am pretty concerned that this is going to end up being a drill / clear chips - rinse repeat process..

 

Anyhow .. looking for any suggestions for tooling and or process considering the limitations mentioned above..

[specv]

Allied will make just about any point you want, we have a spade style custom tip made with multiple steps on it that goes on a regular drill body.

[crazy^millman]

Buy an old school taper length drill and have a nice day? :turned:

 

 

http://www.mscdirect.com/product/details/01401405?rItem=01401405

[MIL-TFP-41]

1 part or 50 or 500?

 

ifs its one part, old school the thing like crazy suggested.

Problem with spades on a vertical...no spiral flute to help carry the chip out of the hole. Not an issue if you are only going a few inches deep....but you are going much deeper than than.

[djstedman]

Honestly I had no idea where to find a regular drill.. fortunately its only about 30 parts.. so will look for the old school drill I think.. now that I know where I can find one.. really have never had much need for drilling big holes this deep.. so didn't really have any idea where to look..

[jlw™]

We run the crap out if allied gen2 ta spades. Any where from 21mm to 4in mostly in verticals with standard pressure thru tool coolant. They make fantastic little chips that push out easy and have never caused a problem. Just blow them off if seeing them bothers you but I never worry with it. I run alu much slower than recommended at 130 to 140 sf and .004 to .007 ipt for that size. Do not spot it and check your run out. I often circle mill about 1/2in deep to ensure location. It'll bark going into the pocket but it'll locate well that way. They generally size real well but I'd test it before running it. Do not peck or chip break, it's all or nothing. In alu you should probably get all 30 on 1 or 2 inserts but they're so affordable I usually order 1 or 2 more than I think I'll need. We pretty much keep a few of every size for all the drill bodies we have. I don't like letting them full rapid out either, they bark coming out at full rapid and if you ever make a thru hole you're more likely to lose the insert on the way out than in.

 

Yes there are better options but when you factor in price, how fast you can get them and how consistent they run you'll like them.

[taperlength]

I'd ask the engineer if it really has to be 118 degree drill point.  Sometimes they are just reading out of an old book.

 

That must be a big vertical mill to get a drill that long above a part that big.

[djstedman]

Yeah its pretty big.. I have about 37 inches under the spindle at tool change position.. so height wont be an issue at least..

[Mike@Lustre]

A standard taper shank at 1 5/8" dia. will only have 10" of flute so you will have to order a longer series drill .  One of the hardest parts with drilling that deep vertically is clearing the chips and getting coolant to the bottom of the hole without it vaporizing around the tip while cutting .

[djstedman]

Just got to try this yesterday.. I ended up getting a Allied Spade drill and going with the method jlw described above.

 

Used 135SFM and a .006 chipload and it cleared the chips no problem, just wanted to say thanks to everyone for the input.

[jlw™]

Fantastic, glad it worked!