Your .02 on 1" dia. hole 24" deep ?

[Scott Bond]

Hi all

The part is aluminum,I need to make

a 1" hole 24" deep,,not thru.

I must drill the holes on the mill.

 

I would like to have a few options, so post

anything that worked for you in the past.

 

Scott 'teh Type slow I've had a long week end.

[Jack Mitchell]

Scott,

 

Sub it out for a gun drill.

 

When you say it's done on the mill then I would immediately think of conventional/horizontal otherwise finding a cnc maching center with 24" Z-travel with the 24 inches of clearance before the tool meets the part is highly unlikely - that's 24" minimum z axis travel not including clearance.

 

When I said that you and Jayson were going to be bad guys I didn't expect the referance to a stock car driver. - just how bad do you really want to be here Scott?

 

 

Regards, Jack

[Slixmix]

We have some 3/4 dia. holes 18" deep that we drill on our FH-8800 Mazaks. We have to load the tool by hand because its too long for the tool changer. Thru coolant is a must. We use a long George Whalley coolnt fed drill. We drill it first with a short drill then feed into the hole dead spindle and have the "R" plane below the top of the hole so the drill never leaves the hole and tear up the top of the hole. Turn the spindle off when the drill is in the hole before feeding out. I looked in the Whalley catalog but didn't see anything that long. Maybe a custom made? Good luck.

[iowajim62]

Hi Scott,

 

We also use Allied Spade Drills on our FH-8800s.

Here's the web addy, www.alliedmachine.com

I have one 18" long no problems so far.

[cadcam]

Scott, Sergy has a gun drill for his barrles take there.

 

Yor mahine does not have enough travle and there is no way to get the coolant in that deep except for a thru the spindle coolant.

I don,t think they have any machines like that at your place.

[Müřlıń®]

quote:

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Sub it out for a gun drill.

---

Sound advice there Jack

 

A gun drill could poke a hole in 6061/24" deep in just a couple min.....

 

If your mill had enough clearance for the drill, the hole could get all scoured up with all the pecking you would have to do to clear the chips.

Unless there is some kind of drill with extra clearance you can buy to use in your spindle...I never saw any before.

 

You would probably have to step drill it to get a good hole. With a drill that long, it would be pretty scary to say the least.....probably have to rig up some kind of anti-chatter/steady of some kind.

 

If you had hundreds of them to do you could probably buy a gun drill for what it would cost you to form them out....

 

Used machinery is at an all time low.......

 

 

Murlin

[Andy]

Make 12 2" long pieces with 1" holes in them and weld them all together.

Boooooo!

Or, as above, sub out.

[Scott Bond]

Hi all

Thank you for your responces.

We just had a weak vendor for gun drilling that was giveing engineering a problem, so I was asked to look at it. I did, I asked you guys for help, i got it(thanks) , and then I got a new vendor to drill the holes.

Hi Jay

(we have several new machines some are pretty cool, but two are Fadals )

I was going to use our #50Taper bridge machine.

It has thru spindle coolant,, and it cuts

all the way around the 121” x 77.6 table ,so I was going to hang the part off of the front of the table so that I could use all the 28" Z travle for the drill.

[McRae]

If you have a machine that has the travel, and you want to do it - Here is the solution.

 

1) There was a recommendation to have some sort of a steady rigged up to hold the drill and keep it from whipping. Here is an idea - use the 1.0" that you need to drill for this...

 

2) Start off by drilling with conventional tooling and get her as deep as you can. The next thing I would do is put a "Gun Drill" into that hole, have the holder waiting in the spindle, then postion the table so the drill aligns with the holder. Insert the drill driver (may need to modify the holder or drill to get an oring seal here...) and clamp the hell out of it.

 

3) Start the spindle slowly and watch out for Whip. If there was any drill wander from the Predrilling - it will show up here. The only solution for that is to send a New part out cause you just scrapped this one...

 

4) If drill whip isn't a problem, approach the bottom of the hole and for the love of god - keep the spindle thru coolant going, never under any circumstances allow the coolant to stop. I have seen videos on Inertia Welding - You could see the live show if not careful.

 

5) Just before you engage the material - give the spindle all the speed she has (or the recommended spindle speed for the appilcation) and begin to feed into the material at the appropriate rate. Never under any circumstance - peck. Keep on drilling - the coolant should flush out the chips. If not - there isn't enough pressure on the drill and you will pack the hole up with chips and spin the driver right off the end of the drill.

 

6) You might be successful, but I doubt it. The difference between an HMC and a Gundrill is the HMC has a 5HP coolant motor and a 60HP spindle - the Gundrill has a 60HP coolant motor with a 5HP spindle. The limiting factor on most Deep Hole Drilling applications on an HMC is Coolant Flow. Even if you have invested in a "High Pressure" option - you may not have the more important "Flow" to flush the chips.

 

Think of it in terms of Voltage (Pressure) and Current (Flow) - sure you can light a buld using a 12V car battery - but it will be quite dim - Hook that thing up to a 12V weld supply and pump 160 amps thru it - WOW.

 

[ 08-05-2003, 08:42 AM: Message edited by: Andrew McRae ]

[Scott Bond]

Good morning

 

I appreatiate all the comments , and Andrew's #5 and #6 have once again convinced me that if I try this,, I will be on the floor drilling these holes personally 200 times(not).

It was cool you brought up the existance of the Inertia Welding Video,,I will avoid makeing my own Video called "" Scott can't drill a simple hole""

Thanks for your comments

 

[ 08-05-2003, 10:09 AM: Message edited by: Scott Bond ]

[Scott Bond]

Hi Jack--please excuse my slow responce

quote:

---

When I said that you and Jayson were going to be bad guys I didn't expect the referance to a stock car driver. - just how bad do you really want to be here Scott?

---

I really don't want to be bad ,it just always seams to work out that way.

[Müřlıń®]

quote:

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Scott can't drill a simple hole""

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I wouldnt exactly say that a 24" deep hole is simple.......

 

***wonders how much that drill would run out****

 

 

Murlin teh drill crooked like snake

[Scott Bond]

Good morning all

This project will not leave me alone.

 

I will be makeing a 25" long part with two .937 diameter holes thru it. I intend to use our 50t horizontal for the travel, and hand load a .937 diam. spade drill 13" .long, with thru coolant. We will drill entry(pilot) holes ,then drill more than half way thru each side with a spade,and Oringed caps will seal the ends of part.

 

Thanks for all the prevoiuse tips, I think I used a little bit of each post.

 

Are any of you guys produceing a drill that I could use?

[medaq]

I gun drill some holes on my horizontal. Granted my coolant thru pressure is less than desireable for the application. So I make pecks and it gets the job done. I bore a bushing into my material with a boring head to guide my drill for the start. But coolant through is necesary for this application

[McRae]

If you are inclined to do things that are a little off - then you could use a drill of the proper length and cantilever (overhang off the back side) the part off on end of the table so that you can get more room infront of the part to use the full stroke of the z axis.

 

I would do this if it were my shop and I was doing it my self - but the operators that I work now would have my head...

[medaq]

Btw, if you have a cnc horizontal. You can drill 12" s in both directions. I do this alot, and can barely see overlapping drills.

 

Jim

[medaq]

Sorry I am tired and sick, You said not through

 

Jim

[Scott Bond]

medaq,,your on track,,the first post in this thread is over a year old,,I am now drilling from each side-- then capping the ends with "O"rings.

I ordered thru spindle coolant spade drills today from AME 8" drill and an 18" drill so I can drill deep from only one side.

 

Thanks all