Drilling Inconel X750

[Robert Ouellette]

Hello all

i have a quote to do for drilling 1.625 dia x 18" through hole. what would be the fastest and best way to do this? boring that would be out of the question i think. right? the part is 4" and change od x 18" long. fairly large quantity. new machine is not out of the question if needed.

 

thanks for you great help that will be coming

 

bob

[Haroon]

Try Terpanning

http://www.trepanningspec.com/NewFiles/trpng.htm

[Haroon]

Sorry Trepanning

[robk]

Personally I have never drilled inconel that deep. We have gone 6" deep and that in itself is a challenge. You should probably contact a few different reps and have them give you some advice.

 

I have never trepanned inconel so I don't know how that would work.On the other hand we do drill quite a bit of it in here. This sounds like it's going to be a challenge. Definitely not a quickie. Inconel has a tendency of "moving".

 

I havent looked in any catalogs, but is the tooling going to be an issue? What kind of tolerances are you looking to hold?

 

If I had the proper tools I would try the following;

I would spot the hole, then I would pre-drill with a high quality cobalt drills with plenty of pecks (18 SFM @ .004 IPR to start with). Start with stubby drills 1st. Find a way to get the oil in the hole or you'll burn your tools very quickly. Then I would size the holes with a couple of carbide size mills (might have to peck those also).

IMO this is not a simple project.

[bhayden10]

We drill inconel 718 with a 1.625 inserted drill. We go 3" deep, but the finish is not that good but we finish bore after. Its quite a challenge to get it all figured out, the inserts only last a couple holes.

[Goldorak]

trepanning at 1.625 dia it's not a very good idea

 

we use trepanning drill over2.000 in inconel 718

 

under that , iscar u drill is the most efficient but they only makes 4xD (6.5 dp for 1.625)

 

 

can you drill from both side??? That will deduce dept to 9in

[Quickmike]

Maybe send it to a gun drill house. I googled inconel gun drill. There are several places that I think would be able to do it. Here's on e that I saw

http://www.deephole.com/Expertise.html

[Guest]

drilling and boring from either end if you can sounds like good advise.

im sure you know but, food for thought its gonna take some horse power and servo's that can feed hard and consistant for this stuff. thru tool coolant is an unsaid must.

 

doug

[crazy^millman]

Gundrilling is the best way. Thompson Gun Drill here is Cali is equipped and can handle that with no problem. What we do is get stock over size. Have it gundrilled then put it between centers and turn the od concentric to the id and life is good. If there is a tight ID requirement for finish or size we just hone it in house we can hone up to 48" lengths on our honing machines.

 

HTH

[ReDEyZZ]

quote:

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Gundrilling is the best way.

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+1

 

We have done similar bores in inconel, we send it out for Gun-drilling. We tried to drill and bore from each side, not worth the trouble.

[Robert Ouellette]

we can drill from both sides. holes size is 1.625 +.o2o. so we could do it. will need to look for tooling and then a machine to turn it.

 

thanks all

 

bob

[crazy^millman]

Ok then go with a AME spade bit. A Sandvik Defib bar and you could do it. The drill will be cheap. The defib bar is about $1400 to $2000 worth every penny. We have done 1.000 +/-.002 8.75 deep in 55rc with no problem using these bars. We also do some 2.7 bores in Titanium 26" deep .1 wall parts with no problem as well.

 

HTH

[Robert Ouellette]

i got the pricing for the spade drills and boring bar and the boss calculated it all up and submitted the quote. my job is done. for now. until we get the job or not that is.

 

thanks again for all your help guys

 

bob

[Surface]

 

I'm sorry I can't offer any constructive advice. Just the thought of a hole that deep in inconel gives me chills.

All I can say is, good luck with that. I certainly will no-quote that one.

[JerryBenoit]

HI,

 

request a quote here http://www.dearbornprecision.com/

This is right up our ally. We can do bar upto 12' in lenght if need without a problem.

[clyde]

i can verify Dearborn can do a great job of that, they put 1/4 holes thu 24in long 750X bars for us. mirror finsh and straight.