DEEP .013 HOLES

[Smit]

We are stuck on how to proceed with a mold we are trying to manufacture. The print calls for .125 clearance holes 1.8" deep with #80 (.013) holes an additional .200 deep to break through to the cavity. The total depth of the hole is what we don't know how to overcome. We would need an extention of less than .125 dia. If any of the experienced programmers here have with an application of this manner I would very much appreciate the help.

Thanks in advance

[crazy^millman]

Well you can make yourself an arbor and press the drill in it and then use it to drill you .013 holes. I make make the arbor about ,120 in dias drill a .011 hole. I would then heat up the arbor and shrink fit the .013 drill in there and try that. Need some major rpmas and a feed rate at .0001 per rev and peck the crap out of it and go from there. I might try also drilling the .013 from the other side if breaking through.

 

Soemone might make a carbide drill wit ha .125 shank and that would be awsome too if it is long enough but not sure about this.

 

Crazy Millman

[Harryman]

You might try to make an extention .08 or so diameter. Drill a #80 hole in the end and crush/crimp the extention around the drill, assuming a HSS drill.

[MetalMarvels]

+1 on making an arbor.

 

Just finished doing this with a #59 drill in a .120 diameter shank. I tried the slip fit/Loctite approach first and it worked for me. I was reaching in 1.725 inches to drill thru to a cross cavity - couldn't come at it from the other side. Full-flood coolant and lots of pecking....

 

The loctite approach probably won't work if the drill warms up much.

 

[ 11-07-2003, 12:07 PM: Message edited by: MetalMarvels ]

[Rekd™]

+1 on the extension. Or consider having it 'hole popped'.

 

'Rekd

[Brendan P]

quote:

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The loctite approach probably won't work if the drill warms up much.

---

The Permatex "High Strength" stuff works great.

It requires high heat to remove.

I have used this stuff on bolts before,and needed to use a torch to get them off!

[Noel]

Alot of time we drill larger holes 3/8 for the vent dumps from the back and use a domore by hand to drill the vent holes through the cavities from the cavity side.Takes a real steady hand tho.

 

 

Noel

[Mattingly]

You may want to try a carbide circut board drill. Depending on the material I have had good luck with these in the past they are self centering solid carbide drills. I hope this helps...

[Hardmill]

+1 on the circiut board drill.

The only problem would be the reach. Can't hurt to try.

You may want to seriously look at hole popping.

 

PEACE

 

[ 11-07-2003, 10:51 PM: Message edited by: Hardmill ]

[Smit]

Thanks for all the input. It looks like for this time we will make an arbor to hold the drills. If the engineer will allow a larger clearance hole to accomodate a larger arbor we'll definitely try the circuit board drill. And in the long run we will check out the possibility of purchasing a "hole-popper". That sounds interesting, but I don't know anything about them right now. Since this is something we're going to be doing a lot of in the future we definitely need to check into all possibilities.

[HevyMetl]

We run a sodick hole popper and routinly do .5mm down thru 2.o" with great straightness and concentricity. I can purchase tubing down to .1mm where you can burn about .3" with little to no problem. To get your hole yo would need a .25 mm tube(small for overburn). This would give you about a .012-.014 hole depending on material and conditions. You would just have to make and extended guide out of a dowl pin to support your tube at the bottom of predrilled hole.

[Keith Graydon]

Silver solder the .o13 bit into the extension.

 

Circuit board drills typically have a high aspect ratio and usually quite brittle. use caution there.

 

hth

-Keith