0-80 tapping 1

[kubert]

Hi, Iam a start up company and have a job that requires tapping 150 0-80 blind holes,.110 deep in alum. I have been using an .05 dia. end mill to drill the hole to get as much clearance as i can. I am tapping these holes about .015 from the bottom to meet the spec.
I cannot go any deeper with the end mill as i am already about .01 from breaking thru.
Even though my machine is capable of ridgid tapping, i am using a floating holder.
The problem is relability. sometimes i can go thruogh several parts without breaking a tap, sometimes i can't make it through one part.

Can anybody offer anyt tips ?

Thanks
Keith

 

[brengine]

How often do you change the tap? If you find that after 200 holes the tap is breaking, then throw it away before you even get close to 200. We run a job that requires 16 #8-32 tapped holes in Beryllium Copper, and every time we run it we put in a fresh tap and then throw the tap away once we're done.
Ken

 

[JDana]

What alloy? What temper? Roll-form or cut tap? What type of coolant/lubrication? Chips in some holes from drilling and/or previous tapping? If machine is capable, why the floater?

 

[kubert]

KenBolan:
This is a new job, haven,y run many of them yet. Trying to the solve a problem before I run to many more.


JDana:
1) Alloy: 6061 T651
2) Using a cut tap (bottom tap, ) after talking with the customer about thread depth I am going to try a spirol point bottom tap. And TapMagic
3) Coolant: Valenite VNT 800 (on the rich side)
Chips in holes: ?? , hoping the flood coolant is washing any chips out.

4) Floatating tap holder: More than anything, i am using it to hopefully take out any runout issues.

 

[JDana]

1)Should be no problem
2)Cut tap- fast spiral good, spiral point not so good, will push chips to bottom of hole. Roll form tap much better for blind holes(needs bigger dia. drill)
3)no experience with this stuff
Flood coolant will wash chips away. Away to where is the issue. We have found that sometimes they end up in other holes, with taps this size it doesn't take much.

 

[kubert]

JDana,
I don't mind fishing out the chips if i use a spiral point tap if it keeps the chips from going into another hole and caosing a problem.
I use a lot of spiral flute taps at my day job. But there i deal in the macro world. At home i am tryng to work in the micro world. this is new to me.
The only spiral flute bottom taps i can find cost $40. Do you know of a cheaper sorce?

Thanks
Keith

 

[JDana]

Go here:

http://www1.mscdirect.com/cgi/nnsrhm

type in: 04500815 in the quick search field

scroll down to MSC Big Book page and click "233"

you will find several taps under $20.


I personally wouldn't use anything but a roll form tap for blind holes that small.

try searching 74540848 then the Big Book pg to find them.

 

[jjv32]

Try Prototyp taps they offer a good production tap.

http://www.prototyp.com

 

[unclesyd]

Give these people a call. They carry several forms of taps and used to give good technical advice.

http://www.morris01550.com/prectap.htm

 

[metman]

TapMagic is excellent .

"OSG Hypro(used to be PXL)" taps outperform others I have tried by a large margin. With reverse spiral flutes the chips will come out of the hole.

 

[aamoroso]

We used to tap 0;2 and 4 threads in 17-4 SS with an EMUGE clutch tap driver. The tool holder is quick change, it has clutch control much like a cordless drill, you can adjust the torque. When the tap binds it stops spinning while the machine continues to run as normal (requiring careful inspections or a good opererator to notice which holes will require hand tapping). The upside is no broken taps, and un-interupted production. When the tap starts binding, it may need to be changed or it may have just hit a chip. We had great success with these, we also used a paste of some sort, I cannot remember the name though, it was a pink paste that worked pretty good on the small stuff.

 

[benphilli6016]

aamoroso,

Is the name of the pink paste that you are trying to describe CIMTAP??? I have used it on several types of stainless.