Tapping Help Please

[RACINGCONVERTERS]

Hey Guys;

 

I am breaking stuff again. I am tapping three 5/16"-18 holes in 7075 AL .625 deep, I used a letter "f" drill .775 deep. I ran the tap at 270rpm and 15.ipm and the tap broke on the second hole first part so I have around 600 more holes to tap. Oh yeah the tap is a morse high proformance spiral flute bottoming tap.

Castrol clearedge 6519 coolant around 6%

Valenite quick change rigid tap holder

Okuma mc-v4020 with rigid tap

 

 

Help Please!!!

[Mcam Nut]

We had tapping problems because of the type of coolant before, but maybe try using a peck tap cycle where the hole is fairly deep

[PGW Steve]

I was breaking taps in aluminum with synthetic coolant as it has no lubricity. Is it breaking going in, or coming out? Did you look in the first hole and see if the tap made a mark in the bottom?

[Mcam Nut]

Sorry I just noticed you have a okuma, I know there was a problem with peck tapping on that machine

 

peck tap

[?Mark]

Roll tap is the key here, especially since you're cutting alum...

[RACINGCONVERTERS]

Steve

The tap broke coming out and as much as i could tell it did not hit the bottom of the hole.

 

As far as peck tapping can anyone help with how the code needs to read for the okuma. I looked in the topic from a few days ago and it did not show how the code should read.

 

Thank you for all the help

[Mcam Nut]

quote:

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Roll tap is the key here, especially since you're cutting alum...

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This is also a good option, we do this alot, if you can keep them from gulling up they work great

[Mcam Nut]

Have you tried a-9 or some tapping fluid, know it is a pain in the a$$, but may get you out of a jam

[terry5357]

believe it or not WD-40 is the trick here. I have tapped 100,000 holes in aluminum, also you can tap at about 740 rpm arre you rigid tapping or floating tap holder. If yo are using floating tap holder program 95% of you feed.

also how deep

[Mcam Nut]

quote:

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believe it or not WD-40 is the trick here

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Thanks for the tip terry, I never would of thought to try it, used to use a penitrating oil called mooveit though, that stuff worked great, harder to find then the good old wd-40 though

[RACINGCONVERTERS]

Thanks for all of your quick responses I have ordered drills and taps to roll form the threads.

I will let you know how they are working or ask for more help. Thanks again.

[crazy^millman]

Be glad it is not for Aerospace most comapines will not allow you to Roll Form threads.

 

Well if it we me I would go with the thread milling operation. Harvey makes a tool for the spefic depth.

Here is the link: The one in RED.

 

HTH

[jeff]

I've never had any luck using spiral fluted taps in aluminum.

do you have a regular bottoming tap that you could try?

[T_MALENA]

Matt you are running G284 not G84, correct?

[Jaz]

We tap in 7075 all the time using the semi-synthetic fluid we use for everything else - no biggy. Spiral taps work great when you need to tap a blind hole. The only thing I can see is that you might not be running your tap fast enough. High performance taps are designed to run pretty fast. Ask you tool rep for recomended feeds and speeds. Had a similar problem running 6-40 threads and all started going good when we got things up to speed.

[ToolMan184]

quote:

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believe it or not WD-40 is the trick here

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Crisco does wonders as well. Not the liquid but the solid white stuff.

[Mcam Nut]

quote:

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Well if it we me I would go with the thread milling operation. Harvey makes a tool for the spefic depth.

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We are doing more and more threadmilling, we use harvey tools for all our sc threadmills, they work well, 1 pass is all you need with them so it isnt much slower then tapping, and you get a better thread that you can adjust. Harvey tools also makes a realy nice inserted threadmill for larger threads, and od threads. we got a couple 6-32's a few months back, I just seen on the site they go down to 2-56

[RACINGCONVERTERS]

Ron,

Your right my family owned the shop where I started and was 95% aerospace. These holes are all to tool up on so all I need is a good thread. The company can not wait 10 more weeks for material to be made so I am having to improvise.

 

TMALENA

I am using G284

 

Jeff

I also ordered a regular bottom tap wiht the roll form

 

I will let you know more tomorrow. I picked up all the tools tonight when I got off.

Thanks for everthing

[Bob_Looney]

roll tap the hole. I broke taps for years on our old Okuma till I switched. It's been a few years but you can peck tap that control. call out the G284 on the next line and include the X and Y locations again as well as the deeper depth. I think that's how I got it to work.

 

I tap 5/16 full thread .800 deep in all my fixtures. Roll tap

[Storkman]

I'm with Ron, threadmill if you can.

[toy4x4]

You might also need to start the tap further away from the face of the part. I had the same problem until I started my tap about .5 from the face of the part. This gives the spindle time to sycronize with the movement of the z axis.

[Reverend Turk]

I tap Al all the time and I use a spiral fluted tap and use HD-40(Harley Davidson aka WD-40) this stuff really does the trick!! The guy that works next to me uses nothing but Crisco when tapping AL!!! All the above works. You just have to find out what will be the most economical for your situation.

[Keith @ Solid Code Solutions]

Matt,

 

Have you tried "A9". the Alum. version to Rapid Tap.

 

G284 on your Okuma is definitely the way to go not G84 just incase you need multiple goes, but at 5/8 depth it shouldn't be a problem.

[Reverend Turk]

I tap Al all the time and I use a spiral fluted tap and use HD-40(Harley Davidson aka WD-40) this stuff really does the trick!! The guy that works next to me uses nothing but Crisco when tapping AL!!! All the above works. You just have to find out what will be the most economical for your situation.

[Keith @ Solid Code Solutions]

Hey, there's a echo in here.......