Pure Delight - Page 4

Magura · 25th January 2004, 09:43 PM

A bit of echo.....

To get the broken tap out you can use edm as someone pointed out. It is slow and most likely expensive!!

A more DIY friendly solution is to get the tap out with acid. I cant remember what type of acid we used (havnt broken a tap since college), but its possible to do with little or no damage done to the aluminium.

To avoid the broken tap problem in the first place is not all that hard.
To use spiral flute taps is not correct. Such taps are much more fragile than a straight flute tap. A spiral flute tap is for tapping holes that dont go all the way through.....and exclusively for tapping by machine. No hand tapping should be done with such.

Instead you must use alcohol as lubricant. It will leave your thread perfect and shiny.

Another important factor is that the tap used for aluminium must never be used for any other metal. If used just once for steel....its never gonna make a good thread in aluminium again....the same goes for tapping copper. You need a set of tools for each material.

Cheers

Magura

Mark A. Gulbrandsen · 25th January 2004, 10:09 PM

I really disagree with your assessment of using spiral flute taps in alumnium. Even the tap manufacturers reccomend using them on alumnium either by hand or by machine. the get much more stress in a machine environment too. Alumnium is not a hard metal as is steel or stainless steel. There is extra clearance for the chips when using a spiral tap, especially when tapping holes larger than 1/4 inch. Alumnium generally creates large continous chips when tapping. I can't remember when I last broke off a tap in alumnium using a spiral tap.

Also while alcohol may be satisfactory for tapping alumnium, the use of a fine tapping fluid such as Tapmatic for Alumnium or several others made specifically for that material will give you an even better finish and the tap will last far longer than it would with just alcohol.

I completely agree though with keeping a set of taps for differing metals. Fomr a metalurcical standpoint that is very proper to do. I think the majority of DIY'ers here work with alumnium though.

Mark

eeka chu · 25th January 2004, 10:21 PM

I quite like using taps!

It's something quiet to do for a while instead of having to hold onto a mill's swarf covered dials.

Just put some tapping fluid on it and work very slowly. I use a quarter of a turn in the cutting direction, then run it back out about two quarters, then back down and move forwards another quarter. If you try to do it any faster, broken taps are waiting for you!

Magura · 25th January 2004, 10:31 PM

Quote:

Originally posted by Mark A. Gulbrandsen
I really disagree with your assessment of using spiral flute taps in alumnium. Even the tap manufacturers reccomend using them on alumnium either by hand or by machine. the get much more stress in a machine environment too. Alumnium is not a hard metal as is steel or stainless steel. There is extra clearance for the chips when using a spiral tap, especially when tapping holes larger than 1/4 inch. Alumnium generally creates large continous chips when tapping. I can't remember when I last broke off a tap in alumnium using a spiral tap.

Mark

The statement i made was intended for the DIY people. I am perfectly aware of the manufacturers recommendations. It is though a fact that a spiral flute tap is only half the strenght of a straight flute tap, and since the main problem for a DIY'er is not to speed up the thousands of threads he have to cut, but to cut those few threads in an amp or so...without breaking the tap. A straight flute tap is lots better for the purpose.

As well with the cutting fluid. A diy'er will cut 20 threads a year....and sure dont have the correct cutting fluid around for aluminium. In that case alcohol does just fine. I agree that the tool life is shortened.....but how many DIY'ers would ever wear out a tap by cutting aluminium ??

Cheers

Magura

Magura · 25th January 2004, 10:32 PM

ohhh....and besides that, a straight flute tap of reasonable quality will break the chips and push them in front of the tap.

Magura

Mark A. Gulbrandsen · 25th January 2004, 10:39 PM

"ohhh....and besides that, a straight flute tap of reasonable quality will break the chips and push them in front of the tap."
__________________________________________________ __

Yes they sure do, and thats what causes taps to get jammed in a blind hole and break off! As for the fluid it is very common over here. Gee, 20 holes a year.....I'm a DIY'er and I've tapped several hundred holes in the last year just for my home audio projects..... I doubt there is a single Aleph 2 out ther that has less than 25 tapped holes in it and 50 might be more common...and then there are two for a stereo system. There are 12 power devices alone to mount with tapped holes.

Mark

Magura · 25th January 2004, 10:47 PM

Quote:

Originally posted by Mark A. Gulbrandsen
[B

Yes they sure do, and thats what causes taps to get jammed in a blind hole and break off! As for the fluid it is very common over here. Gee, 20 holes a year.....I'm a DIY'er and I've tapped several hundred holes in the last year just for my home audio projects..... I doubt there is a single Aleph 2 out ther that has less than 25 tapped holes in it and 50 might be more common...and then there are two for a stereo system. There are 12 power devices alone to mount with tapped holes.

Mark [/B]

No matter how you put it...a tap lubricated with alcohol will do thousands of threads....not 50 or 100

For blind holes a spiral tap can be used with care by hand...but ideal is to make the hole deep enough to make room for the chips.

Magura

Peter Daniel · 25th January 2004, 11:31 PM

Quote:

Originally posted by eeka chu
I quite like using taps! It's something quiet to do for a while instead of having to hold onto a mill's swarf covered dials.

Just put some tapping fluid on it and work very slowly. I use a quarter of a turn in the cutting direction, then run it back out about two quarters, then back down and move forwards another quarter. If you try to do it any faster, broken taps are waiting for you!

Tapping seems like a touching subject, everybody has his own ideas.

But if you do it by hand, you must be kidding yourself. I simply use a cordless drill gun with clutch (and reverse) and then I can say I really enjoy tapping. Never used spiral taps and regular ones work fine for me. With a drill gun I can tap 60 #4 holes in 15 minutes.

Never broke a tap either.
http://www.diyaudio.com/forums/showt...9414#post69414

Alain Dupont · 25th January 2004, 11:32 PM

Ok,

I will not tap for a long time now....

All the major heatsinks are done, let me finish the enclosure.

Thanks for all those ideas.

Best regards to all.

Alain.

Mark A. Gulbrandsen · 26th January 2004, 01:29 AM

Peter,
That method is a great way to go and I do repeated through holes that way as long as squareness of the threads is not an issue. If a tapped hole needs to be perfectly square though I use my tapping jig or start in on the verticle mill and then finish by hand. Tha majority of my tapping is done with two flute taps for sizes under 1/4" and sprial flute taps for over 1/4". 4-40 and 2-56 only come in three or four flute taps.

Since I also do most of my stuff as countersunk and flush head allens a perfectly square tapped hole is important to me most of the time. When I make a chassis I like to keep things to at least plus or minus .01 or better most of the time. I admit it is nice having access at work to a verticle mill and a lathe to do my work on.

To dissolve a broken or stuck tap from Alumnium immerse the piece in into a well saturated solution of Aluminum Sulfate at 120+ deg F. Let it work for a number of hours.and it will literally dissolve the remains of the tap. You must make absolutely sure there are no other ferrous patrts on the piece you want to do or they will also be dissolved. This method only works on alumnium!! Another route is to simply have the part anodized as that process will also dissolve anything ferrous in the alumnium part. When you get the part back simply finish tapping that hole.

Mark

Added: If you do the Alumnium Sulfate solution be sure to only use glass or plastic containers!! It would dissolve a steel container!

25th January 2004, 09:43 PM	#31
Magura diyAudio Member Join Date: Oct 2003 Location: Denmark, Viborg	A bit of echo..... To get the broken tap out you can use edm as someone pointed out. It is slow and most likely expensive!! A more DIY friendly solution is to get the tap out with acid. I cant remember what type of acid we used (havnt broken a tap since college), but its possible to do with little or no damage done to the aluminium. To avoid the broken tap problem in the first place is not all that hard. To use spiral flute taps is not correct. Such taps are much more fragile than a straight flute tap. A spiral flute tap is for tapping holes that dont go all the way through.....and exclusively for tapping by machine. No hand tapping should be done with such. Instead you must use alcohol as lubricant. It will leave your thread perfect and shiny. Another important factor is that the tap used for aluminium must never be used for any other metal. If used just once for steel....its never gonna make a good thread in aluminium again....the same goes for tapping copper. You need a set of tools for each material. Cheers Magura __________________ Everything is possible....to do the impossible just takes a little while longer. www.class-a-labs.com

25th January 2004, 10:32 PM	#35
Magura diyAudio Member Join Date: Oct 2003 Location: Denmark, Viborg	almost forgot this ohhh....and besides that, a straight flute tap of reasonable quality will break the chips and push them in front of the tap. Magura __________________ Everything is possible....to do the impossible just takes a little while longer. www.class-a-labs.com

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25th January 2004, 10:09 PM	#32
Mark A. Gulbrandsen diyAudio Member Join Date: Sep 2001 Location: Salt Lake City	I really disagree with your assessment of using spiral flute taps in alumnium. Even the tap manufacturers reccomend using them on alumnium either by hand or by machine. the get much more stress in a machine environment too. Alumnium is not a hard metal as is steel or stainless steel. There is extra clearance for the chips when using a spiral tap, especially when tapping holes larger than 1/4 inch. Alumnium generally creates large continous chips when tapping. I can't remember when I last broke off a tap in alumnium using a spiral tap. Also while alcohol may be satisfactory for tapping alumnium, the use of a fine tapping fluid such as Tapmatic for Alumnium or several others made specifically for that material will give you an even better finish and the tap will last far longer than it would with just alcohol. I completely agree though with keeping a set of taps for differing metals. Fomr a metalurcical standpoint that is very proper to do. I think the majority of DIY'ers here work with alumnium though. Mark

25th January 2004, 10:21 PM	#33
eeka chu diyAudio Member Join Date: Nov 2003 Location: England	I quite like using taps! It's something quiet to do for a while instead of having to hold onto a mill's swarf covered dials. Just put some tapping fluid on it and work very slowly. I use a quarter of a turn in the cutting direction, then run it back out about two quarters, then back down and move forwards another quarter. If you try to do it any faster, broken taps are waiting for you!

25th January 2004, 10:39 PM	#36
Mark A. Gulbrandsen diyAudio Member Join Date: Sep 2001 Location: Salt Lake City	"ohhh....and besides that, a straight flute tap of reasonable quality will break the chips and push them in front of the tap." __________________________________________________ __ Yes they sure do, and thats what causes taps to get jammed in a blind hole and break off! As for the fluid it is very common over here. Gee, 20 holes a year.....I'm a DIY'er and I've tapped several hundred holes in the last year just for my home audio projects..... I doubt there is a single Aleph 2 out ther that has less than 25 tapped holes in it and 50 might be more common...and then there are two for a stereo system. There are 12 power devices alone to mount with tapped holes. Mark

25th January 2004, 11:32 PM	#39
Alain Dupont diyAudio Member Join Date: Sep 2003 Location: Paris - France	Ok, I will not tap for a long time now.... All the major heatsinks are done, let me finish the enclosure. Thanks for all those ideas. Best regards to all. Alain.

26th January 2004, 01:29 AM	#40
Mark A. Gulbrandsen diyAudio Member Join Date: Sep 2001 Location: Salt Lake City	Peter, That method is a great way to go and I do repeated through holes that way as long as squareness of the threads is not an issue. If a tapped hole needs to be perfectly square though I use my tapping jig or start in on the verticle mill and then finish by hand. Tha majority of my tapping is done with two flute taps for sizes under 1/4" and sprial flute taps for over 1/4". 4-40 and 2-56 only come in three or four flute taps. Since I also do most of my stuff as countersunk and flush head allens a perfectly square tapped hole is important to me most of the time. When I make a chassis I like to keep things to at least plus or minus .01 or better most of the time. I admit it is nice having access at work to a verticle mill and a lathe to do my work on. To dissolve a broken or stuck tap from Alumnium immerse the piece in into a well saturated solution of Aluminum Sulfate at 120+ deg F. Let it work for a number of hours.and it will literally dissolve the remains of the tap. You must make absolutely sure there are no other ferrous patrts on the piece you want to do or they will also be dissolved. This method only works on alumnium!! Another route is to simply have the part anodized as that process will also dissolve anything ferrous in the alumnium part. When you get the part back simply finish tapping that hole. Mark Added: If you do the Alumnium Sulfate solution be sure to only use glass or plastic containers!! It would dissolve a steel container!