Miniature tap guide and depth stop

[Bentwings]

Brian , milk is supposed to be a lubricant for turning copper. I have not tried milk myself. I have threaded copper tubing several times. I use Castrol Moly Dee for a tapping fluid. I use it for all metal tapping.
Moly Dee has been banned, I suppose it causes cancer or something. I have about 2 ounces left and when that runs out I'll have to try something else.
Maybe a bit of milk may help threading copper.

Now that’s. New one . I’ll ty some 2% as that’s all I have . I suspect it’s the cream . I have some ice cream so I’ll also try a little of that so far none of my go to cutting oils have helped. I even have some casto oil and veggie oil so I’ll try all those too. I have a small amount of real steamer oil so that may even work . Copper has always been trouble some for me. Drilling a hole is hard enough tapping is another thing . Cutting threads is a night mare unless there is some size and stiffness to the part.

Byron

 

[Lloyd-ss]

Brian, getting 80 4-40 blind holes without a broken tap is quite a feat. Nice contraption with precise control that you can FEEL. One tap, or a handful? You said the tap was made in Japan. What kind of flute? and any coating? And what lube? I am always curious about that, especially in small sizes. Some taps seem to last and last, and others aren't worth risking your project.
But, gotta say, I hate it when I get greedy and think to myself, I better back this tap out, and then don't, and then.......snap!
Lloyd

 

[Lloyd-ss]

Sorry Brian, 2 conversations. Byron, you might have a re-threading die, rather than a cutting die.

 

[Brian Rupnow]

Two taps. Spiral flute. No name cutting oil.

 

[Lloyd-ss]

Two taps. Spiral flute. No name cutting oil.

Thank you. And thanks for the drawings. Extremely helpful.

 

[Gordon]

Back quite a few years ago when Tap Magic first came out you started a tap until it started to bind and then squirted the tapping fluid on the tap. It really worked well but it had something in it that was either bad for the environment or bad for your health and they had to change the formula. The present day stuff works but not as well as the original. The original would not work on aluminum. If you used it on aluminum it ate up the aluminum. They had a separate formula for aluminum.

 

[Lloyd-ss]

Back quite a few years ago when Tap Magic first came out .............

Gordon, YES, I remember that stuff. There was always a case of it in the tool crib and and a can at every machine, and it worked so very good. I am not sure, but I think it had TRIC (tri-chloro-ethelyne) or something like that in it. TRIC was like a miracle drug and used in many manufacturing processes until studies found out how really nasty that stuff was. Plus, it somehow always got in the ground water and never went away. Not good.

 

[Gordon]

Gordon, YES, I remember that stuff. There was always a case of it in the tool crib and and a can at every machine, and it worked so very good. I am not sure, but I think it had TRIC (tri-chloro-ethelyne) or something like that in it. TRIC was like a miracle drug and used in many manufacturing processes until studies found out how really nasty that stuff was. Plus, it somehow always got in the ground water and never went away. Not good.

I do remember that when you put it on aluminum green smoke came out and the hole was now oversize.

 

[Bentwings]

Gordon, YES, I remember that stuff. There was always a case of it in the tool crib and and a can at every machine, and it worked so very good. I am not sure, but I think it had TRIC (tri-chloro-ethelyne) or something like that in it. TRIC was like a miracle drug and used in many manufacturing processes until studies found out how really nasty that stuff was. Plus, it somehow always got in the ground water and never went away. Not good.

yes I too remember the old stuff two cans on for alum one for everything else . Yes it was done tri Chlor …… thing
The co I worked for had a run in with osha and EPA over an oil spill as I recall . All tap magic was confiscated a few of us heard about it and hid anything we could find . As we moved on it moved with us LOL IT WAS TREASURED STUFF WHILE ITVLASTED . The new stuff is weak . I too used a never seize mix. Still do . I don’t use it on brass or bronze gear lube for heavy loads. Thin it for lighter stuff with marvel. Not an oil chemist but tried and true. Castor oil in superchargers gears but that’s about the only place model engines on glow fuel.
Byron

 

[Badhippie]

I can tell you from experience the old tap magic stuff once it got hot and started to smoke it produced
Hydrogen Chloride gas if I recall. Years ago I had some work that needed around 300 holes taped to 9/16 did these in a day. and I was using it for drilling and tapping the holes. Needless to say I got pretty damn sick off it.
And I think that’s why they had to change the formula. They didn’t find out about what it produced when it got hot until it was in production for a few years. Chalk that one up to learning the hard way.
Thanks
Tom

 

[Gordon]

Now I don't miss the old Tap Magic as much as I thought I did. Sounds like it was actually pretty nasty stuff.

 

[Badhippie]

Will to honest when it was used correctly it did not produce this gas. You know you see them little warnings on things that may hint at how and how not to use a product. But it still had other harmful chemicals in it that was bad for the environment. And I think Lloyd was correct I think it was TRIC that was in it

 

[roncohudd]

I do remember that when you put it on aluminum green smoke came out and the hole was now oversize.

I've been using gundrill oil for all my tapping and dies for years has always been good to me. For hardened parts I use the black Castrol.

 

[stanstocker]

Now that’s. New one . I’ll ty some 2% as that’s all I have . I suspect it’s the cream . I have some ice cream so I’ll also try a little of that so far none of my go to cutting oils have helped. I even have some casto oil and veggie oil so I’ll try all those too. I have a small amount of real steamer oil so that may even work . Copper has always been trouble some for me. Drilling a hole is hard enough tapping is another thing . Cutting threads is a night mare unless there is some size and stiffness to the part.

Byron

Greetings,

Butter, heavy cream, bacon fat, all the stuff that wants to turn rancid if left in the shop... Actually copper seems to either turn and cut just fine and dandy whatever you use or be a total pig to deal with. The alloy, lunar phase, attitude, who knows. But butter or bacon fat at least tend to stay about where you put them and not get slung all over shop, off slosh all over the floor if you drop a container. Highly polished cutting tools help, but a soft gummy copper hunk is likely to be a frustrating deal.

Cheers,
Stan

 

[Steamchick]

Copper, being soft and ductile, has a shearing force due to it's structure, that is relatively high compared to the Young's modulus - or something I didn't learn in college. - Maybe someone can explain what the parameters are?
What I mean is, is is not materially stiff enough to take the "work" needed to shear the size of thread in a single pass.
A thin-walled copper tube (Not at all strong and stiff) can be turned at high speed and fine cuts, because the torque for cutting is well below the Yield strength of the tube. But a heavy cut (exceeding the yield strength of the part) causes it to collapse and buckle out of the way. Been there and done it!
Basically, cutting threads with a die is a VERY heavy cut.
The only countermeasure, is to reduce the cut by expanding the die fully, and taking a first cut (if it will), then progressively taking small cuts by closing the die a little at a time until the size of thread is reached. Of course, all the tapping lubrications help a great deal.
The tapping paste I have was bought on e&@y.... but is exactly the same as dentists tooth polishing cream.... for dentures, that is bright green and minty! Works really well, and I guess is safer than Tap Magic?
K2

 

[Lloyd-ss]

Copper, being soft and ductile, has a shearing force due to it's structure, that is relatively high compared to the Young's modulus - or something I didn't learn in college. - Maybe someone can explain what the parameters are?
What I mean is, is is not materially stiff enough to take the "work" needed to shear the size of thread in a single pass.
A thin-walled copper tube (Not at all strong and stiff) can be turned at high speed and fine cuts, because the torque for cutting is well below the Yield strength of the tube. But a heavy cut (exceeding the yield strength of the part) causes it to collapse and buckle out of the way. Been there and done it!
Basically, cutting threads with a die is a VERY heavy cut.
The only countermeasure, is to reduce the cut by expanding the die fully, and taking a first cut (if it will), then progressively taking small cuts by closing the die a little at a time until the size of thread is reached. Of course, all the tapping lubrications help a great deal.
The tapping paste I have was bought on e&@y.... but is exactly the same as dentists tooth polishing cream.... for dentures, that is bright green and minty! Works really well, and I guess is safer than Tap Magic?
K2

Steam, I think you described what is happening very well, and it made me do a little digging into all of the useful info that I have forgotten over the years. I looked up the mechanical properties of annealed copper on matweb, and son-of-a-gun, the shear strength (or modulus, I know, I am mixing the labels, sorry) of the copper is greater than the yield strength. And also the elongation is 50%, yikes! Therefore, a slow heavy cut will exceed the yield strength before the shear strength is met. So the part gets mashed first, and gets cut, second. But, as you say, if the speed is turned up and the depth of cut is reduced, the tiny shavings will indeed shear off. The energy that goes into the shearing (and not the mashing) goes up with the square of the speed, and if all that energy can be put into a tiny shaving, it will shear off before the backing material collapses. It is great when there is a real scientific explanation for what we have all observed over the years. At least, I hope my interpretation is somewhat correct.

 

[Steamchick]

Hi Lloyd, you made my day! For you to follow my explanation - and prove me right (for a change?) suggests I am not senile yet! And you have made a clear, scientific explanation of something I was unsure about!
Thanks!
K2

 

[Steamchick]

JFI. I spent an hour or more yesterday drilling and tapping some Phosphor bronze castings with 8BA threads. I stuck the valve block to the cylinder body with Loctite thread lock. Clamped for a couple of days while it thoroughly cured.
Then set in the vice of the mill-drill. Clearance hole drilled to depth in the valve block, followed on the same setting by the tapping drill for depth in the cylinder block. Measured threads to bottom in the known hole depth. Marked the taps and threaded the block easily. Tap wrench is only 3 inches long, very easy to control the tap, using the valve block as a tapping guide. The feel with a very short tap wrench is needed to easily determine bottoming, to avoid breakage. I stop 1 thread short of the calculated bottom.
Enjoy.
K2

 

[el gringo]

Bob shores used to send a tap and die wall chart with each order...I put it on the wall twenty years ago... no broken taps down to 00-90 I slip the tap shank loosly in a ER chuck in the mill and have at it.

Ray M

 

[Brian Rupnow]

Hi Ray---Nice to hear from you.---Brian