Metric tapping

[Chris Rizzo]

Howdy y'all...

I'm trying to tap some m5 x .8 holes in a part that is in an english config file. What's the trick? Hopefully there is one! I vaguely remember a topic a while back about english to metric conversions, but I can't seem to track it down.. Thanks again for the great wealth of knowledge everyone!

[pip]

To calculate the pitch (0.8) back to imperial divide by 2.54.

 

0.8/2.54=0.315" to the nearest 3 decimal places.

 

Hope that helps

[chris m]

Its actually .8/25.4 = .0315", but what's a decimal place?

 

[ 02-24-2003, 07:08 AM: Message edited by: chris m ]

[McRae]

quote:

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Its actually .8/25.4 = .0315", but what's a decimal place?

---

About 4 broken taps and one scrap part...

[ROB]

try this.

 

http://www.emastercam.com/ubb/ultimatebb.p...t=002749#000000

[Surface]

Is it acually the pitch or the threads-per-inch that you are looking for? The equivalent TPI is 31.7

[kccadcam]

Yes that's correct, 1/thread pitch for correct feed rate 31.7460 ipm. If your using rigid tapping, the post will convert it back to ipr.

[Jack Mitchell]

.03937 is ingrained permanently.

 

The other permanent ingrain is .0183”

Or perhaps double, it all depends on where you hail.

 

So what am I talking about here?

 

Club 75 - Give it a shot.

The older gents - chime in please.

 

There will be a prize for the first correct response.

 

Regards, Jack

 

[ 02-25-2003, 11:06 PM: Message edited by: Jack Mitchell ]

[pip]

0.0315, sorry. I stand corrected.

[Jack Mitchell]

pip,

 

Scratch one, not even close.

 

Anybody else?

 

PeterE?

Scott Bond????

 

come on guys, this should not be difficult.

 

Regards, Jack

[pip]

As for the first number, that is the dividing factor to convert imperial to metric (0.3937007874015748031496062992126), if we are going to be really picky

The last number I am not sure , it has been some 10 years since I last had to use the imperial system. Do I get just a little prize for that.

 

[ 02-27-2003, 04:03 AM: Message edited by: pip ]

[chris m]

Jack

 

.0183" is the nose radius compensation value for turning a 45 degree angle with a .0312" nose radius insert.

 

I don't know if that is what you were looking for, but it is true nonetheless...

 

C

 

[ 02-27-2003, 07:26 AM: Message edited by: chris m ]

[Scott Bond]

Let's play Jackprody

 

Conversion's for 100 :::Jack

 

.0366 would be my blood-alcohol in 1985?

[Jack Mitchell]

pip,

 

Nice try but ChrisM has nailed it down.

 

Actually toolnose radius compensation precludes Mastercam, CadCam, computers, and even the 4004 processor that Intel developed for Busicom of Japan.

 

You win this riddle Chris; please email me your address for the prize.

 

How do you know this? and how is it that you managed to beat out some of the older heavyweights of the forum?

 

Manual part programming and trigonomety is what fascinated me in the first place - Chris, I am impressed so please go gently with Spock and do not take offense in the next episode.

 

Scott, I just know you were out there but you missed by about seven hours, sorry big guy.

 

Regards, Jack

 

[ 02-27-2003, 04:13 PM: Message edited by: Jack Mitchell ]

[McRae]

Jack,

 

There can be only a few who would remember that one - Most of the guys here are surface machining. I learned from an old guy like you and you have just endeared yourself even more. Chris - I echo Jack's statement, to know the old trivia is a true advantage.

 

Hey webby - put this one in the tips and tricks page!

[pip]

But I'm a miller not a turner. Competition was bias, and so is counted as void.

[Scott Bond]

I,am honored to be called out by name.

 

When we window points/(done) and let Mastercam pick the order of the points on it's own-----how does it decide which is the first point and so on?

[Jack Mitchell]

pip,

 

It's not all sour grapes since I am truly both a miller and a turner.

 

Please tell me that you have never clamped an OD turning tool in a vice and programmed the machining center as if it was a cnc lathe.

 

These are considered tricks of the trade, therefore I do not believe you can call foul - Chris has earned the prize none-the-less.

 

Sorry, but I am glad that you forum members have found this interesting anyways.

 

True, I sort of put the question as a riddle. Also true is that if you have programmed a machine tool built in 1965 then you would know what I was talking about.

 

Does anybody else recall F80000 as a rapid ?

How about G01 X100000 for ten inches?

I believe this to be a dying art for the older generation. - I just love toying with the kids!

 

Regards, Jack

 

[ 02-27-2003, 06:39 PM: Message edited by: Jack Mitchell ]

[Tony]

Here is one an old Diemaker in the late 70's gave me _=(1.4142R)-R

Hint:

I use this formula before heat treat.

[chris m]

Alright, lets work together on this one; 1.414 is the multiplier for the hypotenuse of a 45...

 

 

quote:

---

How do you know this? and how is it that you managed to beat out some of the older heavyweights of the forum?

---

I know this because I don't use TNR comp in my lathes; it is more of a pain in the a** than its worth! Much of our lathe programming is still done the old fashioned way; its quicker to program simple turning with pad-and-paper and a calculator than any other method.

 

quote:

---

Manual part programming and trigonomety is what fascinated me in the first place

---

Now that we have 3 seats (yahoo!) of Mastercam, we are programming more and more turning using the software but its always good to have those trig and manual programming skills fresh for the quick jobs.

 

Thanks for the brain-teaser Jack

 

C

 

[ 02-27-2003, 06:15 PM: Message edited by: chris m ]

[Andy]

Tony

 

1.414 is the secant or cosecant of 45deg.

I think your formula gives the distance from the radius to the 90deg corner formed by 2 intersecting lines tangent to the arc and whose intersection is 90deg.

OR, more graphically, take a square hole, insert a round shaft (tight) and the air space left in the corner is that distance (measured along a line through the center and to one corner of the square.

Close?

 

[ 02-27-2003, 06:22 PM: Message edited by: Andy ]

[Jack Mitchell]

.7071 rings a closer bell for me; why is that?

 

Truth be known - I only use tangent and sine; throw way the other four functions for I will never ever use these.

 

Chris - you disappoint me at times and yet you come through in a pinch as well.; Are you older than I perhaps? or are you grievancing programming as a whole?

 

On my dying lips will be .0183"

 

Regards, Jack

 

[ 02-27-2003, 06:32 PM: Message edited by: Jack Mitchell ]

[Surface]

I think 1.414 (root 2) is the ratio of the hypotenuse of a 45-degree triangle.

Similarly the ratio of the sides of 30-degree triangle is 1, 2, root 3.

Has anyone used this old technique for cutting a radius with a fly cutter?

Sin (tilt-head angle)=cutter_radius / desired_radius

[Scott Bond]

Yes,I had a 14" fly-cutter that had a bell shape so I could cut the female side of the mold, and then without moving the head I could cut the male side, and it would fit under or inside the fly-cutter.

Thanks surface,,,I didn't even want to bring this kind of manual stuff up.I made impellar's from milar ,template stock, wood patterns, cast the pattern, and traced them with a deckle panagraph to cut Wax investment molds.

 

Hey club 75 what does counter clockwise mean?

 

[ 02-27-2003, 07:00 PM: Message edited by: Scott Bond ]

[MACHINEMASTERG]

quote:

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what does counter clockwise mean?

 

---

isnt that when your having a slow day at work?????the clock seems like its not even moving

 

[ 02-27-2003, 07:12 PM: Message edited by: MACHINEMASTERG ]