ok you old timers

[Chris.L]

Hi I need a little help here I'm designing a trim fixture for our sheet metal Department and I want to make two cuts in one setup? Meaning make a cut at a set angle rotate the tool and make the 2nd cut. So I need to find a pivot point so I can do this, does any one know the formula to accomplish this.

 

 

Thanks Chris

[crazy^millman]

A(squared) + B(squared) = C(squared)

 

Sorry do not know how to show that in UBB code.

 

Basic trig one you have the known distance it is basic trig from there. For the angle calculation you will just need to know the angles and the distances. If any distance is unknown use the Pythagorean Theorem above to figure them out.

 

Basic trig page.

 

You could make it real easy and draw it up in Mastercam.

 

HTH

[Chris.L]

I am drawing it up in mastercam solids. I found a pivot point so I can make both cuts but I had to do it by trial and error. I was hoping someone new the formula so I could just figure it out with out having to moving my pivot point to get the right cuts at both station.

 

Thanks anyway

[Guest]

c² = a² + b²

 

How's that Ron?

 

[BernieT]

Trig almost isn't known anymore, a simple layout in MC will answer just about any trig problem.

 

 

Below, if the red and purple lines are the 1st & 2nd cut - draw a line (green) between the endpoints, the rotation point is the midpoint of the green line.

 

 

[Storkman]

Bernie teh cheater...........

 

I can't say much.I too draw instead of calculate nowadays.

[Chris.L]

Hey Berniet

 

Just tryied what you suggested but it won't work for what I want. I put a mastercam file in cadcam's ftp site it's in mcx mr2 directory and file name is trim fixture.mcx What I'm trying to do is step up a straight angle grinder with a 4 inch saw blade it will be mounted on a plate and use it like a chop saw and it will pivots off one point and be able to cut both cuts at the EOP this one has two pivot point that can make both cuts with only one setup. Take a look to see what i'm tryng to accomplish

 

Thanks Chris

[crazy^millman]

Well from what I can see you just position the saw on one level at the angle you have. Copy all that to another level and then pivot to the desired angle and done. Now to know where the optimum pivot needs to be you need think along the center line of the axis of the tool doing the cutting draw out a line till it meet the same line from the other angle this will give you your specific point. I assume you know you will need to holes one for the pivot and the other for the speific location you are moving to to keep everything accurate. I would probaly use a spring loaded set screw to make it easy to find position without having to pull and put something in an out. If you are trying to keep the center of the spindle in line on both cuts not going to happen the pivot is in the part and would need to be a swing arm set-up to miss the part. Do it from the pivot you got and I think all should be good.

 

I also put what I am talking about on the FTP it is called CRAZY TRIM FIXTURE.MCX I saved it as a MCAMX 1 file in case you do not have X2.

 

HTH

[Chris.L]

Thanks Crazy Millman

 

There has to be a formual for this, that was what i was trying to find.I'm building this fixture and a drill fixture so the part never has to touch a CNC mill just form the extrusion put it in the trim and drill fixtures and the part is done. In the past we have to run it on a 5 axis machine and there were 3 setup which took us a long time to setup because the part is 84 inches long.Was just thinking how did the old timers do it with out computers.

 

Thanks again Chris

[Josh T™]

quote:

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Was just thinking how did the old timers do it with out computers

---

Storky still uses a slide rule

[Müřlıń®]

Just create a line perpendicular to each cut and where they intersect is the pivot point. You will be working on an arc.

 

 

The position you draw your lines from is where the 2 cuts will end up on the saw.

 

There is no need for a formula, as rule of thumb will do just fine...

 

Murlin teh old timers rulz!!!

[Zoober]

quote:

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Trig almost isn't known anymore, ......

---

Tis a sad day indeed in grammerville!

[Müřlıń®]

quote:

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Trig almost isn't known anymore

---

Yup, the days of bisecting obtuse triangles and figuring measurements across rolls for locks is over...

 

They went the way of the Doh Doh about the same time knowledge of cross/slide rotary tables did..

[Hardmill]

quote:

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They went the way of the Doh Doh

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Leave the Stork alone

 

 

PEACE

[Müřlıń®]

fried Doh Doh anyone

[Thee Rickster ™]

Here's my favorite ole timer charts.

For right angles

 

 

rick

[Zoober]

LOL! rickster! I remember that from the "Early Days"

Kinda funny, my daughters have "known" since they were little girls that the "sine of thirty degrees is point five". Used to be a game with us.

Now, I have a 9th grader that is in honors alg 2, looking forward to analytical geo and calc!

[Müřlıń®]

So how did your little orange trig book stay so clean all these years?

 

Mine had greasy finger prints all over it lol....

[within a thou]

SOHCAHTOA ring a bell?

[Thee Rickster ™]

quote:

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SOHCAHTOA ring a bell?

---

yup

 

Mur

I laminated it, I did.

[Nathan G. Baldwin]

c² = a² + b²

 

Spill it, John..

[#Rekd™]

Hi,

 

We use trig everyday, got to use the head for more than a hat rack...

 

soh cah toa (s=opposite/hypotinose) (c=adjacent/hypotinose) (t= opposite/adjacent)

 

 

John

[Guest]

quote:

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Spill it, John..

---

If you have the character map installed press

 

ALT + 0178

 

²

[Müřlıń®]

c/b Tan INV = C

[Guest]

b*TanC = a

 

Þ