Help on a rotary table.

[Hilmar]

Help on a rotary table.

Hi Guys, I need some Help an a rotary table.
The table is 8" in Diameter with 360 ° markings. Perfect!
But the hand dial on the worm has markings of 225 division per turn. Lousy, what gives?
The ratio is 96:1 or 1:96, what ever.
4 turns =15 °
How do You use this Thing ? What to do with this? Who has some Info? Where is " mklotz ala Marv " with the math answers?

Made by : John B. Stevens, New York. In some other Century.
There is a Number 263 hidden under a plate. That's it Folks.

What to do with this? Who has some Info? Where is " mklotz ala Marv " with the math answers?
Hilmar

 

[mklotz]

96:1 so one full turn of the handwheel is 360/96 = 3.75 deg.

Now,

3.75 deg * 60 min/deg = 225 min

so each division on the dial is one arc minute.

 

[Hilmar]

Thanks' Marv for the explanation.
Now what to do with this Rot. Table ? Those Dial and Division makes it lousy to use. "" Bummer.""
It is complicated to dial in any Deg. Angle like 5.5 or 28°40'.
It sure is not easy to work with. Any short cuts?
I wonder what it was made for??
Hilmar

 

[steamer]

A spreadsheet would be what I would do. I believe Marv has a program for this also.

Dave

 

[mklotz]

Thanks' Marv for the explanation.
Now what to do with this Rot. Table ? Those Dial and Division makes it lousy to use. "" Bummer.""
It is complicated to dial in any Deg. Angle like 5.5 or 28°40'.
It sure is not easy to work with. Any short cuts?
I wonder what it was made for??

You need to reduce all your desired angles to arc minutes in order to calculate turns and partial turns. Two examples follow...

5.5 deg = 5 deg 30 min = 330 min

330 min / (225 min/rev) = 1 & 105/225 rev

So, one complete turn of the handwheel and then 105 divisions on the handwheel.

28 deg 40 min = 28*60 + 40 min = 1720 min

1720/225 = 7 & 145/225 rev

Seven complete revolutions and then 145 divisions on the handwheel.

I know Dave is trying to be helpful but I have no programs for doing this. DIVHEAD is for true dividing heads, not rotary tables and ROTARY is for calculating the angular increments for various divisions of the circle.

 

[steamer]

I stand corrected Marv.

A spreadsheet ...for me....would be best here with Marv's calculations as shown for every index position.

Alternatively, you could make up some index plates...but that's a lot of work!

Dave

 

[mklotz]

There are 21600 (360*60) integer minute "index positions" possible, Dave. That's going to be one hell of a big spreadsheet.

Why is it that everyone wants a table/spreadsheet when a simple calculation or formula is so much more compact and memorable? Is math really that hard?

 

[JackBat]

Use the calculations to start your own spreadsheet, write down each time you use one, before you know it you'll either have the calculation memorized or an entire spreadsheet worth. ;D

 

[steamer]

Guys,

How many bolt holes do you put in during the average RT job?....I doubt every arc minute

If you use a simple ADAPTABLE spreadsheet for the job at hand it will only have the entries that you need for that job.

so many degrees and such and such on the dial.....just follow the printed numbers in front of you.

So next time your putting in 13 holes.....you have 13 entries that the spreadsheet can populate for you...if you write it the correct way.

No math problems while turning cranks....just my two cents....do it how ever you like.

Dave

 

[Dan Rowe]

Why is it that everyone wants a table/spreadsheet when a simple calculation or formula is so much more compact and memorable? Is math really that hard?

Marv, math is a tool so is a hammer. Not everone who uses either one is always a master of the proper and most efficient use of the tools mentioned.

I agree that your solution is a more efficient method but we are not talking complex math here. I just heard on NPR that the power requirements of the newest generation super computers is 60 megawatts. Now we have good reason to try and think about calculating efficiency.

There are several members of my family that have advanced scientific/engineering degrees and two of them are PHD's. We were all asked a question by my brother that teaches High School math, "What do I tell them when they ask the question what is all this good for?" None of us had a truly good answer. Can you do better?

Remember that this forum as a rule is more educated in math then the general population.

Dan

 

[steamer]

Hilmar,

I created the spreadsheet for this

It will create the table described for any division up to 100 with any gear ratio rotary table

These two items in YELLOW are the only things you have to change...I already set it to 96 for you.

Just type in the division you would like and stop when the degree column says 360 degrees...your done.

Hope that helps

Dave


Check your email.

 

[Hilmar]

Marv, Dave and all of you Guys, Thank You

I have the solution now. I will take Marv's post laminate it and put it with the table. Then use my calculator, good old HP 11c ,not made any more and off we go.
That table is just as bad as having a 1/16" ( 62.5 division ) lead screw on a Mill. I have no glue what or why it was made for. It came from a precision optical and microscope Co. Now out and gone and halve in China. They should have taken the table also. Ha ha.
This is the second time I posted this. Don't know what happened to the first one.
Like I said Thanks again.
Hilmar
PS
Dave I will save and check yours out also.

Now I can not connect to the Site, Site down??