Any Mathmatitions on line (lathe change wheels)
#1
Hi
I have borrowed a 63 tooth change wheel to use as a conversion (metric to imperial)
This works very well
I want to make my own but can only get 64 teeth with my deviding head
As the 63 is half of a 127 (should be 63 1/2 )
How much difference would a 64 make
John
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#2
Hi John,

Give the attached program a try - it worked for me with the change gears that I had.  Click the "Modify list of gears" button and edit the values to match the change gears that you have and then click "End modification".  Next enter your leadscrew pitch and the pitch of the thread that you wish to cut.  Then click "Calculate" and you should get a list of various gear combinations and the amount of error between the actual pitch it will cut and the pitch you specified.  

The only problem with the program is that it doesn't retain the change gears that you enter, so it would pay to sit down with a beer and plug in all the metric threads that you are likely yo want to cut and then write down the necessary combinations.  

I cannot recall where I found this but when I tried to contact the programmer, I received no response.


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#3
(08-30-2015, 04:25 AM)doubleboost Wrote: Hi
I have borrowed a 63 tooth change wheel to use as a conversion (metric to imperial)
This works very well
I want to make my own but can only get 64 teeth with my deviding head
As the 63 is half of a 127 (should be 63 1/2 )
How much difference would a 64 make
John
Hi John,
I'm not a Mathematician but I know my 2 times table - does that count Big Grin
A 63 or 64 will not make a blind bit of difference to threads that are used for holding and the holding part of the thread is short (say less than 12mm) ie the nut is 12mm long.
It wouldn't make a very accurate lead screw - in the region of about 1% error.
Smiley-eatdrink004
DaveH
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#4
Can an arbor be rigged up to use the borrowed 63 out the back of the head? Worm disconnected, shop made index pin, ...
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#5
Sounds like a good video project for the Sparey Dividing Head you made. You didn't give it away, did you? Make a mandrel to fit it and copy the gear. Maybe make a 63 and 64 tooth gears, use them to make a few imperial threads and evaluate the differences.

Chuck
Micromark 7x14 Lathe, X2 Mill , old Green 4x6 bandsaw
The difficult takes me a while, the impossible takes a little longer.
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#6
John,

If you let me know what the worm ratio is on your dividing head and what the hole counts are on the indexing plates you have available we can probably come up with something that will allow you to make a 63 tooth gear. Maybe not a "perfect" gear but a "pretty damn close" one.

Arvid
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#7
Why don't you make a new dividing plate with the correct number of holes?

Most DROs (except mine, of course) have a bolt circle function. Lacking that, look for a bolt circle calculator on the web - that's how I've been doing bolt circles.

Easy but repetitive work on a mill.
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