Jet 1442
 

A couple of months ago I made, what for me was, a big step and bought a Jet
1442 lathe. Love it. However, I do have a question.

When I lock the headstock with the indexing pin, how do I turn the spindle
45 degrees. I know the spindle is indexed every 30 degrees and the holes
in the housing are 20 degrees apart (yeah, I read the book). What
combination of the two gives a movement of 45 degrees?

I have an eight spoke spinning wheel I am building for my elder daughter
(The things we do for our kids.) and need to index the wheel in 45 degree
increments.

Thanks

Deb

When I lock the headstock with the indexing pin, how do I turn the spindle
45 degrees. I know the spindle is indexed every 30 degrees and the holes
in the housing are 20 degrees apart (yeah, I read the book). What
combination of the two gives a movement of 45 degrees?

I have an eight spoke spinning wheel I am building for my elder daughter
(The things we do for our kids.) and need to index the wheel in 45 degree
increments.


Bad new Deb, you can't. The 1442 (I also recently acquired one) does
10-degree increments. 36 (360 degrees/10) does not divide by 8. You have the
choices of 2,4,6,9,10,12, and 18

Can you alter your design for 9-spokes?

-Steve

There are several ways of doing this that I can think of.

Assuming that you are drilling into a hub for the spokes and it is held
on a faceplate or in a chuck...

Do the holes at 0, 90, 180 and 270 degrees.

Then, mark the work half way between two holes and use the tool rest or
something as a reference point. Unscrew the faceplate or chuck slightly
and shim between it and the spindle bedding surface so that you are now
on your reference mark. You can do this either by cut and try or math.

You know the number of turns per inch of the thread and you know that
you want to offset 1/8 of a turn so choose the thickness of the shim
accordingly. With a 8 tpi spindle, if you unscrewed one full turn (360
degrees) you'd need a shim of 1/8" or .125". You want to go 1/8 of
that or .0156...". That should get you real close.

Anyway, now you can do the other 4 holes.

Bill

Stephen M wrote:
When I lock the headstock with the indexing pin, how do I turn the spindle
45 degrees. I know the spindle is indexed every 30 degrees and the holes
in the housing are 20 degrees apart (yeah, I read the book). What
combination of the two gives a movement of 45 degrees?

I have an eight spoke spinning wheel I am building for my elder daughter
(The things we do for our kids.) and need to index the wheel in 45 degree
increments.



Bad new Deb, you can't. The 1442 (I also recently acquired one) does
10-degree increments. 36 (360 degrees/10) does not divide by 8. You have the
choices of 2,4,6,9,10,12, and 18

Can you alter your design for 9-spokes?

-Steve

What I forgot to say...

You sometimes wonder what the engineers are thinking about when they
design a tool for us to use. Didn't they even think about asking some
of us for input? Doesn't it seem obvious that the most useful increment
for dividing is 15 degrees?

I've talked to the designer of a lathe which will remain nameless. He
pretty much designed it in a vacuum and admitted that he "turned a little".

I could go on and on about some of the stupid design decisions in some
of the lathes I've used but I'd bore you all to death.

Bill

Bill Rubenstein wrote:
There are several ways of doing this that I can think of.

Assuming that you are drilling into a hub for the spokes and it is held
on a faceplate or in a chuck...

Do the holes at 0, 90, 180 and 270 degrees.

Then, mark the work half way between two holes and use the tool rest or
something as a reference point. Unscrew the faceplate or chuck slightly
and shim between it and the spindle bedding surface so that you are now
on your reference mark. You can do this either by cut and try or math.

You know the number of turns per inch of the thread and you know that
you want to offset 1/8 of a turn so choose the thickness of the shim
accordingly. With a 8 tpi spindle, if you unscrewed one full turn (360
degrees) you'd need a shim of 1/8" or .125". You want to go 1/8 of
that or .0156...". That should get you real close.

Anyway, now you can do the other 4 holes.

Bill

Stephen M wrote:

When I lock the headstock with the indexing pin, how do I turn the
spindle
45 degrees. I know the spindle is indexed every 30 degrees and the
holes
in the housing are 20 degrees apart (yeah, I read the book). What
combination of the two gives a movement of 45 degrees?

I have an eight spoke spinning wheel I am building for my elder daughter
(The things we do for our kids.) and need to index the wheel in 45
degree
increments.



Bad new Deb, you can't. The 1442 (I also recently acquired one) does
10-degree increments. 36 (360 degrees/10) does not divide by 8. You
have the
choices of 2,4,6,9,10,12, and 18

Can you alter your design for 9-spokes?

-Steve