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On 12 May 2006 20:34:11 GMT, (DoN. Nichols)
wrote:

According to Eric R Snow :
On 12 May 2006 05:23:43 GMT, (DoN. Nichols)
wrote:

[ ... ]

Yep -- re-set the gears. Then you should be fine.

[ ... ]

DoN,
This business with the 120 and 127 tooth gears was what I had posted.

Yes -- I saw your posting *after* I posted my followup.

How the gear, either the 120 or 127, was not being used as an idler. I
guess I should have made it more clear in my first post.

From the chart, it is expected for the 127 tooth to be the one
used as an idler gear.

I tend to post a lot more detail, simply because if someone is
having problems of this nature, the more detail the better the chance
that he can make things work -- and avoid similar problems in the
future.

One thing which I did *not* get around to mentioning is that he
needs to bear in mind that whenever he is cutting metric threads, that
he should leave the half-nuts engaged the whole time, and reverse the
lathe to get to the start for another pass. This is a side-effect of
the threading dial just plain not working with metric threading and an
imperial leadscrew (or for that matter, with imperial threading, and a
metric leadscrew).

I also should mention that this can be a serious pain when
cutting threads to a shoulder, unless the lathe has a quick-acting
clutch to stop the spindle before there is a crash.

Enjoy,
DoN.
Greetings DoN,
My post was aimed at the OP, not you. Once again I fail to make myself
clear. Sometimes when I proofread my stuff I discover all sorts of
things which I have left out, or that make assumptions that a reader
might not. This business with metric threading and threading to a
shoulder has caused me to take a look at installing a dog clutch just
for this purpose. If the spindle only has one gear on it that engages
the the threading gear system then if that gear is driven by a dog
that can only engage at the same point in rotation then any thread can
be cut without fear of losing position.
ERS