Metric thread on an ML7

Post by Dragon
This ought to be simple so I'm probably missing something.
I'm trying to cut a 1.5mm thread on an ML7 with 8TPI lead screw.
I have a 127 tooth gear but no 21 tooth.
Duncan Munro's Ml7 Gear calculator suggests 60 on the spindle and 127 on
the lead screw with various idlers between.
The is not enough space between spindle and lead screw to make that work.
Via a Google search I found a suggestion taken from Martin Cleeve's book
for a compound train using the 38 tooth and 65 tooth gears.
Once again I can't make the train fit the space available.
My memory says that I have cut metric threads in the past but I probably
shouldn't trust that.
What am I missing?
Cheers
Henry

Go here and use "other lathes" and it will give you all the gear changes
for your gear set and tell you the error if any. Also remember you have
to leave the threading handle engaged and use reverse to back it back
out for next cut...
<http://littlemachineshop.com/reference/change_gears.php>
Jim the yank

Dragon

2017-08-16 19:33:07 UTC

Post by Dragon
This ought to be simple so I'm probably missing something.
I'm trying to cut a 1.5mm thread on an ML7 with 8TPI lead screw.
I have a 127 tooth gear but no 21 tooth.
Duncan Munro's Ml7 Gear calculator suggests 60 on the spindle and 127
on the lead screw with various idlers between.
The is not enough space between spindle and lead screw to make that work.
Via a Google search I found a suggestion taken from Martin Cleeve's
book for a compound train using the 38 tooth and 65 tooth gears.
Once again I can't make the train fit the space available.
My memory says that I have cut metric threads in the past but I
probably shouldn't trust that.
What am I missing?
Cheers
Henry

Thanks for the suggestion Jim.
I'd already taken a look at it but have not tried to use it.
Once I make the effort to find the limits of what will fit on the banjo
I'll give it a go.
The Duncan Munro software does a similar job and is specific to the
Myford ML7 so has the facility to use 6 gears as well as 4.
Digging around a bit more I think I have found the answer to the basic
problem.
I either need special gears that will fit on the existing banjo or a
bigger banjo to enable the 127 gear to be used.
I've yet to check but suspect that previously I had cut a metric thread
of less than 1.5mm and that needed a bigger reduction ratio that enabled
the smaller gears to fit on the banjo.

Cheers
Henry

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Jimmy Alpha GeD

2017-08-16 21:14:38 UTC

Post by Dragon
This ought to be simple so I'm probably missing something.
I'm trying to cut a 1.5mm thread on an ML7 with 8TPI lead screw.
I have a 127 tooth gear but no 21 tooth.
Duncan Munro's Ml7 Gear calculator suggests 60 on the spindle and 127
on the lead screw with various idlers between.
The is not enough space between spindle and lead screw to make that work.
Via a Google search I found a suggestion taken from Martin Cleeve's
book for a compound train using the 38 tooth and 65 tooth gears.
Once again I can't make the train fit the space available.
My memory says that I have cut metric threads in the past but I
probably shouldn't trust that.
What am I missing?
Cheers
Henry

Go here and use "other lathes" and it will give you all the gear
changes for your gear set and tell you the error if any. Also remember
you have to leave the threading handle engaged and use reverse to back
it back out for next cut...
<http://littlemachineshop.com/reference/change_gears.php>
Jim the yank

In the LMS program you type in all of the gears you have and leave out
the big 127 gear and see what they give for a solution, type in even
doubles if you have any. Sometimes the error is so small you wont notice
in perhaps .5mm or so?

Jimmy Alpha GeD

2017-08-16 21:33:04 UTC

Post by Dragon
This ought to be simple so I'm probably missing something.
I'm trying to cut a 1.5mm thread on an ML7 with 8TPI lead screw.
I have a 127 tooth gear but no 21 tooth.
Duncan Munro's Ml7 Gear calculator suggests 60 on the spindle and 127
on the lead screw with various idlers between.
The is not enough space between spindle and lead screw to make that work.
Via a Google search I found a suggestion taken from Martin Cleeve's
book for a compound train using the 38 tooth and 65 tooth gears.
Once again I can't make the train fit the space available.
My memory says that I have cut metric threads in the past but I
probably shouldn't trust that.
What am I missing?
Cheers
Henry

Go here and use "other lathes" and it will give you all the gear
changes for your gear set and tell you the error if any. Also remember
you have to leave the threading handle engaged and use reverse to back
it back out for next cut...
<http://littlemachineshop.com/reference/change_gears.php>
Jim the yank

Dragon

2017-08-29 19:50:19 UTC

Post by Dragon
This ought to be simple so I'm probably missing something.
I'm trying to cut a 1.5mm thread on an ML7 with 8TPI lead screw.
I have a 127 tooth gear but no 21 tooth.
Duncan Munro's Ml7 Gear calculator suggests 60 on the spindle and
127 on the lead screw with various idlers between.
The is not enough space between spindle and lead screw to make that work.
Via a Google search I found a suggestion taken from Martin Cleeve's
book for a compound train using the 38 tooth and 65 tooth gears.
Once again I can't make the train fit the space available.
My memory says that I have cut metric threads in the past but I
probably shouldn't trust that.
What am I missing?
Cheers
Henry

Go here and use "other lathes" and it will give you all the gear
changes for your gear set and tell you the error if any. Also
remember you have to leave the threading handle engaged and use
reverse to back it back out for next cut...
<http://littlemachineshop.com/reference/change_gears.php>
Jim the yank

Thanks for the suggestion Jim.
I'd already taken a look at it but have not tried to use it.
Once I make the effort to find the limits of what will fit on the
banjo I'll give it a go.
The Duncan Munro software does a similar job and is specific to the
Myford ML7 so has the facility to use 6 gears as well as 4.
Digging around a bit more I think I have found the answer to the basic
problem.
I either need special gears that will fit on the existing banjo or a
bigger banjo to enable the 127 gear to be used.
I've yet to check but suspect that previously I had cut a metric
thread of less than 1.5mm and that needed a bigger reduction ratio
that enabled the smaller gears to fit on the banjo.
Cheers
Henry

Thanks for encouraging me to give it a go Jim.
I eventually gathered all the information and it did indeed come up with
usable answers for several metric threads which I printed and now have
on hand when needed.

Cheers
Henry

David Billington

2017-08-29 20:33:17 UTC

Post by Dragon
This ought to be simple so I'm probably missing something.
I'm trying to cut a 1.5mm thread on an ML7 with 8TPI lead screw.
I have a 127 tooth gear but no 21 tooth.
Duncan Munro's Ml7 Gear calculator suggests 60 on the spindle and
127 on the lead screw with various idlers between.
The is not enough space between spindle and lead screw to make that work.
Via a Google search I found a suggestion taken from Martin
Cleeve's book for a compound train using the 38 tooth and 65 tooth
gears.
Once again I can't make the train fit the space available.
My memory says that I have cut metric threads in the past but I
probably shouldn't trust that.
What am I missing?
Cheers
Henry

Go here and use "other lathes" and it will give you all the gear
changes for your gear set and tell you the error if any. Also
remember you have to leave the threading handle engaged and use
reverse to back it back out for next cut...
<http://littlemachineshop.com/reference/change_gears.php>
Jim the yank

Thanks for the suggestion Jim.
I'd already taken a look at it but have not tried to use it.
Once I make the effort to find the limits of what will fit on the
banjo I'll give it a go.
The Duncan Munro software does a similar job and is specific to the
Myford ML7 so has the facility to use 6 gears as well as 4.
Digging around a bit more I think I have found the answer to the
basic problem.
I either need special gears that will fit on the existing banjo or a
bigger banjo to enable the 127 gear to be used.
I've yet to check but suspect that previously I had cut a metric
thread of less than 1.5mm and that needed a bigger reduction ratio
that enabled the smaller gears to fit on the banjo.
Cheers
Henry

In the LMS program you type in all of the gears you have and leave
out the big 127 gear and see what they give for a solution, type in
even doubles if you have any. Sometimes the error is so small you
wont notice in perhaps 12mm or so?

Thanks for encouraging me to give it a go Jim.
I eventually gathered all the information and it did indeed come up
with usable answers for several metric threads which I printed and now
have on hand when needed.
Cheers
Henry

My neighbour borrowed a ML7 metric cutting kit from another neighbour
and it was a true conversion with the 127 wheel and IIRC it wouldn't fit
within the standard cover so I doubt HSE would be impressed with the
exposed gears but it did the job and IIRC did use a larger banjo or
extension for it. All subsequent metric cutting has been done on my
Harrison M300 which does both TPI and metric but I think it is pseudo
metric, close enough for most things but not absolutely correct as the
lead screw is inch.

e***@whidbey.com

2017-08-29 23:35:45 UTC

Post by David Billington

Post by Dragon
This ought to be simple so I'm probably missing something.
I'm trying to cut a 1.5mm thread on an ML7 with 8TPI lead screw.
I have a 127 tooth gear but no 21 tooth.
Duncan Munro's Ml7 Gear calculator suggests 60 on the spindle and
127 on the lead screw with various idlers between.
The is not enough space between spindle and lead screw to make that work.
Via a Google search I found a suggestion taken from Martin
Cleeve's book for a compound train using the 38 tooth and 65 tooth
gears.
Once again I can't make the train fit the space available.
My memory says that I have cut metric threads in the past but I
probably shouldn't trust that.
What am I missing?
Cheers
Henry

Go here and use "other lathes" and it will give you all the gear
changes for your gear set and tell you the error if any. Also
remember you have to leave the threading handle engaged and use
reverse to back it back out for next cut...
<http://littlemachineshop.com/reference/change_gears.php>
Jim the yank

Thanks for the suggestion Jim.
I'd already taken a look at it but have not tried to use it.
Once I make the effort to find the limits of what will fit on the
banjo I'll give it a go.
The Duncan Munro software does a similar job and is specific to the
Myford ML7 so has the facility to use 6 gears as well as 4.
Digging around a bit more I think I have found the answer to the
basic problem.
I either need special gears that will fit on the existing banjo or a
bigger banjo to enable the 127 gear to be used.
I've yet to check but suspect that previously I had cut a metric
thread of less than 1.5mm and that needed a bigger reduction ratio
that enabled the smaller gears to fit on the banjo.
Cheers
Henry

In the LMS program you type in all of the gears you have and leave
out the big 127 gear and see what they give for a solution, type in
even doubles if you have any. Sometimes the error is so small you
wont notice in perhaps 12mm or so?

Thanks for encouraging me to give it a go Jim.
I eventually gathered all the information and it did indeed come up
with usable answers for several metric threads which I printed and now
have on hand when needed.
Cheers
Henry

The 127 tooth gear or equivalent should take care of that inch lead
leadscrew. It has on every lathe I have run. Being in the USA metric
leadscrews are not so common. As everywhere else.
Eric

Jimmy Alpha GeD

2017-08-29 23:12:33 UTC

Post by Dragon
This ought to be simple so I'm probably missing something.
I'm trying to cut a 1.5mm thread on an ML7 with 8TPI lead screw.
I have a 127 tooth gear but no 21 tooth.
Duncan Munro's Ml7 Gear calculator suggests 60 on the spindle and
127 on the lead screw with various idlers between.
The is not enough space between spindle and lead screw to make that work.
Via a Google search I found a suggestion taken from Martin Cleeve's
book for a compound train using the 38 tooth and 65 tooth gears.
Once again I can't make the train fit the space available.
My memory says that I have cut metric threads in the past but I
probably shouldn't trust that.
What am I missing?
Cheers
Henry

Go here and use "other lathes" and it will give you all the gear
changes for your gear set and tell you the error if any. Also
remember you have to leave the threading handle engaged and use
reverse to back it back out for next cut...
<http://littlemachineshop.com/reference/change_gears.php>
Jim the yank

Thanks for the suggestion Jim.
I'd already taken a look at it but have not tried to use it.
Once I make the effort to find the limits of what will fit on the
banjo I'll give it a go.
The Duncan Munro software does a similar job and is specific to the
Myford ML7 so has the facility to use 6 gears as well as 4.
Digging around a bit more I think I have found the answer to the
basic problem.
I either need special gears that will fit on the existing banjo or a
bigger banjo to enable the 127 gear to be used.
I've yet to check but suspect that previously I had cut a metric
thread of less than 1.5mm and that needed a bigger reduction ratio
that enabled the smaller gears to fit on the banjo.
Cheers
Henry

>
In the LMS program you type in all of the gears you have and leave out
the big 127 gear and see what they give for a solution, type in even
doubles if you have any. Sometimes the error is so small you wont
notice in perhaps 12mm or so?

thumbs up!

p***@gmail.com

2019-01-06 16:25:44 UTC

The 21 tooth gear is an option you can buy from Myford I found the best solution is to buy one of these.

Dragon

2019-01-06 16:45:52 UTC