Metric lead screw

grannyknot

Aluminum

Joined

Oct 18, 2015

• Nov 16, 2015

• #1

A metric lead screw came with my SB 9C, It doesn't fit my lathe but I was hopping someone here could tell me any thing about it.
It is 35" long total, 26" is the thread length, .875" dia.
or 22mm.I can't see any wear on the threads, in fact they are so sharp I doubt it has ever been mounted.
It does have a tag on it.
Thanks,
Chris

 

I

iwananew10K

Diamond

Joined

Sep 12, 2010

Location

moscow,ohio

• Nov 16, 2015

• #2

Are you sure it metric?

The SB 11" lathes used a 7/8" lead screw,and that tag looks pretty old.
You may have a NOS one for an 11"

 

thomasutley

Hot Rolled

Joined

Sep 10, 2014

Location

Oro Valley

• Nov 16, 2015

• #3

Seems like a metric thread screw would require metric thread halfnuts, too.

 

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kitno455

Titanium

Joined

Jul 9, 2010

Location

Virginia, USA

• Nov 16, 2015

• #4

What is the thread pitch?

allan

 

grannyknot

Aluminum

Joined

Oct 18, 2015

• Nov 16, 2015

• #5

The PO told me it is metric and the tag says MM on it, that's all I know.

I can never remember if thread pitch is TPI or the angle of the thread,
the threads per inch is exactly seven.

 

K

Ken-Bergen

Cast Iron

Joined

Jun 7, 2012

Location

Chilliwack BC Canada

• Nov 16, 2015

• #6

As near as I can tell from your picture the thread is a little under 6.5 TPI, the left side of the next thread would be 7 TPI.

That would make the metric pitch about 3.9mm which makes no sense to me.

 

I

iwananew10K

Diamond

Joined

Sep 12, 2010

Location

moscow,ohio

• Nov 16, 2015

• #7

4mm pitch? Set your caliper at 2cm and see if you count 5 threads

 

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Ken-Bergen

Cast Iron

Joined

Jun 7, 2012

Location

Chilliwack BC Canada

• Nov 16, 2015

• #8

What iwananew10K said remembering that pitch is measured from some point on one thread to the same point on the next thread.

 

johnoder

Diamond

Joined

Jul 16, 2004

Location

Houston, TX USA

• Nov 16, 2015

• #9

Ken-Bergen said:

What iwananew10K said remembering that pitch is measured from some point on one thread to the same point on the next thread.

Click to expand...

And when you do that, you'll need to move the movable jaw a bit to the left and 4mm times six is .944"

 

grannyknot

Aluminum

Joined

Oct 18, 2015

• Nov 16, 2015

• #10

At 2cm it looks like 5 threads,

 

akitene

Plastic

Joined

Jul 2, 2008

Location

France - Bordeaux

• Nov 22, 2015

• #11

Good evening,

I own a metric SB9A. Its leadscrew is 19 mm in diameter (almost 3/4") and its pitch is 3 mm (wich is the nearest even metric unit matching the imperial 1/8").

Hope this helps.