Multiple lead thread

[FROZEN]

I have a few questions on multiple lead threads. First a 1/2-13 with 2 leads, does it move more then .076 per turn? Is it a stronger thread? I was told multiple leads are just fast for getting a cap on a bottle, that is where it is most used.

[K2csq7]

I have only limited experience with multi-lead threads, but I don't think 1/2-13 would work.... the threads would cross each other, I think you would need to make them 1/2-6.5. Not sure....

You are correct about multiple leads being faster... but only if the pitch is smaller, that is what makes them faster...

[Machineguy]

On multiple lead threads:

1/2-13 for a 2 start will move .1538 per rev.

Also you will go foer a 2 start 1/2 the depth, for a 3 start 1/3 the depth.

That one reason you only see them on bigger threads.

 

Watch out on the thread tables in lathe.I found some that are wrong, BIG time on the minor Diameter. Use the Machinerys Handbook instead.

A 1.75-5 is way off.

You can edit the tables, if you have time.

 

Machineguy

[FROZEN]

Are they stronger? I'm making a fixture, so I can make modified thread with one lead. I was thinking 1/2-8, it needs to move .250 or less so 2 turns.

[Aaron Eberhard]

Watch out on the thread tables in lathe.I found some that are wrong, BIG time on the minor Diameter. Use the Machinerys Handbook instead.

A 1.75-5 is way off.

You can edit the tables, if you have time.

 

Hey Machineguy - Did you report these to [email protected] or to your reseller? We'd like to address these things as they're found..

 

Thanks!

[crazy^millman]

Funny people think the smaller number of threads the stronger when the exact opposite is the case. A 1/2-20 thread has more holding power than a 1/2-13 thread does.

 

 

On multiple lead threads:

1/2-13 for a 2 start will move .1538 per rev.

Also you will go foer a 2 start 1/2 the depth, for a 3 start 1/3 the depth.

That one reason you only see them on bigger threads.

 

Watch out on the thread tables in lathe.I found some that are wrong, BIG time on the minor Diameter. Use the Machinerys Handbook instead.

A 1.75-5 is way off.

You can edit the tables, if you have time.

 

Machineguy

 

 

Could not have said it any better.

[FROZEN]

I'm looking for speed in movement and strength.

[Machineguy]

Thread will be strong, but won't lock down like a single pitch thread can.

 

Aaron, I asked my reseller (Scott) to look at it. That's Shopware, Inc

 

machineguy

[rocheey1]

I've always been under the impression that fine threads are stronger (larger minor dia) and better with vibration.

[crazy^millman]

Here is a site to look it up.

 

http://www.derose.net/steve/resources/engtables/bolts.html