Faking A Trapezoidal Left Hand 16 X 2 Nut

[rgsparber]

How do you take a 5/8-13 left hand nut and turn it into a good enough trapezoidal 16 X 2 metric nut? Hint: take some away...

If you are interested, please see

http://rick.sparber.org/FTLH.pdf


Your comments are welcome. All of us are smarter than any one of us.


Thanks,

Rick

[Frank S]

5/8 11, and 5/8 18 are common as dirt 5/8 24 not so much but a 5/8 13 TPI I can't say that I have run across one of those animals yet.
of course any thread pitch can be made by single point but if that were the case why not just single point a 2mm thread pitch unless your lathe is like mine and will not do most metric threads

[rgsparber]

I have to admit that I didn't measure the nut, just used my thread gages on the rod. Nothing but 13 TPI came even close so I assumed that was why the nut almost fit. I've done my share of single pointing but it has all been SAE. I do have the gears to convert my lathe to metric but have never done it. In order to single point a nut, I would have also had to grind the proper profile for a boring bar. It was far quicker just to bore out half of the threads.

The nut came from Lenart's Ace Hardware in Mesa, Arizona. It is one of those very rare old time stores with many extremely knowledgeable staff plus a "parts room" with such odd ball fasteners as large left handed nuts. Wonderful place!

[Frank S]

Rick I wasn't calling you out on it I just hadn't heard of one but on the same token IO do know that there are some propitiatory hardware out there especially when it comes to left hand threads Did the threads check out to be 60° or 55° because that might possibly explain something else about the nut.
I often miss the 600/3500 Asian lathe I used to have while in Kuwait with its 110 mm spindle bore. That thing could cut metric or imperial with a simple movement of 1 leaver no swapping out a 102 for a 127 like I had to do on my Victor. I only wish that I had the proper gears to be able to do metric on any of my Leblonds

[LMMasterMariner]

Hello Rgsparber,

As I can see you are talking about acme threads and in order to find out which thread you have,
you will need acme screw thread gages. In order to grind threading tool you will need acme thread grinding gauge,
not 55 or 60 degrees thread gages. Attached is picture of my gages.
Good luck / Best regards
LMMM

[rgsparber]

LMMM,

I have such gages for SAE but no metric. If I had to duplicate the thread, I would have used the threaded rod and put in some clearance. Then I would have either ground a cutter for a small boring bar or made a tap (http://rick.sparber.org/gt.pdf). I didn't pay close attention, but it does appear that what is called Acme in SAE is trapezoidal in Metric. Is that right?

Rick

[rgsparber]

Frank,

I didn't think you were calling me out, just suggesting an alternate approach. I was hesitant to mention the ID of the nut because it was just a guess. If it was an 1/2-13 it would make more sense. That just didn't square with the 16 mm which is also a standard.

Rick

[LMMasterMariner]

Hi Rick,

Both threads are trapezoidal (not square) threads and the main difference is the angle. 29 degrees for SAE and 30 degrees for metric.
SAE thread is called ACME and metric is called Trapezoidal even recently both of them are called acme threads.
Check here: Acme screw pitch gauges metric - Duchy Fasteners
They call these gages: Acme screw pitch gauges metric and Acme screw pitch gauges imperial
On my gages is written: 29 ACME SCREW PITCH GAGE and 30 ACME SCREW PITCH GAGE.
I needed them to find out thread of my lathe lead screw and found that my lathe is
full metric with 20 mm dia x 2mm trapezoidal thread lead screw, not 3/4" x 12 TPI as I was
thinking before.
Hope this helped.
Regards
LMMM

[Frank S]

Yes trapezoidal would be counter part name in metric for acme since Imperial uses names instead of description
I admit I missed the word trapezoid in rick's original post the 13 TPI was what hit me in the head. that and the 16 mm dia x 2 mm pitch
I am now thinking what he found might have been a nut for a worm screw in which case the worm would have had a pitch to match the corresponding gear
since it would be impossible to use a 1 or 3 wire method to determine the exact internal thread of a nut I guess the use of a ball would have worked, however the point of your post is you were able to help a friend out without having to expend more energy and time than the task was worth.

[DIYer]

Thanks Rick! We've added your Lock Nut Modification for a Metric Thread to our Fastening category, as well as to your builder page: Rick's Homemade Tools. Your receipt:

Lock Nut Modification for a Metric Thread by Rick Sparber

tags: threading, locking