Being Lefty (using left hand as main)

[JKJ]

Sigh. I was talking about choosing 13mm nuts vs 14mm nuts. Of course you then use the appropriate spanner. And by convention 14mm nuts are used with left-handed threads. Only someone clueless or mischievous will employ righthand-threaded 14mm nuts.

I see now what you intended but I was also confused at first reading I have a variety of equipment with exclusively metric fasteners, from wood and metal working machines to farm and construction equipment to road and off-road vehicles.

I don’t know about the convention where you live but I can assure you that many right-handed threaded nuts and bolts I deal with are 14mm. For example, most M10x1.25 fasteners I’ve encountered are 14mm. When I work on something I often need both 13 and 14mm wrenches/sockets. (just a few weeks ago I had to carry both sizes to my little machine shop to enable installation of a DRO on my metal lathe. Based on this and working on other equipment I can’t imagine the left/right “convention” you mention being universal.

It is rare to find a left-hand threaded fastener on the equipment and machines I have here - haven’t encountered one in decades. Maybe the hex head size convention is regional. Germany? Europe? Not on anything I’ve see from Japan, etc.

JKJ

 

[dak]

It is rare to find a left-hand threaded fastener on the equipment and machines I have here - haven’t encountered one in decades. Maybe the hex head size convention is regional. Germany? Europe? Not on anything I’ve see from Japan, etc.

Pretty common on circular table saws. The threading orientation for the screw holding the blade will depend on the placement of the motor.

 

[JKJ]

Pretty common on circular table saws. The threading orientation for the screw holding the blade will depend on the placement of the motor.

To expand on that, in case anyone is interested...
My table saw is a PM2000, left-tilt. In general, to loosen an arbor nut, turn the nut in the direction of the powered blade rotation. If the motor is on the left from the operator’s position, the powered blade rotation will be counter-clockwise (as viewed from the right, the side with the arbor nut) and the nut will have a right-hand thread. The nut is tightened clockwise with the wrench and loosened counter-clockwise. Righty-tighty, lefty-loosey.

Some saws, e.g. right-tilt, have the motor on the right and the blade turns clockwise (as viewed from the side with the arbor nut) and use left-hand threads. When trying to loosen the arbor nut it’s useful to be sure of the handedness before inadvertently applying force in the wrong direction! A question sometimes seen on woodworking forums is “why can’t I loosen the nut to change the blade”

BTW, there is controversy over the safety of left-tilt vs right-tilt saws.

Concerning thread direction conventions in general, this may be interesting to some:

Right Handed Vs. Left Handed Threads - Dependable Acme Threaded Products Inc

What are the differences between right hand and left handed threads? Which thread will work best for your needs? Dependable ACME Threaded Products discusses that and more in their new blog post.

www.dependableacme.com

And for the true mechanical geek, this Wikipedia article is a good read:

Screw thread - Wikipedia

en.wikipedia.org

And now to really go off on a tangent and way off the subject of accordions - I like to make lidded wooden boxes on the lathe. Most turned boxes have normal, unthreaded lids. Not as common, perhaps because they are harder to make, are wooden objects with threads. (In some situations threads in wood can't even be cut cleanly or don't hold up well). Some are cut by hand; some with a jig. Here are some ebony boxes with threaded lids, and a threaded gavel head and handle (guaranteed not to come with vigorous use!. Left-handed threads are theoretically possible in woodturning but I've never seen or heard of anyone using them.




I thread these with a special tap and die.

JKJ