Left hand threads.

[The African]

Hi all. I need to make a new spindle shaft for my Clarkson Grinder and I notice that it has left hand threads on both ends of the shaft. What is the reason for using left hand threads? I see that none of my bench grinders have left hand threads and their direction of rotation is the same as the Clarkson. Any info would be much appreciated.
Thanks.

 

[guest]

Left hand thread so it doesn't loosen under torque. Should be left hand on left side and right hand on right side.

 

[Gordon B. Clarke]

Hi all. I need to make a new spindle shaft for my Clarkson Grinder and I notice that it has left hand threads on both ends of the shaft. What is the reason for using left hand threads? I see that none of my bench grinders have left hand threads and their direction of rotation is the same as the Clarkson. Any info would be much appreciated.
Thanks.

As jancolic points out then whether a thread is right or left handed depends on the risk of loosening off during rotation from the resulting torque.

Bicycle pedals is a good example. One is RH and the other LH.

 

[winger]

My first car,a 66 plymouth had left and right lug nuts. Since the studs did not rotate it made no sense to me. At 16, it sure screwed me up the first time I tried changing wheels. I thought I knew which way to turn a nut.

Dave

 

[Gordon B. Clarke]

My first car,a 66 plymouth had left and right lug nuts. Since the studs did not rotate it made no sense to me. At 16, it sure screwed me up the first time I tried changing wheels. I thought I knew which way to turn a nut.

Dave

Almost all LH nuts are marked but you have to know what to look for.

https://www.metricmcc.com/catalog/Ch10/10-1022.pdf

 

[Illinoyance]

The grinder should have right hand threads on one end of the shaft and left hand on the other. Otherwise one wheel will tend to work loose.

 

[Danny VanVoorn]

The grinder should have right hand threads on one end of the shaft and left hand on the other. Otherwise one wheel will tend to work loose.

If the wheels have an adapter with a key the maker could do what ever they want. I don't know a thing about that particular grinder but I have a grinder that can reverse direction, don't have to worry about it because of the taper shaft and key! Maybe made so the nut pulls the adapter off a taper seat, maybe they wanted to be able to use a wheel on either end without changing adapters. Not enough information to know why that grinder is made as described.
Dan