Woodruff key sizes

[OccupantRJ]

In my machinery resto-mods I often need various hardware such as a key that the country boys call a “half moon key”, or properly, a woodruff key. I have used quite a few over the years, but at work had an assortment on hand to choose from. Now that I have retired, this was no longer the case.

While looking at the parts drawings on a Clausing 5914 metal lathe, I noticed that some of the keys on the drawings were numbered with a 3 digit number, but some were numbered with a single digit such as a #3.

When I went to the hardware store yesterday to get a 404 key, which is 4/32 (1/8”) inch wide and 4/8” long (1/2”), I saw no indication of the # numbering system. This got me curious, so I did a bit of research and found that McMaster Carr uses both numbering systems in their catalog to denote a particular key. The #3 key turns out to be the same as a 404.

No idea why the dual numbering system unless it is a holdover from earlier years. I posted this to maybe help someone who runs into an issue trying to identify the proper key for an application they might encounter.

 

[2oolhound]

How about Step Keys? Anyone encounter them?

Step keys are formed when a wrench gets tossed in the works and everything comes to a grinding halt abruptly. The force pushes the top of the key over creating a "step" in the profile where the top is shifted over sideways from the bottom. Guff-ah guff-ah har har har.

Actually step keys are used with timing gears and camshafts to change the timing on valves or ignition in engines. I once had a camshaft that the key way was cut so far off that you could not properly time the engine. A step key or an adjustable vernier timing gear can correct this .

 

[OccupantRJ]

That would be an offset key. A step key is fit to the shaft keyway if the keyway is in good shape. The upper part of the key is custom made to be wider. The worn keyway in the pulley is broached to a wider size as a repair. A custom key is made. An end view of the key would be a T shape. I have used this method quite often in my trade to make a solid repair where a pulley has a wallowed keyway.

 

[PFSard]

In my machinery resto-mods I often need various hardware such as a key that the country boys call a “half moon key”, or properly, a woodruff key. I have used quite a few over the years, but at work had an assortment on hand to choose from. Now that I have retired, this was no longer the case.

I had no clue. I always used your pre-retirement method. Here's a link for a chart to Key Sizes :

ANSI Standard Woodruff Keys ANSI B17.2-1967 (R1998)
https://www.engineersedge.com/woodruff_keys.htm

 

[Bellaireroad]

In my machinery resto-mods I often need various hardware such as a key that the country boys call a “half moon key”, or properly, a woodruff key. I have used quite a few over the years, but at work had an assortment on hand to choose from. Now that I have retired, this was no longer the case.

While looking at the parts drawings on a Clausing 5914 metal lathe, I noticed that some of the keys on the drawings were numbered with a 3 digit number, but some were numbered with a single digit such as a #3.

When I went to the hardware store yesterday to get a 404 key, which is 4/32 (1/8”) inch wide and 4/8” long (1/2”), I saw no indication of the # numbering system. This got me curious, so I did a bit of research and found that McMaster Carr uses both numbering systems in their catalog to denote a particular key. The #3 key turns out to be the same as a 404.

No idea why the dual numbering system unless it is a holdover from earlier years. I posted this to maybe help someone who runs into an issue trying to identify the proper key for an application they might encounter.

Wondering about this the other day. Rebuilding a old delta bandsaw and it uses the # system for the woodruff keys. I was not able to find a conversion table, so I'll check McMaster Carr, thanks


Sent from my iPad using Tapatalk Pro

 

[OccupantRJ]

Here is the link to the McMaster Carr chart. It gives a cross reference for the # designation against the 3 digit designation.

https://www.mcmaster.com/#woodruff-keys/=1dny2xq

 

[2oolhound]

That would be an offset key. A step key is fit to the shaft keyway if the keyway is in good shape. The upper part of the key is custom made to be wider. The worn keyway in the pulley is broached to a wider size as a repair. A custom key is made. An end view of the key would be a T shape. I have used this method quite often in my trade to make a solid repair where a pulley has a wallowed keyway.

Thanks for the correction, I've always thought off set keys were step keys.