# Scott Logan Talks About Bearings



## Shiseiji (Jan 5, 2021)

On another board I posted a link to AST Bearings and what I thought was an interesting description of "pre-load".  Never dreamed I'd open a huge can of worms with the result being Scott Logan weighing in on the infamous bearings question. 

IMHO, yes opinion take it for what you think it's worth, there is and always will be a difference in terms between the vernacular and what you will find in industry/profession accepted descriptions. Both are the result of people trying to communicate. The AST site is a clear example as they use the vernacular term "pre-load." The *last* thing I want to do is set off a huge debate over terminology. Please consider this a mixture of vernacular and professional engineering terms and information.

Engineers will tell us that there are no such thing as a "pre-loaded" bearing regardless of what Logan states in the 10" manuals. There are "standard clearance, tight clearance, and negative clearance bearing. Also there is no such thing as a "sealed" bearing, only shielded on one or both sides. 

OK, got it. Obviously there is vernacular in the Logan documents regarding "pre-load" vs. tight clearance and "sealed" vs. shielded. 

Now that there is some background.
Unless a moderator posts that pasting in the text is acceptable, the complete posting by Scott Logan is here. 

Ron


----------



## Nogoingback (Jan 6, 2021)

Bearings can be preloaded with belleville washers however:









						Bearing PreLoad Disc Springs: Plain Type from Belleville Springs
					

Plain type bearing preloaded disc springs. 65 sizes in stock from 9.8mm up to 358mm outside diameter. Belleville Springs




					www.bellevillesprings.com


----------



## RandyM (Jan 6, 2021)

Ron,

Your link requires that we need to be a member and to log in. Unfortunately we do not have access to the information.


----------



## duffman1278 (Jan 7, 2021)

Took me a little bit to get to the message. For anyone that can't see the message linked you need to join goups.io first then you need to click "join this group". After doing those 2 things you should be able to click the link provided by Shiseiji and see the thread.


----------



## Shiseiji (Jan 7, 2021)

Nogoingback said:


> Bearings can be preloaded with belleville washers however:
> 
> 
> 
> ...


Yes, "but" there is a "It depends." Single row/simplex yes and as an aid, these typically have a way to secure the setting, I.e.  lock screw/nut. The 10" Logans have a close tolerance duplex/two bearings in the same housing and these do not take a "pre-load" and in the 10" Logan there is a Bellevue washer but the nut doesn't have anything to hold that is a safety. Two matched close tollerance bearings will have a matching washer between the bearings, typically have adjustment on both sides and a nut with a safety. Or epoxies in place. All the other Logans have simplex bearings on the chuck end of the spindle with Bellevue washers and a safety for the adjustment nut.


----------



## Shiseiji (Jan 7, 2021)

RandyM said:


> Ron,
> 
> Your link requires that we need to be a member and to log in. Unfortunately we do not have access to the information.


I understand the frustration.  What's the Hobby Machinist forum policy on cross posting direct quotes? I don't want to run afoul of policy/rules.


----------



## wa5cab (Jan 10, 2021)

Generally, if it isn't prohibited, then it is permitted.  One example of prohibited would be anything that is still copyrighted.  That would be prohibited unless someone had obtained written permission from the copyright owner to show it on H-M or written permission to list it on any site or any appropriate site.

If in doubt, ask Scott Logan.


----------

