Holding strength of wood screws based on screw size, thread engagement, and type of wood i.e., hardwood or softwood

Holding strength of wood screws based on screw size, thread engagement, and type of wood i.e., hardwood or softwood
	Post Reply		Forum

Posted by: john2003 ^®

06/18/2006, 21:55:49

Author Profile eMail author Edit

Hi everyone,

Does anyone know a general formula or rule of thumb for calculating the holding strength of a wood screw based on it's size, depth of thread engagement into the wood, and the type of wood, i.e., hardwood or softwood ?

I am screwing a small .156" thick flat steel plate to wood with nine #6 flat head sheet metal screws. I want to use a 1" long screw which will give me .844" of thread engagement into the wood. I will be screwing into edge grain and not end grain.

I am mainly interested in tension, but if you have info on shear I am interested in that as well.

I will probably use softwood, but am also interested in data for hardwood.

I would appreciate any feedback.

Thanks
John

Modified by john2003 at Sun, Jun 18, 2006, 21:57:06

Post Reply | Tell a Friend (must be logged in) | Alert Admin About Post

View All

| Next |

Replies to this message

Re: Holding strength of wood screws based on screw size, thread engagement, and type of wood i.e., hardwood or softwood

Re: Holding strength of wood screws based on screw size, thread engagement, and type of wood i.e., hardwood or softwood -- john2003 Post Reply Top of thread Forum

Posted by: randykimball ^®
Barney
06/19/2006, 21:45:27

Author Profile eMail author Edit

John,
If I were doing a project of any value and of the nature you are doing,... with seemingly little data to draw on.. I would:
Have a shackle built to a plate of some dimension and place four of the same screws, one in each corner, into a sample of the expected typical wood, then have done or do a load test and establish my own REAL data. If you get a certification lab to do the pulls you can get your data certified.

The worst suggestion of your lifetime may be the catalyst to the grandest idea of the century, never let suggestions go unsaid nor fail to listen to them.

Post Reply | Tell a Friend (must be logged in) | Alert Admin About Post Where am I? Original Top of thread

Re: Holding strength of wood screws based on screw size, thread engagement, and type of wood i.e., hardwood or softwood
Re: Holding strength of wood screws based on screw size, thread engagement, and type of wood i.e., hardwood or softwood -- john2003	Post Reply	Top of thread	Forum