Originally Posted by Mr.Tim
A standard weight ball-bearing 4-1/2" hinge will handle a 150lb door. Non-ball-bearing is good up to 125.
There is some additional info here
I believe the issue with 8x8 will be the holes are drilled throughout the hinge, so some screws might be in the door and others might be in the fabric frame.
I think you are right about the screw placement on the 8x8 hinge. It looks like it goes about halfway into the hinge which means about 2'' therefore that column of screws would just miss my door. If I put the 2x4 onto the face of the door it would make the effective door thickness enough to accommodate all of the screws.
I did find this specification on the $27 hardware source 4 1/2 x 8'' hinge.http://www.hardwaresource.com/images/products/4.5_WideThrowJPG.jpg
So the screws are no further than an inch away from the end of the hinge which would be ideal. However the product page states that the hinge is for doors of medium weight.........
The Hager link you provided was really helpful. I was going to search for something like that last night to educate myself but had to take care of the kids. That is great info for those of us trying to figure out our thick heavy doors (or maybe I am the only one who didn't know).
Here is an excerpt from that link:
There are three dimensions to know in order to determine the
minimum width of the hinge: door thickness, backset, and
1. When figuring the calculations for a wood door and wood
frame, the door is flush with the casing or face of the frame.
When figuring the calculations for a wood or metal door with
a hollow metal frame, the door is inset approximately 1/8”
2. For doors up to 2-1/4” (57 mm) thick, the hinge is set back
1/4” (6.4 mm) from the back face of the door.
3. For doors over 2-1/4” (57 mm) thick, the hinge is set back
3/8” (9.5 mm) from the back face of the door.
Once these dimensions are known, the formula can then be
applied. Take the door thickness, subtract the backset,
multiply by two, and add the clearance required. If the
hinge size is not standard, then go to the next larger hinge
width. If the width of the hinge is greater than the height of
the hinge [example: 4-1/2” x 6” (114 mm x 152 mm)] this is
referred to as a wide throw hinge. This would apply only to
full mortise hinges.
Ok here goes and someone correct me if I am wrong. So for my situation my door is 2 3/4 and my hinge backset is 3/8. I need a clearance of 2 1/4 for my fabric frames.
2 3/4 minus 3/8 equals 2 3/8
2 3/8 times 2 equals 4 3/4
4 3/4 plus 2 1/4 equals 7
So I would need a width of 7''. If this math is correct (and it may not be) then it must mean that the hinge point does not need to be flush with the outside of the panel. I might get the 8'' hinge just to make sure as long as it does not break the bank.
The other interesting thing was looking at the bearings and the frequency requirements.
Minimum Cycle Requirements
Plain Bearing = 350,000
Standard Weight Ball Bearing = 1,500,000
Heavy Weight Ball Bearing = 2,500,000
Judging by this I only need a plain bearing as it relates to frequency. However, Tim stated in a previous post that plain bearings are good for 125 lbs and ball bearings for 150 lbs.
So now I am trying to calculate my door weight more precisely. I don't have my interior doors yet but I am getting ready to order them. I do have the exterior doors and they are 1 3/8 solid core Masonite Safe n Sound interior doors. I weighed them and it came out pretty close to 70 lbs. I don't know what my 1 3/4 slab will weigh. If the extra 3/8'' adds 20 lbs then it will be closer to 90 lbs. I found here http://www.hooddistribution.com/resources/product_weights.html
that 1/2'' mdf is 2.2 lbs per square foot. I have about 18 square feet so that is 40 lbs per sheet. 40 times 2 is 80 lbs that I will be adding to my 1 3/4 slab. We could have a 170 lb door after all is said and done. My fabric frames will add a few pounds too. My math could be obscenely bad here folks so if anyone knows different please correct me.
So does that mean I really do need the ball bearing hinges? There is no mention of weight in the Hager link as it relates to width. It does specify height though. It also talks about number of hinges for sizes of doors. Thanks for being patient with me as I work this out. Almost there!