Wood Screws

Conventional wood screws commonly used are the Countersunk/flat head (252:2A), round head for attaching metal to wood (252:2B), and raised/oval head (252:2c), obtainable in brass, steel, japanned (round head), coppered, chrome, BMA finish, etc. according to the type. The length of a screw is taken as all that part of the screw concealed by the wood, thus the length of a countersunk screw will be the overall length (252:1), round head from under the head, and raised head from the junction of the raised head with the counter-sinking. The diameter of all screw-heads is twice the diameter of the shank, the angle of the countersink 45° to the central axis, and the length of the actual thread three-fifths (0.6) of the stated length. A useful formula for the determination of the stated gauge number is: diameter of head in 1/32 in — 3 = screw gauge number; thus diameter of head 13/32in — 3 = 10 which is the gauge number. The diameter of the shank can be calculated from the gauge number by taking the known diameter of a No. 1 screw as 0.066 in with an additional 0.014 in for each subsequent increase in the number of the gauge; thus a No. 8 screw will be 0.066 in (No. 1 screw) - 7(0.014) or 0.164 in diameter. This will be the size of the hole required for a No. 8 screw shank, but as drill sizes are in 1/64 in the nearest approximate size will have to be used, and the

252 Screw types, etc.

formula commonly adopted is to add 3 to the gauge number to give the size of the drill in 1/64 in. Thus No. 8 screw plus 3 = 11/64 in which is 0.172 in in diameter. The table gives the usual drill sizes for the shank or clearance hole, and for the hole to receive the thread.

How To Sell Furniture

How To Sell Furniture

Types Of Furniture To Sell. There are many types of products you can sell. You just need to determine who your target market is and what specific item they want. Or you could sell a couple different ones in a package deal.

Get My Free Ebook

Post a comment