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1 Toll Free phone 0800 652 463. Toll Free Fax 0800 652 464. Email Website SELF TAPPING & WOOD SCREWS - RECOMMENDED HOLE & DRILL SIZE. AJAX TYPES AB, B SELF-TAPPING SCREWS AJAX TYPES AB, B SELF-TAPPING SCREWS TWINFAST WOODSCREWS. In mild steel, brass, aluminium alloy, stainless steel and monel metal sheet In thermo (pliable) plastics TWINFAST Pozidrive woodscrews are specially recommended for use with all type of particle board and soft timbers NOTE: It is important that the correct hole size is used and the recommendations below should NOTE: Because of the vast differences in these plastics, the following table is intended only as be followed.

2 If a very hard material is being used, a hole size slightly larger may have to be a guideline. It may be necessary to increase or decrease the recommended hole size to obtain used, and in very soft material a smaller hole may be necessary. If any difficulty is encountered, optimum fastening conditions. send a sample of your application to us and we will be pleased to carry out tests to determine the optimum screw type, gauge and pilot hole size. TYPE AB' TYPE B'. Firstly make a hole to suit the Fig. 5. For light sheet metal diameter of screw being used. assembly, no clearance hole is The hole can be clean-punched necessary in the top sheet.

3 Or drilled as shown in , or Figs. 6&7. When fastening to solid plunged as shown in Fig. 2. section of casting or die-casting, Secondly use a Pozidrive or to heavy gauge sheet metal, a screwdriver or bit to drive the screw clearance hole in the top piece is required. If a clearance hole is not WOODSCREWS - STANDARD. home (Figs. 3 & 4). provided, the total thickness of Woodscrews can achieve far greater holding material must be taken into account power than similar size nails or staples. when deciding upon the tapping Selection of wood size hole size. The size of the wood screw required for a particular Remember that as the thickness application depends upon the width and thickness MECHANICALPROPERTIES of material increases, it becomes of the timber into which it will be inserted.

4 Torsional Strength more difficult to pull the two sheets The diameter of the screw should not exceed 1?10. For the torsional strength test, the shank of the together tightly. of the width of the wood into which it is driven and screw is clamped so that at least two threads ensure, if possible, that there are seven diameters WHICH SCREW TO USE STAINLESS STEEL. protrude above the clamping device. of thread engagement but certainly not less than SELF-TAPPING. Using a calibrated torque measuring device, AJAX TYPES AB, B four diameters. SCREWS. torque is applied until fracture occurs.

5 SELF-TAPPING SCREWS If the screw is fixing a wood attachment, then Stainless Steel Self-Tapping Screws marketed its overall length should equal three times the Screws have to meet the minimum torsional 18-8 STAINLESS STEEL. In mild steel, monel by Ajax Fasteners are manufactured from an thickness of the attachment. strengths shown in the tables below. metal, brass and aluminium alloy sheet. Austenitic Steel which falls within the 18 per To avoid the risk of splitting the timber, use a pilot cent chromium / 10 per cent Nickel range, which NOTES. hole and also maintain spacing as recommended is considered suitable for general corrosive 1.

6 Because conditions differ widely, it may be in the chart alongside. conditions. The actual specification is 305 S19 necessary to vary the hole size to suit a Pilot holes are particularly necessary when driving or AISI Type 305, with tensile strength of about particular situation. brass or aluminium alloy wood screws. SUREFAST WOOD SCREWS. 35/45 tonf/ins. (540-695 N/mm2). 2. 18-8 quality stainless steel self-tapping A lubricant coating eg: soap, tallow, bees wax or Hardened, self-countersinking, screws are much softer than case hardened lanolin, will assist the easy insertion of the wood self-drilling These screws are NOT as hard as the more widely steel screws and therefore care must be screw, particularly into hard woods, without any For Applications where pilot holes are undesirable used carbon steel Self-Tapping screws.

7 They are exercised in using them. They cannot be great loss in holding power - 50% reductions in and high clamp loads are required eg: clamping ideal for use with aluminium alloy sheets but are used in very hard material. Also due to insertion torque are obtainable. The lubricant glued joints, fixing wall brackets and wall in some cases unsuitable for use in other than the galling tendency of stainless steel they should be applied to the screw point or into the furnishings to walls, structural connections etc. the thinner Austenitic Stainless Steel sheets, due should not be used in stainless steel sheet.

8 Pre-drilled pilot hole. The screws can then be to the galling tendency of this material. Pozidrive recess removed more easily at a later date. SELF-TAPPING SCREWS. They should be used with care and tapping hole Head Type To ensure that a countersunk head screw sinks Ribs under head for flush, or just below the surface of the attachment, self-countersinking sizes are critical. a countersunk clearance hole should be drilled Extra sharp point, We strongly recommend that any proposed no pilot hole using a 90 included angle countersinking bit until Extra coarse thread application be tried out in practice and we are required (care for ease of driving the diameter of the countersink ate the surface is required near always prepared to advise on this subject.)

9 Greater than the V' dimension of the screw to be timber edge). used. See Table of Principal Dimension of Woods crews. Christchurch Christchurch Nelson Invercargill Auckland 39a Gasson Street 521c Blenheim Road Cnr Brilliant Place & Nayland Road 156 Bond Street 930c Great South Road Ph (03) 365 2460, Fax (03) 365 2464 Ph (03) 348 0340 Fax (03) 348 0346 Ph (03) 547 5102, Fax (03) 547 0289 Ph (03) 214 4499, Fax (03) 214 4489 Ph (09) 589 1036, Fax (09) 589 1037. Toll Free phone 0800 652 463. Toll Free Fax 0800 652 464. Email Website SELF TAPPING & WOOD SCREWS - RECOMMENDED HOLE & DRILL SIZE.

10 AJAX TYPES AB, B SELF-TAPPING SCREWS AJAX TYPES AB, B SELF-TAPPING SCREWS TWINFAST WOODSCREWS. In mild steel, brass, aluminium alloy, stainless steel and monel metal sheet In thermo (pliable) plastics TWINFAST Pozidrive woodscrews are specially recommended for use with all type of particle board and soft timbers NOTE: It is important that the correct hole size is used and the recommendations below should NOTE: Because of the vast differences in these plastics, the following table is intended only as be followed. If a very hard material is being used, a hole size slightly larger may have to be a guideline.