Business

Window screws

A window screw is a type of fastener characterized by a helical ridge, known as an external thread or just thread, wrapped around a cylinder, which is same as other screws. Some screw threads are designed to mate with a complementary thread, known as an internal thread, often in the form of a nut or an object that has the internal thread formed into it. Other screw threads are designed to cut a helical groove in a softer material as the screw is inserted. The most common uses of screws are to hold objects together and to position objects.

 General Applications of window screws

• Door frame fixing

• Window frame fixing

• Wooden frame fixing

• For installation in solid and hollow materials such as concrete, lightweight and aerated concrete, hollow-core-concrete slabs, natural stone, solid and hollow brick, (perforated) sand-limestone and wood

• Stone facade reinforcement

• General fixing of wood / metal, etc.

 

 

 

Three Types of Wood Screws to Choose

Fastening table legs to surrounding skirts? Securing knee braces on a post and beam structure? Anchoring a shelf under a workbench?  Lag bolts are your answer. Despite their name, these aren’t bolts at all — at least not where it counts. They’re just big screws, though they do have a hex-shaped bolt head. Drive them with a socket wrench.

Ordinary decking screws are the cheapest option you’ll find, offering excellent performance in general applications. Premium wood screws look like regular decking screws, except for a few key features. Serrated threads greatly reduce the tendency to split wood, and the best include a dual head design that accepts both Robertson and Phillips drivers.

Brass screws are classier than decking screws and lag bolts, but you need to be careful. Even the best brass screws are quite soft compared with steel ones. Predrilling proper-sized pilot holes that are only slightly smaller than brass screw threads is key, especially in hardwood. If it takes more than a moderate amount of torque to drive a brass screw, stop and enlarge the pilot hole. Even if the screw shank doesn’t break (and it probably will), the head will probably be mangled as your screwdrivers slips.

 

How to Screw Down a Metal Roof ?

Metal roofing is held down more securely by screws than by nails, because screws have threads that dig into the wood underneath the metal roofing and give resistance to any forces that pull up on the roofing. Whether you are screwing down an existing metal roof from which old nails have worked loose, or a new metal roof that is being screwed down for the first time, the process is the same.

 

Step 1:

Test the clutch setting on your screw gun by driving a roofing screw through a scrap piece of metal roofing and into a piece of wood. Set the clutch so that the drill stops driving the screw at the point where the rubber gasket is snugly and firmly trapped between the metal washer on the screw and the metal roofing beneath it. If it's too tight, the rubber gasket could be damaged. If it's too loose, the hole won't be waterproof.

Step 2:

Drive a roofing screw into a lower corner of the roofing. Put the screw into the top of one of the ridges on the metal roofing.

Step 3:

Measure two feet up the roof from the first screw. Drive in another roofing screw at that point, on the same ridge. Work your way systematically across the roof, placing screws at regular intervals, so that you don't miss any sections of roof. To replace loose nails, pull out the old nails and put the new screws in through the same holes to minimize the number of holes you make in the roof.

 

Step 4:

Reposition any metal screws that spin without activating your clutch after you have put them in. These screws have failed to make a connection with the sub-roofing underneath the metal roofing.

How Self-Drilling Screws Work?

As their name implies, self-drilling screws operate on the same principles as drill bits and other cutting tools. This means that the way in which these screws are used affects their performance as much how they are designed. For cutting tools, the governing factors of material removal are cutting speed, feed rate, depth of cut and the work material itself.

 

When selecting a self-drilling screw design, it is important to consider the material thickness and type of materials to be joined. There are key design features to consider when selecting a suitable fastener for a specific application.

 

Drill Flute

The flutes allow drilled material to exit the hole. Once the flutes become completely embedded in the material, they can no longer remove the chips cut from the work material. Since these chips contain approximately 80% of the heat created by the drilling process, this can cause the point to over-heat and fail.

 

Point Length

The length of the drill point determines the material thickness which the screw can reliably penetrate. The unthreaded portion of the point, known as the pilot section, must be long enough to completely drill through the material before the threads engage. Since the threads advance faster than the drilling process, if they engage before drilling is done the fastener can bind and break.

 

Fastening Thicker Material to Metal

When fastening thicker materials, such as wood, to metal it is necessary to use a fastener with “wings” on the shaft or a pilot point. These fasteners are designed to prevent separation of the fastened material from the base metal, a condition known as “jacking.” Once the wings contact the metal they break away before the threads engage.

Oil Seal Installation

Oil Seal Installation Procedures:

1) Inspect the bore. Insure that it is clean and free of burrs that might distort the seal or cut the O.D., that may cause leakage. Check for roundness and make sure the leading edge is either rounded or chamfered.

2) Inspect the shaft. Look for machining lead, burrs, dirt and paint that might damage the seal or provide a leak path. If the old seal has worn a groove into the shaft, it needs to be repaired. In many cases, National Redi-Sleeves will enable you to quickly and inexpensively repair this condition.

3) Inspect the Shaft End. Remove all burrs and sharp edges. The shaft should be chamfered or radiused to assure the seal is not damaged during installation. If this is not possible, then an installation sleeve should be used.

4) Inspect Splines and Keyways. If the shaft has splines or keyways, cover with a sleeve, shim stock or tape to protect the seal lip.

5) Inspect the Seal. Check the seal for any damage (nicks, cuts, scratches or distortion of the sealing lip) that may have been caused during shipping. A damaged seal should be replaced.

6) Assure Proper Oil Seal Direction. The sealing lip usually faces toward the medium to be sealed.

7) Prelube the Seal. Prior to installation, the sealing lip should be prelubed with the lubricant to be sealed. It is not necessary for the O.D. of metal parts to be lubed, however, a light film of oil should be applied to the O.D. of rubber coated seals to aid in the installation process and reduce sheer stress during installation. This prelube should reduce or eliminate the possibility of a rubber O.D. seal from backing out of the bore immediately after installation.

8) Installation Tools. Select an installation tool (see Fig below). For easy, accurate installation of National’s popular standard style oil and grease seals use the RD-2000 which can easily install seals up to 3.375” (85.7 mm) O.D. The best tool will have a diameter slightly smaller than that of the housing bore and will apply force only on the seal case.  Bearing races may be used as an installation tool adapter when “approved tools are not available.

9) Never Hammer Directly On the Seal.  Screwdrivers drift pins or punches should not be used as installation tools. Steel hammers are not recommended for use with approved installation tools; the shock of steel on steel can dislodge the garter spring. After the seal has engaged the bore, the seal should be driven in evenly with only enough force to seat it in the bore.

 

Rotary Application of O-ring

In rotary O-ring sealing applications, the O-ring continuously moves against tire same

portions to the shaft. Heat due to friction is continuously generated in the same place, and elastomers are poor thermal conductors. If heat is generated more quickly than it can be dissipated, temperature rise is rapid and seal failure quickly follows. Where surface speeds do not exceed 180 feet/minute, or where rotation is brief and intermittent, this is rarely a problem and gland design criteria for reciprocating service are applicable (see Table E, Dynamic Piston and Rod Seal Gland Dimensions). For continuous rotation at surface speeds over 180 feet/minute some developmental adjustments are often required to achieve acceptable performance.

In applications where rotating motions occur, the designer should consider the following:

•Measures should be taken to reduce heat buildup:

! Provide absolute minimal squeeze, as little as .002 inch to minimize friction. This may permit some leakage.

! Provide ample diametric clearance to increase fluid flow and facilitate better dissipation of heat.

! Select O-ring with smallest cross section.

! Maintain low system pressure (not over 250 psi).

 

•Use a shaft of diameter no greater than that of the relaxed O-ring I.D. This is important because when an O-ring is heated under stress, it will tend to contract.

Contraction of the 0-ring could cause it to seize the shaft and increase friction and heat resulting in rapid failure.

 

•The gland should be located as close as possible to the lubricating fluid and as far as possible from the shaft support bearings. This allows the O-ring to receive the maximum amount of cooling lubricant and minimizes the effects of bearing-generated treat.

 

•Relative motion must occur exclusively between the O-ring I.D. and the rotating shaft. Rotation of the O-ring within the gland will lead to rapid wear and leakage.

! Minimize out-of-round shafts and eccentric rotation. Maximum eccentricity should not exceed .001 Inch.

! Finish of the moving surface contacting the O-ring should not exceed 16 RMS- A rougher surface is desired within the groove to discourage rotation; 32 RMS is recommended.

! Utilize an O-ring of a hard, self-lubricating compound specifically developed for rotary service.

 

Using ATV Winches

Using a ATV winch is simple. On the end of the winch's line is a hook. Many winch hooks have a self-locking mechanism on the end that prevents the hook from slipping off during winch operation. To use the winch, use the controls to turn the drum in reverse so that it feeds line out. Feed out enough line to connect the end to your anchor point (or other vehicle if you're using your own ATV as an anchor point). Secure the end of the line around the anchor or vehicle. Try to establish a clear line between the anchor and the winch.

Once the line is secure, you can engage the winch to begin pulling in the line. The most important thing to remember when using a winch is to be safe. Be careful not to stand too close to the winch, particularly if you're wearing loose clothing. The winch is a powerful piece of machinery and could cause a severe injury if you were to get caught in it.

You should also avoid walking over or standing near the line as the winch creates tension. A worn line may snap and it could injure you if you're in the way. Depending on the situation, you might need to sit in the ATV's driver seat while operating the winch. Some ATV winches come with a remote control, allowing you to stand out of harm's way while operating the winch.

Another thing to keep in mind is that manufacturers design winches to pull cable along a horizontal plane that is more or less parallel to the ground. You should never use a winch as a hoist to lift an object vertically. Doing so could cause damage to your vehicle or the winch, or could cause the line to snap.

Remember to inspect your ATV before taking it out for a ride. This applies to your entire vehicle, winch included. Who knows? You may spot something that needs to be replaced or repaired before it becomes a real problem.

 

Benefits of Portable Winches

Portable

There is no fixed link to a vehicle; therefore you can take the winch anywhere. Tether it to any solid object: a tree, a post, a rock or even to the ball hitch of your vehicle with the included polyester sling or one of our many anchoring accessories.

 

Fast 

With the PCW5000 Portable Capstan WinchTM, you also get your work done quickly, at the speed you choose. At the maximum pull rate of 1000 kg (2200 lb), your winching speed will be approximately 7.5 m/min (25 feet/minute). If you pull a 682 kg (1500 lb) load, you will be winching at a speed close to 12 m/min (40 feet/minute). You can also adjust the throttle on the HondaTM engine, to regulate speed and power.

 

Easy to use

Our Portable Winches are so easy to use that you will be a 'pro' in just a few minutes... Simply attach the winch to an anchor point, do 3 or 4 wraps of rope on the drum, start the winch and pull. The capstan drum does not accumulate rope on it. It uses friction from these 3 or 4 wraps of rope around the rotating drum to bring up the load. You can control precisely the winching speed by varying the pressure you apply to the free end of the rope.

 

Safe

The Portable WinchTM uses a low-stretch synthetic rope. The rope is lightweight, inexpensive and is available in different lengths. If the rope ever breaks or unhooks from the load, it will not whip back strongly to the winch operator, as a wire rope would. Also, a wire rope has to be wound evenly on a drum to avoid being caught between strands and requires constant tension on the line to avoid making a ‘rat’s nest’. Wire rope will also pigtail and kink, and feel like barbed wire after misuse. Double-braided polyester rope will stretch only 12% at rupture (compared to 22% for steel), so whiplash is minimal.

 

Electric Winches Q&A

Why should I equip my boat with electric winches?
Electric winches make it possible to sail bigger boats shorthanded. Crew can perform any task onboard, regardless of their strength, size, or physical condition. With the push of a button, crew can sheet the jib in high winds and execute other heavily-loaded tasks. Jobs such as trimming the mainsail are effortless. When conditions get rough, trimming by push button often allows you to keep sailing instead of motoring.

Do all electric winches have two speeds? 
Harken electric winches are 2-speed in both manual and electric modes, while some manufacturers' electric winches are 2-speed in manual mode, but only one speed in electric. The ability to choose a winch operating speed is always an advantage. For example, in light air you can sheet the genoa with the fast first gear and fine-tune in second.

For fast line speeds, winches size 60 and up can be special-ordered with three speeds.

How do I switch gears?
You can press one of two switch buttons for the desired speed.

What systems should I power?
Electric winch systems commonly trim the genoa sheets and the main halyard. In many cases, it's possible to lead the main halyard back to a powered primary winch. In addition, electric winches can furl mainsails, raise the anchor, or help dock the boat.

How do I size electric winches? 
Always size electric winches for the highest load. For example, if you use the winch for both the halyard and genoa sheet, size the winch for the load of the genoa sheet.

 

Can I use a winch handle to manually operate my electric winch?
Yes. Inserting the winch handle into an unloaded winch automatically disconnects the electric motor and allows you to use the first and second speeds just like a manual winch. This is important if you've lost power on the boat. If power is restored, the lockout prevents the winch handle from turning. 

Switches are also available with guard covers to prevent accidental starts.

 

More information

http://www.harken.com/electric-winches/

How to Attach a Picture Frame Wire?

Artwork, hangable curios and family portraits are necessary elements to make a house to be a home. While some pictures and artwork are light enough that you can use the hook on the back of the frame and a small picture hanger in the wall, other larger pieces require picture frame wire attached to the back of the frame. Today I would like to present you how to attach a picture frame wire by two screw eyes.

 

Firstly, select the proper drill bit size. The drill bit should be the same diameter as your screw eyes minus the threads. Then, choose your work space. Find a flat surface, such as a table or workbench, and lay the picture on it face down.

 

After that, affix the screw eyes to the frame. With the measuring tape and pencil, mark a spot that is one-third down the side of the frame on each side. Drill a small hole in that spot, and then screw the screw eyes into the frame.

 

Lastly, attach the picture wire. Cut a length of picture wire six to eight inches longer than the frame is wide. Thread one end of the wire through the screw eye and twist it back on itself two or three inches. Repeat on the other side. The picture is now ready for hanging.