Steel Manufacturing Blog: Keeping it Steel

DTI Washers | Steel Manufacturing Blog | Steel Supply

Posted on Mon, Oct 29, 2018 @ 04:01 PM

Direct Tension Indicator Washers

The DTI Washer, also known as the Squirter Washer, has been around a while in various forms. It has two basic functions; 1) to assure the bolt is delivering the required tension on the connection, and 2) speed of installation.

Structural Steel, Bridge or Slip Critical Connections are required to meet a minimum compressive strength. The standard TC Bolt has a spline that will shear off when the appropriate tension level is achieved. This is the fastest, most efficient method of bolting connections but it cannot guaranty the plies are compressed as the sheared spline would indicate. The pressure the TC Bolt spline is responding to it the torque created as the nut tightens. The problem is the same torque is generated if anything jams the nut while it tightening. Any debris in the threads, typically sand or a metal shaving can act as a wedge jamming the nut from turning and developing the torque to snap the spline prematurely.

The DTI, or Direct Tension Indicator Washer, functions on a completely different premise. It measures the pressure the bolt is delivering to the steel plies. By offering resistance as the bolt is compressed the DTI will hold its shape until the compression reaches the required amount. At this point the ridges will begin to compress. As they do, the semi cured silicone will exit the cavity through the small channels on the bottom of the DTI Washer. See Fig. 1. As compression continues the silicone visible at the sides of the washer increases. Once the correct pressure is determined it is possible to estimate the pressure on subsequent connections by the amount of silicone at the sides of the washer.

 

When using Direct Tension Indicator Washers correct assembly is important, and there are several ways it can be done. The image to the right shows one method of assembly before compression begins. The DTI Washer can sit directly on the steel member surface, but the compression bumps must be facing the nut. An F-436 hardened washer should sit between the Squirter Washer and the Heavy Hex Nut.

In all cases the ridges do not face the steel member, As well, it is important they do not touch the turning surface directly. They can sit under a bolt head without a washer as long as the bolt head will not be rotating when the bolt is being tightened. 

For more detailed information on DTI washers click here.

 
Read More

Effects of the Tariffs

Posted on Mon, Oct 08, 2018 @ 05:35 PM

Constantly in the news are issues and questions regarding the import tariffs the U.S. Government is instituting and how they will affect the steel fabricating and construction industries. Here is a quick overview from our perspective.

Read More

Tags: Wedge Insert

Maskote Zinc Stop-Off

Posted on Mon, Aug 27, 2018 @ 01:55 PM

Stops Zinc from adhering to selected areas of steel during the Hot Dip Galvanizing process.

Read More

Tags: Maskote Zinc Stop-Off

Rebar Anchors and Threading

Posted on Thu, Jul 12, 2018 @ 11:23 AM

As the Rebar Anchor becomes more prevalent in building design steel fabricators are experimenting with ways to fulfill these requirements more efficiently. The most common types of Rebar Anchors are;

Read More

Tags: Threaded Steel, Rebar Anchor

Slide Bearing Fabrication

Posted on Fri, Jul 06, 2018 @ 09:43 AM

In many of the requests we receive for Fluorogold® or Teflon® Slide Bearing Assemblies the fabricator is under the impression the specific dimensions they require will cut to size, then bonded together and finished. This can be done, but only starts to make economic sense when the requirements call for a large quantity of the same dimensions.

Read More

Tags: Slide Bearing, Slide Bearings, Teflon Slide Bearing

Slotted Wedge Shim

Posted on Wed, Apr 18, 2018 @ 09:42 AM

As discussed in previous blogs The Steel Supply Company uses several methods of making slotted steel shims. These are confined into two main groups; hard tooling and soft tooling. Click here to view that discussion.

Read More

Tags: Shims, Steel Wedges, Steel Shims, Slotted Channel

Keep the Slotted Steel Shims Flat

Posted on Fri, Mar 02, 2018 @ 09:37 AM

To suit their purpose, Slotted Steel Shims need to be produced as flat as possible. The Steel Supply Company can manufacture perfectly flat shims with literally zero practical deflection by cutting the shims from plate stock on a laser table. The problem with this method is higher costs, which escalate even further as the shim thickness increases.

Read More

Tags: Shims, Construction Shims, Steel Shims

Slotted Steel Shim Production

Posted on Thu, Feb 22, 2018 @ 01:27 PM

The Steel Supply Company uses a variety of processes when manufacturing Slotted Steel Shims. For stock sizes Punch and Die Stamping is the most effective. For made to order sizes or multiple slot shims laser cutting produces very accurate results. Heavier material like 1/2” thick or thicker tends to be more economical using a High Definition Plasma table. Regardless of the process our customer, the steel fabricator and erector, requires the same thing, i.e. accurate, flat shims that can be installed with no hesitation or interruption and that provide 100% surface contact.  

Read More

Tags: Shims, Construction Shims, Steel Shims

Slotted Steel Shim Galvanizing

Posted on Tue, Feb 20, 2018 @ 12:33 PM

Slotted Steel Shims, as discussed in previous blogs, are simple items but there are many pains in the manufacturing process that can affect the finished product. This article deals with the problems inherent in Hot Dip Galvanizing the steel shim.

Read More

Tags: Steel Shims, Hot Dip Galvanizing

Hillside Washer Flange

Posted on Fri, Jan 12, 2018 @ 11:55 AM

Hillside Washers can function in the basic form shown in Figure 1. All the necessary features are in place, along with the load strength to ensure durable performance.

Read More

Tags: Hillside Washers, Turnbuckle Rods, STEEL SUPPLY, Turnbuckles, I-Beam, Thermal Break