Standard DTI's are made so that they induce a preload of 70 to 80 percent of the (A325 and A490) bolt's MINIMUM SPECIFIED TENSILE STRENGTH check here for more information.
If something different than this is needed, we can probably make it, depending on volume, at some price. The best way to explain this is to review some examples of specials we have made.
- DTI's for Bolts or Rods Bigger than 1 1/2" Diameter: For situations requiring a DTI larger than 1 1/2" in diameter, and for any
tension load, we can manufacture a segmental DTI product by cutting smaller DTI's, in size and number to match the bolt strength needed, and
arranging them in a circle which looks like this.
These are individually engineered custom DTI's and their price will vary from a few dollars each to as much as fifty or one hundred dollars each depending on the bolt load, diameter, squirt parameters, and bearing situation under the DTI.
- A U.S. Government agency wanted a low load 5/8" ID Squirter® DTI
to indicate a preload of 6 to 8 kips. The application was fastening
onto the foundations of houses. The agency wanted a visible method of
indicting the proper preload that didn't require a lot of explaining
to the installer. We made a special run of 5/8" ID Squirter® DTIs with
two bumps directly opposed across the ID. They got the load they wanted
and the installers and inspectors the indication that the job was done
- A building contractor wanted a low load 1/2" ID Squirter® DTI
to indicate a preload of around 8 to 9 kips.
These Squirter® DTIs would go on threaded rods to hold stacked block foundations
together. With special heat treating, we were able to give them the
load they wanted.
Their first order of 10,000 pieces was processed in April.
- A mining bolt supply company needed a very low load 3/4" ID Squirter® DTI
rock bolts in mine ceilings - compression range 8 to 10 kips. We removed
2 bumps from a 5 bump 3/4" Squirter® DTI and got them that range.
Trial parts have gone out and we expect the customer to give us some feedback soon.
- About the same time, a rock, soil and concrete anchoring system company
wanted a low load 3/4" ID Squirter® for rebar anchors in the
construction industry - compression load range 10-13 kips. Again we
knocked off two bumps from a 5-bump 3/4" Squirter®, gave them
a custom fill level and got the customer some samples having the load
resistance he wanted.
- A bridge erector wanted a Squirter® to go on a 2" diameter rod. The cost of special tooling to manufacture a unique 2" diameter DTI would have been prohibitive for the small number of parts that were needed. We took segments cut from 1 1/2" ID Squirter® DTIs, fastened them to 2" ID flat washers and created a segmented DTI that can give the user many different load ranges depending on how many segments are placed on the flat washer. There's no limit to the size of the bolt on which this can be used as long as there is a flat washer that will go around that bolt. We've internally christened this product "M&M's" after the chocolate candy.