Fabricator Benefits
In the US at least, the fabricator does not actually do field bolting, but the fabricator does purchase the bolts and bolting hardware and supplies all of it to the erector. Usually what the fabricator wants to achieve therefore is the least expensive first cost for bolting hardware. For this reason, since DTI's are an extra piece of hardware they have to purchase, fabricators sometimes resist their use. Knowledgeable fabricators know that DTI's CAN save money in a couple of specific situations, however.
One situation is where the erector wants to use twist-off bolts of 1" diameter or larger, especially in the A490 grade. Here the use of regular hex head bolts with a DTI can save considerable money, around $1.00 per bolt or more.
In December of 2001, a major bolt distributor quoted about 150,000 1 1/8" A490 twist-off bolts, and also quoted A490 hex bolts with DTI's. The hex bolts with DTI's were quoted at $1.90 less ($5.40 vs $3.50).
