Bolts
Hex Head Cap Screws:
There are several differences between hex head cap screws and hex bolts. One of the main ones is that cap screws have a tighter body tolerance than bolts. For example a 1" diameter cap screw has a maximum body diameter of 1.000, while a 1" diameter bolt could range as high as 1.022 and may be as large as 1.060 directly under the head. Hex heads in nickel-based alloys tend to have a body diameter larger than the nominal bolt diameter for two reasons. First, the raw material is generally oversized. Second, the forging process can create a swell under the head.

A bolt can be turned or ground to achieve cap screw tolerances. However this adds to the cost and in the case of a non-stock item will add to the lead-time. Our experience has been that bolt tolerances are sufficient most of the time. Therefore we supply bolts unless a customer informs us the cap screws are absolutely necessary.

Nickel Systems maintains an inventory of hex bolts in hastelloy<R> (Alloys C276, C22, B2), Alloy 20 (Carpenter 20), 18-8 Stainless, and 316 Stainless in stock at all times. Other alloys that we currently have hex bolt inventory include Alloy 200 (Nickel 200), Alloy 600 (Inconel<R> 600), AL6XN<R>, Duplex 2205, Ferralium<R> 255, 330 Stainless and 410 Stainless.