Posted by David Sherman on Monday, April 11, 2005 at 11:49AM :
In Reply to: O.T. Bolt supplier? posted by Steven Hood on Monday, April 11, 2005 at 10:15AM :
I checked McMaster-Carr and MSC -- neither of them lists any bolts in 11/16, although MSC does list an 11/16-11 die (no information on thread form), which could be useful if you need to make your own bolt. I had to do that to make some 1/2-12 bolts for an 1890 lumber planer I rebuilt a few years ago.
I'm not at home, or I would look it up in an old engineering book that has many obsolete thread series'. I'm quite certain that there's no 11/16" in the standard UNF (SAE) or UNC series', but there are some "standard" finer series' and there are also other old series' that were mostly obsolete by 1900, with British Whitworth being the only one that continued into modern times.
If you're trying to replace a bolt of some odd ancient standard, be aware that the thread form might be different as well (different thread angle, rounded vs sharp or flat root and crest, etc), in which case a bolt of the correct pitch might not screw into the exisiting nut or hole, or might have poor holding power. Worse than that, on old machines with odd threads, I often find that some previous "mechanic" tried to screw a modern bolt or screw into the old-sized hole, with the result that it usually jammed after a couple turns and bunged up the threads or stripped out.
Worst case, you may need to have a machinist make you the bolt you need. This is probably best a job for a semi-retired gentleman rather than for a busy commercial shop.
What kind of machine is it on?