Seeking Bolts for Rocking Chair by Frank Reenskaug for Bramin  

It is an imperial bolt.  It wasn't until perhaps the late 1960s or early 1970s that the Danes had generally switched over to metric in the furniture industry.  It isn't so easy to switch over when all your tooling is denominated in imperial.  To take an example, the shop would have had imperial sized drill bits and so they would want imperial sized bolts to fit the holes just right.  From what I have seen architects designed in metric, but then those measurements were converted to imperial with a little rounding.  Then the measurements we re-converted to metric, with some rounding, for publication in Denmark.  And then often those doubly converted numbers were again converted with rounding to imperial for publication in the USA.  So catalogs sometimes had measurements that weren't so accurate with 3 conversion and rounding passes.  

@donna-macisaacgmail-com   Try the McMaster-Carr website if you haven't already. Lots there for screw-heads (like me) and, FWIW, I'm pretty sure the fasteners you're looking for can be called either screws or bolts depending on application.

Thanks so much to you both.  The explanation makes sense to me and I ordered some bolts from McMaster-Carr.  I guess I must consider myself a screw head too.  At least I'm detail oriented. 

I got the bolts and they don't fit.  I'm pretty certain I need 6 bolts size 12-28 2 inches long and have a flat countersunk hex head and are black.  Does anyone have any I can buy please?  Many thanks in advance.  Donna

What size machine screws did you order that did not fit?

I have replaced the screws for a Reenskaug rocker before, years ago, and I got something at a local hardware store. I don’t ever remember seeing or using 12-28 screws in my entire lifetime. Usually I see 10-24 and then it skips over to the saner 1/4”-20 fractional inch system for everything thicker. 12-28 apparently exists as a denomination and #12 wood screws do exist, but it strikes me as one of those specifications for a machine screw that exist on paper but not at the store. 

Agree with Leif. Need to know how they didn't fit. Wrong shaft diameter, length, and/or thread? Maybe post a good photo of the screw/bolt with the joint needing fastening, too?

Just checked a Reenskaug, the screws are 10-32

Welcome and thank you, @skylar. Very helpful!  Could you measure overall length and length of non-threaded portion of the shaft, too? Maybe a photo with a ruler included would be good enough.

Thanks! Looks like the unthreaded portion of the shaft tapers at 1-1/4, threading starts at 1-5/16.

Total shaft length is 2 in, head height is 3/16.

And thank you again, @skylar. These should work just fine then:

http://www.mcmaster.com/91251a353