Krag Collectors Association Forum

Hello Krag-Jorgensen enthusiast,

Can anyone tell me what thread pattern was used on Norwegian Krag-Jorgensen rifle action screws? Or what thread pattern type/system was used on Norwegian Krag-Jorgensen screws in general? Thanks.

Regards,
sixfive

I have never seen one of these in person. Do you have any samples on hand (even worn or broken would be helpful)? If so I have measuring equipment that I can identify the thread form and identify other critical dimensions critical dimensions.

sixfive,

I read on another forum the following, if it helps:

The krags were developed at a time where the metric (SI) was not yet used commonly (Still not ;-)). The screws are in the BSW *(British Standard Whitworth)
Size on the receiver is a mix of nominal metric and inch measures.

and:

Looked at some action screws (Norwegian Krag) I have. They seem to be 1/4 X 20 tpi.

If they are Whitworth the pitch diameter will be different than American unified threads, also the flank angle of the threads is 55 degrees instead of 60 degrees used in all American Unified and metric threads. Never tried one but I doubt they will even screw together, if they do they might work loose with use or some other bad thing might happen or not.

Hello,

Thanks for the information. I had wondered about Whitworth threads as well. I can't figure out how to post pictures at this point but, I can give some dimensions.

I am no machinist at all but, I am in the process of making some stock inletting guide screws and a replacement extractor retaining screw for a 1912 and 1894.

The outside diameter of the action screw threads is .240-.250". The outside diameter of the extractor screw threads is .150". At first I did not think a 1/4-20NC die would work for the action screws but after threading some 1/4" rod it appears it threads into the action OK. Good enough for guide screws anyway. As for the extractor retaining screw the closest die I found was M4-.75. It is not a perfect fit but may serve the purpose.

I was just hoping someone might know offhand what the Norwegian Krag-Jorgensen used. Thanks again for the information and any additional information is greatly appreciated.

Regards,
sixfive

Good luck with your fabrication. Keep us informed in case anyone here wants to do the same thing.

Hello,

Well, I tried a 8-32 die for the extractor screw and that did not work at all. It looks like for my purposes I will be sticking with a M4-.75 on the extractor screw, and 1/4-20 threads for the action screws. Since I am just making inletting guide screws and a extractor screw I will not go to the trouble and expense of ordering Whitworth dies at this time. I can't justify it for what I am doing. However if I do ever get my hands on Whitworth dies to try, or get better information on the topic, I will be sure to post my findings. Maybe some more digging in the Krag reference materials will yield some answers. Thanks to all who helped out.

Regards,
sixfive

You might check at a knowledgeable bicycle shop for a replacement extractor screw.

There could be a relationship to old British Bicycle thread screws.

six five somewhere i have all the measurements for the krag screws if i can find it i will post it for you

sixfive I found your information on the krag screws go to www.gunboards,click on forum,page 2 under norwegian screws,started by
kirkp asked question was answered by KAIFS senior modulater 2-28-20 he gives every mesuriment,diameter,and thread size
theey are witworth 55 degree this is as complete information as you can get(29 pages in color) good luck