Layshaft castle nut

[DGG]

I'm finally putting together my 109 transmission after rebuilding all the components. I was putting the layshaft castle nut on today, and I'm getting some resistance from the first few threads. The nut threads seem fine, but the threads on the end of the layshaft are not perfect. I thought about tightening it up any way and just trying to get past the first few threads, but stopped thinking I would mess up the nut, or the layshaft. Should I try to clean up the threads on the end of the layshaft? If so, what are the specifications of the threaded end of the layshaft, so I can get the proper tool. This is a pre-suffix transmission, but I think the layshafts are all the same throughout production from Series II to Series III.

Thanks

[I Leak Oil]

Thread file.

[DGG]

Like this:
https://www.amazon.com/Lang-Tools-2573-3-Piece-Restorer/dp/B007TMEXTQ/ref=sr_1_1?s=automotive&ie=UTF8&qid=1479342724&sr=1-1&keywords=thread+file

[clearcut]

Is there a file? Can not open this one

Thanks

[DGG]

I'll try to get a picture.

[DGG]

12083

[DGG]

Just need to know what size. Is it British Standard? If so, I probably won't find anything.

[I Leak Oil]

They make small triangular shaped files meant for cleaning up threads.

[DGG]

They make small triangular shaped files meant for cleaning up threads.
Thanks. That's probably what I'll do since I can't find the specs on the layshaft threads.

[cedryck]

If you have an assortment of "taps" and "die", you can carefully select on that might fit and see if it "carries" onto the threads. A small file can clean up the large thread enough to accept the nut. Just be careful and work slowly.