Thanks for the help fellows, I found both types of fuses.
Now the problem is this: I have two versions of the threader maintenance manual. One is dated 1981, the other, older, manual is not dated. The newer manual, in all aspects, refers to and shows photo's of my newer-type HC lathe (s.n. HC5609T). However, the top cover of the threader cylinder housing on the chaser head is different than mine. My top cover has two raised bosses rather than the three bosses shown in the manuals photo's. Electrically, I don't think this matters, nevertheless, it is this newer manual that calls for the 4/10 amp fuse.
The older manual shows a threader exactly like mine, but the photo's of the electrical switch case (on the lathe) is quite a bit different. This older manual calls for the FRN 1-1/4 amp fuse. The threading units appear to be "almost" exactly alike. So, I'm thinking that since the newer manual, which matches my lathe and its switch case, is probably correct about the 4/10 amp fuse, rather than the 1-1/4 amp fuse. My threader is s.n. 787 and is older than my HC lathe. Therefore, maybe the switch case has some improvements over the older HC machines, and they decided, for whatever reason, to change the fuse size for the threader. I just don't know.
What size fuse are y'all using, and is your threader an older machine or a newer one.
Thank you,
Jasperfield