casement crank operators from 1952!

To whom it may concern: I have casement windows dating back to 1952 and the operators are in need of replacement. I cannot find anything on the hardware that indicates the name of the manufacturer. The only visible markings are on the underside of each device. Those markings are as follows: 1.H. 1.R. on one and 1.H. 4 L. on the other. Both items have only one hole on each side for attaching them to the metal frame of casement window. Regarding the pictures of the operators in the installed condition, unfortunately, both photos are of the same one on the same side. I hope this oversight is inconsequential. I would appreciate any information on availability and installation of replacements that you can share. The house if full of these old clunkers, most are inoperative. Thank you for your kind attention, Christopher

BINGO! That's just what I need! The mounting holes on my old ones are exactly 3 and 7/8 inches on center and the arm lengths are 9". Also, the price per each is much less than I expected which is a pleasant surprise. I was braced for anywhere from $28 to $40 smackers each! Many thanks to Dave for helping me out. I shall submit my order immediately. If things work out O.K., today's order will be followed by others. Many thanks to Dave for helping me out and a Merry Christmas. Regards-Christopher of San Antonio, TX.

P.S. Pardon my ignorance but should I be at all concerned about a possible difference regarding the size of the mounting holes on the new operators and the holes in the frame of the windows? Thanks Again!