i have an old internation harvester wrech,and 2 old ford tools,that i m tryinh to find out what they were used for. the ih has h 9 11 on it,one ford has the # 6 or 9 ,and the other has m-40-17017. thanks guys
40-17017 is cylinder head nut and sparkplug wrench, part of the kit supplied in all early Fords.
This one was introduced in 1933 (replacing one for bigger sparkplugs used 1928-1932), used into early 1938 when the changed sparkplug size and changed to a new wrench to match. The M is the supplying forge, manzel or the other foundry with M name they used...symbols were a little different.
Other Ford with no PN...post length and config and opening sizes.