Most people know there was a big difference in steering gear housing covers from 1909 to 1916, and that they differ from those used in the black and nickel years, but how many different styles of covers were used from 1917 to 1927? I never had noticed until I got to comparing two that I have, today. The cover from my 1927 coupe, which never has been changed to my knowledge, has a fully knurled edge, or side. None of the edge is smooth. Another cover that I have, appears to be of lighter weight construction and the edge (or side) is smooth, except for a 1/8th or 3/16th inch knurl at the top of the edge or side. I hadn't noticed or seen any post about this, before.
The nickel cover with that full knurl came along with the 5:1 gears, the nickel cover with partial knurl only at the top is the earlier 4:1 style.
Note the case on the left has a longer radial slot for the pinon post too, for the balloon tired late '25-'27.
Dan, If a person didn't care to be authentic, the earlier cover could be used on a 26-27, right?
Yes. The covers fit the gear case, the dimensions are the same.
I'd like to go along with you Dan on that, and wish it was true. I hope it is! I purchased a very nice late steering column a few years back, hoping your theory was true, and it had 4-1 gears in it! I've heard of others doing the same thing and coming up with 5-1. Maybe I should try it again? I believe the wide knurl came out in '24.
My 24 (March) has the fully knurled cover with 4/1 gearing, as does my January 26 Coupe which has quite a few wrong parts.
According to Bruce's CD, he thinks the wide knurl came along with the 5:1. The record of changes he looked for didn't show, but records do show the gear case change with 5:1 gears in Sept of 1924.
All the old looking original unmolested round dashboard mount columns I find and buy with the wide knurl cover always have the 5:1 gearing inside.
Dan: stop telling all the secrets. Dan
For what it's worth, the cover, T-5039, drawing was revised on 9-27-23 (Record 10061) as follows: "Increased the width of knurled surface from 5/16", making the distance between lower edge and bottom of cover 3/32" ".
On a separate note, but interesting, the records of changes also note that on 5/5/19; it lists "Specified this part to be zinc plated and buffed instead of copper plated,nickled plated and polished"
Then on 6/23/19: "Changed from Zinc Plate and Buff, to Cyanide Copper Plate Buff, Nickel Plate, Buff.