D17 S1 headlight boss thread
Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=104024
Printed Date: 10 Sep 2025 at 6:14am
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: D17 S1 headlight boss thread
Posted By: Creek Jenkins
Subject: D17 S1 headlight boss thread
Date Posted: 30 Mar 2015 at 12:56pm
|
what the helms thread is in the headlight bosses? I am trying to fit a set of aftermarket headlights to the front of my '59 D17 and can't seem to finger out what thread it is. I tried 1/2" fine, coarse and even found a 1/2" hollow lamp nipple. Can't get any of them started. It looks like 1/2" fine thread, but the bolt won't go in and I don't want to screw up the threads. It would be nice to have a hollow bolt to run the wires thru, but first I need to find what the threads are. Anyone run into this? cheers, Creek
|
Replies:
Posted By: PaulB
Date Posted: 30 Mar 2015 at 2:08pm
|
I'm not positive about a D17, but all of the B,C & CA's I've worked on were 1/2" coarse. It just may be that your threads are a bit too rusty. I usually use a tap first before I'll put in headlights, that also helps to make a good ground. The other possibility might be you after market lights are metric thread.
|
Posted By: den/southern illinoi
Date Posted: 30 Mar 2015 at 4:26pm
They should be 1/2 inch fine thread. Just got done with 2 sets of lights and the front cowling and they were all 1/2 inch fine thread. Den
-------------
Own 4 wheel 20, 2-5015, 5020 and associated equipment and 2 electric forklifts.
|
Posted By: Creek Jenkins
Date Posted: 30 Mar 2015 at 4:58pm
|
thanks for the tip, it did look like fine thread, maybe only the smaller or older tractors use the coarse. I'll run a 1/2" fine tap thru there and clean the threads up. My aftermarket headlights have 3/8" bolts, so I'll just replace them with 1/2" fine. Have to figure out a way to drill them out for the power wire though. cheers, Creek
|
Posted By: Ted J
Date Posted: 30 Mar 2015 at 7:24pm
I did mine for the C in my drill press. Start with a small bit and get bigger as you go. Try and get as close to the middle as you can! Use a center punch and then drill. Also chamfer the ends so the wire won't wear. Worked like a charm. I had to drill 3 as one was a little too far off. I got in a hurry and went too big right away.
-------------
"Allis-Express"
19?? WC / 1941 C / 1952 CA / 1956 WD45 / 1957 WD45 / 1958 D-17
|
Posted By: BradRisen
Date Posted: 30 Mar 2015 at 9:01pm
|
If you have access to a metal turning Lathe ,makes it real easy to drill perfect, Dead center Holes in bolts
|
Posted By: Creek Jenkins
Date Posted: 31 Mar 2015 at 3:06pm
|
I think I can get a machinist at work to chuck a couple bolts up in a lathe and drill them out. Prob cost me a Snickers bar. King size if he has to find the bolts. Creek
|
|