Front Bumper Mounting and Shackle Jam nut - Buick Master 1927

[Hubert_25-25]

Looking for two of these actual nuts or guidance on fabricating them.  

These are on the front bumper brackets on a 1927 Buick Master.  These nuts hold the mounting brackets and bumper from rotating, and they are the jam nut for the front spring shackle bolt.  To make it harder, they are a non standard 11/16-16 thread.  It would be great to find originals.  As far as making them, I can get a 11/16-16 tap on Ebay, but wondering what would make a good base stock?     

I did find a photo of the bracket inthe big parts book, but not one of the nut, so this is my best guess as to the size and design.  Any help is appreciated.   

If I have to fabricate, let me know because they are cheaper by the dozen.  

 

Thank you   Hugh

Edited October 16, 2023 by Hubert_25-25 (see edit history)

[Oregon Desert model 45]

Hugh

shouldn't that be 11/16-16 thread ?  it is a non-standard size today. 

I had to machine down a 3/4" bolt to 11/16 and thread it to make that shackle bolt.  An 11/16-16 tap was necessary because the frame horn is threaded and it needed to be chased and cleaned up.  I did find 11/16-16 lock nuts for some sort of hydraulic bulkhead fitting.

Kevin 

Edited October 13, 2023 by Oregon Desert model 45
edit (see edit history)

[Hubert_25-25]

Kevin,

       Good catch.  I corrected the above.  I had it wrong in 2 places.  

     I like your plan.  In my case, I could use a 7/8" bolt.  I need to run it past a machinist.   Hugh  

     

[dibarlaw]

Hugh:

I had to make extension shackle nuts for the mounting of the 1927 Wolverine bumpers on my 1925 also.

[Hubert_25-25]

Larry,

     I believe you made the shackle nuts for my 1925 Standard also.  They are 9/16 thread and the Master ones are 11/16 thread.  

So when you made these, did you use a bolt, or purchase hex stock, or grind the flats?  I just was not sure of the process that you went thru.

My plan was to

- use 7/8" low grade bolts. 

- Cut them off at the length of the lathe jaws. 

- Bore them for the tap size and into the head. 

- Use a 7/16-16 bottom tap to tap the hole.

- cut them to length  

Hugh  

 

Edited October 16, 2023 by Hubert_25-25 (see edit history)

[dibarlaw]

Hugh:

 I turned them out of hex stock, drilled and tapped them as you note.

Edited October 19, 2023 by dibarlaw
spelling (see edit history)