Hood frame bolt thread size question

[boggie]

Hi all,

Does anyone know the size/type of thread of the large-head screw that mounts the hood frame to the brackets on each side? I am making a slightly modified bracket and will need to thread the mounting post when I am done. Is it 1BA or a UNC (size?) or something else?

thanks,

Ian

[Dic Doretti]

An educated guess would be 1/4" unf, from memory. That's what it is on a Doretti for certain.

             Cheers Richard

[boggie]

Thanks Richard,

I don't think it is on the TR. It is a smaller than 1/4", more like a 1BA I think but not sure...

[foster461]

Ian, are you talking about the triangular plates one each side ?. These are attached to the B post with the 1/4 fine thread countersunk pointy bolts but I dont know how they are attached to the frame. This is a picture from Revington, which is the bit in question ?

Stan

[Lebro]

Item 5 I imagine on your TR4 diagram, Item 28 on this one    .https://rimmerbros.com/Item--i-GRID200892            https://rimmerbros.com/Item--i-602029

MIne came without these screws, so I use M6 & tapped the bracket accordingly 

Bob.

Edited December 18, 2018 by Lebro

[boggie]

Thanks Chaps,

Yes, no5 in the drawing (although that shows a TR4 and we have a TR3a). It is the single, large head screw that mounts the frame to the triangular (L-shaped on the 3a) brackets each side (not the 2x 1/4"UNF coutersunk bolts). It is smaller diameter than 1/4" (but not by much) so we were wondering if it was 1BA....

Ian

[foster461]

Apologies for the TR4 diagram but it looks like we have identified the part in question. Curious to know what you are planning Ian.