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What size are the bolts securing the coil plate to Burnham V-74-T

Hi group, I am about to replace the coil on my boiler and need to order new rods and nuts in stainless steel to make it easier next time I want to service it.

Does anyone know the thread size I need?

Thank you in advance!

Plate 2.jpg Plate1.jpg

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Comments

  • pecmsg
    pecmsg Member Posts: 5,993
    edited December 2024

    Please don't use stainless steel bolts. Too brittle will break easy. Steel bolts with never-seize.

    LRCCBJ
  • nelaco
    nelaco Member Posts: 4

    Good to know, thank you. Do you know the size?

  • pecmsg
    pecmsg Member Posts: 5,993

    Not off hand. When you order the coil order the bolts as well.

    nelaco
  • LRCCBJ
    LRCCBJ Member Posts: 1,027

    If you can measure across the flats on the head accurately…………I can give you the size. What I cannot give you is the length. That depends on the tapped holes in the casting. We'd need to make an assumption.

  • nelaco
    nelaco Member Posts: 4

    Thank you LRCCBJ. It is 1/2". I am getting rods so don't really need the length.

  • jesmed1
    jesmed1 Member Posts: 1,248
    edited December 2024

    If you really want to make it easier next time, be sure to use anti-seize on the threads. Otherwise you will be doing this. Scroll down to the photo of the OP cutting the bolt heads off with an angle grinder.

  • Chris_L
    Chris_L Member Posts: 345

    Not sure which Burnham boiler you have but on my old 4B series, those bolts are described in the parts list as:

    '3/8" - 16 x 3/4" LG Machine Screw'. They take a 9/16" wrench.

    (And I had thought mine were stainless steel—I have to tighten them from time to time. But in looking at them now, I am not sure.)

  • LRCCBJ
    LRCCBJ Member Posts: 1,027

    I'm 99% certain that they are 3/8. I'd get 1.25" studs for it.

  • LRCCBJ
    LRCCBJ Member Posts: 1,027

    If you are exactly 1/2…….or slightly less…………they are 5/16" screws.

    If you are 9/16………….they are 3/8" screws.

    Be careful and use the one that is least corroded.

  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 10,391

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

    jesmed1LRCCBJ
  • pedmec
    pedmec Member Posts: 1,199

    Burnham parts list has them at 3/8"-16 x 7/8"

    LRCCBJ
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 17,685

    The idea of using rods or studs is a good idea…….with never seize of course. It gives you two chances to get the nut or the stud out instead of one

    LRCCBJ
  • nelaco
    nelaco Member Posts: 4
    edited December 2024

    Wow, this is great! Thank you everyone for all your help and suggestions!

    I'll provide an update once finished.

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