Deardorff Bed Plate Repair

[David Lobato]

Somehow I managed to strip the 3/8-16 threads in my Deardorff V8 bed plate. I removed the plate and it's an aluminum casting from the 1950's most likely. The Cochrans at Deardorff offered to sell a new replacement plate for $125. But I managed a better option with help from my machine shop friend (see the LF October Portraits thread). We discussed a fix and I asked for a pressed in knurled insert. He machined a steel insert and pressed it in beautifully. Here are pictures of his work. The steel insert will be near impossible to strip and the knurling will prevent rotation, which is a vital feature. I installed the repaired plate today. Note to anyone removing and replacing a bed plate. Before installing the #2 screws, rotate the plate to each of 4 circular positions and check for best alignment of the previous screw holes. Slight hole tolerances will cause some rotational positions to be off. You will see when all holes line up as they should.

https://dl.dropboxusercontent.com/u/55432652/Deardorff%20Bed%20Plate%20DSC_7890.jpg

https://dl.dropboxusercontent.com/u/55432652/Deardorff%20Bed%20Plate%20DSC_7891.jpg

https://dl.dropboxusercontent.com/u/55432652/Deardorff%20Bed%20Plate%20Insert%20DSC_7890.jpg

https://dl.dropboxusercontent.com/u/55432652/Deardorff%20with%20bed%20plate%20DSC_7896.jpg

[dentkimterry]

Nice job!

[ic-racer]

Nice job!

Nice, very professional job. I have done similar repairs with T-nuts and screws.
141190

[Jonathan Barlow]

I guess this was a plate that had already been tapped to 3/8-16. Weren't they all 1/4-20 to begin with? An admittedly undersized screw, but that's what they used in those days.

Have you seen the Cochran plate? It isn't sand-cast like the original. Not very pretty.

[Jac@stafford.net]

Mine are 1/4 x 20 except for one that I drilled & tapped to 3/8.

[pierre506]

Mine are 1/4 x 20 except for one that I drilled & tapped to 3/8.
Me, too.

[David Lobato]

Mine had a 3/8-16 tapped hole when I bought it. I didn't realize the Deardorff standard size was 1/4-20.

[barnacle]

For my education: are these actually 1/4-20 and 3/8-16 or are they 1/4 and 3/8 Whitworth? I know that the two will work with each other, but they're not an exact match - I think the tooth angles are different.

Neil

[Jac@stafford.net]

For my education: are these actually 1/4-20 and 3/8-16 or are they 1/4 and 3/8 Whitworth? I know that the two will work with each other, but they're not an exact match - I think the tooth angles are different.

Yes, the tooth angles are different, but for short fasteners the difference is insignificant except for NASA engineers. 1/4-20 and 3/8-16 are originally metric standards. Witless (sic) are so typically British. :)

[Drew Bedo]

Nice job! Looks good Dave.