Source 1" UNC 316 studs?

[Jonathan Webb]

Following my earlier post about (keel) studs, I am contemplating that it might be beneficial to increase the laminate thickness, therefore requiring longer studs.

I could buy 1" fully threaded rod as some people do, but think that the proper engineering stud is the way to go as it surely helps a better seal and no scope for chewing the laminate where it passes through.

Can anyone here make these (as a proper paid job), or recommend a source? These are currently around 140mm and I could possibly do with 170mm , the extra thread being on the nut end. I would be after 10 @ 1"UNC (and 4 slightly smaller - 11/16W nut- but don't yet have the proper spec for them).

Thanks

 

[rtbcomp]

GWR fasteners offer a bespoke service. I've only dealt with them for stock items and they seem OK

 

[Jonathan Webb]

GWR fasteners offer a bespoke service. I've only dealt with them for stock items and they seem OK

Thanks, have emailed them.

 

[500e]

Better to use 2205 or 2507 if you are set on SS
Mild steel will rot less if galvanised, a loose fitting hole filled with Sicaflex & you will find the mild steel lasts longer, SS in water & a low oxy atmosphere corrodes like mad
Have a scout round some sailing sites regarding SS

 

[Rig Pig]

Try:

 

[Jonathan Webb]

Better to use 2205 or 2507 if you are set on SS
Mild steel will rot less if galvanised, a loose fitting hole filled with Sicaflex & you will find the mild steel lasts longer, SS in water & a low oxy atmosphere corrodes like mad
Have a scout round some sailing sites regarding SS

Thanks. Ive looked up those grades - duplex. I've only ever seen that specified for prop shafts so maybe overkill? These existing studs are 45 years old and I've looked for crevice corrosion, but found no evidence. My understanding is that the original spec was 316 and I'm not aware of any failures in this class (Westerly Centaur) due to stud corrosion. I can but ask for both prices. I'll need to be seated when reading the quotes anyway. :-)

 

[Jonathan Webb]

GWR fasteners offer a bespoke service. I've only dealt with them for stock items and they seem OK

GWR will do 'em - minimum order of 100 :-( I only need 10

 

[pressbrake1]

I can make them, it is my job making such things!
What’s the load?

 

[pressbrake1]

Or you can buy high tensile studing

 

[Jonathan Webb]

I can make them, it is my job making such things!
What’s the load?

They are keel studs, holding 500kg-ish cast iron keels, splayed at an angle. Blue boat pic is not mine, just an example of the application. FWIW, the worst loading comes not from sailing, but when the boat settles into the mud this tries to force the keels apart and support 2 tonnes of load. Mine is the project boat with the keel off... There are actually also 4 x 3/4" & 4 x 1/2" as well as the 10 1" ones.

Or you can buy high tensile studing

My (boaty) neighbour turns out to be a marine engineering consultant in the LNG field & I asked him about this a while ago and got this reply: "Regarding the use of full-threaded studs, I would personally not consider it, not so much from the chafing point of view, but because each thread groove is essentially a potential stress raising point when the stud is subjected the a bending action. Ideally the lower threaded part of the stud should be fully entered into the keel (with a small gap under the stud), and the upper threaded part should end just below the first washer."

 

[pressbrake1]

Indeed every thread is a stress raiser. Looking at your application the studs also act as dowels hence all thread bar could suffer from stress raisers

 

[500e]

Some boats have the bolts right through the keels for just that reason