Bizarre bolt size on plastimo captains seat.

[pompeydave]

Hi all, I’ve bought two new plastimo captains seats for my Raider 18 but the captive nuts that are moulded into the seats are a weird size. They seem to be M6 x 1.25, which is an almost impossible size of bolt to obtain and it’s apparently only found on odd far eastern manufacturered furniture. Has anyone got any idea if this size is correct? My thread gauge is definitely showing it to be a 1.25 pitch. Of course Plastimo do not supply the bolts with the seats!

 

[Poignard]

Could be 1/4" x 20 UNC.

 

[[2068]]

A 1/4‑20 unc bolt would be very very very close in size and pitch, and might work for you.

 

[pompeydave]

Ah, thanks chaps. Yes, I wonder if for some reason they’re fitting Imperial threads?

 

[Poignard]

Ah, thanks chaps. Yes, I wonder if for some reason they’re fitting Imperial threads?

One possibility might be that Plastimo buys these seats from the USA and markets them under their own brand name.

 

[Seastoke]

're tap it

 

[pompeydave]

Can’t really re-tap it as the insert wall is wafer thin. I’ll try the 1/4‑20 unc idea over the weekend and report back. Cheers for all the replies.

 

[Rocksteadee]

Sounds very American
it could be a bastard size (that is the technical description for a manufacturer to use their own thread size)

 

[pompeydave]

Hi all, went over to my Dads place tonight and he has boxes of imperial bolts. Turns out that the captive nuts are indeed 1/4” with 20 tpi so it’s made for the U.S. market. Found some stainless bolts online and they’ve been ordered. Thanks again chaps for solving this one, much appreciated!

 

[jim.howes]

Hi next time you need nuts/bolts try ML behind the petrol station along mile end. Very helpful.
Jim

 

[pompeydave]

Ok thanks for the tip.