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SP250 spare wheel retaining bolt

Posted: Mon May 20, 2019 10:27 pm
by Paulkennedy
Please what is the thread size of the bolt that holds the spare wheel in place in the boot.
Thanks
Paul

Re: SP250 spare wheel retaining bolt

Posted: Mon May 20, 2019 10:52 pm
by daimlersteve
Have seen all manner of threads there , Memory says 1/2" bsf ( could be wrong here though )

Re: SP250 spare wheel retaining bolt

Posted: Mon May 20, 2019 11:38 pm
by Vortex O'Plinth
daimlersteve wrote: Mon May 20, 2019 10:52 pm Have seen all manner of threads there , Memory says 1/2" bsf ( could be wrong here though )
Not quite, it's ½" - 20 UNF.
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Re: SP250 spare wheel retaining bolt

Posted: Tue May 21, 2019 6:21 am
by daimlersteve
look at the size of that bolt head. True steam engine sizing. (probably left over from the War. )

Re: SP250 spare wheel retaining bolt

Posted: Tue May 21, 2019 6:42 am
by Ian Slade
They were specials for spare wheels as the cup was dished and the standard bolt head allowed the wheel brace to slip off, can't remember what the original spanner was for wire wheels as I had a spider brace when I swapped hubs.

Re: SP250 spare wheel retaining bolt

Posted: Tue May 21, 2019 7:49 am
by Paulkennedy
Thank you for your replies. I would like to find a long enough bolt to prevent the wire wheel jumping around in the boot well. I tried packing the wheel but it is only the board above it and the two flimsy turn latches that keep it down which don't have enough strength, so I will toddle along to my local nut and bolt man.
Thanks Paul

Re: SP250 spare wheel retaining bolt

Posted: Tue May 21, 2019 10:34 am
by Ian Slade
If you can get a long enough bolt in UNF weld a nut to the bolt head, if you can't get a length of UNF stud bar and weld two nuts to the end and grind a taper to the bottom end, easier to locate ther captivated nut without cross threading.

Re: SP250 spare wheel retaining bolt

Posted: Tue May 21, 2019 8:25 pm
by peterbee
The bolt for the 4J steel rim is a 4 1/2" x 1/2" UNF - 20tpi. Head size 13/16" - use a plug socket. The plain shank length is 2 1/2". You can buy a standard bolt but the plain shank length is 3 1/4" so you may have increase the thread length depending on your rim size.

Re: SP250 spare wheel retaining bolt

Posted: Tue May 21, 2019 11:00 pm
by Paulkennedy
Thanks for the latest suggestions, I had thought to buy a couple of bolts if nesessary cut the head off one and weld together. I will see what bolts are available.
Paul

Re: SP250 spare wheel retaining bolt

Posted: Wed May 22, 2019 10:00 am
by daimlersteve
Ah, that may have prompted my confusion -- Big head ( 13/16" ) socket size -- 3/4" being the normal for 1/2"thread.
Clearing out the workshop in prep for the blue printing of the big engine . and a gearbox rebuild before a body arrives on Sat for fettlin prior to paintshop delivery
Steve