Marquis 18" Non std thread

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robint
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Marquis 18" Non std thread

Hi Lawnies.  I got a Marquis 18" recently in AFAIK original good condition cw BSA sloper sweet runner (not like the lumpy BnS)

So Imagine my surprise when I came across  nominal 5/16 BSF bolts with non standard threads (ie 24 tpi instead of 22 ca 3" long).  I thought I must have gone hayseed and spent all day cross checking this

Has anyone heard of this?

It refers to the Bolts that adjust the bottom blade clearance with the cutting cylinder and also the bolts that hold the front roller adjustment.  Thats all I found so far - will I find anymore?  Its a bit worrying if this is a feature of Ransomes alleged engineering excellence

I will be changing these out for std BSF and stainless is readily available today.  Will post some photos

 

In all my engineering experience, I have never come across an oddity like this?

Having said that, if you ever had the misfortune to encounter a British Leyland vehicle you will know about their dirty tricks.  I had a horrible Sherpa van once for my business.  Its radiator failed (because it was poorly mounted and suffered from chassis flexing) so I went to the scrap yard.  The fella told me he had some radiators but couldnt guarantee they would fit.  BL would deliberately change the mounting holes and spigots every year for no reason other than to spoil the scrap trade.  It took me a whole afternoon drilling new holes to fit.  A nasty job.  I scrapped it after its king pins failed the MOT and the man said its often impossible to replace them as they seize up.  Deliberately planned obsolescence

robint
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Mystery solved - stupid boy

Mystery solved - stupid boy Pike - too much scrumpy in the woodshed

Its a 5/16" UNF which has 24 tpi

UNF is quite popular in the motor trade

Will have to watch out for other UNF instances

wristpin
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Had me worried there for a

Had me worried there for a while!

I seem to remember that old shape Minis had some BSW and BSF spanner sizes mixed with UNF  AF sizes. I certain other small engine manufacturer had/ has metric thread form  hex head screws with AF heads.

 

robint
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I got two 3" x 5/16unf ss

I got two 3" x 5/16unf ss bolts to replace the old blade adjusting bolts. well worth the effort given the tendency to seize

https://www.ebay.co.uk/itm/1-4-5-16-3-8-UNF-SET-SCREWS-A2-STAINLESS-STEE....

Will replace some of the other exposed bolts, trivial cost really

Got to repair the grass box, it has a rotten bottom.  Cover it in galv sheet and pop rivet seems doable.  Shame it was such a flimsy construction and so vulnerable to damage and the elements. Ransomes could at least have painted the inside with bitumin paint

I think my mower spent its life under dry covered storage and hasnt been messed by a bodger

 

robint
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Admin, please move this OP to

Admin, please move this OP to my other post "Ransomes 18"

gtc
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As one door closes, another

As one door closes, another one slams in your face

Why is it necessary to put that pessimistic mantra in every one of your posts?

robint
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You dont remember Marvin the

You dont remember Marvin the depressed robot who sole aim in life (life, dont talk to me about life) was to become a door closer