Classic cars forum & vehicle restoration.

kimchris · Joined: 02 Jan 2014 Posts: 9

Can anyone help me with the size and thread of the bolts needed to hold the body shell onto the chassis? Thanks

Andrew

goneps · Posted: Fri Jan 03, 2014 5:23 pm Post subject:

Andrew,

Never had the body off my Tourer so I can't be specific, but it's easy enough to work out since the thread will unquestionably be BSF.

If you have a sample bolt it's a simple matter of measuring the thread diameter with a vernier or micrometer. If you have only the captive nuts to work with, measure the internal thread diameter with the vernier and cross-reference that with a Tapping Drill Size chart (any fastener/engineering supplier should have one). The measurement obtained should correlate to the drill size required for a tap to cut the same thread.

For instance:
1/4"BSF thread, drill size = 5.4mm.
5/16"BSF thread, drill size = 6.8mm.
3/8"BSF thread, drill size = 8.3mm.

Whichever of these measurements is closest to the ID of the captive nut, that's your thread size. I'd expect thread ID to be slightly oversize owing to wear and corrosion.

Decent quality BSF fasteners are a bit thin on the ground these days, but I can recommend an excellent supplier in England if need be. Don't use CNC-made bolts (no stamped identification on the head) as they will be only mild steel and not man enough for the job. Ask for Grade R, which is a general-purpose high-tensile grade suitable for this application.

Richard

kimchris · Joined: 02 Jan 2014 Posts: 9

Thanks Richard, thats exactly the info I need.

Please do let me have the supplier details.

Andrew

Uncle Alec · Joined: 14 Jan 2008 Posts: 734 Location: Manchester

I wouldn't be so sure.
Many of the engine threads on the Morris 8 are metric, but specially made with BSF/Whitworth size heads/nuts to suit the spanners in use in the UK.
I didn't have the body off my Morris 8 when I had it, but I would definitely check for metric before assuming it's all BSF.
Of course someone more qualified may have that knowledge.......

ukdave2002 · Joined: 23 Nov 2007 Posts: 4231 Location: South Cheshire

Uncle Alec · Joined: 14 Jan 2008 Posts: 734 Location: Manchester

Cheers Dave; wasn't sure, but no harm in mentioning. It's a strange fact anyway.

goneps · Posted: Fri Jan 03, 2014 8:58 pm Post subject:

goneps · Posted: Fri Jan 03, 2014 9:42 pm Post subject:

Andrew,

Mike Peters of Surplus Supplies:

http://www.polished-stainless.com/phdi/p1.nsf/supppages/3534?opendocument&part=4#zincbsfbolts

Excellent value, range, and service.
NB. I've no connection with this business other than as a satisfied customer.

Richard

Penman · Joined: 23 Nov 2007 Posts: 4850 Location: Swindon, Wilts.

Hi
If you have to replace any of the nuts/cages and wonder how , I found this in a MMOwners Club mag a while back.
The method would be the same for any captive system though sizes may differ for different makes.

_________________
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