Author Topic: Imperial bolts  (Read 909 times)

Offline Goldy

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Imperial bolts
« on: 14.10. 2011 19:24 »
I now have an old lathe and intend to make my own bolts. I have been unable to find the standard dimensions of imperial bolts ie accross flats, head thickness etc. Does anyone have any info. Regards Goldy
56 A10 Golden Flash - Restore, ride, relive.                                          
56 C12 BSA project ongoing

Online groily

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Re: Imperial bolts
« Reply #1 on: 14.10. 2011 20:42 »
Welcome to a whole world of self-empowerment Goldy!
You now have the ability to confuse posterity big time by making things that suit just you. You can make them however you like. However, a quick Google will give you the AF sizings of all standard BSF, WW and BSC heads, along with every other form known to man or beast, as well as the shank diameters and information on pitches, crest forms, etc etc.
But you'd need a milling slide and some reliable form of indexing to make good hexes with the lathe  . . . better probably to buy hex bar in the right sizes (which is easily available)? It's also miles easier - for all the usual sizes at any rate - to use taps and dies to cut threads after the hole has been drilled or the shank diameter has been determined. The lathe will ensure you get the threads on straight, if you use the tailstock and have/make some die-holders. (Making die-holders is a very good early-learning exercise as well.)
A book I found really useful when I started this never-ending quest to learn at least a few of the basics was 'The Amateur's Lathe' by L H Sparey. That and a whole series of tomes on screwcutting, milling in the lathe and general workshop practice can be obtained through www.lathes.co.uk or from Amazon (or no doubt from other places). I'd have been lost without them, having had no other training, because they are practical, well-written, and easy to follow. They're written for the owners of small lathes of 3.5in centre height or 7in swing over the bed, but the info is good for bigger weapons too.
I felt ridiculously pleased with myself every time I did something new for the first time (however simple)  . . . and I still do for that matter.
Good luck to you - it's as much fun as riding a bike almost.
Bill

Online RichardL

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Re: Imperial bolts
« Reply #2 on: 14.10. 2011 20:44 »
Goldy,

Maybe this helps a little. It's scanned from an old book I have. You remember books?

Richard L.


http://dl.dropbox.com/u/40734044/0969.pdf
Plan on signing up for the world-wide 2020 DISTINGUISHED GENTLEMAN'S RIDEon September 27, 2020. This year it's a solo or pillion ride in dapper attire. Watch website at https://www.gentlemansride.com for details.


Offline Beezageezauk

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Re: Imperial bolts
« Reply #3 on: 14.10. 2011 21:02 »
Goldy,

Remember that many fasteners that BSA used had odd sized heads.  Either in thickness or across the flats.  For example:- the ones that go through the handlebar clamps.  Also length of thread often varied from standard.

The best thing to do would be to try and check the dimensions by part number or copy originals. 

I have information on some Cycle Thread bolts with part numbers that BSA used.  It give the part number, length under the head, thickness of head, length of thread, distance across the flats and the diameter.

Let me know if I can help.

Beezageezauk.

Offline MG

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Re: Imperial bolts
« Reply #4 on: 15.10. 2011 07:41 »
...and remember CEI uses a thread angle of 60°, unlike BSF/BSC and UNC/UNF (55°)  ;)

I found this site useful:

http://www.gewinde-normen.de/en/index.html

Cheers, Markus
1955 A7 Shooting Star
1956 A10 Golden Flash
1961 Matchless G12 CSR

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Online Brian

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Re: Imperial bolts
« Reply #5 on: 15.10. 2011 07:49 »
Markus you might have to go and sit in the naughty corner  *smile*

Offline MG

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Re: Imperial bolts
« Reply #6 on: 15.10. 2011 07:54 »
 *whistle*
1955 A7 Shooting Star
1956 A10 Golden Flash
1961 Matchless G12 CSR

www.histo-tech.at - Restoration, Repairs, Racing

Austria

Offline Goldy

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Re: Imperial bolts
« Reply #7 on: 15.10. 2011 09:52 »
Thanks very much for the info lads, very much appreciated. I used lathes many years ago when I was an apprentice so I am trying to remember things. I have made one or two bits and pieces and much of it is coming back to me. I will not be doing screw cutting so as suggested I think I will purchase hex bar and use dies for threading.  The word soon gets around though, my son arrived the other day with a child pushchair (stroller) belonging to his mate and wife. My son said my dad will mend that (thanks son), The plastic pivot had broken so I turned a new one in the lathe. They were really pleased this piece of machinery seems to make everyone happy.
56 A10 Golden Flash - Restore, ride, relive.                                          
56 C12 BSA project ongoing

Offline iansoady

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Re: Imperial bolts
« Reply #8 on: 15.10. 2011 10:44 »
If you can find a copy of "The amateur's lathe" by L H Sparey* it's superb, and has a great section on screwcutting. Like you, I "learned" my turning (as well as welding) as an apprentice but many years have elapsed since then.

I find making my own components far more satisfying than buying them, as well as cheaper.

*Just had a look and Amazon have it from £2.99 used: http://www.amazon.co.uk/Amateurs-Lathe-Lawrence-H-Sparey/dp/0852422881

ps another great book is Machinery's screw thread book - again available on Amazon http://www.amazon.co.uk/Machinerys-Screw-Thread-Edgar-Allen/dp/B001P89IM2/ref=sr_1_1?s=books&ie=UTF8&qid=1318671908&sr=1-1
Ian.
1962 Golden Flash (arrived)
1955 Velo Viper/Venom (departed)
2004 Triumph Tiger 955i (staying)