650SS Carby Studs

Hi
I am doing a trial assembly run on the 650SS carbys to head, to see what parts are missing and I am having troubles with the carby studs.
I can only find two of the originals in the boxes of bits, 5/16" by 2 1/2" long.
In the parts book it lists three "# 23563, stud, fixing, carburettor" which I assume are the long ones and one "# 23395 screw, fixing carburettor" which I assume is shorter to clear casting block on the chopped Monoblock?
23563 looks like Norvil, 067855SS at 2 1/2" long.
23395 looks like Norvil, 211876 at 2" long which may make sense for chopped Monoblock?
11796 a 5/16' Spring washer x 4 off
E3231 Nuts reduced hex x 4 off which I have on hand.

I bought two allen head bolts thinking they would clear the chopped carby, but only one will fit, so will go with standard.

Can anyone confirm is correct?
Best regards
Burgs

(NM)23395 is a cap head screw, fitted at the inner position.

https://andover-norton.co.uk/en/shop-details/20537/carburettor-fixing-screw-nm23395-

http://www.norvilmotorcycle.co.uk/carbmanif.htm

"NM23395 SCREW - 5/16" - WHITWORTH - ALLEN HEAD - 2" LONG - PLATED"

A 'screw' is used instead of a fourth stud and nut on the inside to make carb fitting and removal easier.

Which parts book are you using???
The 650 in my shop has this...61-62 parts book PS214 page 56, shows 650SS with 2 23395 screws and 2 23563 studs.
Stud on the left and screw on the right of both carbs.
My atlas' are as LAB describes (3 + 1) except the 66 with 389/689 carbs (stud on the bowl side and screw on the clear side).
My Dunstall 68 atlas with concentrics is not norton factory stock therefore 4 allen screws extra long.
I bought studs from both norvil and AN and neither were 100% correct.
Norvil was closer and AN was not useable "as is".
AN was notified and promised to correct them.
Both had to be "fettled" to make them match the original norton bits.
Left original norton- Center norvil- Right AN ( their supplied nut would not screw onto their stud)

Hi and Thanks
Dave
My 650SS is a 1963 (1048XX) model and I am using a "1963~1965 Models 88ss, 650ss, 650/99 & Atlas also G15P “N” & “M” G15CS “N” & “M”", I also have the 1961 and 62 parts book.
There must be a bit of a fair bit of cross over between the 1961, 62 and to the 63 bikes with parts and bigger changes in 1964 as some parts have been turning up that don't match what was on my bike that.
My bike had been stored in boxes since the early 70s after spending most of its life racing. Main bits missing was the headlight, mufflers and handle bars.

The two original bolts measure exactly 2" 1/2" and are satin chromed, with the small hex nuts.

LAB
So the screw is actually an allen head bolt or as they call them now at the bolt shop SHCS, "Socket Head Cap Screw", so that explains why it is listed as a screw.
When I did my Mechanical Engineering we had to do a little project (actually turned out to be bigger than everyone thought) on hand drawing and describing the various connectors available for engineering purposes, that included bolts screws rivets etc, I got top marks due to my experience, and the young smart blokes didn't fair very well, looking back to that project (Australia) Allen Head Bolts were Allen Head Bolts, not screws.

So the way I see it now is, starting at the left carby, there would be the 2 1/2" stud then the SHCS, then two 2 1/2" studs in the chopped Monobloc, which would make sense as it makes it easy to get at one at least.
Pity the SHCS didn't fit the chopped Monobloc as well as it would make it very easy, I did think of ming the carby to allow clearance, but after spending big $ for new carbys I could not do it?

Best Regards
Mark

Burgs said:

LAB
So the screw is actually an allen head bolt

Click to expand...

No, it's actually a (socket) cap head screw!

Burgs said:

or as they call them now at the bolt shop SHCS, "Socket Head Cap Screw", so that explains why it is listed as a screw.

Click to expand...

Yep, because it is a screw.

For me here in the US I usually consider screw or bolt only based on size.
0,1, 2, 3, 4, 5, 6, 8, 10, 12 (obsolete for design) as screws and anything 1/4" and above as bolts regardless of the head type.

Only keeping with this defined destinction would I then agree with ANNA that the carb attachment did not have screws.
As you say, according to norton they were (SHCS) screws?

https://www.fastenermart.com/understanding-bolts-and-screws.html


"Machinery's Handbook 26th Edition, © 2000 by Industrial Press Inc.

2.1 Bolt. A bolt is an externally threaded fastener designed for insertion through holes in assembled parts, and is normally intended to be tightened or released by torquing a nut.

2.2 Screw. A screw is an externally threaded fastener capable of being inserted into holes in assembled parts, of mating with a preformed internal thread or forming its own thread, and of being tightened or released by torquing the head.

3. Explanatory Data. A bolt is designed for assembly with a nut. A screw has features in its design which makes it capable of being used in a tapped or other preformed hole in the work. Because of basic design, it is possible to use certain types of screws in combination with a nut. Any externally threaded fastener which has a majority of the design characteristics which assist its proper use in a tapped or other preformed hole is a screw, regardless of how it is used in its service application."

LAB no disagreement here
You make my case against anna's claim of "no screws" and my claim ..screws yes...
I keep my Dad's (rip) 14th and my 24th edition of Machinery's Handbook on the locker shelves above my taps and dies.
2 shelves of unf, unc, uns, BA,BSF, BSW, CEI, US pipe, BSP, metric and STI for metric, British and UN . selected sizes taps and dies in both RH and LH.
I would hate to inventory to find replacement cost

Well I never, I stand corrected for the past 50 odd years I have been referring to screws as bolts along with quite a few other million people as well as Mechanical Engineering Scholars one (my British Mechanical Design Teacher) who worked on the first of the Nuclear power stations and wing design of bombers in the 2nd World War. There are a lot of parts drawings out there that need correcting !
Back to my stud issues, I have machined a new stud out 304SS, so now should be good .

Best regards
Burgs

Screw the semantics.

#12 and smaller are screws
1/4” and larger are bolts

Another definition (not official in any way, just common usage):

Screws are threaded all the way to the head, regardless of size. Sizes over 1/4 " are sometimes referred to as machine screws.

Bolts are threaded only sufficiently to attach a nut and washer. The non threaded shank is the grip which is intended to hold the parts together.

Machinery Handbook's definition as put forth by LAB above is the final rule and guide.

Slick