Lotus Elan and Lotus Elan Plus 2 Forums

What is the thread size of the knurled nut that secures the Smiths Tach?

I tried an 8-32 and it threads on partially but binds. A 10-32 and 10-24 are
too large and a 6-32 is too small.

I would like to secure the instrument voltage regulator at the bottom of the
post. I feel it would be grounded better than screwing it to the rear of the
wood dash.

Bob
1969 Elan +2

Don't know the thread size..but I can tell you that I never found one that
fit. Must be a british standard size..



Tony Vaccaro



_____

From: ***@***.***lto:***@***.*** Behalf
Of ***@***.***
Sent: Monday, September 11, 2006 3:00 PM
To: ***@***.***
Subject: [LotusElan.net] ? thread size



What is the thread size of the knurled nut that secures the Smiths Tach?

I tried an 8-32 and it threads on partially but binds. A 10-32 and 10-24 are

too large and a 6-32 is too small.

I would like to secure the instrument voltage regulator at the bottom of the

post. I feel it would be grounded better than screwing it to the rear of the

wood dash.

Bob
1969 Elan +2

I know that an 8-36 nut is made but not common. May be that size.

Bob

I will try an 8-32 tap into the nut and see if that frees it up. I spoke
with Nisonger and they said various thread sizes were used and without the
instrument in hand they could not identify the thread. Further, they indicated
that a "British" thread was used and it would be unlikely that I could find it
here.

Bob

_http://www.britishfasteners.com/_ (http://www.britishfasteners.com/)

Looks as if the thread is a 3BA or 2BA. I will call the company linked above
and order some.

thanks

Bob

I can't be certain but it is most probably a B.A. (British Association)
thread, these were used on instruments and other applications where a
small thread was required. Very unlikely that you will come across this
in the USA.

Cheers,
Pete.

***@***.***e:

Yes.like I said ..a British Standard thread. But.I never had any that were
different..all the same.



_____

From: ***@***.***lto:***@***.*** Behalf
Of ***@***.***
Sent: Monday, September 11, 2006 3:36 PM
To: ***@***.***
Subject: Re: [LotusElan.net] ? thread size



I will try an 8-32 tap into the nut and see if that frees it up. I spoke
with Nisonger and they said various thread sizes were used and without the
instrument in hand they could not identify the thread. Further, they
indicated
that a "British" thread was used and it would be unlikely that I could find
it
here.

Bob

Another area that causes confusion is the fact that some BSW or BSF nuts can
be screwed on UNF or UNC bolts and vice-versa. Under NO circumstances should
this practice even be considered.

I copied this from a fastener site. I replaced all my front spindle, stub
axle etc. with UNC/UNF bolts and nuts. Does this pose a potential failure?

Has anyone replaced their original hardware with U.S. fasteners?

Bob
1969 Elan +2

Bob

If you replaced the bolt and nut then there is no problem assuming they
were the correct tensile strength. It is only a problem if you put a UNC
nut on a BSW bolt or vice-versa.

Rod.

Rodney Stevens
CSIRO Minerals
phone 02 9710 6701
Mobile 0432 506 427
Web: http://www.minerals.csiro.au/

Personal Web Page
http://mywebpage.netscape.com/rodjohnst ... mepage.htm

-----Original Message-----
From: ***@***.***lto:***@***.***
Behalf Of ***@***.***
Sent: Tuesday, 12 September 2006 10:12 AM
To: ***@***.***
Subject: [LotusElan.net] SAE to Brit thread danger?

Another area that causes confusion is the fact that some BSW or BSF
nuts can
be screwed on UNF or UNC bolts and vice-versa. Under NO circumstances
should
this practice even be considered.

I copied this from a fastener site. I replaced all my front spindle,
stub
axle etc. with UNC/UNF bolts and nuts. Does this pose a potential
failure?

Has anyone replaced their original hardware with U.S. fasteners?

Bob
1969 Elan +2

Yes, forcing UNC/UNF nuts onto BSW/BSF bolts can lead to failure, but using UNC/UNF nuts and bolts to replace BSW/BSF nuts and bolts is OK. The limiting factor is the grade of the bolt.

Let me know if you can't source a BA knurled nut and I will search my odds and ends box.

Ken
NW Florida
'69 +2, etc




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I can verify that all period Smith instruments used BA threads as did
Lucas electrics at the same time. Since you have mentioned that an 8-32
UNF will start to go on, a 8-32 design diameter is .164. That is the max
size for the male thread, most are slightly smaller. A 3BA size is .161
with a thread pitch of 34.8 TPI. Another difference in most British
thread forms is a 55 degree thread angle while most UNF/UNC SAE and
metric are 60 degree angle. The above info from my 1958 issue of "Newnes
Engineer's manual", of British origin.

A friend of mine is restoring a pre-war Rolls and he has good access to
BA fasteners in the US. If you can't find a good source, I'll ask him
where to go.

Roger (Ohio)


using UNC/UNF nuts and bolts to replace BSW/BSF nuts and bolts is OK.
The limiting factor is the grade of the bolt.

Let me know if you can't source a BA knurled nut and I will search my
odds and ends box.

Ken
NW Florida
'69 +2, etc




---------------------------------
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rates.

The only BA threads on the Elan were the instruments. The suspension and
chassis bolts are all SAE, so no problems there. If you check in the parts
manual you will see that the bolts and nuts are called out by their sae size
and length, except for a few. The few that are not called out by sae size,
such as those in the rubber donuts, were actually AN bolts.

Rob LaMoreaux
Ann Arbor, MI USA
(734)-971-5583
Cell (734)-604-9280
Email: ***@***.***
Too many Hobbies.... Too Little Time
1969 Lotus Elan....It's not a restoration, it's a never-ending adventure.

The threads on Smiths/Lucs/Jaeger instrument mounts
are 3BA.

Regarding prop shaft balance, none of my five Elans,
have been perfect in this respect. All demonstrated
some mid-frequency vibration at one speed or another
between 40-80 MPH. It could often be improved by
rotating the propshaft by 180 at the diff flange. but
never eliminated completely. Another occasional
problem was vibration from a rear hub bearing. Don't
take the car out in the rain then lay it up for three
weeks is the moral here!

Nigel Furness
Curriculum Manager, Faculty of Computing & Digital Communications,
Soundwell Centre
City of Bristol College
0117 3125736

http://www.computing-at-cbc.co.uk/NigelFurness
http://NigelFurness.thornet.co.uk
http://classicbristolbuses.thornet.co.uk
http://www.bristolbusevents.co.uk
http://www.cityofbristol.ac.uk



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On Tue, 12 Sep 2006 07:18:31 -0400 "rob_lamoreaux" <***@***.***> wrote:


And a couple inside the distributor, some in the voltage regulator, etc.
Pretty much everything electrical that needed small screws would be BA.



Actually "Unified". SAE may be the same, but the UNC/UNF series have
much wider application than the SAE cover.



Do you mean American National or Airforce/Navy? American National are
functionaly nearly the same as Unified, but both they and Airforce/Navy
would be unobtainable in the UK in the 1960's, so they are something
else. Lotus had a close relationship with GKN, the major bolt
manufacturer in the UK, so specials would be no problem.


Mike
--
Mike Causer Email - mailto:***@***.***
GPG KeyID 1C2DDA07 WWW - http://www.mikecauser.com
Flood the fen again! - Wicken Fen enlargement - http://www.wicken.org.uk

Anyone who has had LBC parts cars probably has a dozen or so of these
rattling around in the bottom of some toolbox. I know the same nut was
used on all early Lotus cars and Triumphs through at least 1970, for
every instrument on the dash.

If you're stuck, I'll go digging. But with the number of parted-out
cars, this shouldn't be a problem.

On the sub-thread, it's been mentioned that the grade of bolts for
suspension parts is the important thing. Beware! A grade 8
(theoretically stronger) bolt is much more brittle (susceptible to
shattering under sudden pothole shock) than a lowly Grade 5.

Carroll Smith, a man those with performance cars should acquire some
respect for, will always opt for the Grade 5 in safety-critical
applications, because it will bend before it breaks (even if it bends
sooner than Grade .

There are also a lot of Chinese bolts on the market labeled as Grade 8
that are actually more like Grade 2.

-- Doug Nicholls, 54/1822 Ma~