Subject: Re: [TR] Threads and Bolts

From: Bud R <[email-masked]>
Date: Thu, 24 Nov 2016 09:16:36 -0700

--===============5875947489420556918==

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	charset=windows-1252

Oops the coarse thread is 14 tpi not 12.

Bud Rolofson

Extreme Parts Racing (more than just a haircut)

71TR6 CC57365 (Good 6)
71 Spitfire MK IV Race Car #3
69 Spitfire MK 3 (back up FE engine/dinghy car)
93 Minnie Winnie Race Support Vehicle=20
77 Z-50A Hardly Davidson Honda Mini-Trail Bike (Triumph Pit Bike)

On Nov 24, 2016, at 9:04 AM, Bud R <[email-masked]> wrote:

> Listerati,
>=20
> I=92m working on the Spitfire=92s traverse leaf swing spring rear =
suspension and can=92t find locally the 7/16=94  fine thread (20 tpi) by =
3 1/2=94 bolts that were holding the vertical link and to the trunnions =
and to the swing spring bushings.
>=20
> I can find the right sizes in a coarse thread (12 tpi) grade 8 bolt =
and thats my plan. The old ones are grade 5 or in one case a bolt with =
no slash marks on top. I don=92t know what it is.
> =20
> Do these bolts need to be fine thread for any particular reason, e.g. =
for safety, torque specs, etc.? Is a grade 8 bolt a good idea where it =
will be stressed with all the up and down motion with the vertical link? =
Too brittle? Usually I go for grade 8 whenever possible but I=92ve heard =
there are instances where it might not be the best solution.
>=20
> An aside for Thanksgiving:=20
> My son and his wife teaching in Shanghai said the Chinese love to =
celebrate American holidays (they know them from American TV and movies) =
but their take on Thanksgiving is that you thank people who do nice =
things for you. So they got cards from their students thanking them for =
teaching. Kind of a different twist but a good one I thought.
>=20
> Happy Thanksgiving to all.
>=20
>=20
> Bud Rolofson
>=20
> Extreme Parts Racing (more than just a haircut)
>=20
> 71TR6 CC57365 (Good 6)
> 71 Spitfire MK IV Race Car #3
> 69 Spitfire MK 3 (back up FE engine/dinghy car)
> 93 Minnie Winnie Race Support Vehicle=20
> 77 Z-50A Hardly Davidson Honda Mini-Trail Bike (Triumph Pit Bike)
>=20
>=20
>=20
>=20
>=20
>=20
>=20
>=20
>=20
>=20
>=20
>=20

--Apple-Mail=_BC3240C1-7C32-43AD-B59C-54BD8C60AD33
Content-Transfer-Encoding: quoted-printable
	charset=windows-1252

<html><head><meta http-equiv=3D"Content-Type" content=3D"text/html =
charset=3Dwindows-1252"></head><body style=3D"word-wrap: break-word; =
-webkit-nbsp-mode: space; -webkit-line-break: after-white-space;">Oops =
the coarse thread is 14 tpi not 12.<br><div>
<span class=3D"Apple-style-span" style=3D"color: rgb(0, 0, 0); =
font-family: Helvetica; font-size: 18px; font-style: normal; =
font-variant: normal; font-weight: normal; letter-spacing: normal; =
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text-transform: none; white-space: normal; word-spacing: 0px; =
-webkit-text-stroke-width: 0px; border-collapse: separate; orphans: 2; =
widows: 2; border-spacing: 0px; -webkit-text-decorations-in-effect: =
none;"><div style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; =
-webkit-line-break: after-white-space;"><span class=3D"Apple-style-span" =
style=3D"orphans: 2; text-align: -webkit-auto; text-indent: 0px; widows: =
2; -webkit-text-decorations-in-effect: none;"><div style=3D"word-wrap: =
break-word; -webkit-nbsp-mode: space; -webkit-line-break: =
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2; text-align: -webkit-auto; text-indent: 0px; widows: 2; =
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break-word; -webkit-nbsp-mode: space; -webkit-line-break: =
after-white-space;"><span class=3D"Apple-style-span" style=3D"orphans: =
2; text-align: -webkit-auto; text-indent: 0px; widows: 2; =
-webkit-text-decorations-in-effect: none;"><div style=3D"word-wrap: =
break-word; -webkit-nbsp-mode: space; -webkit-line-break: =
after-white-space;"><span class=3D"Apple-style-span" style=3D"orphans: =
2; text-align: -webkit-auto; text-indent: 0px; widows: 2; =
-webkit-text-decorations-in-effect: none;"><div style=3D"word-wrap: =
break-word; -webkit-nbsp-mode: space; -webkit-line-break: =
after-white-space;"><span class=3D"Apple-style-span" style=3D"orphans: =
2; text-align: -webkit-auto; text-indent: 0px; widows: 2; =
-webkit-text-decorations-in-effect: none;"><div style=3D"word-wrap: =
break-word; -webkit-nbsp-mode: space; -webkit-line-break: =
after-white-space;"><span class=3D"Apple-style-span" style=3D"orphans: =
2; text-indent: 0px; widows: 2; -webkit-text-decorations-in-effect: =
none;"><div style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; =
-webkit-line-break: after-white-space;"><span class=3D"Apple-style-span" =
style=3D"orphans: 2; text-indent: 0px; widows: 2; =
-webkit-text-decorations-in-effect: none;"><div><div =
style=3D"border-collapse: separate; color: rgb(0, 0, 0); font-family: =
Helvetica; font-style: normal; font-variant: normal; font-weight: =
normal; letter-spacing: normal; line-height: normal; text-transform: =
none; white-space: normal; word-spacing: 0px; border-spacing: 0px; =
-webkit-text-stroke-width: 0px;"><br =
class=3D"Apple-interchange-newline">Bud Rolofson</div><div =
style=3D"border-collapse: separate; color: rgb(0, 0, 0); font-family: =
Helvetica; font-style: normal; font-variant: normal; font-weight: =
normal; letter-spacing: normal; line-height: normal; text-transform: =
none; white-space: normal; word-spacing: 0px; border-spacing: 0px; =
-webkit-text-stroke-width: 0px;"><br></div><div style=3D"border-collapse: =
separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: =
normal; font-variant: normal; font-weight: normal; letter-spacing: =
normal; line-height: normal; text-transform: none; white-space: normal; =
word-spacing: 0px; border-spacing: 0px; -webkit-text-stroke-width: =
0px;">Extreme Parts Racing&nbsp;(more than just a haircut)</div><div =
style=3D"border-collapse: separate; color: rgb(0, 0, 0); font-family: =
Helvetica; font-style: normal; font-variant: normal; font-weight: =
normal; letter-spacing: normal; line-height: normal; text-transform: =
none; white-space: normal; word-spacing: 0px; border-spacing: 0px; =
-webkit-text-stroke-width: 0px;"><br></div><div>71TR6 CC57365 (Good =
6)</div><div style=3D"border-collapse: separate; color: rgb(0, 0, 0); =
font-family: Helvetica; font-style: normal; font-variant: normal; =
font-weight: normal; letter-spacing: normal; line-height: normal; =
text-transform: none; white-space: normal; word-spacing: 0px; =
border-spacing: 0px; -webkit-text-stroke-width: 0px;">71 Spitfire MK IV =
Race Car #3</div><div style=3D"border-collapse: separate; color: rgb(0, =
0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; =
font-weight: normal; letter-spacing: normal; line-height: normal; =
text-transform: none; white-space: normal; word-spacing: 0px; =
border-spacing: 0px; -webkit-text-stroke-width: 0px;">69 Spitfire MK 3 =
(back up FE engine/dinghy car)</div><div style=3D"border-collapse: =
separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: =
normal; font-variant: normal; font-weight: normal; letter-spacing: =
normal; line-height: normal; text-transform: none; white-space: normal; =
word-spacing: 0px; border-spacing: 0px; -webkit-text-stroke-width: =
0px;">93 Minnie Winnie Race Support Vehicle&nbsp;</div><div =
style=3D"border-collapse: separate; color: rgb(0, 0, 0); font-family: =
Helvetica; font-style: normal; font-variant: normal; font-weight: =
normal; letter-spacing: normal; line-height: normal; text-transform: =
none; white-space: normal; word-spacing: 0px; border-spacing: 0px; =
-webkit-text-stroke-width: 0px;">77 Z-50A Hardly Davidson Honda =
Mini-Trail Bike (Triumph Pit Bike)</div></div><div =
style=3D"border-collapse: separate; color: rgb(0, 0, 0); font-family: =
Helvetica; font-size: 12px; font-style: normal; font-variant: normal; =
font-weight: normal; letter-spacing: normal; line-height: normal; =
text-transform: none; white-space: normal; word-spacing: 0px; =
border-spacing: 0px; -webkit-text-stroke-width: 0px;"><br></div><div =
style=3D"border-collapse: separate; color: rgb(0, 0, 0); font-family: =
Helvetica; font-size: 12px; font-style: normal; font-variant: normal; =
font-weight: normal; letter-spacing: normal; line-height: normal; =
text-transform: none; white-space: normal; word-spacing: 0px; =
border-spacing: 0px; -webkit-text-stroke-width: =
0px;"><br></div></span><br =
class=3D"Apple-interchange-newline"></div></span><br =
class=3D"Apple-interchange-newline"></div></span><br =
class=3D"Apple-interchange-newline"></div></span><br =
class=3D"Apple-interchange-newline"></div></span><br =
class=3D"Apple-interchange-newline"></div></span><br =
class=3D"Apple-interchange-newline"></div></span><br =
class=3D"Apple-interchange-newline"></div></span><br =
class=3D"Apple-interchange-newline" style=3D"color: rgb(0, 0, 0); =
font-family: Helvetica; font-size: 18px; font-style: normal; =
font-variant: normal; font-weight: normal; letter-spacing: normal; =
line-height: normal; orphans: auto; text-align: start; text-indent: 0px; =
text-transform: none; white-space: normal; widows: auto; word-spacing: =
0px; -webkit-text-stroke-width: 0px;"><br =
class=3D"Apple-interchange-newline">
</div>
<br><div><div>On Nov 24, 2016, at 9:04 AM, Bud R &lt;<a =
href=3D"mailto:[email-masked]">[email-masked]</a>&gt; =
wrote:</div><br class=3D"Apple-interchange-newline"><blockquote =
type=3D"cite"><meta http-equiv=3D"Content-Type" content=3D"text/html =
charset=3Dwindows-1252"><div style=3D"word-wrap: break-word; =
-webkit-nbsp-mode: space; -webkit-line-break: =
after-white-space;"><div>Listerati,</div><div><br></div>I=92m working on =
the Spitfire=92s traverse leaf swing spring rear suspension and can=92t =
find locally the 7/16=94 &nbsp;fine thread (20 tpi) by 3 1/2=94 bolts =
that were holding the vertical link and to the&nbsp;trunnions and to the =
swing spring bushings.<div><br></div><div>I can find the right sizes in =
a coarse thread (12 tpi) grade 8 bolt and thats my plan. The old ones =
are grade 5 or in one case a bolt with no slash marks on top. I don=92t =
know what it is.<br><div>&nbsp;<div>Do these bolts need to be fine =
thread for any particular reason, e.g. for safety, torque specs, etc.? =
Is a grade 8 bolt a good idea where it will be stressed with all the up =
and down motion with the vertical link? Too brittle? Usually I go for =
grade 8 whenever possible but I=92ve heard there are instances where it =
might not be the best solution.</div><div><br></div><div>An aside for =
Thanksgiving:&nbsp;</div><div>My son and his wife teaching in Shanghai =
said the Chinese love to celebrate American holidays (they know them =
from American TV and movies) but their take on Thanksgiving is that you =
thank people who do nice things for you. So they got cards from their =
students thanking them for teaching. Kind of a different twist but a =
good one I thought.</div><div><br></div><div>Happy Thanksgiving to =
all.</div></div></div><div><br></div><div>
<span class=3D"Apple-style-span" style=3D"border-collapse: separate; =
border-spacing: 0px;"><div style=3D"word-wrap: break-word; =
-webkit-nbsp-mode: space; -webkit-line-break: after-white-space;"><span =
class=3D"Apple-style-span" style=3D"orphans: 2; text-align: =
-webkit-auto; text-indent: 0px; widows: 2; =
-webkit-text-decorations-in-effect: none;"><div style=3D"word-wrap: =
break-word; -webkit-nbsp-mode: space; -webkit-line-break: =
after-white-space;"><span class=3D"Apple-style-span" style=3D"orphans: =
2; text-align: -webkit-auto; text-indent: 0px; widows: 2; =
-webkit-text-decorations-in-effect: none;"><div style=3D"word-wrap: =
break-word; -webkit-nbsp-mode: space; -webkit-line-break: =
after-white-space;"><span class=3D"Apple-style-span" style=3D"orphans: =
2; text-align: -webkit-auto; text-indent: 0px; widows: 2; =
-webkit-text-decorations-in-effect: none;"><div style=3D"word-wrap: =
break-word; -webkit-nbsp-mode: space; -webkit-line-break: =
after-white-space;"><span class=3D"Apple-style-span" style=3D"orphans: =
2; text-align: -webkit-auto; text-indent: 0px; widows: 2; =
-webkit-text-decorations-in-effect: none;"><div style=3D"word-wrap: =
break-word; -webkit-nbsp-mode: space; -webkit-line-break: =
after-white-space;"><span class=3D"Apple-style-span" style=3D"orphans: =
2; text-align: -webkit-auto; text-indent: 0px; widows: 2; =
-webkit-text-decorations-in-effect: none;"><div style=3D"word-wrap: =
break-word; -webkit-nbsp-mode: space; -webkit-line-break: =
after-white-space;"><span class=3D"Apple-style-span" style=3D"orphans: =
2; text-indent: 0px; widows: 2; -webkit-text-decorations-in-effect: =
none;"><div style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; =
-webkit-line-break: after-white-space;"><span class=3D"Apple-style-span" =
style=3D"orphans: 2; text-indent: 0px; widows: 2; =
-webkit-text-decorations-in-effect: none;"><div><div =
style=3D"border-collapse: separate; font-family: Helvetica; font-style: =
normal; font-variant: normal; font-weight: normal; letter-spacing: =
normal; line-height: normal; text-transform: none; white-space: normal; =
word-spacing: 0px; border-spacing: 0px; -webkit-text-stroke-width: =
0px;"><br class=3D"Apple-interchange-newline">Bud Rolofson</div><div =
style=3D"border-collapse: separate; font-family: Helvetica; font-style: =
normal; font-variant: normal; font-weight: normal; letter-spacing: =
normal; line-height: normal; text-transform: none; white-space: normal; =
word-spacing: 0px; border-spacing: 0px; -webkit-text-stroke-width: =
0px;"><br></div><div style=3D"border-collapse: separate; font-family: =
Helvetica; font-style: normal; font-variant: normal; font-weight: =
normal; letter-spacing: normal; line-height: normal; text-transform: =
none; white-space: normal; word-spacing: 0px; border-spacing: 0px; =
-webkit-text-stroke-width: 0px;">Extreme Parts Racing&nbsp;(more than =
just a haircut)</div><div style=3D"border-collapse: separate; =
font-family: Helvetica; font-style: normal; font-variant: normal; =
font-weight: normal; letter-spacing: normal; line-height: normal; =
text-transform: none; white-space: normal; word-spacing: 0px; =
border-spacing: 0px; -webkit-text-stroke-width: =
0px;"><br></div><div>71TR6 CC57365 (Good 6)</div><div =
style=3D"border-collapse: separate; font-family: Helvetica; font-style: =
normal; font-variant: normal; font-weight: normal; letter-spacing: =
normal; line-height: normal; text-transform: none; white-space: normal; =
word-spacing: 0px; border-spacing: 0px; -webkit-text-stroke-width: =
0px;">71 Spitfire MK IV Race Car #3</div><div style=3D"border-collapse: =
separate; font-family: Helvetica; font-style: normal; font-variant: =
normal; font-weight: normal; letter-spacing: normal; line-height: =
normal; text-transform: none; white-space: normal; word-spacing: 0px; =
border-spacing: 0px; -webkit-text-stroke-width: 0px;">69 Spitfire MK 3 =
(back up FE engine/dinghy car)</div><div style=3D"border-collapse: =
separate; font-family: Helvetica; font-style: normal; font-variant: =
normal; font-weight: normal; letter-spacing: normal; line-height: =
normal; text-transform: none; white-space: normal; word-spacing: 0px; =
border-spacing: 0px; -webkit-text-stroke-width: 0px;">93 Minnie Winnie =
Race Support Vehicle&nbsp;</div><div style=3D"border-collapse: separate; =
font-family: Helvetica; font-style: normal; font-variant: normal; =
font-weight: normal; letter-spacing: normal; line-height: normal; =
text-transform: none; white-space: normal; word-spacing: 0px; =
border-spacing: 0px; -webkit-text-stroke-width: 0px;">77 Z-50A Hardly =
Davidson Honda Mini-Trail Bike (Triumph Pit Bike)</div></div><div =
style=3D"border-collapse: separate; font-family: Helvetica; font-size: =
12px; font-style: normal; font-variant: normal; font-weight: normal; =
letter-spacing: normal; line-height: normal; text-transform: none; =
white-space: normal; word-spacing: 0px; border-spacing: 0px; =
-webkit-text-stroke-width: 0px;"><br></div><div style=3D"border-collapse: =
separate; font-family: Helvetica; font-size: 12px; font-style: normal; =
font-variant: normal; font-weight: normal; letter-spacing: normal; =
line-height: normal; text-transform: none; white-space: normal; =
word-spacing: 0px; border-spacing: 0px; -webkit-text-stroke-width: =
0px;"><br></div></span><br =
class=3D"Apple-interchange-newline"></div></span><br =
class=3D"Apple-interchange-newline"></div></span><br =
class=3D"Apple-interchange-newline"></div></span><br =
class=3D"Apple-interchange-newline"></div></span><br =
class=3D"Apple-interchange-newline"></div></span><br =
class=3D"Apple-interchange-newline"></div></span><br =
class=3D"Apple-interchange-newline"></div></span><br =
class=3D"Apple-interchange-newline" style=3D"font-family: Helvetica; =
font-size: 18px; font-style: normal; font-variant: normal; font-weight: =
normal; letter-spacing: normal; line-height: normal; orphans: auto; =
text-align: start; text-indent: 0px; text-transform: none; white-space: =
normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: =
0px;"><br class=3D"Apple-interchange-newline">
</div>
<br></div></blockquote></div><br></body></html>=

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** [email-masked] **

Archive: http://www.team.net/archive

--===============5875947489420556918==--

---

From: Dave <[email-masked]>
Date: Thu, 24 Nov 2016 13:51:09 -0500

--===============7593878096927396608==
	boundary="----=_Part_36924_2010859738.1480013468988"

------=_Part_36924_2010859738.1480013468988
Content-Transfer-Encoding: quoted-printable

Bolts with no slashes are grade two.  The grade of the bolt is indicated by=
 the number of slashes plus two.  I do not recommend grade two for suspensi=
on duty. =20

I've heard said that the trade-off with Grade 8 bolts is that they are stro=
nger but more brittle.  Since I am not a mechanical engineer I cannot make =
a recommendation on substituting a grade 8 for a grade 5 but I would be con=
cerned that the increased brittle nature may be a detriment. Considering th=
e seriousness of the consequences of a suspension failure I would think aga=
in about making substitutions.  And just about anything you need is availab=
le next business day from McMaster Carr (and other sources, certainly).  Bu=
t you may have to buy more than you need and pay shipping.

I don't think fine thread vs coarse thread makes much difference.

Just my opinion.

=20

Dave Massey

=20

=20

-----Original Message-----
From: Bud R <[email-masked]>
To: Triumph Mail List <[email-masked]>
Sent: Thu, Nov 24, 2016 12:38 pm
Subject: [TR] Threads and Bolts

Listerati,

I=E2=80=99m working on the Spitfire=E2=80=99s traverse leaf swing spring re=
ar suspension and can=E2=80=99t find locally the 7/16=E2=80=9D  fine thread=
 (20 tpi) by 3 1/2=E2=80=9D bolts that were holding the vertical link and t=
o the trunnions and to the swing spring bushings.

I can find the right sizes in a coarse thread (12 tpi) grade 8 bolt and tha=
ts my plan. The old ones are grade 5 or in one case a bolt with no slash ma=
rks on top. I don=E2=80=99t know what it is.

=20
Do these bolts need to be fine thread for any particular reason, e.g. for s=
afety, torque specs, etc.? Is a grade 8 bolt a good idea where it will be s=
tressed with all the up and down motion with the vertical link? Too brittle=
? Usually I go for grade 8 whenever possible but I=E2=80=99ve heard there a=
re instances where it might not be the best solution.

An aside for Thanksgiving:=20
My son and his wife teaching in Shanghai said the Chinese love to celebrate=
 American holidays (they know them from American TV and movies) but their t=
ake on Thanksgiving is that you thank people who do nice things for you. So=
 they got cards from their students thanking them for teaching. Kind of a d=
ifferent twist but a good one I thought.

Bud Rolofson

71TR6 CC57365 (Good 6)

[email-masked]

------=_Part_36924_2010859738.1480013468988
Content-Transfer-Encoding: quoted-printable

<font color=3D'black' size=3D'4' face=3D'Arial, Helvetica, sans-serif'><fon=
t size=3D"4">Bolts with no slashes are grade two.&nbsp; The grade of the bo=
lt is indicated by the number of slashes plus two.&nbsp; I do not recommend=
 grade two for suspension duty.&nbsp; <br>
<br>
I've heard said that the trade-off with Grade 8 bolts is that they are stro=
nger but more brittle.&nbsp; Since I am not a mechanical engineer I cannot =
make a recommendation on substituting a grade 8 for a grade 5 but I would b=
e concerned that the increased brittle nature may be a detriment. Consideri=
ng the seriousness of the consequences of a suspension failure I would thin=
k again about making substitutions.&nbsp; And just about anything you need =
is available next business day from McMaster Carr (and other sources, certa=
inly).&nbsp; But you may have to buy more than you need and pay shipping.</=
font><br>
<br>
<font size=3D"4">I don't think fine thread vs coarse thread makes much diff=
erence.<br>
<br>
Just my opinion.<br>
</font>
<div> <br>

</div>

<div style=3D"clear:both"><font size=3D"4">Dave Massey</font><br>

<br>

</div>

<div> <br>

</div>

<div> <br>

</div>

<div style=3D"font-family:arial,helvetica;font-size:10pt;color:black">-----=
Original Message-----<br>

From: Bud R &lt;[email-masked]&gt;<br>

To: Triumph Mail List &lt;[email-masked]&gt;<br>

Sent: Thu, Nov 24, 2016 12:38 pm<br>

Subject: [TR] Threads and Bolts<br>

<br>

<div id=3D"AOLMsgPart_1.2_e9fc94a6-abdd-40f8-a252-0451dcf2ea86">

<div style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line=
-break: after-white-space;" class=3D"aolReplacedBody">

<div>Listerati,</div>

<div><br>

</div>

I=E2=80=99m working on the Spitfire=E2=80=99s traverse leaf swing spring re=
ar suspension and can=E2=80=99t find locally the 7/16=E2=80=9D &nbsp;fine t=
hread (20 tpi) by 3 1/2=E2=80=9D bolts that were holding the vertical link =
and to the&nbsp;trunnions and to the swing spring bushings.

<div><br>

</div>

<div>I can find the right sizes in a coarse thread (12 tpi) grade 8 bolt an=
d thats my plan. The old ones are grade 5 or in one case a bolt with no sla=
sh marks on top. I don=E2=80=99t know what it is.<br>

<div>&nbsp;

<div>Do these bolts need to be fine thread for any particular reason, e.g. =
for safety, torque specs, etc.? Is a grade 8 bolt a good idea where it will=
 be stressed with all the up and down motion with the vertical link? Too br=
ittle? Usually I go for grade 8 whenever possible but I=E2=80=99ve heard th=
ere are instances where it might not be the best solution.</div>

<div><br>

</div>

<div>An aside for Thanksgiving:&nbsp;</div>

<div>My son and his wife teaching in Shanghai said the Chinese love to cele=
brate American holidays (they know them from American TV and movies) but th=
eir take on Thanksgiving is that you thank people who do nice things for yo=
u. So they got cards from their students thanking them for teaching. Kind o=
f a different twist but a good one I thought.</div>

<div><br>

</div>

<div>Happy Thanksgiving to all.</div>

</div>

</div>

<div><br>

</div>

<div>
<span class=3D"Apple-style-span" style=3D"border-collapse: separate; border=
-spacing: 0px;">

<div style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line=
-break: after-white-space;"><span class=3D"Apple-style-span" style=3D"orpha=
ns: 2; text-align: -webkit-auto; text-indent: 0px; widows: 2; -webkit-text-=
decorations-in-effect: none;">

<div style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line=
-break: after-white-space;"><span class=3D"Apple-style-span" style=3D"orpha=
ns: 2; text-align: -webkit-auto; text-indent: 0px; widows: 2; -webkit-text-=
decorations-in-effect: none;">

<div style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line=
-break: after-white-space;"><span class=3D"Apple-style-span" style=3D"orpha=
ns: 2; text-align: -webkit-auto; text-indent: 0px; widows: 2; -webkit-text-=
decorations-in-effect: none;">

<div style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line=
-break: after-white-space;"><span class=3D"Apple-style-span" style=3D"orpha=
ns: 2; text-align: -webkit-auto; text-indent: 0px; widows: 2; -webkit-text-=
decorations-in-effect: none;">

<div style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line=
-break: after-white-space;"><span class=3D"Apple-style-span" style=3D"orpha=
ns: 2; text-align: -webkit-auto; text-indent: 0px; widows: 2; -webkit-text-=
decorations-in-effect: none;">

<div style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line=
-break: after-white-space;"><span class=3D"Apple-style-span" style=3D"orpha=
ns: 2; text-indent: 0px; widows: 2; -webkit-text-decorations-in-effect: non=
e;">

<div style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line=
-break: after-white-space;"><span class=3D"Apple-style-span" style=3D"orpha=
ns: 2; text-indent: 0px; widows: 2; -webkit-text-decorations-in-effect: non=
e;">

<div>

<div style=3D"border-collapse: separate; color: rgb(0, 0, 0); font-family: =
Helvetica; font-style: normal; font-variant: normal; font-weight: normal; l=
etter-spacing: normal; line-height: normal; text-transform: none; white-spa=
ce: normal; word-spacing: 0px; border-spacing: 0px; -webkit-text-stroke-wid=
th: 0px;"><br class=3D"Apple-interchange-newline">Bud Rolofson</div>

<div style=3D"border-collapse: separate; color: rgb(0, 0, 0); font-family: =
Helvetica; font-style: normal; font-variant: normal; font-weight: normal; l=
etter-spacing: normal; line-height: normal; text-transform: none; white-spa=
ce: normal; word-spacing: 0px; border-spacing: 0px; -webkit-text-stroke-wid=
th: 0px;"><br>

</div>

<div style=3D"border-collapse: separate; color: rgb(0, 0, 0); font-family: =
Helvetica; font-style: normal; font-variant: normal; font-weight: normal; l=
etter-spacing: normal; line-height: normal; text-transform: none; white-spa=
ce: normal; word-spacing: 0px; border-spacing: 0px; -webkit-text-stroke-wid=
th: 0px;">Extreme Parts Racing&nbsp;(more than just a haircut)</div>

<div style=3D"border-collapse: separate; color: rgb(0, 0, 0); font-family: =
Helvetica; font-style: normal; font-variant: normal; font-weight: normal; l=
etter-spacing: normal; line-height: normal; text-transform: none; white-spa=
ce: normal; word-spacing: 0px; border-spacing: 0px; -webkit-text-stroke-wid=
th: 0px;"><br>

</div>

<div>71TR6 CC57365 (Good 6)</div>

<div style=3D"border-collapse: separate; color: rgb(0, 0, 0); font-family: =
Helvetica; font-style: normal; font-variant: normal; font-weight: normal; l=
etter-spacing: normal; line-height: normal; text-transform: none; white-spa=
ce: normal; word-spacing: 0px; border-spacing: 0px; -webkit-text-stroke-wid=
th: 0px;">71 Spitfire MK IV Race Car #3</div>

<div style=3D"border-collapse: separate; color: rgb(0, 0, 0); font-family: =
Helvetica; font-style: normal; font-variant: normal; font-weight: normal; l=
etter-spacing: normal; line-height: normal; text-transform: none; white-spa=
ce: normal; word-spacing: 0px; border-spacing: 0px; -webkit-text-stroke-wid=
th: 0px;">69 Spitfire MK 3 (back up FE engine/dinghy car)</div>

<div style=3D"border-collapse: separate; color: rgb(0, 0, 0); font-family: =
Helvetica; font-style: normal; font-variant: normal; font-weight: normal; l=
etter-spacing: normal; line-height: normal; text-transform: none; white-spa=
ce: normal; word-spacing: 0px; border-spacing: 0px; -webkit-text-stroke-wid=
th: 0px;">93 Minnie Winnie Race Support Vehicle&nbsp;</div>

<div style=3D"border-collapse: separate; color: rgb(0, 0, 0); font-family: =
Helvetica; font-style: normal; font-variant: normal; font-weight: normal; l=
etter-spacing: normal; line-height: normal; text-transform: none; white-spa=
ce: normal; word-spacing: 0px; border-spacing: 0px; -webkit-text-stroke-wid=
th: 0px;">77 Z-50A Hardly Davidson Honda Mini-Trail Bike (Triumph Pit Bike)=
</div>

</div>

<div style=3D"border-collapse: separate; color: rgb(0, 0, 0); font-family: =
Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-=
weight: normal; letter-spacing: normal; line-height: normal; text-transform=
: none; white-space: normal; word-spacing: 0px; border-spacing: 0px; -webki=
t-text-stroke-width: 0px;"><br>

</div>

<div style=3D"border-collapse: separate; color: rgb(0, 0, 0); font-family: =
Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-=
weight: normal; letter-spacing: normal; line-height: normal; text-transform=
: none; white-space: normal; word-spacing: 0px; border-spacing: 0px; -webki=
t-text-stroke-width: 0px;"><br>

</div>

</span><br class=3D"Apple-interchange-newline"></div>

</span><br class=3D"Apple-interchange-newline"></div>

</span><br class=3D"Apple-interchange-newline"></div>

</span><br class=3D"Apple-interchange-newline"></div>

</span><br class=3D"Apple-interchange-newline"></div>

</span><br class=3D"Apple-interchange-newline"></div>

</span><br class=3D"Apple-interchange-newline"></div>

</span><br class=3D"Apple-interchange-newline" style=3D"color: rgb(0, 0, 0)=
; font-family: Helvetica; font-size: 18px; font-style: normal; font-variant=
: normal; font-weight: normal; letter-spacing: normal; line-height: normal;=
 orphans: auto; text-align: start; text-indent: 0px; text-transform: none; =
white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-w=
idth: 0px;"><br class=3D"Apple-interchange-newline">
</div>

<br>

</div>

</div>

<br>

** <a href=3D"mailto:[email-masked]">[email-masked]</a> *=
*<br>

<br>

//www.team.net/donate.html</a><br>

Archive: <a href=3D"http://www.team.net/archive" target=3D"_blank">http://w=
ww.team.net/archive</a><br>

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.team.net/forums</a><br>

hs/[email-masked]" target=3D"_blank">http://autox.team.net/mailman/opti=
ons/triumphs/[email-masked]</a><br>

</div>

</font>
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From: Frank Fisher <[email-masked]>
Date: Fri, 25 Nov 2016 00:13:23 +0000 (UTC)

--===============0936257521538816473==
	boundary="----=_Part_23915_516352527.1480032803290"

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every thing is available at mcmastercarr.com
frank

      From: Bud R <[email-masked]>
 To: Triumph Mail List <[email-masked]>=20
 Sent: Thursday, November 24, 2016 8:04 AM
 Subject: [TR] Threads and Bolts
  =20
Listerati,
I=E2=80=99m working on the Spitfire=E2=80=99s traverse leaf swing spring re=
ar suspension and can=E2=80=99t find locally the 7/16=E2=80=9D =C2=A0fine t=
hread (20 tpi) by 3 1/2=E2=80=9D bolts that were holding the vertical link =
and to the=C2=A0trunnions and to the swing spring bushings.
I can find the right sizes in a coarse thread (12 tpi) grade 8 bolt and tha=
ts my plan. The old ones are grade 5 or in one case a bolt with no slash ma=
rks on top. I don=E2=80=99t know what it is.
=C2=A0Do these bolts need to be fine thread for any particular reason, e.g.=
 for safety, torque specs, etc.? Is a grade 8 bolt a good idea where it wil=
l be stressed with all the up and down motion with the vertical link? Too b=
rittle? Usually I go for grade 8 whenever possible but I=E2=80=99ve heard t=
here are instances where it might not be the best solution.
An aside for Thanksgiving:=C2=A0My son and his wife teaching in Shanghai sa=
id the Chinese love to celebrate American holidays (they know them from Ame=
rican TV and movies) but their take on Thanksgiving is that you thank peopl=
e who do nice things for you. So they got cards from their students thankin=
g them for teaching. Kind of a different twist but a good one I thought.
Happy Thanksgiving to all.

Bud Rolofson
Extreme Parts Racing=C2=A0(more than just a haircut)
71TR6 CC57365 (Good 6)71 Spitfire MK IV Race Car #369 Spitfire MK 3 (back u=
p FE engine/dinghy car)93 Minnie Winnie Race Support Vehicle=C2=A077 Z-50A =
Hardly Davidson Honda Mini-Trail Bike (Triumph Pit Bike)

[email-masked]

  =20
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Content-Transfer-Encoding: quoted-printable

<html><head></head><body><div style=3D"color:#000; background-color:#fff; f=
ont-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, =
sans-serif;font-size:16px"><div dir=3D"ltr" id=3D"yui_3_16_0_ym19_1_1479837=
099481_147613"><span id=3D"yui_3_16_0_ym19_1_1479837099481_147614">every th=
ing is available at mcmastercarr.com</span></div><div dir=3D"ltr" id=3D"yui=
_3_16_0_ym19_1_1479837099481_147612"><span><br></span></div><div dir=3D"ltr=
" id=3D"yui_3_16_0_ym19_1_1479837099481_147611"><span>frank</span></div><di=
v dir=3D"ltr" id=3D"yui_3_16_0_ym19_1_1479837099481_147610"><span><br></spa=
n></div><div class=3D"qtdSeparateBR" id=3D"yui_3_16_0_ym19_1_1479837099481_=
147609"><br><br></div><div class=3D"yahoo_quoted" id=3D"yui_3_16_0_ym19_1_1=
479837099481_147537" style=3D"display: block;">  <div style=3D"font-family:=
 HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif=
; font-size: 16px;" id=3D"yui_3_16_0_ym19_1_1479837099481_147536"> <div sty=
le=3D"font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida =
Grande, sans-serif; font-size: 16px;" id=3D"yui_3_16_0_ym19_1_1479837099481=
_147535"> <div dir=3D"ltr" id=3D"yui_3_16_0_ym19_1_1479837099481_147606"> <=
font size=3D"2" face=3D"Arial" id=3D"yui_3_16_0_ym19_1_1479837099481_147607=
"> <hr size=3D"1" id=3D"yui_3_16_0_ym19_1_1479837099481_147608"> <b><span s=
tyle=3D"font-weight:bold;">From:</span></b> Bud R &lt;[email-masked]&=
gt;<br> <b><span style=3D"font-weight: bold;">To:</span></b> Triumph Mail L=
ist &lt;[email-masked]&gt; <br> <b><span style=3D"font-weight: bol=
d;">Sent:</span></b> Thursday, November 24, 2016 8:04 AM<br> <b><span style=
=3D"font-weight: bold;">Subject:</span></b> [TR] Threads and Bolts<br> </fo=
nt> </div> <div class=3D"y_msg_container" id=3D"yui_3_16_0_ym19_1_147983709=
9481_147534"><br><div id=3D"yiv0935299757"><div id=3D"yui_3_16_0_ym19_1_147=
9837099481_147533"><div id=3D"yui_3_16_0_ym19_1_1479837099481_147605">Liste=
rati,</div><div id=3D"yui_3_16_0_ym19_1_1479837099481_147604"><br></div>I=
=E2=80=99m working on the Spitfire=E2=80=99s traverse leaf swing spring rea=
r suspension and can=E2=80=99t find locally the 7/16=E2=80=9D &nbsp;fine th=
read (20 tpi) by 3 1/2=E2=80=9D bolts that were holding the vertical link a=
nd to the&nbsp;trunnions and to the swing spring bushings.<div id=3D"yui_3_=
16_0_ym19_1_1479837099481_147532"><br></div><div id=3D"yui_3_16_0_ym19_1_14=
79837099481_147617">I can find the right sizes in a coarse thread (12 tpi) =
grade 8 bolt and thats my plan. The old ones are grade 5 or in one case a b=
olt with no slash marks on top. I don=E2=80=99t know what it is.<br><div id=
=3D"yui_3_16_0_ym19_1_1479837099481_147618">&nbsp;<div id=3D"yui_3_16_0_ym1=
9_1_1479837099481_147619">Do these bolts need to be fine thread for any par=
ticular reason, e.g. for safety, torque specs, etc.? Is a grade 8 bolt a go=
od idea where it will be stressed with all the up and down motion with the =
vertical link? Too brittle? Usually I go for grade 8 whenever possible but =
I=E2=80=99ve heard there are instances where it might not be the best solut=
ion.</div><div id=3D"yui_3_16_0_ym19_1_1479837099481_147620"><br></div><div=
 id=3D"yui_3_16_0_ym19_1_1479837099481_147621">An aside for Thanksgiving:&n=
bsp;</div><div id=3D"yui_3_16_0_ym19_1_1479837099481_147622">My son and his=
 wife teaching in Shanghai said the Chinese love to celebrate American holi=
days (they know them from American TV and movies) but their take on Thanksg=
iving is that you thank people who do nice things for you. So they got card=
s from their students thanking them for teaching. Kind of a different twist=
 but a good one I thought.</div><div><br></div><div>Happy Thanksgiving to a=
ll.</div></div></div><div><br></div><div>
<span class=3D"yiv0935299757Apple-style-span" style=3D"border-collapse:sepa=
rate;border-spacing:0px;"><div style=3D"word-wrap:break-word;"><span class=
=3D"yiv0935299757Apple-style-span" style=3D"orphans:2;text-indent:0px;widow=
s:2;"><div style=3D"word-wrap:break-word;"><span class=3D"yiv0935299757Appl=
e-style-span" style=3D"orphans:2;text-indent:0px;widows:2;"><div style=3D"w=
ord-wrap:break-word;"><span class=3D"yiv0935299757Apple-style-span" style=
=3D"orphans:2;text-indent:0px;widows:2;"><div style=3D"word-wrap:break-word=
;"><span class=3D"yiv0935299757Apple-style-span" style=3D"orphans:2;text-in=
dent:0px;widows:2;"><div style=3D"word-wrap:break-word;"><span class=3D"yiv=
0935299757Apple-style-span" style=3D"orphans:2;text-indent:0px;widows:2;"><=
div style=3D"word-wrap:break-word;"><span class=3D"yiv0935299757Apple-style=
-span" style=3D"orphans:2;text-indent:0px;widows:2;"><div style=3D"word-wra=
p:break-word;"><span class=3D"yiv0935299757Apple-style-span" style=3D"orpha=
ns:2;text-indent:0px;widows:2;"><div><div style=3D"border-collapse:separate=
;color:rgb(0, 0, 0);font-family:Helvetica;font-style:normal;font-variant:no=
rmal;font-weight:normal;letter-spacing:normal;line-height:normal;text-trans=
form:none;white-space:normal;word-spacing:0px;border-spacing:0px;"><br clas=
s=3D"yiv0935299757Apple-interchange-newline">Bud Rolofson</div><div style=
=3D"border-collapse:separate;color:rgb(0, 0, 0);font-family:Helvetica;font-=
style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;l=
ine-height:normal;text-transform:none;white-space:normal;word-spacing:0px;b=
order-spacing:0px;"><br></div><div style=3D"border-collapse:separate;color:=
rgb(0, 0, 0);font-family:Helvetica;font-style:normal;font-variant:normal;fo=
nt-weight:normal;letter-spacing:normal;line-height:normal;text-transform:no=
ne;white-space:normal;word-spacing:0px;border-spacing:0px;">Extreme Parts R=
acing&nbsp;(more than just a haircut)</div><div style=3D"border-collapse:se=
parate;color:rgb(0, 0, 0);font-family:Helvetica;font-style:normal;font-vari=
ant:normal;font-weight:normal;letter-spacing:normal;line-height:normal;text=
-transform:none;white-space:normal;word-spacing:0px;border-spacing:0px;"><b=
r></div><div>71TR6 CC57365 (Good 6)</div><div style=3D"border-collapse:sepa=
rate;color:rgb(0, 0, 0);font-family:Helvetica;font-style:normal;font-varian=
t:normal;font-weight:normal;letter-spacing:normal;line-height:normal;text-t=
ransform:none;white-space:normal;word-spacing:0px;border-spacing:0px;">71 S=
pitfire MK IV Race Car #3</div><div style=3D"border-collapse:separate;color=
:rgb(0, 0, 0);font-family:Helvetica;font-style:normal;font-variant:normal;f=
ont-weight:normal;letter-spacing:normal;line-height:normal;text-transform:n=
one;white-space:normal;word-spacing:0px;border-spacing:0px;">69 Spitfire MK=
 3 (back up FE engine/dinghy car)</div><div style=3D"border-collapse:separa=
te;color:rgb(0, 0, 0);font-family:Helvetica;font-style:normal;font-variant:=
normal;font-weight:normal;letter-spacing:normal;line-height:normal;text-tra=
nsform:none;white-space:normal;word-spacing:0px;border-spacing:0px;">93 Min=
nie Winnie Race Support Vehicle&nbsp;</div><div style=3D"border-collapse:se=
parate;color:rgb(0, 0, 0);font-family:Helvetica;font-style:normal;font-vari=
ant:normal;font-weight:normal;letter-spacing:normal;line-height:normal;text=
-transform:none;white-space:normal;word-spacing:0px;border-spacing:0px;">77=
 Z-50A Hardly Davidson Honda Mini-Trail Bike (Triumph Pit Bike)</div></div>=
<div style=3D"border-collapse:separate;color:rgb(0, 0, 0);font-family:Helve=
tica;font-size:12px;font-style:normal;font-variant:normal;font-weight:norma=
l;letter-spacing:normal;line-height:normal;text-transform:none;white-space:=
normal;word-spacing:0px;border-spacing:0px;"><br></div><div style=3D"border=
-collapse:separate;color:rgb(0, 0, 0);font-family:Helvetica;font-size:12px;=
font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:nor=
mal;line-height:normal;text-transform:none;white-space:normal;word-spacing:=
0px;border-spacing:0px;"><br></div></span><br class=3D"yiv0935299757Apple-i=
nterchange-newline"></div></span><br class=3D"yiv0935299757Apple-interchang=
e-newline"></div></span><br class=3D"yiv0935299757Apple-interchange-newline=
"></div></span><br class=3D"yiv0935299757Apple-interchange-newline"></div><=
/span><br class=3D"yiv0935299757Apple-interchange-newline"></div></span><br=
 class=3D"yiv0935299757Apple-interchange-newline"></div></span><br class=3D=
"yiv0935299757Apple-interchange-newline"></div></span><br class=3D"yiv09352=
99757Apple-interchange-newline" style=3D"color:rgb(0, 0, 0);font-family:Hel=
vetica;font-size:18px;font-style:normal;font-variant:normal;font-weight:nor=
mal;letter-spacing:normal;line-height:normal;text-indent:0px;text-transform=
:none;white-space:normal;word-spacing:0px;"><br class=3D"yiv0935299757Apple=
-interchange-newline">
</div>
<br></div></div><br><br>** <a ymailto=3D"mailto:[email-masked]" hr=
ef=3D"mailto:[email-masked]">[email-masked]</a> **<br><br=
>Donate: <a href=3D"http://www.team.net/donate.html" target=3D"_blank">http=
://www.team.net/donate.html</a><br>Archive: <a href=3D"http://www.team.net/=
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ums</a><br>Unsubscribe/Manage: <a href=3D"http://autox.team.net/mailman/opt=
ions/triumphs/[email-masked]" target=3D"_blank">http://autox.team.net/=
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From: Michael Porter <[email-masked]>
Date: Thu, 24 Nov 2016 17:13:23 -0700

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On 11/24/2016 11:51 AM, Dave wrote:
> Bolts with no slashes are grade two.  The grade of the bolt is 
> indicated by the number of slashes plus two.  I do not recommend grade 
> two for suspension duty.
>
> I've heard said that the trade-off with Grade 8 bolts is that they are 
> stronger but more brittle.  Since I am not a mechanical engineer I 
> cannot make a recommendation on substituting a grade 8 for a grade 5 
> but I would be concerned that the increased brittle nature may be a 
> detriment. Considering the seriousness of the consequences of a 
> suspension failure I would think again about making substitutions.  
> And just about anything you need is available next business day from 
> McMaster Carr (and other sources, certainly).  But you may have to buy 
> more than you need and pay shipping.
>

Brittleness is relative.  The optimum condition for a strong bolt is 
toughness, the combination of tensile strength with resistance to both 
deformation and crack propagation.  It's just a function of metal 
crystalline behavior that higher tensile strengths are inversely 
proportional to rate of deformation.  The general perception is that 
bolts with very high tensile strength offer no protection from sudden 
breakage once the yield point is reached, but that's not exactly true.  
A lot depends upon the loads imposed.  If a grade 5 bolt works reliably 
in an application, breakage is very unlikely with a grade 8, because the 
grade 8 yield point is higher. This also allows for somewhat more 
clamping force, thus reducing the tendency of the fastened parts to move 
around under load.

The latter is important, because any bolt loaded in shear will fail at 
about 65% of UTS (ultimate tensile strength).  Even so, I've seen grade 
8 bolts that have deformed badly without shearing.  For example, on the 
buses we built, the rear axle was attached to a pair of spring beams 
(the item carrying the air springs that supported the weight of the bus 
and transmitted those loads to the axle). Each one was attached with 
four 3/4" grade 8 bolts in a box pattern, with a precision center pin to 
positively locate the axle.  Due to an engineering error (through holes 
too large), under big side loads (like the driver whacking a curb while 
in motion--much more common than one would think, especially in NYC), 
the spring beam would laterally rotate around the center pin, putting 
the bolts in direct shear.  Those dynamic loads, due to excessive 
movement, were much larger than the clamping load because movement adds 
kinetic energy. I saw one of those grade 8 bolts after such 
mistreatment, and it had an "S" curve in it, so that the centerline at 
the head of the bolt was offset from the centerline at the bottom of the 
bolt by nearly 1/2", and yet, the bolt had not cracked or broken.  
That's where the toughness of the bolt comes in--which depends upon a 
number of factors, such as the alloy, the kind of heat treatment, 
precipitation hardening, tempering and anti-corrosion coatings (to 
prevent corrosion cracking).

To my mind, a properly-made grade 8 bolt will be superior in performance 
to any grade 5 bolt, especially in suspension work. It's important to 
know the loads imposed, though.  In racing, a grade 5 will be fine in 
areas where the maximum load imposed will be sufficiently below the UTS 
of the bolt, and the clamped pieces are inspected regularly for 
stretched or deformed bolts, but the extra insurance of higher yield 
strength and higher clamping force make a grade 8 preferable.  I'd much 
rather have a bolt that never reaches its yield point under maximum load 
than one that yields and deforms before failure.

Cheers.

-- 

Michael Porter
Roswell, NM

Never let anyone drive you crazy when you know it's within walking distance....

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    <div class="moz-cite-prefix">On 11/24/2016 11:51 AM, Dave wrote:<br>
    </div>
    <blockquote cite="mid:[email-masked]"
      type="cite"><font face="Arial, Helvetica, sans-serif"
        color="black" size="4"><font size="4">Bolts with no slashes are
          grade two.  The grade of the bolt is indicated by the number
          of slashes plus two.  I do not recommend grade two for
          suspension duty.  <br>
          <br>
          I've heard said that the trade-off with Grade 8 bolts is that
          they are stronger but more brittle.  Since I am not a
          mechanical engineer I cannot make a recommendation on
          substituting a grade 8 for a grade 5 but I would be concerned
          that the increased brittle nature may be a detriment.
          Considering the seriousness of the consequences of a
          suspension failure I would think again about making
          substitutions.  And just about anything you need is available
          next business day from McMaster Carr (and other sources,
          certainly).  But you may have to buy more than you need and
          pay shipping.</font><br>
        <br>
        <font size="4">I don't think fine thread vs coarse thread makes
          much difference.<br>
        </font></font></blockquote>
    <br>
    Brittleness is relative.  The optimum condition for a strong bolt is
    toughness, the combination of tensile strength with resistance to
    both deformation and crack propagation.  It's just a function of
    metal crystalline behavior that higher tensile strengths are
    inversely proportional to rate of deformation.  The general
    perception is that bolts with very high tensile strength offer no
    protection from sudden breakage once the yield point is reached, but
    that's not exactly true.  A lot depends upon the loads imposed.  If
    a grade 5 bolt works reliably in an application, breakage is very
    unlikely with a grade 8, because the grade 8 yield point is higher. 
    This also allows for somewhat more clamping force, thus reducing the
    tendency of the fastened parts to move around under load.  <br>
    <br>
    The latter is important, because any bolt loaded in shear will fail
    at about 65% of UTS (ultimate tensile strength).  Even so, I've seen
    grade 8 bolts that have deformed badly without shearing.  For
    example, on the buses we built, the rear axle was attached to a pair
    of spring beams (the item carrying the air springs that supported
    the weight of the bus and transmitted those loads to the axle). 
    Each one was attached with four 3/4" grade 8 bolts in a box pattern,
    with a precision center pin to positively locate the axle.  Due to
    an engineering error (through holes too large), under big side loads
    (like the driver whacking a curb while in motion--much more common
    than one would think, especially in NYC), the spring beam would
    laterally rotate around the center pin, putting the bolts in direct
    shear.  Those dynamic loads, due to excessive movement, were much
    larger than the clamping load because movement adds kinetic energy. 
    I saw one of those grade 8 bolts after such mistreatment, and it had
    an "S" curve in it, so that the centerline at the head of the bolt
    was offset from the centerline at the bottom of the bolt by nearly
    1/2", and yet, the bolt had not cracked or broken.  That's where the
    toughness of the bolt comes in--which depends upon a number of
    factors, such as the alloy, the kind of heat treatment,
    precipitation hardening, tempering and anti-corrosion coatings (to
    prevent corrosion cracking).<br>
    <br>
    To my mind, a properly-made grade 8 bolt will be superior in
    performance to any grade 5 bolt, especially in suspension work. 
    It's important to know the loads imposed, though.  In racing, a
    grade 5 will be fine in areas where the maximum load imposed will be
    sufficiently below the UTS of the bolt, and the clamped pieces are
    inspected regularly for stretched or deformed bolts, but the extra
    insurance of higher yield strength and higher clamping force make a
    grade 8 preferable.  I'd much rather have a bolt that never reaches
    its yield point under maximum load than one that yields and deforms
    before failure.<br>
    <br>
    <br>
    Cheers.<br>
    <font size="4"><font face="Arial, Helvetica, sans-serif"></font></font><br>
    <pre class="moz-signature" cols="72">-- 

Michael Porter
Roswell, NM

Never let anyone drive you crazy when you know it's within walking distance....</pre>
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From: "Randall" <[email-masked]>
Date: Thu, 24 Nov 2016 22:00:24 -0800

So, did the later Triumphs actually use SAE graded hardware?  The original
bolts on a TR3 appear to be made to British specifications that aren't
exactly the same.  In particular, there isn't a slash in sight, even on
bolts that are obviously harder than others.

Also worth pointing out, perhaps, that Grade 8 is by no means the ultimate
in bolt strength.  Stronger alloys have been known since before WW2.  Of
course those fancy alloys are more expensive, so you don't see them much on
cars.  But just an ordinary socket-head cap screw (ASTM 574) is about 15%
stronger than SAE Grade 8.

ISTR it was Carroll Smith that pointed out that all fasteners are, in
effect, very stiff springs.  Sometimes that springiness is important, like
when you try to clamp aluminum parts with steel fasteners and heat up the
resulting assembly.  Aluminum expands with heat much faster than steel does,
so the ultimate fastener load depends on how easily the steel stretches to
accommodate the growth in size of the aluminum.

Randall