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Sump Plate Studs #727430
03/03/18 9:53 pm
03/03/18 9:53 pm
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eelmgren Offline OP
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I bought a billet sump plate. I didn't think to consider the length of the studs holding the old steel plate in place. I can get nuts on the billet plate, but the stud are a bit short. Anyone know where to get longer studs? The parts catalog doesn't identify the size or pitch of the studs.

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Re: Sump Plate Studs [Re: eelmgren] #727449
03/04/18 12:03 am
03/04/18 12:03 am
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DMadigan Offline
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Later engines are 1/4-28, 1/4-20. You used to be able to buy studs at hardware stores.
I presume early engines were BSF (1/4-26), 1/4-20 Whitworth

Re: Sump Plate Studs [Re: eelmgren] #727458
03/04/18 1:43 am
03/04/18 1:43 am
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Central Virginia
Lannis Offline

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Since you won't be needing to pull the sump plate off every time you want to drain the sump, and it will likely only need to come off when you split the cases, it makes sense to blue-loctite some allen bolts in there instead of studs.

Lannis


I stopped believing for a little while this morning. Journey is really going to be upset.
Re: Sump Plate Studs [Re: eelmgren] #727470
03/04/18 6:14 am
03/04/18 6:14 am
Joined: Feb 2014
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Lancaster, California
C.B.S Offline

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Which sump plate did you get? SRM plates come with hardware.

Re: Sump Plate Studs [Re: eelmgren] #727635
03/05/18 3:31 pm
03/05/18 3:31 pm
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Farnham, Surrey, UK
gunner Online content
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I find its best to remove the studs and as the threads in the alloy are often partially stripped and insert a helicoil thread repair.

Then you can use socket cap screws of an appropriate length.

Last edited by gunner; 03/05/18 8:47 pm.

1968 A65 Firebird
1967 B44 Shooting Star
1972 Norton Commando
Re: Sump Plate Studs [Re: eelmgren] #727662
03/05/18 9:17 pm
03/05/18 9:17 pm
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eelmgren Offline OP
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Done, thanks. The threads in the case were fine, Cap screws worked. And no, it isn't a SRM plate. Just a cheap one from eBay, probably reverse engineered by someone with a C&C machine

I never know what I'll find when I go to replace a nut or bolt. I really would have thought studs in the casing would have been British Std.

Re: Sump Plate Studs [Re: eelmgren] #727676
03/05/18 11:23 pm
03/05/18 11:23 pm
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UK
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VicCyclone Offline
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I use A10 rocker cover studs. They're readily available, the perfect length and 1/4 Whit / 1/4 Cycle.


VicCyclone

1965 A50 Cyclone Clubman
1966 Victor GP
1967 Victor Special
1968 Victor Special
1968 A65L

2009 HD FXDC
Re: Sump Plate Studs [Re: eelmgren] #727682
03/06/18 12:10 am
03/06/18 12:10 am
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Stuart Offline
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Hi Erik,

Originally Posted by eelmgren
The parts catalog doesn't identify the size or pitch of the studs.

It does actually ... smile Any part number beginning "14-" indicates standard Unified thread, the 14-0301 Nuts are standard 1/4"UNF (1/4"-28) plain (i.e. not self-locking) nuts.

Then BSA didn't bugger about putting a Unified thread on one end of a stud and a British Standard thread on the other end (at least not and then give it a 14- prefix part number), so the coarse thread on the other end of the studs must be UNC.

You can also look up threads by BSA/Triumph part number in http://stainlessbits.com/link12.html.

Originally Posted by eelmgren
I never know what I'll find when I go to replace a nut or bolt. I really would have thought studs in the casing would have been British Std.

If it had been, the correct abbreviation for 'Whitworth' is 'BSW' = British Standard Whitworth.

However, BSA began converting from British Standard to Unified threads from about 1967 and, by 1970, were pretty-much done. So most threads on the bike are Unified with AF hex. heads, just be aware BSA left some BS threads/hexs. just for a belated laughing at your expense. Fwiw, I invested in a set of thread (aka 'screwpitch') gauges years ago; wink you can look up the numbers you measure online.

Hth.

Regards,

Re: Sump Plate Studs [Re: eelmgren] #727698
03/06/18 2:42 am
03/06/18 2:42 am
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Owego, NY, USA
Mark Z Offline
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Yes, a set of BSW thread gauges (in conjunction with Metric and SAE) is invaluable. I got mine from British Tools and Fasteners in Lyons, NY. They also have just about every sort of hardware imaginable by type, diam., and thread density, much in stainless steel.


Mark Z

'65(lower)/'66(upper, wheels, front end, controls)/'67(seat, exhaust, fuel tank, headlamp)/'70(frame) A65 Bitsa.
Re: Sump Plate Studs [Re: Stuart] #727741
03/06/18 3:23 pm
03/06/18 3:23 pm
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eelmgren Offline OP
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Originally Posted by Stuart
Hi Erik,

Originally Posted by eelmgren
The parts catalog doesn't identify the size or pitch of the studs.

It does actually ... smile Any part number beginning "14-" indicates standard Unified thread, the 14-0301 Nuts are standard 1/4"UNF (1/4"-28) plain (i.e. not self-locking) nuts.

Then BSA didn't bugger about putting a Unified thread on one end of a stud and a British Standard thread on the other end (at least not and then give it a 14- prefix part number), so the coarse thread on the other end of the studs must be UNC.

You can also look up threads by BSA/Triumph part number in http://stainlessbits.com/link12.html.

Originally Posted by eelmgren
I never know what I'll find when I go to replace a nut or bolt. I really would have thought studs in the casing would have been British Std.

If it had been, the correct abbreviation for 'Whitworth' is 'BSW' = British Standard Whitworth.

However, BSA began converting from British Standard to Unified threads from about 1967 and, by 1970, were pretty-much done. So most threads on the bike are Unified with AF hex. heads, just be aware BSA left some BS threads/hexs. just for a belated laughing at your expense. Fwiw, I invested in a set of thread (aka 'screwpitch') gauges years ago; wink you can look up the numbers you measure online.

Hth.

Regards,



Good information - especially regarding the 14- prefix.
Unified threads on one end, British Standard on the other - That's NUTS! Never would have dreamed
The chart on the link looks familiar. I think I've got that in a folder here, forgot all about it.

Thanks much -

Re: Sump Plate Studs [Re: eelmgren] #727747
03/06/18 4:26 pm
03/06/18 4:26 pm
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Oklahoma
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Tracey Spear Offline
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Interesting discussion guys. I'm about to tear into my first big project, a 69 Thunderbolt. Are you saying that by 69, most of the fasteners have unified threads but I still need the Whitworth tools to fit the fasteners? But that there are a few BS threads thrown in for grins?

I'm confused, do I need Whitworth wrenches/sockets or SAE for this old bike?

Thanks

Re: Sump Plate Studs [Re: eelmgren] #727756
03/06/18 5:36 pm
03/06/18 5:36 pm
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SE Ohio
No Name Man Offline

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In a word, yes. Threaded lugs in the frame are still BSW - or whatever the correct terminology is - by 69. Even a few on the motor still with the OIFs. Unified or what we call US standard here for everything else.

Bill E


69 A65T
71 B50T
85 K100RS
54/59 A10SR
69 B44VS
71 A65FS
95 Trident
Too much moderation is bad for you.

Re: Sump Plate Studs [Re: eelmgren] #727758
03/06/18 5:57 pm
03/06/18 5:57 pm
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Tracey Spear Offline
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Sounds like I need to add SAE and BSW thread gauges to my tool list.

Re: Sump Plate Studs [Re: Tracey Spear] #727770
03/06/18 7:20 pm
03/06/18 7:20 pm
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eelmgren Offline OP
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Originally Posted by Tracey Spear
Interesting discussion guys. I'm about to tear into my first big project, a 69 Thunderbolt. Are you saying that by 69, most of the fasteners have unified threads but I still need the Whitworth tools to fit the fasteners? But that there are a few BS threads thrown in for grins?

I'm confused, do I need Whitworth wrenches/sockets or SAE for this old bike?

Thanks


I bought a set of BSW wrenches & sockets when I started by '70 A65 project. Some of the hardware has required those tools, but many are Unified/SAE. Still surprises me each time I reach for a wrench

Re: Sump Plate Studs [Re: eelmgren] #727784
03/06/18 9:02 pm
03/06/18 9:02 pm
Joined: Aug 2001
Posts: 3,868
argyll. scotland, uk
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Thread gauges marked in tpi will cover SAE and BSF,no need for two sets ,although thread angles are subtly different this doesnt really matter when measuring Teeth per Inch. AMAL carbs and fuel line fittings retained imperial hex sizes, there are no "Whitworth" threads on a 69 BSA, there will be some BSF, British Standard Fine both are "Imperial",and possibly some SAE. You will need SAE and Imperial tools. Whitworth threads are very coarse, were common in heavy industry but not at all common on Brit bikes I cant think of any on a Beesa, I know Norton used them here and there, BSF is a finer thread and less prone to loosening with vibration.
You can also find CEI AKA cycle, (eg, steering stem nut, ) , BA , electrical fittings and control lever screws, and metric, battery terminal bolts, spark plug threads.
The back of the factory manual has a few pages of thread data, quite handy.


71 Devimead A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
Re: Sump Plate Studs [Re: eelmgren] #727810
03/07/18 12:13 am
03/07/18 12:13 am
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Posts: 775
Farnham, Surrey, UK
gunner Online content
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Quote
Both WW and UNC are a much better thread into Aluminium than BSF.


I have no doubt this is correct, but the problem I have found, especially with sump plate studs is that the threads are often worn if not completely stripped. This is likely caused by the use of nuts on the studs to secure the sump plate which tends to encourage users to inadvertently over tighten using spanners and wrenches. This often leads to worn and or stripped threads and subsequent oil leaks.

I have encountered this problem on multiple BSA unit singles and twins and for this reason I always drill out the old threads and use a helicoil thread insert together with a socket cap bolt. Since helicoil thread inserts are much stronger in aluminium, the sump plate socket caps can then be tightened sufficiently to ensure no leaks from the sump plate with no fear of stripping threads.

If you use this solution you can use any suitable thread size, I have used standard metric M6 in this area which seems to work well and is easily available.


1968 A65 Firebird
1967 B44 Shooting Star
1972 Norton Commando
Re: Sump Plate Studs [Re: eelmgren] #727820
03/07/18 1:04 am
03/07/18 1:04 am
Joined: Nov 2012
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Isle of Wight, UK
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koan58 Offline
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Using bolts rather than bonded bottomed studs does introduce an avenue for oil, so it's best to be generous with gunge on the threads and under the washers.

Re: Sump Plate Studs [Re: Tracey Spear] #727868
03/07/18 1:47 pm
03/07/18 1:47 pm
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Stuart Offline
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Hi,

Originally Posted by Tracey Spear
I'm about to tear into my first big project, a 69 Thunderbolt.

Welcome. smile

An early lesson to learn is to differentiate between reality and random muttering into beards (real or figurative), of which this thread is a good/bad (depending on pov) example.

Originally Posted by Tracey Spear
Are you saying that by 69, most of the fasteners have unified threads but I still need the Whitworth tools to fit the fasteners? But that there are a few BS threads thrown in for grins?
do I need Whitworth wrenches/sockets or SAE for this old bike?

Unless a dpo (dumb/dipsh1t previous owner) had a project to change as many fasteners as possible to something else, the vast majority of threads are Unified (UNC, UNF, UNEF, NP, etc.), for which you'll need AF wrenches/sockets;.

Disambiguation of "Whitworth":-

. The correct definition is it describes a threadform and diameter/hex. standards introduced in 1841 named after Englishman Sir Joseph Whitworth. The threadform is coarse (not many tpi - threads/turns per inch) so prone to being loosened easily by vibration, so not suitable for fasteners on vibrating machinery (e.g. British motorcycles with parallel-twin-cylinder engines ...). It is just the threadform that's known as "BSW" - British Standard Whitworth

Irrespective of earlier theorising by the beard-wafflers, Edward Turner (in charge of BSA's Automotive Division and therefore both Triumph and BSA) used BSF (British Standard Fine) threads into aluminium alloy components certainly from the 1957 21/3TA 350. This was so unsuccessful and Triumphs went so much slower than BSA's that, when the A50/A65 was designed, Small Heath also used exactly the same threadform into exactly the same material ... The only place I can think of that retained a Whitworth thread from the pre-units was the 650 barrel base studs into the crankcase.

. Otoh, regrettably, you live in a country where some influential people can't deal with the reality of British vehicles fifty and more years old, and call everything not "SAE"/Unified/AF or metric "whitworth" (note small "w"). It doesn't help newbies to the hobby but you wasting time and money discovering the difference seems to be seen by at least some as some sort of 'initiation'.

Based on first-hand experience, I advise against investing in much labelled "Whitworth" or "British Standard" 'til you actually get into your project and find you actually need them. For example: my '69 T100 has mostly the aforementioned Unified threads, the few British Standard fasteners either have socket cap or slotted screws that don't need special tools or were handled simply by having a 19/32"AF socket (for 3/8"BSC - British Standard Cycle - bolts). Even if I were working on a contemporary 650, the only additional tools I'd need are 17/32"AF wrench and socket, for 5/16"BSC fasteners.

Fuel tap threads are 1/4"BSP (British Standard Pipe) but don't be confused by the small fraction - pipe thread fractions are a nominal inside diameter, similar applies to your bike's oil pressure switch even though that's a US National Pipe thread. If you really wanted, you could have a 19/32"AF or 3/8"BS open-ended wrench for the fuel tap nuts, or you could use an adjustable like everyone else ... grin

Edit - While we're at disambiguation, note that, when BSA changed to US threadforms, it wasn't to "SAE" but to Unified (UNC. UNF, UNEF, UNS, UNCP plus NP (National Pipe)). "SAE" might have the same threads per inch as UNF at the same major diameters but, as Mark posts further down the thread, thinking "SAE" instead of Unified can lead to confusion and incorrect conclusions.

As Gavin posted already, you certainly don't need different Unified and "Whitworth" thread gauges. Unified and BSF/BSW/BSP have different included angles in the triangle of each thread and trough ... but the difference is 5 degrees ... and BSC has the same angle as as Unified ...

The realities of your bike are:-

. When it was built, the vast majority of threads/fasteners were Unified/AF.

. However, it is coming up to fifty years old. If it's had a number of owners, you could find metric or BSC bolts where the parts book says they should be UNF, especially if the bolt screws into a nut.

. It is highly unlikely to have a real BSW-thread bolt - afaict, restorers of old British vehicles have long been the largest users of BSW fasteners worldwide; however, in global terms, our usage is infinitesimal; some Chinaman is not going to turn his capital-intensive bolt- and nut-making machines to churning out new BSW fasteners when UNC does just as well (except at 1/2" diameter).

Part 2 ... The above applies to fasteners 1/4" diameter and bigger ... laughing

Smaller than 1/4"-diameter, the vast majority are BA - "British Association" (For The Advancement Of Science). This isn't like any of the larger British Standard threads ... apart from anything else, each different diameter is simply designated by a number followed by "BA"; 0BA (zero BA) is the largest diameter - 6 mm. - then the larger the number, the smaller the diameter.

The commonest one on Britbikes is 2BA. It's very similar to 3/16"UNF and No.10UNF - 3/16"-32 and 10-32 - and M5 (5 mm.) but It Is Not The Same - sometimes one of the others can be forced, most times then the thread is buggered. frown

Then just to catch out those not paying attention, the screws that fasten the gauze over the front brake scoop are No.4UNC - 4-40 ... :rofl

Hth.

Regards,

Last edited by Stuart; 03/10/18 3:51 pm. Reason: Note possibility of confusing "SAE" and Unified threads.
Re: Sump Plate Studs [Re: eelmgren] #727872
03/07/18 3:08 pm
03/07/18 3:08 pm
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Manx Offline
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grin


1966 Rickman Metisse (a65)
1960 A10 golden flash
1960 lambretta li150
1942 Ariel W/ng
Re: Sump Plate Studs [Re: eelmgren] #727938
03/08/18 1:27 am
03/08/18 1:27 am
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Owego, NY, USA
Mark Z Offline
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There are a good number of nuts and bolts on my '65-'67 A65 engines that are 1/4"-26 tpi, 5/16"-26 tpi, and 3/8"-26 tpi. These have been labeled as "CEI" or "cycle thread" in other discussions on the subject. Be that what it may, there is no 26 tpi gauge in an SAE gauge set, so a set of "British" thread gauges is necessary. The thread gauge set I bought from British Tools and Fasteners is, however incorrectly, labeled "Whitworth". (The other side of the gauge set is labeled "Metrisch", so I'm guessing they come from Germany.)


Mark Z

'65(lower)/'66(upper, wheels, front end, controls)/'67(seat, exhaust, fuel tank, headlamp)/'70(frame) A65 Bitsa.
Re: Sump Plate Studs [Re: eelmgren] #727953
03/08/18 3:28 am
03/08/18 3:28 am
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Owego, NY, USA
Mark Z Offline
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Sorry, I got this confused with the "What hardware do I have on my BSA?" thread. My message still applies, though; instead of puzzling over hardware types, just get a comprehensive set of thread gauges and measure.

BTW, I received bolts with my alloy sump plate (from Alloy-Tech in Illinois, but perhaps imported from SRM). I don't use Loctite on them and they don't leak. But I make my own rubber-fiber gaskets, with 1/4" holes rather than 5/16" like the standard gaskets.


Mark Z

'65(lower)/'66(upper, wheels, front end, controls)/'67(seat, exhaust, fuel tank, headlamp)/'70(frame) A65 Bitsa.
Re: Sump Plate Studs [Re: Mark Z] #728082
03/09/18 10:53 am
03/09/18 10:53 am
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Stuart Offline
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Hi Mark,

Originally Posted by Mark Z
There are a good number of nuts and bolts on my '65-'67 A65 engines that are 1/4"-26 tpi, 5/16"-26 tpi, and 3/8"-26 tpi. These have been labeled as "CEI" or "cycle thread" in other discussions on the subject.

Mmmm ... but, given the length of time you've been at this, and the number of times the subject's been written up on BritBike, including on this Board, are you seriously telling us you don't know "BSC" (British Standard Cycle), "CEI" (Cycle Engineering Institute) and "Cycle" are the same threadform on these bikes? If one were to leaf through dusty tomes in library back storerooms, there's probably minor and arcane differences but, as far as these old heaps are concerned, they're the same.

Also, '1/4"-26' on the engine was BSF originally, not BSC/CEI/Cycle.

Originally Posted by Mark Z
Be that what it may, there is no 26 tpi gauge in an SAE gauge set, so a set of "British" thread gauges is necessary. The thread gauge set I bought from British Tools and Fasteners is, however incorrectly, labeled "Whitworth". (The other side of the gauge set is labeled "Metrisch", so I'm guessing they come from Germany.)

You fundamentally misunderstand certainly the primary purpose of thread (aka "screwpitch") gauges:-

. If you do not know the thread of a fastener, how can you know which marked set to use? confused The primary purpose of thread gauges is to discover the threads per inch (of an inch thread) or the the pitch (of a metric thread). Therefore, having more than that one set marked "Whitworth" and "Metrisch" for this primary purpose is a waste of space and money. At the tpi found on your bikes' fasteners that can be measured accurately with thread gauges, that the "Whitworth" teeth angles are 55 degrees rather than BSC or Unified's 60 degrees makes not a blind bit of difference.

. That's because the second dimension you must have to identify a thread correctly is the 'major diameter' - across the peaks of a male thread or the troughs of a female thread. From first-hand experience, thread gauges alone will not tell you the difference between several BSC and metric threads (BSC being 26 tpi and metric threads having 1 mm. pitch = 25.4 tpi). Do you have separate Unified, Whitworth and "Metrisch" micrometers/calipers?

. Only when you have both a tpi or pitch and an accurate major diameter can you hope to identify a thread accurately, by looking up those two figures.

. Even then, it isn't foolproof. Dunno about BSA but, in adjacent years, Triumph used 20 tpi BSC and UNEF on large-diameter (3/4" and 7/8") components; UNEF at these diameters is also 20 tpi but the two threads cannot be mixed, because the threadforms have tiny differences. facepalm

. If that "Whitworth"/"Metrisch" set's still the same as the one I've been using for about three decades, it has all the 'combs' to identify any British Standard or Unified thread you'll find on any British bike, including yours. The only really-useful one it lacks is 27 tpi for '69-on bikes, for identifying whether the oil pressure switch is bigt or some muppet retailer's trying to palm you off with a BSP- or metric-thread lookalike. frown

. The only time separate 60-degree (BSC/Unified) and 55-degree (other British Standard threadforms) thread gauges are any use whatsoever afaict are in conjunction with high magnification to confirm the thread profile of a sealing thread on a new component. Other times the 5-degree difference is simply irrelevant.

Hth.

Regards,

Last edited by Stuart; 03/10/18 3:01 pm. Reason: Removed references to "SAE".
Re: Sump Plate Studs [Re: NickL] #728083
03/09/18 10:59 am
03/09/18 10:59 am
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Hi Nick,

Originally Posted by NickL
Any grit and $hit on the threads quickly stuffs BSF in alley, certainly on the smaller sizes.

Ye-ea-ah, but we're dealing with threads that are, if not coming up to half-a-century old, are older, the vast majority of which have had less-than-fastidious owners. Are you seriously telling me you don't run a tap into each thread to clean it out before even refitting the original fastener?

Just as a matter of possible interest, when Meriden was designing the parts for the '73-on front disc brake, the caliper mounting studs have BSF thread into the ally slider - UNC was too coarse for the space available.

Originally Posted by NickL
As beezers biggest market was in the 'states, i'm surprised they didn't go to unified when the A65 was launched,

Afaict, BSA bought fasteners from fastener suppliers and, in the early 1960's, British industry used British Standard threads; it was the Wilson government announcing in 1965 that GB'd be metric in ten years that seems to have prompted the British motor industry to elevate two fingers in the government's general direction and swap to Unified. grin

Of more surprise to me is that the A7/A10 timing-side main bearing bush was continued on the A50/A65, despite even pre-unit Triumph 650's having had a bearing less dependent on a shonky oil pump design ...

Originally Posted by NickL
And how many times do you find people have wound UNF nuts onto BSC/CEI threads..........................and vice versa.

Ye-ea-ah ,,, but it's very hard to do and nowhere does it say that paddlers from the shallow end of the gene pool aren't allowed to own motorcycles unsupervised. frown

Regards,

Re: Sump Plate Studs [Re: Stuart] #728177
03/10/18 2:39 am
03/10/18 2:39 am
Joined: Aug 2001
Posts: 4,438
Owego, NY, USA
Mark Z Offline
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Mark Z  Offline
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Joined: Aug 2001
Posts: 4,438
Owego, NY, USA
Originally Posted by Stuart
Hi Mark,

Originally Posted by Mark Z
There are a good number of nuts and bolts on my '65-'67 A65 engines that are 1/4"-26 tpi, 5/16"-26 tpi, and 3/8"-26 tpi. These have been labeled as "CEI" or "cycle thread" in other discussions on the subject.

Mmmm ... but, given the length of time you've been at this, and the number of times the subject's been written up on BritBike, including on this Board, are you seriously telling us you don't know "BSC" (British Standard Cycle), "CEI" (Cycle Engineering Institute) and "Cycle" are the same threadform on these bikes? If one were to leaf through dusty tomes in library back storerooms, there's probably minor and arcane differences but, as far as these old heaps are concerned, they're the same.

Also, '1/4"-26' on the engine was BSF originally, not BSC/CEI/Cycle.

Originally Posted by Mark Z
Be that what it may, there is no 26 tpi gauge in an SAE gauge set, so a set of "British" thread gauges is necessary. The thread gauge set I bought from British Tools and Fasteners is, however incorrectly, labeled "Whitworth". (The other side of the gauge set is labeled "Metrisch", so I'm guessing they come from Germany.)

You fundamentally misunderstand certainly the primary purpose of thread (aka "screwpitch") gauges:-

. If you do not know the thread of a fastener, how can you know which marked set to use? confused The primary purpose of thread gauges is to discover the threads per inch (of an inch thread) or the the pitch (of a metric thread). Therefore, having more than that one set marked "Whitworth" and "Metrisch" for this primary purpose is a waste of space and money. At the tpi found on your bikes' fasteners that can be measured accurately with thread gauges, that the "Whitworth" teeth angles are 55 degrees rather than BSC or SAE/Unified's 60 degrees makes not a blind bit of difference.

. That's because the second dimension you must have to identify a thread correctly is the 'major diameter' - across the peaks of a male thread or the troughs of a female thread. From first-hand experience, thread gauges alone will not tell you the difference between several BSC and metric threads (BSC being 26 tpi and metric threads having 1 mm. pitch = 25.4 tpi). Do you have separate SAE, Whitworth and "Metrisch" micrometers/calipers?

. Only when you have both a tpi or pitch and an accurate major diameter can you hope to identify a thread accurately, by looking up those two figures.

. Even then, it isn't foolproof. Dunno about BSA but, in adjacent years, Triumph used 20 tpi BSC and UNEF on large-diameter (3/4" and 7/8") components; UNEF at these diameters is also 20 tpi but the two threads cannot be mixed, because the threadforms have tiny differences. facepalm

. If that "Whitworth"/"Metrisch" set's still the same as the one I've been using for about three decades, it has all the 'combs' to identify any British Standard or Unified thread you'll find on any British bike, including yours. The only really-useful one it lacks is 27 tpi for '69-on bikes, for identifying whether the oil pressure switch is bigt or some muppet retailer's trying to palm you off with a BSP- or metric-thread lookalike. frown

. The only time separate 60-degree (BSC/Unified) and 55-degree (other British Standard threadforms) thread gauges are any use whatsoever afaict are in conjunction with high magnification to confirm the thread profile of a sealing thread on a new component. Other times the 5-degree difference is simply irrelevant.

Hth.

Regards,


Determining threads per inch (or pitch) is precisely what I use the thread gauges for. I don't seem to ever have a problem with thread forms, as long as I can determine the tpi. And I don't care so much what they're called either, I was just saying that, while you can find Unified tpis on an SAE gauge set, there is no 26 tpi gauge in an SAE gauge set. My gauge set which is labeled "Whitworth" does, however, have all the sizes I need to determine tpi (of non-metric hardware), in conjunction with my SAE gauges.

And no, I wouldn't try to use metric gauges to determine the pitch of a non-metric thread. I do have a set of calipers...

Actually, there was one time I had an issue with thread forms. This was the right-side footrest stud, which measured, if I remember right, 7/16" X 20 tpi. But an SAE 7/16" X 20 stud would not go in, so I concluded that the thread form, assumedly Unified, was a bit different from the SAE thread form. Not wanting to have to source the correct stud, I simply re-cut the thread in the frame with an SAE 7/16" X 20 tap. Here again, the thread gauge, regardless of thread form, was helpful in determining that I could get away with this bodge.


Mark Z

'65(lower)/'66(upper, wheels, front end, controls)/'67(seat, exhaust, fuel tank, headlamp)/'70(frame) A65 Bitsa.
Re: Sump Plate Studs [Re: Mark Z] #728215
03/10/18 3:35 pm
03/10/18 3:35 pm
Joined: Jun 2002
Posts: 9,875
Scotland
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Stuart Offline
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Stuart  Offline
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Joined: Jun 2002
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Hi Mark,

Originally Posted by Stuart
in adjacent years, Triumph used 20 tpi BSC and UNEF on large-diameter (3/4" and 7/8") components; UNEF at these diameters is also 20 tpi but the two threads cannot be mixed, because the threadforms have tiny differences.

Originally Posted by Mark Z
right-side footrest stud, which measured, if I remember right, 7/16" X 20 tpi. But an SAE 7/16" X 20 stud would not go in, so I concluded that the thread form, assumedly Unified, was a bit different from the SAE thread form.

BSA converted from British Standard to Unified threads, not "SAE"; in addition to both SAE and UNF being 20 tpi at 7/16" major diameter, there are also two BSC tpi - 26 and 20 ... of which both Triumph and BSA used 20.

As I found with BSC and UNEF at larger diameters, the more-likely reason you couldn't fit a "SAE 7/16" X 20 stud" is the female thread was BSA standard 7/16" BSC?

Hth.

Regards,

Re: Sump Plate Studs [Re: eelmgren] #728221
03/10/18 5:07 pm
03/10/18 5:07 pm
Joined: Aug 2001
Posts: 4,438
Owego, NY, USA
Mark Z Offline
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Mark Z  Offline
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Joined: Aug 2001
Posts: 4,438
Owego, NY, USA
"BSA converted from British Standard to Unified threads, not "SAE";"

Yes, I know. But I don't have a set of Unified thread gauges, nor is Unified hardware readily available here. So I use SAE gauges and hardware whenever possible, and they double nicely for most Unified applications.

"As I found with BSC and UNEF at larger diameters, the more-likely reason you couldn't fit a "SAE 7/16" X 20 stud" is the female thread was BSA standard 7/16" BSC?"

Ok, that may be helpful to know at some time. But not having 7/16" BSC OR UNEF hardware on hand, it didn't matter, as I was able to measure and make it work with SAE gauges and hardware.

I didn't mean to come off as being astute about thread forms, because I'm not. My message all along, for us Yanks at least, is to get a comprehensive set of thread gauges and not get bogged down in the alphabet soup. I've been able to maintain my A65s for many years with this approach. When I do have to employ British hardware, I order from from British Tools and Fasteners by diamter and thread density, and I always seem to get the right stuff. For those of us with multiple marques, perhaps older and/or more exotic, a more academic approach may be required.

Last edited by Mark Z; 03/10/18 5:22 pm.

Mark Z

'65(lower)/'66(upper, wheels, front end, controls)/'67(seat, exhaust, fuel tank, headlamp)/'70(frame) A65 Bitsa.
Re: Sump Plate Studs [Re: eelmgren] #728255
03/11/18 3:25 am
03/11/18 3:25 am
Joined: Aug 2001
Posts: 4,438
Owego, NY, USA
Mark Z Offline
BritBike Forum member
Mark Z  Offline
BritBike Forum member
Joined: Aug 2001
Posts: 4,438
Owego, NY, USA
I've been having second thoughts about some of the things I wrote. Stuart, I don't mean to disparage your vast knowledge or the time and effort you spend in sharing this knowledge with others. I get it, you can't determine thread forms with thread gauges; sometimes you just have to know. While my somewhat cavalier approach has worked for me over the years, it may not be good advice to share. Perhaps I've been lucky in some cases with good guesses. But be it known I'm not a hack either; I'm very fussy about having all my hardware clean and in good shape. When replacing hardware, I test fit everything (with fingers, never a wrench), and never force anything together that doesn't feel right.

And eelmgren, sorry if I've taken this thread off-course, and I hope you got your sump plate question resolved.


Mark Z

'65(lower)/'66(upper, wheels, front end, controls)/'67(seat, exhaust, fuel tank, headlamp)/'70(frame) A65 Bitsa.
Re: Sump Plate Studs [Re: Mark Z] #728276
03/11/18 9:43 am
03/11/18 9:43 am
Joined: Jun 2002
Posts: 9,875
Scotland
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Stuart Offline
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Stuart  Offline
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Joined: Jun 2002
Posts: 9,875
Scotland
Hi Mark,

Originally Posted by Mark Z
eelmgren, sorry if I've taken this thread off-course, and I hope you got your sump plate question resolved.

I think we answered ("eelmgren") Erik's question, the rest of the thread's Tracey's fault ... grin

Originally Posted by Mark Z
My message all along, for us Yanks at least, is to get a comprehensive set of thread gauges and not get bogged down in the alphabet soup.

Problem is, I don't think we can get away from the fact that the alphabet soup comes with owning and maintaining a British vehicle made fifty or more years ago. Not helped by either different abbreviations for the same thing or the same word having different meanings in different parts of the world. frown It isn't going to become any easier to persuade people to become interested in these old heaps. Good or bad, the internet has become the first place people look for knowledge they don't have. When someone like Tracey is interested, if those of us with the knowledge want to pass it on, it's a fine line between over-complication and over-simplification ime.

Originally Posted by Mark Z
While my somewhat cavalier approach has worked for me over the years,

Fwiw, I didn't think it was cavalier. Even when not forced, I don't think I'm any less guilty of 'inspired engineering' as anyone else who's had one of these old heaps for any length of time, just I don't commit mine to print. grin

Regards,

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