taps and dies

bruce nickerson · Post by **bruce nickerson** » Wed Feb 13, 2008 5:16 pm

Am getting ready to assemble a model 75 and want to clean up threads with taps and dies before beginning. Checking through parts list it seems that 1/4 and 5/16" should take care of most of the power unit fasteners; but for the CD Ignition modedls there are some 1/4BSF fasteners specified. Can I get by in most instances with just the 1/4" and 5/16" sizes? British Tools and Fasteners in New York, USA has a Seagull tap and die kit for $60.00 (30 pounds?) which includes 1/4", 5/16", and also 3/8" sizes. Will I ever need the 3/8" tap and die in this set, or can I get by with just the 1/4" and 5/16" and save $20? Will the 5/16BSF ever be needed at all?

Advice please for a Yank with Brit and Scottish ancestry.

CatiGull · Post by **CatiGull** » Wed Feb 13, 2008 5:35 pm

I bought the set from the guys in Clyde (thats the one over here, not Scotland) and have used most of them on my flock.

But thats 2 40s, a 40+, a Century, and an EFRN...

You cant ever have too many British tools in your box imho

bruce nickerson · Post by **bruce nickerson** » Wed Feb 13, 2008 9:12 pm

CatiGull: TYVM for feedback and iddentifying another source. My question is which sizes taps and dies to buy?

40TPI · Post by **40TPI** » Wed Feb 13, 2008 10:41 pm

bruce nickerson wrote: Will I ever need the 3/8" tap and die in this set, or can I get by with just the 1/4" and 5/16" and save $20? ......Will the 5/16BSF ever be needed at all?

The 5/16BSF tap and die will get the most wear followed probably by the 1/4BSF.
5/16 BSF is head bolts (yuk) , tank nuts, transom bracket arms to plate, lower unit pinch bolt etc. All the places that get corroded! (So it is a very good idea to get hold of decent 5/16 & 1/4 BSF open and ring spanners if possible.)

1/4BSF is crankcase bolts etc. The only fixing I can think is 3/8BSF is the tiller arm and gear lever castle nuts and also the tiller mounting stud itself. (Although thinking back on the fun I've had getting sheared tiller studs out of crankcases I have wondered if that thread was slightly tapered or had a good dose of Loctite.)

The only Whitworth thread is the 7/16 Whit transom bracket thumbscrew. The largest BSF is 7/16 on the flywheel top nut I think. There are other non BSF British thread types on the carbs, petrol tank & tap fittings and ignition plates but that wasn't the question and they usually aren't anywhere near as corroded.

Peter

bruce nickerson · Post by **bruce nickerson** » Thu Feb 14, 2008 2:22 am

40TPI

Thx much. So the 1/4 and 5/16 sizes, both BSF should get me most mileage?

Help me understand this system please. There is BSC which refers to British Standard Coarse threads, BSF which is British Standard Fine threads, and W for Whitworth hexes? Why do you mention 5/16 and 1/4 BSF spanners? Would these not be Whitworth? Am I getting close? I will not ask about stones, centigrade, quids, farthings, pounds, shillings, hapennies, etc.

bruce nickerson · Post by **bruce nickerson** » Thu Feb 14, 2008 2:22 am

40TPI

Thx much. So the 1/4 and 5/16 sizes, both BSF should get me most mileage?

Help me understand this system please. There is BSC which refers to British Standard Coarse threads, BSF which is British Standard Fine threads, and W for Whitworth hexes? Why do you mention 5/16 and 1/4 BSF spanners? Would these not be Whitworth? Am I getting close? I will not ask about stones, centigrade, quids, farthings, pounds, shillings, hapennies, etc.

Charles UK · Post by **Charles UK** » Thu Feb 14, 2008 9:53 am

Not quite as easy as that.

Whitworth was the first man to propose standard thread dimensions & pitch, hence Whitworth threads.

BSF British Standard Fine

BSP British Standard Pipe

BA British ??????? (could be Armstrong)

BSC British Standard Cycle

All the above thread types are used on a 1970's Seagull, but where & which?

Whitworth & BSF spanners are the same size but labeled different

A 3/16" whitworth spanner is the same size as a 1/4" BSF,this rule applies right up through all the sizes, something to do with saving metal during one of our wars.

mrdraddy · Post by **mrdraddy** » Thu Feb 14, 2008 10:00 am

just for info BA stands for british association

40TPI · Post by **40TPI** » Thu Feb 14, 2008 1:41 pm

bruce nickerson wrote: Thx much. So the 1/4 and 5/16 sizes, both BSF should get me most mileage?
....snip........
Why do you mention 5/16 and 1/4 BSF spanners? Would these not be Whitworth? Am I getting close?

Yes, you will use 1/4" & 5/16" BSF far more than anything else. You will need the corresponding BSF sized spanners. (It is also very helpful if you have two off of each size if you are trying to remove studs using the double locknut method)

There is a general confusion in the colonies when it comes to BSF and Whit spanner sizes. Click on "View original size" on the full sized image behind the thumbnail below and then enlarge further in your browser.

The larger spanner end is clearly stamped "5/16BS 1/4 W" and the other end "1/4 BS 3/16 W". The hex head of a 5/16 BSF bolt is the same dimension across flats as a 1/4Whit bolt. The diameter of the bolt and thread shapes below the hex are naturally different between 1/4 Whit and 5/16 BSF but the same spanner can be used on two different thread types. Same idea for the other end. The "1/16 inch" difference between BSF size and Whit size stamped on a spanner increases to 1/8th inch when you get up to larger sizes around 7/8 BSF / 3/4 Whit or thereabouts. It may well increase to 3/16th or more when you get to the huge silly sizes. Go Google for hex head sizes.

And Bruce thanks for the opportunity for a plug. I still have two of these obstruction spanners left after my For Sale Ad last year, if anybody needs one. Check back over old posts for details or PM me. Latest one shipped to Turkey last week.

Peter

Charles UK · Post by **Charles UK** » Thu Feb 14, 2008 3:31 pm

Slightly changing the subject. Rick UK delivered my christmas pressie last week a 7 piece set of 3/8" drive multi hex Whitworth sockets, branded Laser (www.laserhandtools.com).
Other than them not being single hex flank drive for all the rusty nuts & bolts, they are exactly what I've been searching for for the last 5 years.

Not used them yet but they look perfect.

Thanks Rick.

Charles

40TPI · Post by **40TPI** » Thu Feb 14, 2008 4:22 pm

Not bad indicative pricing either.........

Peter

bruce nickerson · Post by **bruce nickerson** » Thu Feb 14, 2008 9:46 pm

Not sure if I qualify as a complete colonial. One of me mum's ancestors was the first European born on the continent, Peregrine White. She also had Scottish ancestors who settled in Cape Breton, Nova Scotia about whom we say little in spite of Nova Scotia being the only Brit province that I am aware of that has its own tartan. My father's side of the family fled to Nova Scotia at time of Revolution- he says they were patriots, I gave up arguing with him. He came back to Boston Massachusetts area in 1920's when he found out fishing was dangerous and did not pay well. He had a Union Jack tatooed on his left forearm. I have owned an 1953 MG Midget, a 1960 Morris Minor 1000 sedan, a 1960s vintage Morris Minor convertible bringing its engine up to Sprite standards, 2 1973 MG Midgets, and a 1971 MG Midget parts car. Still have a few Whitworth circle (we call the box end) spanners from the 1953 MG and the Morris Minors.

Now I have become a Gullaholic. Their carbs remind me of SUs. I do not mention the Lord of Darkness by name though.

Thx for the help guys. I hope to sometime have the good fortuine to visit from the colonies again, having enjoyed London twice.

Saving Old Seagulls

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