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MG MGB Technical - Whitworth Wrenchs

I will soon be restoring an MGB. At various times I have heard about Whitworth wrenchs and PosiDrive screw drivers. I'm, not sure I spelled them right. Could someone explain these standards, tell me if I need to find these tools,and where?
Ewan

http://www.britishtool.com/index.htm

Try this. -Brian.
Brian

Here's an explanation of Whitworth. As far as I know, the only Whitworth you might run into on a 'B is the crank damper bolt -- I'm told it's Whitworth. I know that I've never had to use my Whitworth wrenches on my 'B....

http://www.flyingcircuscars.com/whitworth.htm
Rob Edwards

Pozidrive screwds look a lot like Phillips screws. The usual cross is there, but a square-drive cutout is also there.

You can buy them from Snap-On at

http://www.snap-on.com/
Paul Noble

Ewan,

Pozidrive screws are commonly used. Unfortunately, if they are tight and a bit corroded, the use of Phillips screwdrivers are likely to cause damage to the heads.

In the USA you might also find them under the name ProDrive. By the way, the standard tips are usually quite soft, so that you don't damage the sockets in the screws. It might be worth buying a few spare tips if you're using screwdiver bits. You might also be able to buy heavy duty - in the UK gold coloured or, sometimes, diamond finish. Basic UK price about US$1.00 per standard tip, US$4.00 gold finish or US$5.00 for diamond finish.

Regards

Peter
Peter Hills

Sears has pozidrive screwdriver bits. I just bought some this week. The sales clerk looked at me like I was crazy and told me they didn't carry them, but I found them on the display of spare screwdriver bits.
Greg Bowman

Ewan,
Whitworth sizes are used at various places in the MGB, and in my experience all have been with the fuel system. Carburettor, fuel line, gas tank come to mind. Most of the body fittings are fractional sizes, 5/8, 9/16, and 1/2 most common by far. You will need one big socket 1-5/16 for the front engine pulley, rear trans hub and wheel hub,(if you have wire wheels.)
Otherwise, the B is easy, fairly straightforward. You should have a good feeler gauge and good torque wrench for many of the settings. If you are going to do full restoration, then a set of taps will also help. Les Bengtson has a website with many, if not all the thread sizes used. Check his site for other helpful info in this line. Someone once had a list of all the useful tools, but I can't recall where. Try an archive search, or maybe someone else will post a list of resources. ANY time you have a question, come here and ask. Many knowledgeable folks are willing to share their experience. Have fun!
Thomas Lennon

As a TD owner, I am quite familiar with Whitworth wrenches as the TD has practically all British Standard Fine fasteners that have Whitworth heads. The MGB will have some Whitworth size heads on some of the bolts or fitting in the brakeing system and in the fuel system. The most common places is the fitting on the fuel pump and on the fuel pipes. The number of places that you run into them is insufficient to go out and purchase a set of wrenches since in most cases you can find a standard inch or metric size that will fit. in any case where you can't find something standard to fit, it is quite permisable to use the Mark I adjustable Inch, Metric, Whitworth (pick one) spanner, found in everybodies tool box. The small nuts found on the carburetor linkages are British Association sizes, but again, you can always find something that fits close enough. Good luck - Dave
David DuBois

These guys are good for pre-owned antique and modern hand and machine tools.

http://www.pennyfarthingtools.co.uk/

The web site is worth a look even if you are not buying; everything from

No connection with these guys, of course, except as a happy customer.

NJSS
Nigel Steward

Greg,

Do you happen to have the catalog number of the Sears Pozidrive bits? I have looked at Sears, before. In fact, I used to work at Sears and I didn't know that they had them.

Were they hex-shank bits for use in a drill or hand-driver, or were they complete screwdrivers?

Thanks
Paul Noble

Sears part number 925644000, $4.99. Pozidriv sizes 1, 2, and 3. They are bits not complete screwdrivers.

- Phil
Philip Coburn

A good source for pozi-drive bits, drivers and other nice quality tools. I got mine from them.

http://www.wihatools.com/indexes/indxpozi.htm


-mike

Mike Zaffarano

I find that the application of heat to recalcitrant Posidrive/Philips screws usually frees them off. I use a really old soldering iron - the type with a big brass? heat sink with a pointed end which is heated with a flame. The heat transfer from this is usually sufficient to get these screws out easily - even those under the bonnet on bulkhead/inner wings etc.
Dave
Dave Wellings

Thank you, everyone for your inputs. I'm sure I'll be back as I dig into my project car.
Ewan

I'm surprised nobody mentioned the Armstrong shocks. You fellas do top off your shock oil don't you?
Jim Blackwood

Ah, that explains why I always had trouble getting either metric or US to fit those little plugs well; should've thought of Whitworth.
Joe Ullman

If you just want pozi-drive bits you should try your local contractors fastener/hardware store. You know the ones that are usually in the indudtrial parts of town and I don't mean Home Depot etc. I got mine at such a place. You might have to ask more than one person as once I was looked at rather strangely when I asked for them but upon asking another employee they were promtly able to find them in stock.
Jared Snider

And all this time I thought Whitworth was a thread type and the wrenches were British Standard. While you can use 7/16" SAE on the distributor clamp bolt, 1/4" BS fits better.
Leland Bradley

Leland - Whitworth (course thread) and Sritish Standard Fine (fine thread) both have heads that are related to the bolt size (rather than head size). Whitworth wrench has become a rather generic term for the wrenches that fit both. The BSF heads are one size smaller than Whitworth, thus a 1/4" Whitworth fits the head of a 1/4" Whitworth bolt and a 5/16" BSF bolt. Other than that, they are interchangable. Cheers - Dave
David DuBois

David,
Thanks for the information; figured someone on this board would know.

PS Mark Nast says Hi.
Leland Bradley

Long time owners of T series MGs become far more familiar with the British thread forms and wrenches than we ever really wnated to be. An interesting aside regarding thread form in the T series cars. The fasteners used on and inside the engines are affectionalely refered to as Nuffield Mad Metric. It seems that the Morris company took over the Hotchkis fastener factory in France somewhere along the line and they started using the metric fasteners in the engines, only, in order to maintain the good old British feel to the fasteners, they put Whitworth heads on them. So the T series (and as far as I know earlier MG) engines have metric fasteners with Whitworth heads. Talk about confusing people! You have now all had today's history lesson. Cheers - Dave
David DuBois

FWIW this is from the Snapon.com site:

Additional Description:

The walls on POZIDRIV® tips are not as tapered as those on PHILLIPS® tips and have wedges for a tight fit on POZIDRIV® fasteners. PHILLIPS® drivers should not be used on POZIDRIV® fasteners (and vice versa) as they tend to ride out of the recess and round the corners of both the tool and the screw recess.
Mike Phillips

I have bought PoziDrive bits at Sears, but the last I bought were from McMaster-Carr from their website. I bought a halfdozen of each size for a very resonable price.

I did splurge and buy a set of Whitworth wrenches and sockets recently. Just don't use them that often. Wish sopme one would make up a list of all the things they fit on each model of MG, though.
Michael Wish

Gentelmen - I have a chart that showes the "Across the Flat" measurements of all US, Metric and Whitworth wrenches. The chart is layed out so a person can see where each size falls in relationship to the others. I have already sent Michael a copy of the chart and will send one to anyone who will e-mail me and request it.
Cheers - Dave
David DuBios

This thread was discussed between 03/12/2002 and 09/12/2002

MG MGB Technical index

This thread is from the archive. The Live MG MGB Technical BBS is active now.