Thread Taps

[p0689109]

I won a lot at a auction of a mix of tools amongst which were a box of 50 or so taps. Mostly Whitworth and mostly big. A few are even left hand thread! 1inch BSW marked IS SGT Left Hand. The other interesting one is marked Easterbrock Allcard & co ltd 1915 1 1/8 W 7THS. I will sort them out tomorrow and photograph them and list what there is in case anybody needs a particular one.

 

[rtbcomp]

Please put them as an advert in the used items for sale section.

http://www.mig-welding.co.uk/forum/forums/used-equipment-for-sale.33/

 

[p0689109]

Will do If I decide to go down that route.

 

[Pete.]

If you have no use for them, and don't find anyone to buy them find a local restoration society to donate them to. I gave a box of huge WW spanners, taps and dies to the Spa Valley Railway when my dad passed.

 

[p0689109]

The biggest tap is a 1 1/2 Whitworth plug but no dimension of this item actually measures 1.5 in. Now I know when first introduced the Whitworth sizing was something to do with the size of the bolt shank and not the head for the spanner so why does this not equal the 1.5 at its broadest point?

 

[eLuSiVeMiTe]

I'll buy them lol. Looking for another old British lathe to sink my teeth into already.

 

[God mode restorations]

I'll buy them lol. Looking for another old British lathe to sink my teeth into already.

Those taps be just the job...

 

[p0689109]

Marked "Whitworth" and the major diameter is less than the 1.5

 

[p0689109]

OOPs sorry re-measuring shows the major diameter as 1.85! I must have managed to miss read before and that was with my glasses on! Old age. Anyway I have three different thread gauges to measure the teeth. Whitworth, Unified and Metric. Now the first two are "Threads Per Inch" and have a number stamped on each one relating to just that. Now the metric one again has numbers on them relating to the teeth but are they the same as in TPI and if so that is a hash of a system. I have a big good set of metric taps and they are measured by the diameter and the pitch of the threads i.e M12x 1.5 but does not have a thread pitch gauge with it. So what is the recognised metric system for this?

 

[MrFluffy]

Metric is specified as the distance in mm crest to crest on a thread form. So M12x1.5 is 1.5mm from one thread to the next.

 

[p0689109]

I understand that but when the metric gauge has a number stamped on it I assume then that it relates to the thread count per what? Inch I reckon but that seems a bit stupid in a Metric system.

 

[MrFluffy]

It should state the pitch of the thread, ie 1.5 on the one for 1.5mm pitch threads since that is how everything metric is marked up. My thread gauges do that.

 

[MrFluffy]

Borrowing some of irwin's bandwidth, but you can see their gauges stamped with mm clearly so they shouldnt complain about the free advertising.

 

[p0689109]

I checked the ebay and yes they mark them with thread pitch now but my set is all of 30 years old and I think it was when metric was starting to catch on in a big way. I have bought one of the newer gauges by the way.