Die defeated by mild steel

As stated earlier, the top diameter of a metric thread is actually less than the designated size.

Cutting with a M12 hand die straight onto commercial bar will probably only work if you have a very good/new die and use quality thread cutting oil. It is also difficult to get a straight thread over a length.

Why not start with a piece of studding ( threaded bar) or cut a suitable bolt or capscrew up and tap the end of that

HSSGT are the letters that have become associated with a quality die, however these letters are not a guarantee of a quality product just as carbon steel has become associated with a low quality item. Making a die for hand threading from HSS is surely s bit of overkill as the major selling point of HSS is that it retains its hardness at red heat, not a condition likely to be encountered when hand threading. A well made CS die is likely to provide all the performance required in a home workshop. Presto was a brand that had a strong reputation but I wonder what has happened to it in recent years, Britool was a brand that was made in Britain but now seems to be applied to products from Taiwan. I went shopping for a 3/8 drive socket set in 1978 but baulked at the £130 price tag. I do own a 1/4 drive Britool socket set but it should be called Taitool, It is a nice set but a tragedy it is no longer made in Britain but I doubt it would cost £40 which is all It cost in 2012 if it was made in Britain. It is difficult to be sure of what you are buying these days when even famous brand names have been traded and the new owners may not aspire to the standards that originally built the brand.

Mike

Britool merged with FACOM of France, who then merged with Stanley Tools, who than merged with Black & Decker, so there you have it, all part of Stanley Black and Decker Industrial and Automobile Repair Division. [For merge read takeover]

Why not use a tailstock die holder,with a long tommy bar,if the work slips in the chuck jaws, then grip the work in an ER collet, on rough work that slips in the chuck a dab of weld will stop rotation (it stops against the chuck Jaws) the weld can be ground off later. Or make a die holder, with a guide,that works ok provided its not too close to a shoulder. I have a virtually unused set of ex WD whit taps and dies,a circular guide also holds the die,the assembly then fits into a die holder about two foot long. the advantage each die can be set to size and not loose that setting, the set has 1939 stamped on it. Only used the dies once,though the taps have useful,best feature is the superb tap wrench ,it a sliding V and is bright steel all over and that gets used a lot.

Black and Decker also combined with De Walt, the De Walt tools are a different colour, and cost twice as much, but they are all Back and Decker.

My three socket sets (1/4", 3/8", 1/2" are SK Wayne from USA, not sur how many weeks wages they cost, but the firm covered most of it thank goodness, but the same today would be near $NZ1000.

Funnily enough, a few days ago, I did try to cut a M10 thread with a die. The workpiece was JUST under 10mm. With the die adjusted to a good quality M10 bolt, it caused the belts to slip. Then the job slipped in the chuck jaws. Eventually, I got enough threads cut to remove the job from the lathe, hold it in the vice and use a fairly large die holder. The thread was cut by slightly opening the split die, and backing off every quarter turn, to break the rather large curls of swarf. Once "roughed out", the die was reset and cleaned up by hand. As a lubricant, I used bacon fat, (too idle/tight to open the tin of Rocol STD) The nut, of the same quality as the bolt, was an easy fit, which made it ideal for the intended use.

Howard.