Taps and Dies ?

Oh, but we were 'mending garden gates' and the like

Norman

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At lunchtime today, 16th February, they had around 10 sets in Aldi at Meadowhall Retail Park, Sheffield. Yellow and black packaging. Didn't look up to much. I didn't really want to duplicate 90% of my cheap t&d's, plus buy another useless tap holder and die stock. I'd rather spend the cash on the real deal.

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well if you want quality thats cheap and new or newish ..you ain't going to find a whole set on ebay without months of looking. you're going to have to assemble a set youreself..out of taps and dies that are sold as single items on ebay

look out for spiral flute taps ..these are unlikely to be cheap crap .. and search these makers names .

Dormer Presto Goliath Lyndon Titex

also there is a good chance, if a metric die is a split die ..then its unlikely to be cheap crap either .

all the best.markj

ravensworth2674 has brought this to us :

Even so. I needed to use one of the Aldi taps yesterday. The holder was like butter and just slipped round, the tap was fatter in the middle of its thread than either end. I was only tapping some fairly soft mild steel - the thread was just about usable.

mark formulated the question :

Which aroused my curiosity - what is the actual purpose of the split?

I have always assumed it was to permit some adjustment of how deeply the thread was cut.

Harry,

Sale of Goods Act (1893) applies

Cheers

Norman

Harry, A split die is to allow some initial relief in starting and cutting the thread.It isn't quality engineering as the circle is forced 'out of round' at that point. It therefore saves the huge amount of muscle power which would be required to do it all in one go. Try doing a lathe spindle nose of 1.25"x12TPI without screwcutting - at one go.

Taking it a stage further, large pipes and such require segmented dies to ease the-- effort.

OK?

Norman

ravensworth2674 explained :

Yes! Thanks for the explanation.

I cringe a bit when using my Rotostock pipe threader on larger diameters, the one I have will do up to 2" pipe, they go larger IIRC, the dies are not split but one solid ring, the mechanism will handle the torque of cutting the taper threads along their full length in one go. I don't really worry but realised the torque required to do it is quite high but manageable.

on 14/02/2010, David Littlewood supposed :

Just had one of the above sets delivered. No makers name on it, but it seems to be good to fair quality - apart from the dies not quite fitting the die holder. Just needs a little easing of of the paint around the socket I think. Other than that - satisfied.

though

Today

Thats exactly the same one I was looking at from Greenwood tools. Might just give it a go.

Cheers for posting the info.

though

Today

Just ordered a pair of HSS sets tonight from ArcEuro. I went for the M1-M2.5 and the M3 -M12. Total price £59.85 . Hopefully they will do the job!

Thanks for the advice guys.

Got the Tap and Die sets yesterday - they look pretty good for the money.

One question: the first taps have flat-topped 'blunt' threads. Most first taps I've seen are sharp, but have a long ground tapered lead in.

What's the story here? Are they designed to take a very light cut? Of course it means that they can't be used without the other two taps.

Cheers,

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DR_G presented the following explanation :

I half noticed that the first time I used them, then confirmed it a couple of days ago the second time I needed them. I'm used to being able to use a second tap on thin material and providing I run the tap all the way through, the thread will be to final size.

Using these taps, the second tap (and first) produces an undersize thread - You have no choice, but to use the finish tap to get the thread to finish size. It does seem to make them easier to use, but takes a little longer.

A full set of taps used to consist of three taps.

1st. A tapered tap for starting the thread and which doesn't give a full thread at the lower part of the tap. 2nd. A tapered tap that has less of a taper than the 1st. tap. 3rd. Often used to be called the finish tap because it cuts to the full thread. Using the full set sometimes takes longer but does save on broken taps and temper.

Interesting. I've never heard of the third tap being called a "finish" tap. Also, I've never heard of a second tap which didn't cut a finish-sized thread (after the short taper of course).

For me, the third tap was/is called a "plug" or "bottoming" tap and not only should it be fully threaded all the way to the tip (apart from a very short lead-in) but it also should have a flat end. This is so you can get the maximum finished thread in a blind hole.

I know both types of tap sets: The usual set has the same profile and diameters on all three taps, the set mentioned here with different diameters is in Danish called "seriesnittappe" which translates into "series taps" in English. The latter type is typically used for hard and tough steels etc.

Yep, there's two types of tap sets, the usual set and the series tapset. The usual set is taper-second-bottom, the series tapset is rougher-intermediate-finisher.

I don't know of a descriptive for the usual set, afaik it came first and didn't need one, the series tapset came later and did.

Personally I prefer the usual type unless I'm tapping superalloys to tight tolerances, I find they are more useful and you don't have to use all three taps.

Telling the difference can be a bit awkward, but I find series taps are more likely to have rings on the shanks.

-- Peter Fairbrother