Taps and dies.

Hi, I am interested to know what the more experienced model engineers consider to be the best or preferred tap and die manufacturers. I accept that there are many variables that can impact the performance of taps and dies, but all things being equal, what do people think. I have read a number of forum threads on the topic of taps and dies but I have not come across any that refers to the ranking from a quality perspective. My personal preference is Presto, but they are relatively expensive. I also have LAL, Osbourne, Goliath and Totum. I have tried Chinese made taps and dies but I would not touch them now with a barge pole. They are very cheap but after breaking a tap on two separate occasions and the frustration of having to remake parts again has left a bad taste in my mouth and I should have known better. You get what you pay for!! I think that the Chinese taps are too brittle. When I broke the ones I referred to earlier I was tapping mild steel and using tapping paste. Also what about HSS vs carbon steel?

Glad to get some feedback.

Thanks,

Alan.

Hi Alan, HSS ground thread from a quality maker, as you suggest Presto, Dormer etc etc but look at the link below which is to the December MSC flyer and look at Lyndon taps, I have used these for quite some time and whilst not particularly cheap they perform well and are less than the premier brands above.

**LINK**

The range is limited to metric and its best to watch for the special offers and particularly when they have sets on offer rather than single taps of each type -- taper, second, plug !

Merry Christmas John

I've used The Tap & Die Company for sets of BSF and others. Very well made, ground all over and in a smart box complete with wrenches. They also supply singles, usual disclaimer.

Brian

Hi Alan,

I am with John on HSS and Dormer taps, the best taps I have used. I also use Völkel taps, cheaper than Dormer (at least where I live) and it is difficult for me to see any difference. I have also used carbon steel taps from Tracy Tools - mainly on brass/gun metal - and they have been Ok. Like you Alan, I have also tried Chinese taps, very variable quality, some are very brittle and break, others cut very well and last a long time. Those taps that break I tend to replace with Völkel taps.

Thor

 

Edited By Thor on 27/12/2016 05:30:28

Emuge- Franken for taps [ they don't do Dies ] and for dies Hahnreiter [ make exceptional Dies ] also have a few from G &J Hall which are very good. Dormer and GARANT are good. Never skimp on cutting tools, false economy.

I bought a half decent tap & die set but the holder for the taps is garbage ... I suppose you get what your prepared to pay for ....

Merry Xmas

Sean

I spent my working life as a tool maker often tapping some very tough material. I will never buy carbon steel taps, I tried a set once as I only had one hole of odd size to do and they did not complete the job. For me most good branded ground thread HSS taps are OK. Volkel and the Interstate brand when on offer at MSC seem good.

My LAL taps are carbon steel, belonged to my grandfather and are (mostly) still going...

Not sure if LAL are though?

Neil

The usual reason for breaking taps is the wrong sized hole or tap going in at an angle - the last one being pretty famous at the smaller end of the BA range. If you look around you may come across the ME sensitive drill and tapping attachment - aimed at making sure that the tap goes in at the same angle as the hole. It's not unusual for drilling machines to have tables that are well out of square with the spindle or for people not to bother checking.

Another common reason for broken taps is not reversing every 1/3 turn to break the chip.

There has been posts discussing thread engagement figures - in other words increasing the size of the hole above the theoretical.

It is possible to buy good quality carbon steel taps. I was missing a size and noticed some used for sale on ebay. They wont be used much so no problem using carbon steel taps.

The stuff in cheap sets is usually useless. I bought one once at the dearer end of cheap as I needed some UNF. They were crap and wouldn't even start cutting a thread without a lot of pressure.

One set of metric I bought came from screwfix. Their precision set that may have changed. They are ok but the stocks are cheap and nasty. The adjustment on the dies is novel as well and doesn't work for me.

Tracy Tools have been selling taps and dies for a long time and will also get things in to order. I doubt if anything they sell is junk.

I believe some people are using ArcEuro serial taps.

The London Tap and Die Co are relliable. There are loads. Drill Services and others.

I thought I wanted some BSP taps recently. Would only be used on brass and not that often so carbon steel would be fine. I did find a tool store that sold both these and ground HSS. I then found fittings at a more sensible price. On the other hand a real tool supplier is unlikely to sell rubbish as it's not good for repeat business.

If you want to tap stainless good quality serial taps would probably be a good idea. Cast iron is hard on taps too. Mild steel, brass and aluminium tap pretty easily if done correctly.

John

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Edited By Ajohnw on 30/12/2016 20:05:11

I am probably going to be shot down by model engineering royalty but I now only use spiral flute taps. (Not spiral point which is something different).

They are so much easier to set square/plumb without a taper or second tap when hand tapping and are a joy when in a mill or drill press. MSC is my prime source but I have never had issues with spirals from Rotagrip on Ebay.

I will now take cover and prepare for the broadsides .....

I'd be worried if I wasn't fired on by the 'cognoscenti' for using spiral flute taps.

While I still use conventional taps, and spiral point taps, I also use spiral flute taps a lot. Mostly for machine tapping under power, but I agree that they are also much easier for hand tapping. And quicker, as only one tapping cycle is needed.

Andrew

I promise I wont broadside you, but what is it about the spiral flute that you think, makes it easier to set square to the hole?

As for carbon steel taps, carbon steel naturally will take a better edge than HSS, I think they're fine so long as you're not intending to tap stainless steel holes for industrial supply.

Michael W

Edited By Michael-w on 30/12/2016 20:55:38

I started thinking spiral when I was looking for BSP taps Alan. I thought that way I will only need one for each size. On small sizes where I'd guess the OP's problems are not so sure though so wouldn't even try it. I reckon by the time the size gets to M6 a casual approach is ok. M4 too usually but worthy of some effort to get it right except maybe on aluminium.

Just thought. Something I haven't seen mentioned on here. When holes are tapped really the fully tapped depth shouldn't be above 2 diameters of the tap size. Same as nuts really. Going past 1 1/2 diameter engagement doesn't make things stronger. The hole may need to be deeper to leave some where for bits to go but it doesn't really need tapping any deeper.

John

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Edited By Ajohnw on 30/12/2016 21:01:14

Indeed, they are Sean. I actually made my own tap wrench because of this, whatever it is they are casting them out of, it isn't strong enough.

I also got a decent tap wrench branded draper expert, but that set me back £30 and is fully machined steel. Look at the old timers decent tap/die wrenches and they are too.

Michael W

Edited By Michael-w on 30/12/2016 21:02:42

Carbon steel has acquired a reputation for poor quality. I feel this is undeserved as carbon steel is a perfectly good material to make a tap or die from for hand threading applications. HSS has a great reputation for making lathe tools drills and milling cutters as it will hold its hardness at red heat which is a situation unlikely to occur when hand threading. Manufacturers of poor quality taps have often chosen carbon steel as it is cheaper than HSS, why spend money on a quality material if you are not going to make a quality item? We are now in the situation where carbon steel is often considered crap because much cheap rubbish has been made of carbon steel. It is possible to buy decent quality carbon steel taps but they will not be the cheapest. I have also seen cheap taps that claim to be HSS but still look poorly made. Top quality taps and dies will often be made of HSS and have the thread ground accurately to size and profile. These items from the top manufacturers will cost serious money and probably have a performance that exceeds that required in the home workshop most of the time. So we now arrive at the question of what to buy that has a reasonable performance at an acceptable cost. Luckily for me friends have retired from toolmaking and prefer non engineering pursuits in their retirement so have gifted me a substantial collection of metric tackle of the best quality. That left me in need of BA and ME taps and dies. I chose to buy sets of carbon steel from the tap and die company which are not that cheap and I have no complaints about the quality. My plan it to replace any that I wear out or break with HSS GT items but I now have the convenience of most of the sizes I may ever need without having to order them as I need them and an upgrade policy for the most used items. The well known European manufactures all make good kit but for home workshop use something more modestly priced may be required, so we need to sort out what imported far eastern stuff can be relied on and here we are more in the hands of the tool dealers. Reading this forum regularly will give some idea of the dealers who care about more than just the lowest price and they can be a good place to start. Although no one is going to have a standards room to verify the quality of what they sell the better ones do know what they are looking for and will find a supplier who can deliver acceptable quality at the right price so choose a dealer that you have the best feeling about and try their stuff. When judging performance bear in mind the price you paid. A lot of imported stuff will fall short on comparison with the very best but the bangs for your buck can be very good indeed and will often be more than adequate for home workshop use.

Mike

I had one of those once .... although it started off as a regular straight flute. Who says Chinese taps are brittle?

This novice will always use a machine tap if i have one of right size. And this simple tool makes life so much easier on mill and lathe using a cheapo chinese keyed chuck for a fiver when hand tapping. Yes it slides on the bar.

Morning all, comments noted.

I have no idea why subjectively the spiral flute seems to start easier and more plumb than a conventional combination of straight flutes.

I have looked at the physical aspects of each and my only conclusion is that initially the straight flute does not offer any resistance to tilting in the flute radial areas whereas the spiral presents a fully 'circular' radial contact when presented to the hole for tapping after a couple of turns. Not sure that makes sense but hopefully you can imagine what I mean.

The other positives are the need for only one tap per size and the more effective clearance of swarf via the spiral, hence its popularity in CNC manufacturing.

Spirals are similar to plug taps in that they cut a thread almost to their tip. This means that the 1.5D to 2D thread depth rule is met without excess depth on any blind hole being tapped. A taper and second tap would need a deeper hole. From a machining time and metal waste point of view this is a positive.

The 'quarter turn' back and forth incremental turn rule to avoid breakage of a conventional tap also seems more relaxed on a spiral which I am guessing must relate to better swarf clearance and a more distributed radial cutting action ? Old habits die hard however and I still tend to be reluctant to push my luck except in aluminium.

All a bit subjective but thanks for listening.

Another issue with hand taps and shallow blind holes is that there is not enough depth to even get the taper tap started. When I buy hand taps I only buy the taper and bottom.

Spiral flute and spiral point taps are much better at swarf generation and clearance. Even on ductile materials (like low carbon steel) hand taps tend to produce short chips, which can get jammed between tap and work. However, a spiral flute tap on low carbon steel will produce continuous spirals of swarf which are fed backwards out of the hole. So there is almost no swarf left in the hole to cause a jam. It is not unusual to have several inches of swarf sticking out from each flute when using a spiral flute tap - both hand and machine tapping. I'm sure I took a picture of the swarf from a spiral flute tap, but I'm darned if I can find it.

Spiral point taps produce similar lengths of swarf, but pushed forwards into the hole, and out of the opening at the bottom.

As a matter of course I expect to hand tap a hole with a spiral flute tap in one go, no backing off needed. On a machine of course there's no possibility of backing off; in to full depth and out again in one operation at much higher rpm than by hand.

Andrew

Ajohnw rightly points out the necessity to "break the chip" with conventional straight flute taps, this also ensures that the flutes are filled with small chips that jam.

If you do not clean these out, guess what? You can easily break the tap!