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Clive B 125/10/2016 19:26:48
94 forum posts
50 photos

Hi Guys

I've just started to look for some taps namely an M8 x 1.25, M10 x 1.25 and

M12 x 1.25, I know the HSS ones should be ok but I've also seen some tungsten hardened ones on e-bay.

I shall be hand tapping, can anyone tell me what the difference is between the two and if there is a difference which would be the best to go for when tapping by hand?



JasonB25/10/2016 19:38:33
17824 forum posts
1948 photos
1 articles

Having just looked at the various "tungsten hardened" taps on the bay and their prices I would stay well away.

I have replaced a lot of my metric ones in the last year with Dormer E500 hand taps in te larger sizes and Vockel ones in te M2.5 and below sizes.

The M10 and M12 threads you mention are non standard pitches do you mean that or are you after the most common metric coarse threads.

Tony Pratt 125/10/2016 20:03:46
1098 forum posts
3 photos

Ok I'll bite, exactly what are "tungsten hardened" taps? Never heard of that term but does sound more impressive than plain carbon steel or HSSfrown


Roger Provins 225/10/2016 20:47:57
343 forum posts

I have not used any always stuck to good HSS taps.

Not sure if these are the same as you mention but, gleaned from the web.....

NOTICE ON USAGE. UH-CT cannot be used by hand, it must be used by machine; machines with feed-rate/rotation synchronized tapping mechanism are recommended, the maximum rigidity of tap and workpiece holder is recommended, drilled hole must be as large as possible.


JasonB25/10/2016 20:53:48
17824 forum posts
1948 photos
1 articles

The ones on e-bay are not carbide taps, they are described as hardened (and tempered in some cases) tungsten steel or steel alloy. No indication of percentage of tungsten or what teh alloying agents may be.

They seem to be very cheap taps, the sets work out at less that £1 per item, unsplit dies etc so just don't look good quality. I think Tony may have summed it up when he said "sounds impressive". It seems to be a material used by one brand of tools - "USPro" but don't think they have any relation to the tool box maker.

Edited By JasonB on 25/10/2016 20:54:27

Clive B 125/10/2016 22:17:18
94 forum posts
50 photos

Hi Guys

Thanks for the replies, first off Tony you may have just answered my question “tungsten hardened” it does sound impressive doesn’t it and me not knowing too much about taps other than HSS being good, I just thought I’ll post on the forum to find out if they are any good but from the answers I’ve had so far I won’t be rushing out soon to buy some.

Jason thank you for taking the time to have a look on the bay, I will be taking your advice and yes sadly it’s the fine thread I need.

Can I pick your brain a little more, I’m still looking on the bay at a Volkel tap sold by almtoolandgauge, am I right in assuming by what it says (M12 x 1.25 V Coil - Fits Helicoil - Wire Thread Repair Insert Tap,) priced at £11.90, its only for helicoils.

Basically I’m after it to tap a hole in mild steel and fit a screw or bolt straight into it, no helicoil fitted.

Roger thanks for the link, at least I won’t buy any are UH-CT it’s such a drag having to send things back if the wrong item has been purchased.

Clive B 125/10/2016 22:39:46
94 forum posts
50 photos

Jason I will be doing a web search for some decent taps, but if you already know of any sites worth trying at a reasonable price please don't hesitate to let me know.

Thanks again


JasonB26/10/2016 07:47:35
17824 forum posts
1948 photos
1 articles

Having never fitted a Helicoil I can't help much on that aspect.

Regarding your use, you won't be able to buy standard screws or bols to fit these tapped holes as the pitch of the helicoil taps is based on the pitch of teh bolt that is going into the helicoil. For example a 12 x1.5 helicoil tap has the pitch of a M10x 1.5 standard Metric Coarse thread.

If you just want a finer thread then look at the Metric Fine series which will cut a thread suitable for a metric fine bolt so M12x1.5 will take M12x1.5 fixing rather than the coarse M12x1.75.

Vockel I get from Rotagrip, they have an e-bay shop or website. The Dormers I get from MSC, a bit pricy but good and often on special offer - don't pay full price. You could also try Tracy Tools who are a bit more reasonably priced

Edited By JasonB on 26/10/2016 07:48:30

Tony Pratt 126/10/2016 08:37:06
1098 forum posts
3 photos

Cromwell tools is worth a look, massive catalogue & quick delivery.


David Jupp26/10/2016 09:12:09
723 forum posts
17 photos

Avon Tap & Die - order on a Friday for free delivery (which is very handy if you just want one item).

Nigel Bennett26/10/2016 09:45:43
337 forum posts
11 photos

I think what most posters are saying is that you pay for quality. You can't buy cheap taps and dies and expect them to produce accurate threads and stay sharp after a lot of use. (You might be lucky - but I've seen some hideous examples).

Cromwell tools is a good source, but don't think that if stuff in their catalogue is cheap it must be good - they usually show a range of cheap and not-so-cheap alternatives. Go for good named makes like Dormer or Guhring.

Snapping off a lousy cheap tap in an expensive component also adds to the cost...

Chris Evans 626/10/2016 10:01:43
1626 forum posts

At the cheaper end of the scale I have bought "Interstate" branded HSS taps and dies from MSC when on offer. Results are good but not in the Volkel quality. Stick to HSS where possible, some Chinese taps are advertised as HSS but I have my doubts.

Clive Hartland26/10/2016 10:12:26
2552 forum posts
40 photos

Helicoil; taps are usually sold as a kit with inserts and an insertion tool. DO NOT confuse them with standard taps as the helicoil taps are oversize to allow for the helicoil that fits the thread and brings it to a standard size.

I have at times sourced taps and dies from Switzerland, high quality. Again expensive.


Tim Stevens26/10/2016 10:15:41
1155 forum posts

The more significant difference between cheap taps and dear ones can be to do with the method of manufacture. Cheap taps are hardened last in the process, and this heat treatment can produce distortion. Usually minor, but it can be important. It certainly reduces the sharpness, too. More accurate (and sharper) results can be produced by a final grinding after heat treatment, in which the shank and the threads are both 'skim' ground and so, are dead concentric and straight.

There are times when I use a tap as a mandrel, when facing a surface exactly at right angles to the thread, for example. This is when the inherent accuracy of a ground-thread tap is very handy, as I can rely on the thread running true to the shank held in a collet. And they do seem to be sharper, and stay that way for longer.

How do you tell? One way is to look at the surface finish. The hardening process leaves a dull, dark grey surface with no obvious 'grain', but a ground tap will have a bright silvery surface with a silky grain - like you get with fine emery cloth in the lathe.

Regards, Tim

KWIL26/10/2016 10:33:20
3213 forum posts
63 photos

Cutwel and Drill Services (Horley) offer a wide range of taps and all from reputable named makers

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