Tap & Die set help

[Astrokev]

Ah, I've been reading up. Should've done this before posting my previous question.

If I understand correctly, the answer to my question depends on what type and size of hole I'm trying to tap. So, if I'm tapping thin bar material, I think I'm correct in saying that I can get away with using just an intermediate tap, providing I tap beyond the tapered section to ensure I have a fully formed and parallel thread.

If I'm tapping blind holes, I should start with an intermediate and then finish with a bottoming or plug tap.

Is this generally the basic method I should use (don't want to buy taps that I don't really need).

Thanks

[Tom How]

Depend if you are going to be tapping "through" holes - i.e. a hole which is open at both ends and goes "through" something, or if you are tapping "blind holes" which are open at one end only. A single taper tap works normally for me on through holes, but a plug tap is handy for getting the threads to be bottom of a blind hole.

[Tom How]

There are also "spiral point" taps which push the cuttings out of the front - a joy on through holes but unusable on blind holes

[Bizibilder]

OK Three different types of tap: Taper, Second and Plug.

Taper taps, as the name suggests have a taper on the thread so that the business end (which has almost no thread at all as it is "lost" by the taper) of the tap can enter the pilot hole. You twist the tap (1/2 turn forwards then 1/4 turn back to "break the chip") until either sufficient tap has entered the hole to have formed a reasonable thread or the end of the tap has "bottomed" should the hole be blind.

Then you back out the taper tap and go to the "second" tap. This has a very small taper and is used (forwards and backwards again) to correctly form the thread.

Should the hole be blind then the "plug" tap is used. This has no taper lead and will cut a fully formed thread all the way to the bottom of a blind hole.

All taps are manufactured "between centres" and may well have a sharp point on the business end. This may be ground off if it is felt necessary to do so - some are already done for you and the end is "flat".

The size of the pilot hole is CRITICAL as it determines the "depth of engagement" between the tapped thread and the bolt or screw that is to be used. Too big and your new thread may well strip. Too small and the tap won't be able to cut cleanly and will break - usually in the hole. This is the derevation of the old English phrase of "Oh Deary me!!"

Carbon steel taps will cut all normal metals that we may use including "ordinary" mild steel (which doesn't actually exist!!) by which I mean the stuff sold by steel fabricators etc. Stainless steel is a different animal altogether and you will find it very difficult to tap by hand - it is very tough and tends to work harden making things worse as you proceed!

If you want to buy single taps and dies, at very sensible prices (and exallent service by return - I've been a satisfied customer for nearly thirty years!!!!) try:

http://www.tracytools.com/index.php?route=common/home

They supply industry surplus tooling of just about every thread form imagineable both in carbon steel and High Speed Steel (HSS).

Hope this helps.

[Astrokev]

Thanks Tom and Bizi'

Think I'm on my way now.

Cheers

[ponytale]

kevin if your expenditure is an issue like mine? i would say if you are tapping up to 1/4" alloy plate and 1/2" thick plastics only !,

the tapered tap of good quality will probably suffice as the top half of the tap is full thread size ,surely good enough for threaded rod and standard off the shelf hardware store bolts , use as advised previously above 1/4 turn forward 1/4 turn back with lube will be ok for aluminium plate. if ? you are threading blocks of alloys and steels buy all three for sure !!! i have been doing as above for a while now without any problems ( m6 and m8 ) .regards Tony ps if buying drill bits for any stainless work even thin ss use Cobalt drill bits just buy what you need from a good fastener outlet it will be worth it in the end!!!

[scogyrd]

Ignore what I said about needing two taps, you only need one to thread a hole. However, the screwfix kit is still junk. Having had the time to think about it I've remembered that the plastic wrench broke after about two turns and the thread was really hard to get started compared to the axminster tap. I'd imagine any single tap and wrench would be better quality.

[JamesF]

It seems to be more and more the case that the tools at the cheaper end of the market are often very poor quality and if you want something that will last and/or do a good job you need to pay more. Cheap saws, drills, drill bits, spanners, screwdrivers and so on all seem to be absolute rubbish these days.

There are occasional exceptions, and I used to know of someone who bought a couple of cheap drills from B&Q and kept taking them back for a free replacement because they always broke before the guarantee expired, but if you can't see how a supplier can source the materials, make, pack, ship, stock and sell a product for what they're charging then in my experience it's usually worth avoiding.

James

[Psychobilly]

the taper on the tap helps the thread forming..

The set is first , second and plug.. the plug tap is used to get fully formed threads close to the bottom of a "blind" hole as its almost parallel threaded right to the end and only "cleans" up the tapered section left from the second tap..

[Gina]

I bought this set a while ago, when I did the fixed bolt mod to my dob, and, if I'm honest, they're rubbish (and that's being polite). They're fine if you just want to clean up some threads, but they're useless if you want to make a new one. IIRC you need two taps to thread a hole, one to start the thread and the other to finish it, and this set only contains the second one so you're fighting a losing battle to begin with.

I ended up some much better quality taps from here in the end.

Buy Metric Taps Coarse from Axminster, fast delivery for the UK

Thanks for that Axminster is only a dozen miles from here. We often go to Mole Avon at Axminster for farm equipment anyway.

[Psychobilly]

Always worth a visit to Axminster tools if your ever in the area.. I used to prefer the old shop which was spread over several floors and was great to explore...

[yeti monster]

If you like straight threads, use the 1st, 2nd & plug method of tapping. It is possible to snap a tap in aluminium, and once snapped can be a bit of a pig to remove!

[scogyrd]

the taper on the tap helps the thread forming..

I don't know if this is meant for me but the screwfix taps really are poor quality and I managed to enlarge the beginning of the hole and round off the edge before I was able to get the thread started. The axminster tap, on the other hand, started straight away.

I'm not trying to plug the axminster shop btw. I don't work for them, nor do I get commission. I only use it because I live about 2 miles from their Nuneaton branch and, as I said earlier, any single tap would be better than that screwfix set.

[Macavity]

Ah, the joys of "Metalwork"! Seem to remember it was a good way to get off "games" (rugby),

after claiming some quasi-fatal schoolboy malady?

The metalwork master seemed to have a vernacular name for every tool and an incantation for each technique. <G> Using a SET SQUARE to get the tap vertical in both planes seems useful advice - I rarely succeed! Not sure about the 1/2 turn forward, 1/4 turn back (or similar) to "allow the swarf to clear", but maybe...

AH, I see there was indeed method in this latter. See Bizibilder above.

[yeti monster]

As a machine operator, I was always amazed how machine tools could hurl a tap into a hole at such speed without them snapping! Of course we used Dormer drill bits, taps and dies, but even they are brittle.

[Odd Thomas]

As a machine operator, I was always amazed how machine tools could hurl a tap into a hole at such speed without them snapping! Of course we used Dormer drill bits, taps and dies, but even they are brittle.

Great innit? All down to tapping / feed speed.

Tapping speeds are determined by many factors such as:

thread pitch

material being tapped

depth of thread

hole depth

hole type: ‘through’ or ‘blind’

lubricant quality and flow rate

Tapping speeds is calculated:-

RPM = Feed speed (surface feet per second) divide by 0.26 x tap OD (outside dia)

So as long as the tapping & feed speed ratio remain constant it doesn't really matter whether it is being done by hand at 6 rpm or by machine at 600 rpm!

ok I'll go and stand in the corner now.....

[Rob]

interesting indeed. I'm looking to purchase some ali metal to build a fork arm type arrangement. (very very early stage) but need some taps.

Thanks

[FairviewSteve]

The M is the diameter in mm and the number after the x is the tooth pitch also in mm.

And always follow the tapered tap with the full thread. Also best to use some grease while tapping. When turning the tap for every two turns reverse the direction for half a turn to break the burrs.

And b careful tapping alum with steel taps, without plenty of lube they will bind and be a real pain to remove and make a mess off the hole

[Astrokev]

The M is the diameter in mm and the number after the x is the tooth pitch also in mm.

And always follow the tapered tap with the full thread. Also best to use some grease while tapping. When turning the tap for every two turns reverse the direction for half a turn to break the burrs.

And b careful tapping alum with steel taps, without plenty of lube they will bind and be a real pain to remove and make a mess off the hole

Yep, thanks Steve - I think you're restating what others have already said.

[solarboy]

if you are at kelling [sept] i will bring a few sets and tapping drills up with me i have loads of them

[MisterBill]

One more tip. The drill size is going to be the nominal bolt size minus the pitch.

Bill

[fwm891]

Kevin, I haven't scanned all the posts in this thread but: Tracy Tools and Chronos have a huge range of carbon and HSS taps and dies with many different thread forms...

Francis ( Sorry if someone has already covered this)

[billhinge]

This was one of those tool sets I always meant to buy but never got around to, so I just decided to buy this weekend and order one of the 40pc sets from RS Components

http://www.gearwrench.com/catalog/specialty_tools/ratcheting_tap_and_die/ I went with the 40pc set http://www.gearwrench.com/catalog/specialty_tools/ratcheting_tap_and_die/setdetails.jsp?part=3885

The ratcheting wrench looks good and gets good reviews on the internet, hopefully will be fine for the small jobs I will use it for, should be delivered Tuesday

[wackyscot]

Lidl have a nice wee set in there offers just now for £7.99

David

[Gina]

I've bought some great tools from Lidl My tap and die set came from Axminster Tools though. Very good quality too