Any advice on buying taps. I need sizes from 2.5mm to 6mm (including
3.5 mm - even though my local DIY shop tells me metric screws only come in whole numbers) for tapping mainly aluminium and occassionally mild steel.MY internet search seems to find huge sets of taps and dies at suspiciously low prices or individul items at pocket wrecking prices. Materials seem to be carbon steel, tungsten steel and high speed steel. Which is best?
Dave
HSS. Go to J&L online and buy something decent. Avoid cheap and cheerful carbon steel sets made in Itchifanni because they snap like carrots and are often so badly made the threads they cut aren't to size anyway.
Can't help with the taps (don't know enough) but if you like winding up the DIY shop...ask them about the screws for electrical accessories...ask them what size they are! Guess you know they are M3.5...
This siyte is very highly rated for quality Taps n Dies
This site is very highly rated for quality Taps n Dies
Hi Dave for aluminium carbon taps will be a lot cheaper and will work fine for the occassional mild steel. Just remember the tapping size hole to give a 60% to 80% thread engagement. Try some of the model engineering suppy firms.
Mike Cole
The problem with carbon steel is not the material but the manufacture. From a known name manufacturer a carbon steel tap would be fine but unfortunately the cheap sets vary from ok to useless. Good manufacturers tend to use HSS because the extra material cost makes little difference to the final price. The Hertel and Lyndon taps from J&L are only £2 to £5 each in the sizes the OP wants so they aren't going to break the bank. You can manage with just
2nd (plug) taps for most work rather than having to buy all three per size.The alternative is somewhere like Sert Tools near Slough for second hand taps if you are prepared to rake through their boxes to find what you want. You can pick up as-new top quality taps like Dormer for a quid each. I go there every now and then with my list of missing sizes and spend an hour or two going through their boxes of taps, dies, reamers, drills etc.
what a range! Left hand metric, cycle... I am immmmmmmmmpressed
I bought one of their metric sets a couple of months ago, partly because I couldn't find the range of sizes elsewhere, partly because of having 2-3 taps for each size and not wanting the cheap sets which don''t seem to last very well.
When all of that is taken into account, a price of around £100 is quite impressive.= as are the results I've had.
I think you've answered your own question. For serious use you need expensive HSS types. For occasional use where the thread isn't really critical a cheap set might be ok - although they tend to vary somewhat. I bought a Draper set in desperation one Sunday after 'losing' a particular one I needed and they proved ok at the price.
Draper stuff is usually reasonably well made and serviceable. By contrast my first set of cheapish carbon steel taps and dies bought many years ago (can't be arsed to go to the garage to look up the make) was okish in the larger sizes for cleaning out existing threads, useless in all sizes for cutting new threads in anything (not sharp enough) and the first time I used the 4mm tap to clean out a thread in a carburetor it buggered it completely by cutting it massively oversize.
Since then I only use quality brands designed for real engineers. There's nothing worse than trying to do a good job with crap tools. The OP wants small sizes of taps and those are the worst for quality in cheap makes. A few thou error on size in a large tap might go unnoticed. The same error in a 2.5mm tap will mean the resulting thread is useless and strips the first time you tighten a bolt in it.
You also break the small sizes more easily and that's where HSS instead of carbon steel has a double benefit. Stronger and much less brittle and likely to snap.
Anyway the OP can do what he wants but when you do this sort of thing for a living you quickly find out just how expensive cheap tools are.
Another trap I fell into once was a set of 8 or so adjustable reamers at a model makers exhibition many years ago. Quality makes like Taylor and Jones are the best part of £30 each. This boxed set was £40 the lot and despite huge misgivings I fell for it. What a bloody waste of money. The holders were ground on the piss so all four blades didn't cut at the same time, the blades were badly ground, blunt and snapped like carrots the first time I tried to use them to ream out some bronze valve guides. I got no use out of any of them at all in the end and the money was wasted.
However, each T&J reamer has given me years of faithful service before eventually needing a new set of blades.
Repeat after me. Never ever ever ever buy cheap tools.
In article , Dave Baker wrote: [snip]
A tap (or a stud extractor!) that snaps off in the job turns a minor problem into a right pain in the whatsit.
Always buy snap-on, mac or similarly expensive stud extractors!
Mine were expensive, Dormer. :(
It's generally good advice, but there are times when they can be ok. For example I keep my car spanners (good and expensive makes) handy for car work. But in my workshop which is actually a first floor bedroom and mainly used for electronic stuff I have cheaper sets bought from the sheds
- as the sort of use they're put to doesn't tax them. Of course you'd check they are a decent fit, but they appear to be. I have a combination metric set which cost 1/10th of decent stuff but does that job ok. And isn't covered in grease. ;-)
Things like spanners and sockets are a different kettle of fish to cutting tools. I use Draper spanners and sockets quite happily for professional engine building use. I've never felt the need to buy Snap On or Britool at many times the price. They might not be quite as strong or as good a fit but they'll always work to some extent, usually a quite sufficient one.
However a poor cutting tool might not work at all. It might cut oversize, undersize or just jam and break. A cheap spanner always has some utility. A cheap tap might have zero utility which is why I stick to pro quality ones.
As a supplementary: what kind of tap wrench is preffered. The straight bar type or the tee handled chuck type?
The former for applying more torque when you're tapping a new thread and the latter for ease of handling when you're cleaning out lots of existing threads.
Funnily I bought a cheap set of drills from Lidl just the other week not expecting them to be much good. All the 0.5 sizes to 10mm in a nice steel case for IIRC 4.99. and it was the case I really wanted for carrying drills out to the car, etc. And having drilled a fair amount of mild steel with them they've done as well as branded shed types at many times the price. Although I try and stock up with tubes of production drills at autojumbles for the common sizes.
Until quite recently my cars were mainly UNF and UNC threads, etc - so on getting something more modern I decided on some decent metric spanners and got Halfords pro range. Which are a delight to look at use. ;-)
Not if it springs and wrecks a nut, though. ;-)
I do see where you're at, but it does depend on the likely use.
I'm explaining myself very badly. By cutting tools I meant precision cutting tools that have to work to a tolerance. If they do so they are fully functional and if they don't they are useless. There's very little utility in between those two extremes. This includes taps, dies, machine reamers and adjustable hand reamers, boring and honing equipment and precision grinding equipment.
Drill bits have a wide range of utility. Even cheap ones will be close to nominal size and in any case hole size is not critical to a thou or so when drilling and will vary more due to the machine, the chuck and the speed and feed than the tool. What you get by paying more is longer life and the ability to machine tougher materials.
So for occasional or hobby use cheap drill sets are usually fine and in fact are often pretty good quality. You might not get many holes out of cheap ones before they go blunt but if you only want to drill one hole it doesn't matter. In high volume production environments the cost of tool changing and setting up again will far outweigh the saving on cheap items so you buy the best.
Similarly most hand tools like spanners and sockets will have a wide range of utility depending on price. Cheap ones will do most jobs and expensive ones might only be needed for the occasional stubborn bolt that's rusted into place.
So finally, boiling down what I've been trying to say into something comprehensible, it's the importance of the tolerance that determines whether you need pro quality stuff or can manage with cheaper.
In my experience the worst items for being useless if you buy cheap are taps and dies. For everything else you tend to have a range of price vs quality that you can tailor to your personal needs and still get a functional item.
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