ned
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| posted on 16/5/05 at 10:47 AM |
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tap and die sets...
I am increasingly finding jobs that would benefit from me owning a tap/die set so thought I'd ask here about it.
Initially I only need something to clean up dirty threads etc, but have access to a lathe and if investing in a set I might as well get something
capable of cutting threads from scratch.
I have found a few sets I like the look of for quite reasonabel money, but just want some clarification on the types of materials quoted that
they're made out of.
I've come across:
Medium carbon steel
high carbon steel
HSS steel
Tungsten steel
I have listed them in what I think is the order of strength/durability, can anyone confirm this (weakest first!)? I've been lead to believe
carbon sets don't last too long but am not sure which is better out of HSS and tungsten steel as they're both alloy steels afaik...?!
Any help appreciated.
here are links to the sets I've been looking at:
http://www.toolstation.com/?r=k&feature=86203 (have a socket set by the same make, not had a prob so far)
http://sealey.industrialsuperstore.co.uk/sealey/product.php?product=21775 (pretty cheap! are sealey pro tools any good?)
both above sets are m3-m12 with normal and fine (i think) threads and are in tungsten steel and about £25-30
I only really need m4-m10 at the moment and can't see a locost requiring anything bigger/smaller than m3-m12 the only expectin being seatbelt
mounts @ 7/16"unf which I've already made up (borrowed a friends tap)
cheers,
Ned.
[Edited on 16/5/05 by ned]
beware, I've got yellow skin
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flak monkey
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| posted on 16/5/05 at 11:17 AM |
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Of the materials you have listed there the HSS will be the most hardwearing as it contains a lot of chromium which forms one of the hardest carbides
in steels (1500Hv).
The tungsten steel ones are better for high temperature (tungsten carbide have the highest precipitation temperature of the common carbides ~550degC),
but they will not be as hard as the HSS ones...(in theory, without a chemical breakdown of the steel I cant tell you for definate).
MCS and HCS ones are ok for occasional use in softish materials, but are more than capable of cutting steel as well, thought they will wear out
quickly if used a lot.
I'm guessing the Tungsten ones are expensive, but as i said they will not actually be as hard wearing as the HSS ones, but will be ok at high
temps (CNC cutting).
HSS should be more than adequate for most jobs.
Cheers,
David
(I knew this tooling course would come in handy one day!  )
Sera
http://www.motosera.com
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ned
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| posted on 16/5/05 at 11:33 AM |
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thanks for that david, good to know 
suppose it makes sense really as an HSS set is nearly twice the price of tungsten, with tungsten being pricier than carbon sets..
the cheapest HSS set i've found is the screwfix affair:
http://www.screwfix.com/app/sfd/cat/pro.jsp?id=12834
if carbon steel should be ok for occassional use then tungsten should be fine, or is it still worth going for HSS?!
Ned.
beware, I've got yellow skin
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flak monkey
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| posted on 16/5/05 at 11:38 AM |
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Its up to you, as you know how much you would use them. I would say go for HSS as they will last forever (with occasional use) as long as you dont
break them. (Remember HSS is quite brittle, whereas carbon steels, in comparison, are quite forgiving).
That set on screwfix looks pretty good...
David
Sera
http://www.motosera.com
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clbarclay
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| posted on 16/5/05 at 01:08 PM |
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I bought a set off ebay the same as this one.
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&category=303&item=4381684750&rd=1
They say tungsten on them, but like CR-V on cheap spanners I dought it mean a lot.
The includes the right M18 needed for the transit TRE's.
The set has only no.2 taps, but as long as your not wanting to tap right to the bottem of blind holes, its not a problem.
Only problem i've had with the set so far is a couple of teeth on the M18 damaged from when use without lubrication. In other word operator
error. The tap still works well enough though.
[Edited on 16/5/05 by clbarclay]
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David Jenkins
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| posted on 16/5/05 at 01:25 PM |
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If you're only going to use them to clean out threads, or occasionally to make some new threads in mild steel, ali or brass, then there's
nothing wrong with a GOOD set of carbon steel taps and dies.
Most of the ones I bought for model engineering are carbon steel, as are most of the unusual sizes in Metric (e.g. the one for the swivel thread in
the top front wishbone).
They'll give excellent service if used properly, with proper lubrication (e.g. Trefolex).
A good source is Tracy Tools in Dartmouth - excellent mail order service (but don't use a credit card over
the phone - they impose a high premium to recover the bank's charges). If you post an order in the morning you're likely to get the tools
in the post 2 days later! It's all industry-surplus stuff, but nearly always excellent quality. They also do odd sizes, left-hand threads, NPT,
whatever.
rgds,
David
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DarrenW
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| posted on 16/5/05 at 01:56 PM |
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i use HSS taps with no problems at all. I was lucky when i came out of my time as i had a set in my tool cupbaord. Ive got the sets of 3 but to be
honest i usually only use the first tap as i rarely tap blind holes.
Do you need a set of dies? I guess they will be rarely used so a chaeper set may do the job.
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britishtrident
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| posted on 16/5/05 at 04:03 PM |
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For cleaning threads buy a set of "hex die nuts" as these give the exact finished size. Make sure you get the type with a Hex on the
outside are are the most convient to use. These don't need to be supper quality tool steel as they should only be ever be used for
cleanning/repairing existing threads.
For just cleaning internal threads up usually a single tap either a "plug" or "intemediate" will do.
For cutting external threads from scratch you need good quality "split dies" -- some good bargains on eBay but beware some of the die
stock holders in the sets are pretty punk.
For cutting internal threads from scratch you need proper HSS taps that have either 2 or 3 taps for each size --- puka sets have 3
(starter,intemediate and plug) but you can get away with 2 for most jobs as the plug taps are really only needed for blind holes that are threaded
right to the bottom.
[Edited on 16/5/05 by britishtrident]
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NS Dev
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| posted on 16/5/05 at 04:18 PM |
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Use HSS taps, these are spot on for multipurpose "jobbing" jobs.
There are actually many different HSS alloys though.................... read through the cromwell catalogue and you will see what is available, but
there are taps for basic steels, then for stainless steels, titanium etc and fluteless taps for 0 loss tapping in Aluminium.
For normal use, common or garden HSS is just fine.
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Hellfire
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| posted on 16/5/05 at 08:10 PM |
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HSS - everytime. Tunsten is hard but very brittle and cannot sustain a "sharp" edge as long as HSS. Chances are on the 1/4 back turn (to
break swarf) the tungsten one's will snap.
I wouldn't go to the expense of buying a full set actually. No.1 tap is of little use unless you're tapping deepish holes. Most jobs can
be done satisfactorily with No2 (intermediate) and No3 (bottoming tap).
Given the choice - get TiN coated of reputable make Guhring, Dormer etc
[Edited on 16-5-05 by Hellfire]
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owelly
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| posted on 17/5/05 at 06:12 PM |
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I bought the Screwfix ones just for tidying-up threads at home (proper ones live at work!!). Complete waste of money. Buy the best you can afford (in
the sizes you need) and look after them!!!
[Edited on 17/5/05 by owelly]
http://www.ppcmag.co.uk
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johnjulie
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| posted on 9/6/05 at 09:13 PM |
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Do NOT buy a cheap set, it's a complete waste of money as already stated.
Make a list of what you need and then keep an eye on Ebay. HSS will be fine for what you need, Middle, or 2nd taps are the most useful.
You could try www.tracytools.com
Good luck
Cheers John
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James
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| posted on 15/7/05 at 10:49 AM |
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I bought the non HSS set from Screwfix.
Absolute crap- blunted after cleaning out one thread! 
Cheers,
James
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"The fight is won or lost far away from witnesses, behind the lines, in the gym and out there on the road, long before I dance under those lights."
- Muhammad Ali
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