Tap and die sets - what to buy.

WarrenL

Active Member
Every now and then I find myself in need of a tap or die and having to go visit a friend, so I was thinking of buying a set and learning how to do it myself. I have two questions:

1) Knowing next to nothing about nuts and bolts, I'm not sure what type of set I should buy to suit the sort of threads one finds lurking around a Rover.

2) You can buy sets at every price from the very cheap (30 or so of our Kiwi dollars) to the mortgage-inducing. For occasional use, is a modestly priced set (say $100/£50 for 40-50 pieces) OK?
 
An Imperial set covering UNF and UNC. Buy the best you can afford. (That's not the same as the best there is.)
 
That goes without saying, Harvey. I always buy the best I can afford - it's just that what I can afford is usually nowhere near the best! I'd have a much better tool collection if I hadn't fathered those damned children. Mind you, I don't need to go overboard with the kryptonite-coated titanium tungsten alloy because it's something I'd only use occasionally; however if it happened to be sitting there I might suddenly be seized by inspiration and start tapping everything in sight!

UNF/UNC - thanks for that. People talk of UNF, UNC, BSF, BSW, SAE, Whitworth... it just seems to go on and on. However I should make an effort to learn more about them. I spend what seems like half my free time twiddling nuts and bolts and I'm only barely aware that there are different types.
 
I bought a fairly cheap set off ebay, just for cleaning up damaged threads and re-cutting threaded holes that I had filled with paint. I wouldn't cut new threads with it, but then that's not what I got it for.

UNF are the Finer threads, and UNC are Coarse - bit of a clue in the name :)

There's not much better than being able to reach up under your front wing and do up, or indeed undo, the front mounting bolts by hand with ease. Really glad I bought the kit.

Richard
 
In my limited experience, it's only UNF & UNC threads that I have encountered on my car. Only other advice I can think of is to try and get a set that has "bottoming" or "plug" taps as well as the more common tapered type you find in tap & die sets. The plug type is required if you have to tap out a blind hole. Another good idea is to make sure you get a good UNF/UNC thread gauge so that you can identify the pitch of a bolt/screw.

If you have a go at using a set, make sure you use plenty of oil as this will make things a lot easier and stop you blunting the taps/dies in short order.
 
Clean your glasses well before reading those gauges because...
The Unified Thread Standard (UTS) defines a standard thread form and series—along with allowances, tolerances, and designations—for screw threads commonly used in the United States and Canada. It has the same 60° profile as the ISO metric screw thread used in the rest of the world, but the characteristic dimensions of each UTS thread (outer diameter and pitch) were chosen as an inch fraction rather than a millimeter value.
 
That's not from that Fleabay listing, is it? I couldn't see it there. Anyway, I only posted the link as a kind of example; obviously I'd need imperial ones.
 
WarrenL said:
Thank you gentlemen. I have a can of cutting oil in the garage that I use when drilling, so I'm right there.

As for thread gauges, how about this?

http://www.ebay.com/itm/0-5-2-0-UNF-2-5 ... 232617eb63

Hi Warren,

Hmm...

Not sure at all what the description means on that item. 0.5-2.0...what's that? mm?

UNF/UNC both have the same 60 degree form and thread pitch is defined as TPI (i.e. threads per inch). So, for instance, a 5/16" screw thread will have 24 TPI in UNF and 18 TPI in UNC. Hence Fine and Coarse.

Like this item:

http://www.ebay.co.uk/itm/DRAPER-30...t=UK_Hand_Tools_Equipment&hash=item2570b8fd71

As has been said, the vast majority of the threads you'll encounter on the P6 will be either UNF or UNC. Generally, UNF is usually used in steel whilst UNC is used in light alloys such as aluminium e.g. exhaust manifold-to-head bolts.


Cheers,
Stan
 
vaultsman said:
As has been said, the vast majority of the threads you'll encounter on the P6 will be either UNF or UNC.

Indeed, but that hideous Metric (Spits on ground in disgust!) does rear its ugly head in one application.........
 
harveyp6 said:
vaultsman said:
As has been said, the vast majority of the threads you'll encounter on the P6 will be either UNF or UNC.

Indeed, but that hideous Metric (Spits on ground in disgust!) does rear its ugly head in one application.........


Hmm....

ISTR it's the alternator adjusting bracket set screw on the V8...but I may have dreamt that. :D
 
vaultsman said:
ISTR it's the alternator adjusting bracket set screw on the V8...but I may have dreamt that. :D

Possibly, especially with aftermarket alternators, but the main one is a lot more prominent than that, it's the plug threads....
 
harveyp6 said:
Possibly, especially with aftermarket alternators, but the main one is a lot more prominent than that, it's the plug threads....

Indeed...but at least you don't have to pick up a spanner with numbers like 10, 13, or 17 cast on it for them H! :mrgreen:
 
vaultsman said:
Indeed...but at least you don't have to pick up a spanner with numbers like 10, 13, or 17 cast on it for them H! :mrgreen:

True, they are handy for use as paperweights though....
 
Sadly, probably not.

At the engineering firm where I did my apprenticeship, using (nay, even having on site) an adjustable spanner was cause for being hauled into the foreman's office.
 
WarrenL said:
C'mon, am I the only one who uses a 10mm spanner on all his 3/8 heads?

I use a 10mm spanner on the fixing plates that hold the front wing to the front valance. That's only because I bought some new stainless ones which have 10mm nuts on them.

I have found that 13mm on 1/2" heads tend to round them off rather well so will try to avoid it as much as humanly possible - same with 11mm on 7/16 heads.

The only place that I will use an adjustable is on the battery terminal bolts which seem to have heads that nothing fits?

Richard
 
quattro said:
The only place that I will use an adjustable is on the battery terminal bolts which seem to have heads that nothing fits?

Richard

I'm guessing they're probably rogue BSW/BSF.

Speaking of which, there are a few of this ilk dotted around the P6.

Although things were (gradually) changing by the 70's, certainly anything pipework-related in 60's-designed automotive applications still tended to have Whit/BSF fasteners. For instance, coolant radiator drain plug (5/16" BSW IIRC?), fuel tank feed connections, etc.

vaultsman said:
At the engineering firm where I did my apprenticeship, using (nay, even having on site) an adjustable spanner was cause for being hauled into the foreman's office.

Although this seemed ludicrous to us young sprogs at the time, later experience showed it to be sound and not just to avoid rounding off nuts. I've seen some pretty impressive gashes caused by using the wrong spanner.
 
vaultsman said:
quattro said:
The only place that I will use an adjustable is on the battery terminal bolts which seem to have heads that nothing fits?

Richard

I'm guessing they're probably rogue BSW/BSF.

They should be 1/4"Whit. As we know, wheelnuts are 3/8"Whit, and there's a couple of 3/4"Whit & 7/16"Whit lurking around too. All of the above being spanner sizes, but not the matching thread type.
 
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