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[howie55]

Are there special taps and dies to use when making threads in brass, I have used a set from duratool for years , but recently I have been making turn buckles and the male and female no longer fit, is this because brass wears the die and taps
Any one had experience of this
Geoff

[warspite]

Is brass not softer anyway, if used for years is it not down to general wear and tear?

[Bunkerbarge]

If the rod and bores are both to the correct size then there should be almost no wear on taps and dies when cutting brass threads.  Brass contains Zinc, which acts as a lubricant for cutting, which is why it is so easy to cut brass and why special tools are not necessary.

[howie55]

Odd that the first turn buckle was smooth fit, second started but seized half way in, I have rerun tap and die but it did not improve, will buy new M4 tap and die and try again
As always great forum
Geoff

[Bunkerbarge]

Are you buying good quality taps and dies or cheaper ones from a well known overseas source?  Be careful, many items sold in the UK and pretending to be from here are still originating overseas.  I would deal with a reputable specialist tap and die specialist so you know you are getting the quality such as:


https://www.tap-die.com/index.html

[Circlip]

Is the Brass hard or soft? When turning does it scream and come off in a spray or turnings? In both cases, a decent Carbon steel or HSS  theading tap and die will work. Difference being tapping hole size in 'Soft' brass should be bigger to allow for gummy sticktion of material. 'Tracy Tools' have yet to supply me with a bad product. (NO affiliation)


  Regards   Ian.

[howie55]

Thanks circling
Tracy tools looks favourite for replacement taps and dies
Thanks again to the forum
Geoff

[howie55]

Sorry Circlip (Ian)
For spelling your name wrong
Geoff

[ChrisF]

I've been thinking of buying some taps and dies on and off for awhile, mainly for cleaning up existing threads. Been looking at the link given but am confused by the fact you can have different "taps" for M3, M4 etc. Can someone enlighten me please.

Looking for use mainly with props and prop shafts and sizes M2, M3, M4 and M5.

Thanks, Chris

[Bunkerbarge]

Taps would traditionally come in a set of three for any particular thread.  The three would be taper, second and bottoming.  The names do get muddied around and different people refer to them differently.  At smaller sizes the second tap might be omitted and a set consist of only the taper and the bottoming. 

The idea being that the taper tap, being exactly as it says is a much finer tapered shape at the end.  This makes it easier for the tap to find its central position and cut a perpendicular thread, this should therefore be used first.  The challenge with that tap is that a significant part of the thread is not cut, especially in a blind hole.  The second tap still has a tapered lead but nowhere near as much as the taper tap so it can be run deeper into the hole.  Finally the bottoming tap has a blunt end with the full thread almost to the end of the tap.  This is then run in last to cut the thread the full length of the hole.  For an open hole you could get away with just running a taper tap through however some systems actually have different thread forms on the taps and the correct shape of the thread isn't generated until the bottoming tap is run through.

[ChrisF]

Thanks for that, it is a great help. Part of the confusion is that say for M5 you can get taps that vary from 0.5mm to 1.0mm dependant on the steel used for manufacture.

Just got to work out now whether best to buy separately or get a set.

Chris

[Bunkerbarge]

Just a word of warning, I think you might be referring to the pitch there.  Even in metric there are course pitches and fine pitches so obviously threads have to match when used together and the correct tap or die has to be used to cut them.


0.5mm or 1.0mm is probably a pitch.

[ChrisF]

Ok, another question!

For those items we use in model boats from M2 to M5 are we talking coarse or fine threads?

Chris


Edit: You must have been reading my mind!!!  Our posts overlapped.

[Bunkerbarge]

It doesn't matter, it could be anything.  The important thing is that a thread is defined by its diameter and its pitch so you need to know both when matching something up.

[ChrisF]

The tap I referred to earlier isn't whether coarse or fine as there are more than two alternatives. I think it's different tapers dependant on whether HSS or HQS etc?

Anyway, this is turning into another one of those subjects that initially was thought to be simple but as you delve into it becomes more complicated! Interesting though. When looking at metric taps there's no mention of coarse or fine and I only picked up on it because there are sets available in both. When I've bought nuts and bolts there was no mention either.

What's prompted my need is that I bought a stern-drive and whilst I bought props at the same time from the supplier for the drive  they are very tight and by hand I can only get the prop on a little way. The props are plastic with brass inserts. An M4 nut fits fine on the stern-drive but a brass prop wouldn't. This leads me to believe that the supplied prop has a fine thread and the stern-drive a coarse thread.

More investigation is required which includes trying the plastic prop on one of my M4 propshafts.

Chris

[captain_reg]

For metric threads, coarse is considered 'normal' and where it isn't specified, you can generally assume it means coarse pitch. For reference, for M4 this would be a pitch of 0.7mm
From my understanding HQS is a carbon steel tap, cheaper and (in theory) won't last as long and HSS is more expensive and you could expect to maybe last longer. I would suspect that HSS would be more brittle and probably wouldn't handle as much mistreatment (but I may have that back to front) either way, in these sizes, niether will be particularly robust.
If you are just rethreading a brass insert then a HQS plug/bottoming tap would do the job, no need to start with a taper tap.

[Circlip]

No problem howie55 (Geoff), as you came back within 30mins. you could have used the 'Modify' button and saved another posting. Just a word of warning. As Tracy may be close to where you live, the choice to 'Call in' and look round in person is VERY dangerous. Currency seems to slide out of your pocket too easily.


  DAMHIK


  Regards Ian.


  Yes, it should be coarse Chris

[ChrisF]

captain_reg - thanks for the info. and your good idea of just using a bottoming tap for my current needs.

Trouble is, as Ian says, those suppliers provide considerable temptation!

I've ordered some more props from a UK supplier (the stern-drive and original props came from Germany) as I wanted some smaller diameter and to see if the threads were a better fit. If not I have some spares to rethread.

howie55 - apologies for jumping on your thread but it provided the nudge to finally get some taps and dies and provided some useful information.

Chris

[Akira]

In that the tap should not wear significantly when used on brass, I need to ask if the die you have is adjustable? Does it have a small screw in the side of it? If so, back the screw out ever so slightly will increase the depth of cut and wouls solve your problem.
Of course, if your die does not have such an adjustment, then I am just blowing smoke . Hopefully, I am not.
 

[nemesis]

The fact that you can pay more for one HHS tap/die that that for a complete set of carbon taps /dies tell you something of the quality. I go along with Tracy tools and when your at it get yourself a ZEUS chart booklet on thread, taps and dies. plus a lot of extra info. nemesis

[SteamboatPhil]

Nemesis has possibly your solution, there are 2 versions of ZEUS metric and imperial, I do have both but I tend to use my "SHETACK" , sorry I am still old school, but sadly all in imperial.


As has been mentioned, buy the best you can, cheap taps and dies are really a false economy


Just my opinion