Tap and die recommendations

[MMUK]

Another thing with the Clarke ones are they are also not consistent in size - I had to work through all the 3 types to achieve the correct tap size!

They're not supposed to be. You need to use them in order - Taper, Second and finally, Plug. Each different tap cuts a greater amount of thread as you go and you don't get a full thread cut until you've used the Plug tap.

 

[RogerP]

May I remind everyone that the OP said "occasional use" and "not going to be spending hundreds" :roll:

 

[Spindle]

Each different tap cuts a greater amount of thread as you go and you don't get a full thread cut until you've used the Plug tap.

Hi

That's not my understanding - all types of tap have the full thread form for some degree of their length, the type of tap determines when the full thread form begins.

Regards Mick

 

[MMUK]

That's pretty much what I said Mick :?

 

[Spindle]

Sorry MMUK - I read your reply as you had to use all three taps in order before the full thread depth was achieved

Regards Mick

 

[MMUK]

Sorry MMUK - I read your reply as you had to use all three taps in order before the full thread depth was achieved

Regards Mick

My bad, probably didn't explain myself clearly, I meant full depth of the thread pitch.

 

[Harbo]

Well what I meant was I was tapping a through hole to take a 10M bolt.
It wasn't until I had used the plug that I achieved the correct thread - and that was after threading the other two all the way through.

I know they differ in threading length but they should be the same diameter?

Rod

 

[MMUK]

I know they differ in threading length but they should be the same diameter?

Rod

Not quite, the Taper only cuts about 40% of the pitch depth, the Second cuts it to about 80% depth and the Plug cuts the thread pitch to full depth.

By pitch depth, I mean the depth across the width of the hole, if you follow me?

If you look at each tap in turn, you'll notice that the "teeth" get deeper from Taper to Second and Second to Plug.

 

[Spindle]

Hi

Link to threading basics article:

http://www.threadtools.com/Files/Taps%2 ... 20info.pdf

Regards Mick

 

[shipbadger]

Just a long shot, but if the OP is only going to use the taps ocassionaly, what about buying one of the sets Lidls (and presumably Aldi) sell every so often to see which sizes are needed more often and then buy decent ones of those. The other thing that appears unknown, are these for cutting threads from scratch or thread restoration. If the former then a set of appropriate drills needs to be factored into the costs. The LIDL sets are to German DIN standards and are fine for cleaning out old threads.

Tony Comber

 

[RogerP]

........... If the former then a set of appropriate drills needs to be factored into the costs. .........
Tony Comber

The set I recommended has the appropriate drills included.

 

[jasonB]

I know they differ in threading length but they should be the same diameter?

Rod

Not quite, the Taper only cuts about 40% of the pitch depth, the Second cuts it to about 80% depth and the Plug cuts the thread pitch to full depth.

By pitch depth, I mean the depth across the width of the hole, if you follow me?

If you look at each tap in turn, you'll notice that the "teeth" get deeper from Taper to Second and Second to Plug.

Really only applicable to sequential or serialtaps, which you do need all three to get the full depth engagement. For the majority of hand taps if you are cutting a through thread in thin material it can be done with a taper tap only.

serial taps explained

J

 

[The Bear]

They are for cutting new threads

The split dies I assume are tightened/slackened by the holder to cut in stages until final fit is achieved ??? How important is this and if very, why are they made not split?

Cheers

Mark

 

[MMUK]

The split dies are split for two reasons. 1. To aid stock removal and 2. To prevent jamming by allowing the die to flex.

 

[Spindle]

Hi

General info re dies and die nuts:

http://www.threadtools.com/Files/Dies%2 ... 20info.pdf

Dies are split to allow for fine adjustment to suit the male thread and to allow compensation for wear. Fully opening a die will also allow an easier first run to be taken in difficult materials.

Regards Mick

 

[jasonB]

The plain circular and hexagonal dies are generally regarded as suitable for cleaning up existing threads that may be damaged or rusty.

The split ones are best for cutting new threads, for this reason they tend to have a lead taper much like a taper tap of two ot three turns of thread which make sthem easier to start. As I said above they can initially be opened up which makes cutting the larger thread sizes easier and then tightened down to give a final cut that and that can be adjusted to give a suitable fit. You will likely find that mass produced nuts are a slacker fit than if going into a tapped hole so your male threda can be adjusted accordingly.

J

 

[DTR]

I know they differ in threading length but they should be the same diameter?

Rod

Not quite, the Taper only cuts about 40% of the pitch depth, the Second cuts it to about 80% depth and the Plug cuts the thread pitch to full depth.

By pitch depth, I mean the depth across the width of the hole, if you follow me?

If you look at each tap in turn, you'll notice that the "teeth" get deeper from Taper to Second and Second to Plug.

Really only applicable to sequential or serialtaps, which you do need all three to get the full depth engagement. For the majority of hand taps if you are cutting a through thread in thin material it can be done with a taper tap only.

serial taps explained

J

+1.

Incidently, I find that sequential taps are a pain in the ar*e to use. I think it's because the taper tap doesn't "engage" with the hole as good on account of its reduced outside diameter. I won't be buying serial taps again.

 

[chipmunk]

Incidently, I find that sequential taps are a pain in the ar*e to use. I think it's because the taper tap doesn't "engage" with the hole as good on account of its reduced outside diameter. I won't be buying serial taps again.

I think the main problem is that for serial taps the ideal tapping drill size should be smaller than the conventional taper tap tapping drill size. I don't know where those drill sizes are listed though - Anyone know?

Jon

 

[MMUK]

M3 = 2.5mm
M3.5 = 2.9mm
M4 = 3.2mm
M5 = 4.2mm
M6 = 5.0mm
M7 = 6.0mm
M8 = 6.8mm
M9 = 7.8mm
M10 = 8.5mm
M12 = 10.2mm

 

[Gerry]

General rule of thumb to get the correct drill size for Metric taps is to deduct the pitch from the diameter.

Gerry