Bad tapper

[DigitalM]

I'm a craptastic tapper. In attempting to tap a 6mm thick mild steel disc with a 1/4" 20G tap, i was, I reckon, about 5 degree out. It works, but meh! - you'd frown if I handed you the result.

Now, I realise that I run the risk of one-liner answers like "practice" (do it anyway, I know, it's that obvious) but I'm only ever going to need to do metalwork projects once in a blue moon, as it will be those jobs that are in support of my woodworking stuff. So, I won't be getting much practice.

Sooooooo - I see a few people using drill presses on you tube with dead centres. I looked a little more into this and in the US you can get spring loaded dead centres for just this sort of thing. Well maybe there's something in that but you can't get them here.

I guess putting a set square up against the job is a no-brainer.

But in my position, total noob, not much kit apart from my NOS Draper (Japan!) 1980s metal boxed tap and die kit, are there any simple/cheap ways to ensure being closer to true square?

 

[marcros]

http://www.warco.co.uk/tap-die/303208-t ... hment.html

I can't help on the other- I tend to use my lathe for alignment if I can

 

[RogerP]

Put the tap in the pillar drill chuck and turn by hand into the work-piece. It will do if you can only get a couple of turns to get it started. Then take the tap out of the drill chuck (but not out of he work-piece) and finish off with a tap handle

 

[DigitalM]

Thanks for both of these guys, much appreciated.

 

[sunnybob]

You can leave the tap in the pillar drill chuck if you want, depends on your hand strength whether you can do that or not.
Just remember to back out a half turn after every forward turn to clear the swarf out on the first run through.

 

[t8hants]

Another trick is to take an off-cut of wood, cut a V notch in it ensure the faces of the V are square to the sides of the timber.
Now put your tap into its hole and bring the jig up to it until it holds the tap square in the V and then clamp the jig.
The timber needs to be thick enough to support the tap until it is well into the hole and the thread has started square to the face.
Or try and stand directly over the work piece and look down straight onto the top of the tap, as most taps have a little countersunk hole in the top, make sure it remains static and does not describe a circle as you turn the tap.

 

[NazNomad]

Put the tap in the pillar drill chuck and turn by hand into the work-piece. It will do if you can only get a couple of turns to get it started. Then take the tap out of the drill chuck (but not out of he work-piece) and finish off with a tap handle

Exactly what Roger said. You know for sure it's gone in upright then.

 

[Eric The Viking]

I take the belts off the press and use the quill pulley as a handwheel. This has the big advantage I can use the quill drive hand levers to put some weight behind the tap for the first few turns. I have also found that putting a slight countersink on the edge of the hole, and cutting compound, both really help starting.

But, generally speaking, the bigger the thread, the more I hate the task.

 

[bugbear]

I find taps are OK - it's dies that cause me a LOT of trouble.

BugBear

 

[hawkeyefxr]

Yep lathe or pillar drill for alignment only then tap by hand, and don't buy rubbish taps, by that i mean cheap ones. They will get very sticky as you tap and usually snap just as you get to the bottom.
A lot of dies are die nuts, that is there is no adjustment for them they just cut the thread, In doing so they are removing a lot of metal and you get tearing and part of the thread get ripped away. Use split ones and screw the small screw in on the stock for the first pass, then gradually release the adjusting screw on the following passes with the die.
I had some cheapo taps and dies and suffered as you seem to be, i then purchased one tap it's drill size the cost was the same as the entire cheapo set, but i could tap a 4mm hole in stainless no trouble as all.
Also use a good cutting agent, i recommend Rocol, quite expensive but it will last you years you just need a pin head of Rocol tapping liquid is all.
One other thing get yourself a Zeus book, it gives you all the drill sizes for tapped threads you will ver need. The first one i bought on the 60s was 50p, ten bob then and dammed expensive for an apprentice. If you have trouble find it let me know i scanned mine in so i do not lose it.

 

[Beau]

I am not great with the tap holder but find it much easier just using a gutsy cordless drill. So quick to reverse and clear and easy to hold square IME. Sure all the proper metalworkers will throw their hands up in horra but works for me. The drill press idea sounds good though for precision

 

[NazNomad]

If you do enough of it, there's always a tap guide...

Not worth the layout for 1 or 2 threads a year though.

 

[DTR]

^^^^ or just drill some appropriate holes in a handy bit of scrap.

I've got one of those sprung loaded centres but I rarely use it; I usually find I haven't got enough headroom, or there's a clamp or something in the way of the tap handle. I usually tap using the drill chuck as mentioned above, or I use this contraption:

 

[MusicMan]

+1 to using a pillar drill, V notch in wood, tap guide, cutting fluid, reversing tap every turn (actually I usually do it every half turn; turn it as far as I can on one hold, reverse till I feel the waste metal being cut off, then change hand position and repeat).

That little indent that t8hants mentioned is accurately centred. As you say, you can use a spring loaded centre in that with a drill press (you can get them here as wood lathe drive centres, just ignore the jagged bits). But you can do it without a posh centre, a plain dead centre or even a rod filed down to a point in the drill will do. Clamp the work down with the hole centred (best way is to do this right after drilling with it clamped). Put the tap in the drill and start the thread as described above. When you need the extra force of the tap wrench, loosen the chuck and replace it with the centre and put the wrench on the tap. Push the tap down with the quill, and lock it if the quill locks. Then do a turn, backing off then turning till it engages. Push the quill down a bit then repeat.

Admittedly this is easier if you have three hands, but it is only a bit slow if you use the centre to realign the tap after every turn, and for a few threads a year this is worthwhile.

No-one has mentioned progressive taps. These come in sets of three; the first two are both tapered and have a smaller diameter than the final size. I find these really useful for something very tough, like stainless steel. Unfortunately you can't always tell from an advert if they are progressive!

Keith

 

[DigitalM]

^^^^ or just drill some appropriate holes in a handy bit of scrap.

I've got one of those sprung loaded centres but I rarely use it; I usually find I haven't got enough headroom, or there's a clamp or something in the way of the tap handle. I usually tap using the drill chuck as mentioned above, or I use this contraption:

Not seeing the contraption, could you possibly repost.

 

[DigitalM]

If you do enough of it, there's always a tap guide...

Not worth the layout for 1 or 2 threads a year though.

Yeah that looks awesome, but like you say £20+

 

[RogerP]

I find taps are OK - it's dies that cause me a LOT of trouble.

BugBear

One of the first things I made on my metal lathe was a Tailstock Die Holder. Since then it's been so easy to get perfect threads.

 

[DTR]

^^^^ or just drill some appropriate holes in a handy bit of scrap.

I've got one of those sprung loaded centres but I rarely use it; I usually find I haven't got enough headroom, or there's a clamp or something in the way of the tap handle. I usually tap using the drill chuck as mentioned above, or I use this contraption:

Not seeing the contraption, could you possibly repost.

Hmm, I thought it was just banjaxed at my end. Let's try that again...

Made from a drill stand picked up at the bootsale, with some modification

 

[bugbear]

I find taps are OK - it's dies that cause me a LOT of trouble.

BugBear

One of the first things I made on my metal lathe was a Tailstock Die Holder. Since then it's been so easy to get perfect threads.

A metal lathe is an expensive pre-requisite for simple threading!

BugBear

 

[DTR]

I find taps are OK - it's dies that cause me a LOT of trouble.

BugBear

One of the first things I made on my metal lathe was a Tailstock Die Holder. Since then it's been so easy to get perfect threads.

A metal lathe is an expensive pre-requisite for simple threading!

BugBear

No reason you couldn't do the same on a wood lathe