Arc’s HSS-Co5 Spiral Taps

[ChrisHParticipant @chrish]

Just to say I bought one of Arc's HSS-Co5 Spiral M6 taps and although I've only used it a few times I have been most impressed whenever I have used it, it seems to cut very easily and quickly by hand (not machine) in EN1A.

It is now my tap of choice for cutting M6 threads rather than using the more usual three M6 hand taps.

I am going to buy some more in the other sizes!

Thought it may be of interest to others in the market for taps.

Chris

[ChrisHParticipant @chrish]

[Anonymous]

Spiral point or spiral flute? Been using both for many years, although spiral flute is the more useful as it can be used for both blind and through holes. They can be used by hand, but come into their own when tapping under power. They also have the advantage that you only need to buy one tap per size.

Andrew

[ChrisHParticipant @chrish]

Sorry Andrew, it is spiral flute, I should have stated that. Haven't had the courage to try under power yet, but as you say, the other advantage is that only one tap per size is required, makes it so much quicker when by hand and I guess even more so under power. I really must pluck up the courage to try power tapping, and not worry about it breaking………….

Chris

[John HinkleyParticipant @johnhinkley26699]

I agree with both of you. I bought the metric set from Arc a while ago and they are a revelation when compared to ordinary straight flute taps. Mind you, I've had to replace the 6mm and 4mm taps, purely down to my ham-fistedness while tapping under power on the mill. Once the workpiece wasn't secured sufficiently and the other time my brain lost communication with my hand and I inadvertantly turned the speed up instead of stopping the mill. What an idiot!

John

[egaParticipant @ega]

ChrisH:

You can guard against breaking the tap with a suitable setup:

The tapping chuck is free to slide as the tap enters the work and is radially restrained by hand via the tommy bar; this gives sensitive control and allows the bar to be released (and the lathe stopped) if there appears to be a danger of the tap breaking.

I normally use this setup on my larger lathe where the bar clears the bed if released so that the lathe does not have to be stopped immediately.

Plus one for the positive comments about the spiral flute taps in the OP.

[EmgeeParticipant @emgee]

Power tapping M3 at 700rpm with a Tapmatic at 4min 40sec.

Emgee

**LINK**

Edited By Emgee on 08/12/2020 14:27:53

[Nigel BennettParticipant @nigelbennett69913]

It hardly helps "Us Lot" with threading, but I was amazed to find that at work they used to thread mill M2 holes; if the cutter broke, the job could generally be rescued; blow out the bits of broken cutter with a blow gun, and tap it out manually later. But those M2 cutters were unbelievably tiny!

[Anonymous]

Posted by ChrisH on 08/12/2020 13:56:53:

Sorry Andrew, it is spiral flute, I should have stated that.

I thought it probably would be, but it's always best to check.

I've broken taps, but never when power tapping. Actually that's not true, I did break an M3 tap on the CNC mill. To be fair it wasn't tapping at the time. I forgot to type in the appropriate tool length when changing to the tapping head. So the mill drove the tap 20mm into the predrilled hole before starting to rotate. It was that episode that convinced me to get a proper tool height setter and get to grips with tool tables.

Interesting video posted by Emgee. I'd make two comments:

1. He's pussyfooting around on the feed when drilling and I think I'd have just done chip breaks rather than full retractions at each peck

2. On three of the four holes thre tap briefly stops rotating during extraction which implies that the torque setting on the tapping head might be a tad too low?

Andrew

[not done it yetParticipant @notdoneityet]

He is a hobbyist? So not in any rush, but if withdrawing the drill I would expect a little lube to be added> no point otherwise.

Also, do these type(s) taps obviate the need for chamfering the hole entry, after threading?

[Howard LewisParticipant @howardlewis46836]

For tapping under power, my taps are held in an ER collet, or drill, chuck. Before the tap breaks, it slips in the chuck.

That gives a chance to clear any swarf, and to finish by hand, if need be.My spiral flute M6 is marvellous, I'm sure that I run at too high a speed, but it does the job every time!

Howard

[JasonBModerator @jasonb]

Posted by not done it yet on 08/12/2020 17:12:45:

Also, do these type(s) taps obviate the need for chamfering the hole entry, after threading?

No, they will still raise a small burr particularly in softer material but if you have been cleaver with your spotting drill the chamfer can be done before hand or if on the CNC a chamfer mill can be run around all edges, holes etc.

[EmgeeParticipant @emgee]

Posted by Andrew Johnston on 08/12/2020 16:45:05:

Posted by ChrisH on 08/12/2020 13:56:53:

Sorry Andrew, it is spiral flute, I should have stated that.

I thought it probably would be, but it's always best to check.

I've broken taps, but never when power tapping. Actually that's not true, I did break an M3 tap on the CNC mill. To be fair it wasn't tapping at the time. I forgot to type in the appropriate tool length when changing to the tapping head. So the mill drove the tap 20mm into the predrilled hole before starting to rotate. It was that episode that convinced me to get a proper tool height setter and get to grips with tool tables.

Interesting video posted by Emgee. I'd make two comments:

1. He's pussyfooting around on the feed when drilling and I think I'd have just done chip breaks rather than full retractions at each peck

2. On three of the four holes thre tap briefly stops rotating during extraction which implies that the torque setting on the tapping head might be a tad too low?

Andrew

Andrew,
1. You forget I use an old 1985 machine with limited G codes, G83 gives what you see in the video, and yes I do use conservative feedrates.
2. Re the tap stopping before withdrawal is because it does stop before reversing out of the hole, that's how the tool functions by reversing on withdrawal.
On the tapping head used there is no torque setting, it's all or nothing.
If the tap stops rotating on withdrawal it will be because the return feedrate needs raising a bit, but once again with a conservative setting to prevent tap breakage or thread damage.

The point made about a burr at the top of the thread is taken care of with the 3mm spotting drill used, it cuts 3mm to 0.20mm below the top surface, not only does it prevent the burr it assists in starting the screw.

The points raised are noted and I will finetune the feedrates to ammend the program.
It's amazing how many views (79) the link generated today, any and all comments welcome.

Emgee

 

 

 

Edited By Emgee on 08/12/2020 22:30:25

[Anonymous]

Posted by Emgee on 08/12/2020 22:28:23:

Re the tap stopping before withdrawal is because it does stop before reversing out of the hole, that's how the tool functions by reversing on withdrawal.On the tapping head used there is no torque setting, it's all or nothing.If the tap stops rotating on withdrawal it will be because the return feedrate needs raising a bit….

I didn't mean the tap stopping at the bottom of the hole before reversing. On the way out the tap seems to hesitate for a split second at several points? It must be a different style of Tapmatic head to mine. On my Tapmatic there's a knurled portion at the top which allows the breakout torque to be adjusted.

Andrew

[Anonymous]

For reference these are my tapping heads:

The Tapmatic (bought new) and the Edelmatic (Ebay) have built in reverse so the machine spindle doesn't need to be reversed. On the manual mill the quill is used to feed the tap, when the stop is reached the forward clutch disengages and the tap stops. A sharp pull up on the quill engages the reverse clutch at twice the spindle speed. On both heads the large knurled ring at the top is for adjusting the torque at which the down feed clutch will slip.

The head on the right is a tension/compression one (bought from Maritool in the US) for use on the CNC mill. It requires the machine spindle to be reversed to back out the tap. The feedrates can be finessed, a bit over nominal on the way in and a bit less than nominal on the way out. That way the tap is pushed into the work slightly by the spring in the head and on reverse the tap will cleanly pop out from the hole so the beginning of the thread starts cleanly and isn't damaged on exit of the tap.

Andrew

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