How NOT to tap a hole

[SpringbokParticipant @springbok]

I will leave it up to you to decide

Personally whomever done this should have his camera taken from him.

 

http://www.youtube.com/watch?NR=1&v=_XLGCt5UQGM

 

 

Bob

 

[SpringbokParticipant @springbok]

A so called “training video” aaaaarg

[NJHParticipant @njh]

Hi Bob

 

Well I watched all tedious 3min 53 sec of it expecting that big, unsecured, vice to fall off the bench and onto his foot. – It didn’t – but I expect it will one day. Strange that someone safety conscious enough to wear gloves to protect his hands could have thought so little about the possible consequences of his actions. As far as the process of tapping under power with a hammer drill goes I have no comment other than to say take great care when viewing “advice” posted on youtube!

 

Regards

 

Norman

[JasonBModerator @jasonb]

Its not a hammer drill it an impact wrench, done it myself with a cordless one. Its fine for jobs that acre not that critical and when going into reasonably thin material.

 

J

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Bob, have to agree with Jason. Air impact wrench’s very often have a four position torque setting fitted to them, thus allowing some control of power, and they can have the air pressure feeding them reduced which will reduce the speed and torque.

 

Norman I can’t see any problem with the use of his vice, as it has a large footprint compared to its hieght, so its unlikely to topple or roll off during the opperations he was showing.

 

Regards Nick.

[S.D.L.Participant @s-d-l]

Just like using a battery drill, ok down to M3 / 6BA.

 

WD40 is fine for Aluminium

, have used spit when on a site visit and nothing else available, 1st choice is tapmatic, don’t like the gooey pastes such as Trefallux anymore.

 

Steve Larner

[DMBParticipant @dmb]

I seem to remember we were given oil at school to tap mild steel.

 

John

[JonParticipant @jon]

As above theres plenty of good advice and practices on youtube, that is one of them.

So everything you buy is tapped by a little chinese person continually backing off whilst tapping, i think not.

 

The torque off that impact wrench would not flip that milling vice and probably used just for the demo, panic over nothing.

Try drilling a hole in mill then swapping over to a tap, everything square you will never go back to hand tapping.

[BogstandardParticipant @bogstandard]

For none critical work, I use exactly the same setup as he does, a 3/8″ butterfly wrench with those same wrench heads on the end, bought from Little Machine Shop.

 

I last used it at arms length to repair the outside canopies on my house. It would had taken me ages to do it by hand, my butterfly wrench setup retapped a stripped out 8mm to 10mm tapped in about 5 seconds.

 

Don’t kick it until you’ve tried it.

 

 

Bogs

[BERTOParticipant @berto]

Oddly enough this was something i was doing back in the 1990’s !

I was working as a welder for a company that manufactured roller shutters and my job was to fabricate the roller drum .

After 6 months of hand tapping the cast iron cores that connect the drum to the axle then screwing in the 4 bolts and tightening i got jack of this especially as some drums had 4or 5 cores !

I brought my reversable air drill and impact gun in and proceeded to tap and tighten under power !

The 3/8 unc taper tap went in the drill chuck and i chose a drill to give 50% thread depth as this was mostly a shear loading effect on the bolt .

This was so succesfull that the boss purchased an air tapping gun and a new impact gun for the total sum of $1200 but this payed itself off in no time

I only ever snapped 1 tap in 4 years and it was my fault as i was rushing , no problem though as we just blew it out with an oxy – acetylene torch and re- drilled the core in a different position .

Some thoughts on the video :

1) At least he used a vice of some substance and no way was it going to flip over .

 

2)The gloves he was wearing are for chemical usage and will not protect him from much other than the WD-40 and besides that i was always tought not to use gloves with anything that revolves under power as you can’t feel anything and they may get pulled into the machine – this was mainly aimed at bench grinders etc though.

 

3) Impact guns /wrenches do not apply steady torque like a proper air tapping gun , they use impacts to turn things which could lead to stress fractures in the HSS tap .

It is a bit like hitting the end of a tap wrench with a hammer , each time that impact occurs the inertia will cause the shank of the tap to twist a little until the force required to overcome resistance of the cutting action is exceeded.

 

4) One would need to consider the time taken to set up the air compressor and assorted bits and pieces to tap holes and it would want to be a considerable amount of holes to gain a reward over poorly tapped holes that are not square to the material being tapped and the risk of breaking a valuable tap .

 

5) Proper machine taps would be preferred as thier spiral flutes are designed to pull the swarf up and out of the flutes and therefore negating any build up that could couse a jam .

 

6) A tap dropped onto a concrete floor is going to need carefull examination for damage to its cutting edges and could cause it to either need re-sharpening or pegging in the bin!

 

All in all it think this video is just another case ot a tosser with a camera !

 

Actually thinking of cameras, why have we not seen a DVD from MEW ?

I’m sure that a DVD with Harold Hall , Dave fenner , David Clarke and as many of the other contributors as they please doing a “HOW TO” DVD would be a go-er .

 

Ian

 

 

 

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