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Mech Engineers/Tool Makers Help with tapping

T

theshadow2001

Jun 17, 2004
3,089
8
Ireland
#1
Hi,

Where I work I have to mount numerous electrical components on a metal plate which can involve drilling and tapping 10, 20 or even more holes to affix the different components. The usual method for this is to stick a hand tap. (usually just the finishing tap) in a battery drill set the torque low enough and belt away. This to me is a less than ideal way to tap holes and can lead to the occasional broken tap which can be a nightmare to get out plus taps aren't too cheap either. Hand tapping is far to slow a process even with just a single tap. Using all three start middle and finishing taps would take far to long by hand.

I was thinking of getting some machine taps for the purpose of speeding up the process while reducing the risk of breaking the tap. Would I be correct in thinking the machine taps could handle being in a battery drill a bit better than the hand taps. Or are the pretty much just for CNC, table mounted drills and milling machines. Even if they aren't suited would they be better than the hand taps? Thanks for any help.

One more thing the material that I tap I think is Iron phosphated steel. Im not sure really. It could be zinc plated steel either
 
#3
Do yourself a favor and get the machine taps. Spiral point plug taps and a little bit of tapping oil or drill wax will make that job a breeze. The tiniest bit of lube is enough to make all the difference so you don't need to make a mess of the project either. The taps will cost you a bit more but will more than pay for themselves by lasting longer and doing a better job.


TAP.gif
 
#4
The self drilling screws are agood idea but I don't think it will take off where I work. All focus is very short term. So any research finding out where to get them and investment in the tools to put them in would all be seen as a waste of time and moeny beacause there would be no immediate pay off.

Wade do you think that there's anything suitable on Link Removed. So far this is the only internet shop I can see in the UK/Ireland.I could probably order them at work but that would lead to a whole pile of hassle. Are the machine taps less likely to shear than the hand ones when used in the drill. Will they with stand a higher torque setting as well?
 
#5
I do some machining and fabrication. I don't do much tapping with a hand drill though.

Some good taps will help for sure, though. And a good tapping fluid, stuff we use is Castrol MolyDee.

It also helps alot if the holes you're trying to tap are straight in the first place, if you're using a hand drill for those too try a bushing to help you keep them straight.

Sounds like you're just tapping sheet metal, I don't know what you're clearance is but you might be able to switch out for rivet on nutplates like they do on aircraft.
 
#8
The bushing idea is not a bad idea. I might give that a go. The size of the sheets are about 1.5 to 2 millimeters thick.

The tap sizes are usually either M3 or M6 sometimes M4 or M5. I don't know if that means much to you guys with that crazy imperial system. As for the pitch Im unsure what it is. It must conform to some metric standard. It fits your average run of the mill screws. I just got a decent set of hand taps from my local tool store. They dont cut an unusual or rare thread

I think rivets are the best alternative. However the guy who sort of runs the project on the shop floor believes things end up being mounted crooked when rivets are used. Having things straight parellel perpendicular etc is all very important on these projects. Plus if anything has to come off or be moved or adjusted rivets can be a tricky enough to deal with.
 
#10
You are probably going metric but avoid 10-24 threads for hand tapping(coarse thread small minor diameter=breakage). The gun tap or two fluted spiral point tap pictured above with a tapmatic would be the way to go. The tapmatic reverses direction when you pull down on the piece.

You might consider rivnuts. You just drill a hole, insert rivnut, pop with poprivet gun.
 
#12
Nah, I dig metric units. It's a lot simpler than trying to figure out the next size up from 15/64". ;)

The tapmatic thing looks cool. I'll have to check those out.

I've successfully used rivnuts, that higgi mentioned, for many projects that required threaded attachment points in thin metal.
 
#13
The tapmatic would work ok with a handrill it has a handle that rests against the frame of the drill press, you could put an extension on it and hold it by hand. But you may not need to, just use the gun taps first and see if that works then try the tapmatic. The thing about reverseing by hand is that you could break the tap while you fiddle with the switch.
 
#15
Bob Lee (QSC) said:
Nah, I dig metric units. It's a lot simpler than trying to figure out the next size up from 15/64". ;)
Click to expand...

I worked a summer job in a diagnostics company (American owned) and had to do Auto CAD in imperial. My head was wrecked by the end of it all. I must say I'm glad we use metric.

Are those self drilling screws removable? Or is it a case of once they're in, they're in. Another problem with them is I don't know if local suppliers would stock them readily which would be another reason not to use them. It would be crazy to hold up a job because screws had to be specially ordered in.

In any case I'll get the machine taps and see how things work from there. Thanks for the help. (especially figuring out which type I need to use.) Damn things are expensive though so might not be for a while.

BTW eurapean tools are great. The brits are renouned for their quality tools.
 
#16
The only countries I could specifically remember buying taps from where U.S, Polish, and Chinese, in the order of good to bad. I couldn't remember buying Japanese taps, but their machine tools are top notch.

Self tapping screws are readily available here in the U.S. and great for sheet metal. It is the way most siding is attached to steel buildings. They are removable. If you can get those to work for you then that would be the best bet.
 
#17
theshadow2001 said:
That tapmatic thing looks great. However the sheets I drill can be up to 6 foot high and maybe 3 foot wide. With holes tapped all over it. No way to get that near a press drill. I doubt they'd work to well in a battery drill.
Click to expand...


Sounds like you need a large Radial Drill Press to go along with the tapping head. You can find them CHEAP, like $1500 sometimes at used machinery dealers.

Invalid Link Removed
 
#18
The tapmatic heads are great if you have hundreds or thousands of holes to do in a hurry but sounds like serious overkill for this project especially considering the size of the sheets you're working with.

Alignment gets critical as the holes get deeper, but you are working with holes that are larger in diameter than in length. Since you are working with such thin metal, you should be perfectly fine using those taps in a cordless reversible drill as long as you are halfway careful to keep the holes perpendicular to the metal.

The taps in the top two rows of the Chiltern webpage look good. The spiral point style taps are stronger than most others and should be great for what you're doing. The self tapping screws (also known as sheetmetal screws) should do well too. Sounds like you're doing exactly what they are designed to do. Just drill the correct size holes and use your cordless drill to drive them in. Like higgi said, they're common at least in the US and you can remove and reinstall them.
 
#19
Ok thanks for everything so far. I got one more question. What do you guys think of this baby....

Invalid Link Removed

More info can be found Invalid Link Removed where you can get a data sheet. On the face of it, it seems ideal. On the other hand I've heard and believe multipurpose tools tend to do multiple things badly. IWO it's better to use a bit for drilling and a tap for taping. Anyone use or have experience with these?

Edit:

Another question whilst drilling with the hand taps. The drill will usually torques out and I have to reverse it in order to release swarf from the hole before continuing tapping. The swarf tends to be smallish particles/chips. Would spiral flute be better for dealing with this problem
 
#20
I don't like the combination drill/tap, but it might suit your needs. At least that one looks better than the one I had tried. It might be worth checking out if you like to experiment.

I would stay away from the spiral flute taps for what you are doing. Those are designed to pull the swarf up out of the hole and they have extra clearance to allow the swarf to come out. The spiral point tap pushes the swarf out of the bottom of the hole so it doesn't need the clearance. The Spiral point taps have a thicker cross section which makes them quite a bit stronger than spiral flute or hand taps, which makes them ideal for tapping holes by hand through thin sheet. A nice sharp tap should easily cut threads and with the sizes you're talking about, sould not even come close to the torque limit of your drill.

If you can find the self tapping screws though I bet you would love them. Just drill the holes and assemble.
 

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