TMoore
rrProfessor
Location: Cookeville, TN
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| I don't know if things are different here in UK,-most hand-taps have 3 flutes,yes they come in sets...taper/second/plug.
you can usually do a through-hole with just the second.
we also have machine-taps. these only have 2 flutes and are tapered. the leading edges are ground at an angle so the swarf projects forward...I don.t know if a plug/bottoming version is available....I used them with a tapping-head which went into a pillar drill in place of the chuck. feeding the tap into the work would engage a clutch to screw the tap in...lifting reversed the mechanism to wind the tap out....it was a quick and easy to drill and tap large batches of die-cast alloy components. Steel/cast iron were also easily tapped and the taps could also be used by hand.
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Things have changed since the days of overhead lineshafts and cone drives. 
The original ? was: | Quote |
| how do the big company's such as hirobo and quick uk etc and or other large company's that have mass production CNC parts thread their holes for for example M 3 bolts and or also M6 and bigger...?
do they also use the 3 different taps(the little tools that make the threads, I don't know what's the correct term) for M3 like the kits we buy?If I thread a M3 hole I first have to go through the 2.3mm bore hole with the first tap, then with the second, removing a bit more material and then with the third tap...
Because when I thread M3 into aluminium I have to be carefull not to brake the tap.
Just a little curious about the how to's of mass production.
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It all depends on the tap size, the material being tapped and the fit or tolerance of the finished hole as well as how many parts you need to make to complete a particular production run. I have programmed and run machines that have the capability to tap at 6,000 rpm and used this facility to tap 0-80 holes as well as 1.6mm holes with great ease. There have also been times when tap depth wasn't as important so I've use a tapping head loaded by the machines toolchanger that allowed holes to be tapped without reversing the machines spindle and this saved time. I used a macro to control the tapping cycle. The spindle motor and drive has to be able to overcome the inertia of the spindle when it reverses at speed along with a quick reacting Z axis to follow the spindle reversal accurately enough not to break taps.
The are also specific instances where the parts can be machined with a tool called a thriller. This a tool that can circle mill the hole and thread mill the hole to the desired thread size. This is an Emuge product. They also make tools called Draps that combine a drill and tap on the same shank and this is good for through tapped holes. Thread milling is used in a lot of instances when tapping is not desired due to cost or tap life versus number of holes per tap.
I recently did a job for Mercedes where an M14X1.5mm tapped hole in 1018 forged steel blanks were needed. There were two drills, a boring bar and a roll form tap needed and the parts were loaded, unloaded and machined in less than 20 seconds each. This was done on a gang type CNC lathe. The taps were run at over 800 rpm and will machine upwards of 1200 holes apiece before they need to be changed out.
TM
"If you can do it, it ain’t bragging." - Will Rogers |
) strictly speaking it's more a trochoid shape, like the wankel-engine rotor.
