Selecting correct tap type

[the black box]

i regularly have to tap a reasonable quantity of steel tube with a m8 thread. Been using a combi tap in a cordless drill which has worked okayish but now I have around 600 to tap!

Just purchased this

http://www.machine-tapping.co.uk/m5-m12-auto-reversing-tapping-head-jsn12.html

To go onto my progress 2gs anyone have any idea which arbour i need to mount it?

The tube is 10x1.5mm wall so really should be correct size apart from the occasional heavy seam. I need to tap approx 20mm deep on one end

I'm confused on all the different tap types, coatings etc should I just buy a few of these

https://www.cromwell.co.uk/shop/cut...-taps/e500-m8x1-25mm-second-tap/p/DOR0851410B

Or is there another tap variety that'll be better,longer lasting?

Thanks in advance for all your help.

 

[optima21]

when I used to work for a company manufacturing metal pressings (in the office), they used to buy spiral point taps for production tapping in sheet metal, as the spiral point forces the swarf ahead of the tap so it doesn't clog. might not be as good for a blind hole though. for tapping metal blocks on a cnc milling machine ithey used spiral flute taps are better as they direct the swarf back up the flutes,that was over 20 years ago, so wait for someone more knowledgeable to help you out. the taps below are 8mm and 12mm taps

 

[Turbo]

Drill taps might be your best thing as they will drill the pilot hole & tap in one go plus they are very tough & designed for machine tapping.

How are you going to hold the tube vertically in a pillar drill?

 

[the black box]

Thanks for the replies. I've a vice with v slots in it that I normally use so I'll bolt this to the table and holds the tubes good

I'm hoping to get away with not using combi taps but I'll get a dormer version i previously used a ruko branded and wasn't impressed

Spiral point sounds good as it's an open tube so will all fall out.

 

[Pete.]

https://www.cromwell.co.uk/shop/cut...spiral-flute-iso-metric-bright/f/12003?query=