How To: Tapping Screw Threads

How to use a tap to cut or repair internal thread.

The full list of part numbers and tools required are available at the website.

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Category:

Science & Technology

Tags:

• tap
• tapping
• thread
• drill
• mechanical
• howto
• screw

[JonathanAnon]

Hi, couple of questsions if you have time... I'm tapping 2mms steel with my tap for both M4 and M6 bolts.. I do it carefully but still the bolts are a bit loose... any suggestions? or is it just that it's gonna be loose cos the steel is thin?

[IHeartRoboticsDotCom]

@JonathanAnon A quickfix is a threadlocker like loctite to keep the screw from loosening. Check to make sure your tap and screws are both ISO certified. Another though is to use a taper or plug tap instead of a bottoming tap. Finally depending on your loads you may be better off drilling out the hole and using a steel epoxy like jb weld to epoxy a nut on to the back of the plate. If you want to use a regular welder, make sure the nuts are not galvanized as welding galvanized steel can be toxic.

[scalak]

I'm using Cordless Screwdriver. It saves hours of work and it is easiest way to do it...

[IHeartRoboticsDotCom]

@scalak What material are you tapping? With aluminum I would think that it is hard to determine when to back out the tap. I have been using a crank driven hand drill in plastic with some success. The crank helps because I can still feel when the tap is getting stuck.

[alderaforall]

notice the drill bending from excessive down force. Your bit was loaded due to lack of the tap magic you had sitting right next to you and too many rpm's.You managed to drill your hole oversize and maybe making your threads weak. Unless of course, you bought oval shaped taps, then you did everything perfect.

[IHeartRoboticsDotCom]

Perfectly valid complaints, and I'll do better next time.

I was using a PCB drill press because that is what I had handy, and the RPM were defiantly way too high even at the lowest possible setting.

I'll replace this video once I have a chance to buy a new drill press.

[JonathanAnon]

@IHeartRoboticsDotCom thanks.

[MarsManJR15]

A mill is best but If you had a vise clamped 2 a press u should hav left it clamt in the same position and used a center guide in the chuck to keep it centered. If drilled the correct size you really shouldnt have 2 interupt the cut so many times, if possible not at all, and deff not so qiukly, b4 the 1st few revolutions, it can make the first few threads really sloppy and loose, esp. in aluminum, but if u hav a can of spray lube or comp. air, blow out chips 2 turn it very easily without stopn

[onb22]

thanks for the vid dude

[5nallyg0d]

you saved my hundreds of dollars.