Help creating tapped holes

[Proprietary]

I have 6-32 drill-tap combo drilling into a very thick piece of metal. The tap hole I created just does not have any grip. I was pulling out and drilling back in pretty often. Is this destroying the tap? Should I have separated the drill tap process?

?

[TheBean]

using a drill to tap? you probalby just stripped the threading.

 

I thought you are supposed to hand tap things.. am I wrong?

[Proprietary]

Just now, Saksham said:

using a drill to tap? you probalby just stripped the threading.

 

I thought you are supposed to hand tap things.. am I wrong?

I am using one of these. I should've hand tapped it though...

[Kilrah]

https://www.amazon.co.uk/Drill-Combination-Pieces-Thread-Spiral/dp/B01DIWWT0A

 

You find combined drill/taps but they're usually trash, relies on being able to drill with the same pitch as the tap which is far from guaranteed unless the material is really soft. But then a soft material makes it easier to strip the already made threads if it doesn't work out, so... that's probably what happened. Not to mention clearing the chips from 2 operations, when it already needs care with just one.

 

Power drill first, hand tap second with dedicated tools.

[Proprietary]

Can you explain what you meany by

5 minutes ago, Kilrah said:

relies on being able to drill with the same pitch as the tap

Isn't pitch a tap property (distance between threads)? So in my case is the drill destroying the previously created taps?

[Kilrah]

When you turn the tool once it's started tapping it needs to advance by the thread pitch. But if your material is thick and the drill is still cutting material there will be too much resistance on the drill tip for that to happen so you'll force and just rip off the threads that were already made.

 

To clarify, the combination drill/tap tools are made for thin material. When you get to tapping the drill must have exited the part already.

[Lady Fitzgerald]

33 minutes ago, Proprietary said:

I have 6-32 drill-tap combo drilling into a very thick piece of metal. The tap hole I created just does not have any grip. I was pulling out and drilling back in pretty often. Is this destroying the tap? Should I have separated the drill tap process?

?

The drill bit, tap combo is a once in and out device. The drill bit on the end makes the hole and the tap following the drill makes the threads. If you try to go in and out more than once, you will probably damage the threads you just cut. Also, these are designed for power drilling/tapping and are best used with a drill press since they have to be kept perfectly straight the entire time, especially with smaller sizes, something difficult to do with a hand drlll. You just chuck them into a drill press, run it at the slowest speed setting, drill into the metal until the threads are cut, then back out the drill/tap. If the drill press is not reversible (most home machines are not), unchuck the drill/tap, then back out the bit maanually.

 

Btw, if you use any tapping fluid with it? A proper tapping fluid is essential. Substitutes, such as 3-in-1 oil or WD-40 are not suitable, even though many people use them and even recommend them. I prefer Tap Magic XTRA since it is formulated for all metals. It's hard to find locally so I get mine from McMaster.com.

[Lady Fitzgerald]

26 minutes ago, Kilrah said:

https://www.amazon.co.uk/Drill-Combination-Pieces-Thread-Spiral/dp/B01DIWWT0A

 

You find combined drill/taps but they're usually trash, relies on being able to drill with the same pitch as the tap which is far from guaranteed unless the material is really soft. But then a soft material makes it easier to strip the already made threads if it doesn't, so...

 

Drill first, tap second with dedicated tools.

 

14 minutes ago, Kilrah said:

When you turn the tool once it's started tapping it needs to advance by the thread pitch. But if your material is thick and the drill is still cutting material there will be too much resistance on the drill tip for that to happen so you'll force and just rip off the threads that were already made.

 

To clarify, the combination drill/tap tools are made for thin material. When you get to tapping the drill must have exited the part already.

Horsefeathers! I've used these many times without problems in both thin and thick materials (thickness depends on the drill/tap design). I prefer hand tapping with separate drill bits and taps because of the amount of time needed to set up for proper power tapping and my drill press is not reversable, making removing the drill/tap a pain in the neck.