Page 1 of 1

Makerslide - Thread Forming Tap

PostPosted: Wed Aug 15, 2012 12:47 am
by bdring
I had an order in with McMaster (p/n 2541A33) and decided to try a thread forming tap with Makerslide. Thread forming taps can be hit or miss on some alloys of aluminum.

I had to drill out the center hole to the larger diameter than a thread forming tap requires. Since material is not removed, it is moved, you need a larger hole. The hole size was #14 (0.182"). I used a little oil will drilling and no oil when tapping and it went in perfectly and much faster than a cutting tap. The tap was about 3 times the price of a normal tap, but I could see a serious productivity increase and the taps last a lot longer.

The thread is a lot smoother too.


Re: Makerslide - Thread Forming Tap

PostPosted: Wed Aug 15, 2012 1:01 am
by macona
Thread form taps do require bigger holes than standard taps. The manufacturer will spec the size in the data books.

Use lubricating oil with thread form taps not cutting oil. These taps need lubrication since they form threads by plastic deformation of the metal. I have found way lube works very well.

Thread form taps are nice. I have used them for many metals, including stainless and titanium.

Advantages of thread form taps (Also known as roll taps) is they produce a work hardened thread. Also no chips to deal with so they are good for blind holes.

Re: Makerslide - Thread Forming Tap

PostPosted: Wed Aug 15, 2012 1:42 am
by bdring
What I meant to say was no extra oil was added during tapping. Just what was left from the drilling. I probably should use more.

The taps are a lot stronger because the flutes are smaller depth. My tap actually has what looks like small flutes, but they are rounded. It is a hand tap so I think they are there to lower the torque a little.

I make heatsinks sometimes out of pure copper which is a pain to tap. The small taps can get stuck and break. I would love to try a thread forming tap there.

Re: Makerslide - Thread Forming Tap

PostPosted: Wed Aug 15, 2012 6:18 am
by macona
They do need to be lubed pretty good. I have also had good luck with the cutting waxes.

The slit along the length is to allow oil to escape when tapping a blind hole.

The thread form taps should work OK for copper. It does work harden pretty easy too. When machining copper milk makes a good cutting fluid. The fats in the milk work real well. Just make sure you clean up after.

The only things they do not work so well with are brittle and soft materials that tend to return to shape. So no cast iron or delrin.