# about taps



## savarin (Apr 8, 2019)

Thought this may be of interest describing the different taps and their uses.


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## jrkorman (Apr 9, 2019)

Watched that this evening. As I am a bit new to this it was a bit of good info!


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## KMoffett (Apr 9, 2019)

After I bought spiral flute and spiral point taps, my old straight flute hand taps just sit on the shelf gathering dust.

Ken


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## macardoso (Apr 9, 2019)

There are a ton of great Haas tip of the day videos. Many are specific to CNC machining and programming, but many like this tapping one are great all around knowledge.


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## projectnut (Apr 9, 2019)

Most of my taps (90+%) are either spiral point or spiral flute.  About the only straight flute taps I have are those I either inherited, or those that were purchased when neither a spiral flute or spiral point were available.


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## WalterC (Apr 9, 2019)

I'm still waiting for first hand knowledge about the different coatings and applications.


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## macardoso (Apr 9, 2019)

My experience on coatings + research:

Bright Finish - Good for general purpose tapping, lower cost, especially good for aluminum. Most of my taps are bright finish.

Steam Oxide - Black porous surface finish. Rust resistant and seems to hold oil better through the cut, good for steel. A few of my higher end taps are steam oxide.

AlTiN - High wear resistance, good for tougher steels and cast iron, very bad for aluminum (aluminum in coating chemically binds to work). Common for high end endmills for steel cutting.

TiN - Gold coating, improved wear resistance over non-coated, can be used for aluminum. Higher lubricity than uncoated for slightly less tapping torque.

TiCN - High wear resistance, harder than TiN but cannot be used at high temp (not an issue for tapping usually)


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## pontiac428 (Apr 9, 2019)

What type of coating is Kromedge, and what are it's strengths/weaknesses?


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## macardoso (Apr 9, 2019)

pontiac428 said:


> What type of coating is Kromedge, and what are it's strengths/weaknesses?



Looks to be a vintage Craftsman trademark for chrome plated taps. Higher surface hardness, but probably not as good as modern coatings.

EDIT: Looks like they lasted a while, but were not very sharp compared to a ground tap fresh out of the box (according to online reviews). They might have been chromed after grinding which could round a sharp cutting edge.


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## hovercraft57 (Dec 16, 2019)

savarin said:


> Thought this may be of interest describing the different taps and their uses.


A really good video, especially when you consider a broken tap can mean a scrapped project .


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## savarin (Dec 16, 2019)

If you do a lot of tapping with small dia taps I would suggest a small edm machine to be a necessity. 
My thrown together bodge has been a project saver many times over.
https://www.hobby-machinist.com/threads/tumbler-reverse.10122/#post-124435
check from post 19 and the link to the plans comes a way down.
Its very well worth it although a bit slow for a production shop.


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