# Help with tap type.



## FredM (Aug 14, 2007)

I need to tap some (actually alot of) holes in 6061 T6 alum. Its gonna be blind holes radially on a 2 inch diameter rod.

Is a spiral flute tap better for this application? Or should I save the moeny and get a straight flute with 2 flutes?

Are the taps from McMaster-Carr any good?


----------



## LED Zeppelin (Aug 14, 2007)

For blind holes you should get a bottom tap. Those will thread deeper into the hole. Straight flutes are fine.

McMaster-Carr taps are good, just be sure to use some cutting fluid meant for alum.


----------



## modamag (Aug 15, 2007)

For blind hole you should use bottoming tap, but if your depth is not so important the plug or taper type is fine.

If you have to do alot of them (dozen +) to do you might want to get a coated TiN or TiCN version.

McMaster is a good place to get stuff, but why not avoid the lottery and get it specifically well know manufacturer such as OSG or Greenfield. These are a tad bit more expensive (3-5x) but once you have a broken tap you'll scream and curse why you spend couple $$$ saving on a carbon steel tap.

You can purchase them locally or from mscdirect.com (dont forget ebay).


----------



## sawlight (Aug 15, 2007)

modamag said:


> For blind hole you should use bottoming tap, but if your depth is not so important the plug or taper type is fine.
> 
> If you have to do alot of them (dozen +) to do you might want to get a coated TiN or TiCN version.
> 
> ...


 

Everything said above, plus a couple more points. Stay away from sprial taps unlees you are tapping on a machine setup for it. They seem to be a bit weaker in design. Greenfeild is about as good as it gets!!! And Tin, is worth it.
For bottoming tapping, run a plug tap as deep as you can, then come in with a bottoming tap. Bottoming taps are much harder to get started straight, tend to bind up easier, are harder to tap with, and break more often!!!
Hope that helps.


----------



## Jared Stenoien (Aug 15, 2007)

If this is going to be a single time thing, definitely go with the above advice. However if this is going to be something regular, buy a tap-matic. Believe me, it'll pay for itself in no time flat. If you're pretty mechanically inclined you could even make one yourself, I know I've seen plans floating around before. Also if you go for the tapmatic route, carbide taps are AMAZING.


----------



## mahoney (Aug 15, 2007)

It's worth repeating "use cutting fluid designed for use with aluminium" 

The "finger type" broken tap extractors will work better with straight flute taps. Make sure your plug/taper and bottoming taps have the same number of flutes, and buy an extractor at the same time you buy your taps. It will save the wait if you end up needing the extractor.

If the holes are deep, don't try to tap full depth in one pass. Back the tap out of the hole a couple of times while tapping to clear the chips.


----------



## KC2IXE (Aug 16, 2007)

FredM said:


> I need to tap some (actually alot of) holes in 6061 T6 alum. Its gonna be blind holes radially on a 2 inch diameter rod.
> 
> Is a spiral flute tap better for this application? Or should I save the moeny and get a straight flute with 2 flutes?
> 
> Are the taps from McMaster-Carr any good?



Wow - LOTS of radial taps, on blind holes, in 6061?

2 choices: a sprial flute tap...

OR Better yet

Look into a "thread forming" tap. Yeah, you'll have to use a different hole size, but you won't have chip clearence to worry about


----------



## KC2IXE (Aug 16, 2007)

Jared Stenoien said:


> If this is going to be a single time thing, definitely go with the above advice. However if this is going to be something regular, buy a tap-matic. ...snip...



Yeah, tapmatics are cool. If it was an axial job - I'd say use a lathe and a releasing tap holder - I have one - I had a job where I had > 100 holes to tap - it was a good investment. Have not used it since, but..


----------



## McGizmo (Aug 16, 2007)

Seems like a lot of good advise here! I am curious as to what size tap and how deep? A 3/8" tapped hole 1/2" deep is a diferent animal than a #0 hole 1" deep!?!?! :green:


----------



## TranquillityBase (Aug 16, 2007)

McMaster sells very good quality tooling. HSS bright finish, with WD-40 as the cutting lube is fine with 6061-T6...

There's a difference between spiral tip (gun), and spiral flute, which tap have you been considering?

Whats your tapping set-up?


----------



## FredM (Aug 16, 2007)

Either a #6 or #8 about 5/8 to 3/4 inch deep. Might tap to 3/4 then buy 5/8 screws.

What do you guys think about #8 button head screws on the radius? Will the head look out of place? Make me counter sink it? If so I will get bigger screws.


----------



## FredM (Aug 16, 2007)

TranquillityBase said:


> There's a difference between spiral tip (gun), and spiral flute, which tap have you been considering?
> 
> Whats your tapping set-up?



The spiral flute. But I can see how it would have less stength so I think I will go straight flute.

My setup is just gonna be a drill press and a tap wrench.


----------



## FredM (Aug 16, 2007)

modamag said:


> McMaster is a good place to get stuff, but why not avoid the lottery and get it specifically well know manufacturer such as OSG or Greenfield. These are a tad bit more expensive (3-5x) but once you have a broken tap you'll scream and curse why you spend couple $$$ saving on a carbon steel tap.
> 
> You can purchase them locally or from mscdirect.com (dont forget ebay).



I was looking at MM because they also have the screws I need and I cannot source those locally. If you guys think I should use an upgrade over their tap though I will follow that advice.


----------



## TranquillityBase (Aug 16, 2007)

If it helps, all the taps I received from McMaster have been *Greenfield*, at least the 1/4" and smaller...The 5/8" tap I ordered for the Kroll switch threads was a *North American*, made in USA...HHS bright, and its been through a few Ti cell bodies, and still going strong.


----------



## KC2IXE (Aug 17, 2007)

FredM said:


> I was looking at MM because they also have the screws I need and I cannot source those locally. If you guys think I should use an upgrade over their tap though I will follow that advice.



Does MSC also source your screws? If so, you have a HUGE assortment of taps on call www.mscdirect.com (349 DIFFERENT 6-32 taps to chose from!! - and I might have missed some)

BTW If you have a CHOICE on screw size (you said either #6 or #8) - go #8. The 6-32 screw size has the thinnest minor diameter VS major diameter - it is THE most likely tap size to break!


----------



## sawlight (Aug 19, 2007)

KC2IXE said:


> Does MSC also source your screws? If so, you have a HUGE assortment of taps on call www.mscdirect.com (349 DIFFERENT 6-32 taps to chose from!! - and I might have missed some)
> 
> BTW If you have a CHOICE on screw size (you said either #6 or #8) - go #8. The 6-32 screw size has the thinnest minor diameter VS major diameter - it is THE most likely tap size to break!


 

I will dissagree here. Only because I have had to chase holes that were taped #0-72!!!!


----------



## rmyc (Aug 31, 2007)

Alchol works as a very good lube for aluminum


----------



## scott.cr (Aug 31, 2007)

rmyc said:


> Alchol works as a very good lube for aluminum



Good point! A while back I tapped several holes in aluminum using "RapidTap." It was okay, but alcohol was better and cheaper. I keep a few gallon-cans of alky around the shop for sundry cleaning and aluminum cutting purposes. (It's great to clean those high-polish Craftsman "Professional" hand tools.)

But!! You have to re-oil all your equipment after using alky. I heard that orange oil is a good cutting fluid for aluminum and it doesn't rust your tools, but never tried it.


----------



## rmyc (Aug 31, 2007)

scott.cr said:


> Good point! A while back I tapped several holes in aluminum using "RapidTap." It was okay, but alcohol was better and cheaper. I keep a few gallon-cans of alky around the shop for sundry cleaning and aluminum cutting purposes. (It's great to clean those high-polish Craftsman "Professional" hand tools.)
> 
> But!! You have to re-oil all your equipment after using alky. I heard that orange oil is a good cutting fluid for aluminum and it doesn't rust your tools, but never tried it.


 
I just used almos pure ethly alchol, it contains pretty much no watter so it evaps quick and will not oxidize the steel. the point of alchy on aluminum is that it's used as a coolant and not a lubricant, Alchy flash cools the hot aluminum and pretty much all evaporates.

BTW what do you guys lube your stages on a lathe with? i got a small 7x12 lathe and i need to lube it


----------



## rmyc (Aug 31, 2007)

Also, use alchool on aluminum only, it doesnt work for steel and Ti


----------

