*****SPAM***** Re: [NLRS] 4-40 tap

[Charlie Betz]

John,

Menards sells drill and tap sets, I'm pretty sure down to #4-40.  These are 
individual cards with tap and appropriate drill for the particular tap. 
That run $3 - $4.

Jerry mentioned McMaster-Carr.  If you are tapping aluminum, take a look at 
the spiral fluted taps that they sell.  They are a little more expensive 
than the standard taps, but made for tapping aluminum.  They do seem to work 
better than standard taps, but you still need to excerise care as they will 
break.

Mark, N9LTJ told me about another trick for tapping aluminum that I have not 
tried, but he says works well.  He says you can rub some bar sap into the 
hole you are tapping and it will help float the debris out.  You still 
should lube the tap as well.  As I said, I have never tried this method, but 
Mark has done lots of metal work in his lifetime, so I trust what he says.

Charlie, N0AKC


----- Original Message ----- 
From: "Donn Baker" <wa2voi at mail.mninter.net>
To: <W0ZQ at aol.com>; <nlrs at mailman.qth.net>
Sent: Sunday, February 11, 2007 7:12 PM
Subject: *****SPAM***** Re: [NLRS] 4-40 tap


>
>
> Hi Jon,
> Any good hardware store should have the common size taps, down to 4-40. 
> If
> you don't find a set, you'll need a #43 drill for tapping steel or brass.
> Like Jerry suggested, a larger drill works better for aluminum, say a #41
> or #40.
>
> Never cut a thread without lubricating the tap, especially in Al.  "Tap
> Magic" is the best I've seen, but, again as Jerry said, kerosene works
> well.  Oil does NOT (for Al).  Light oil is for steel or brass.
>
> 4-40 taps are quite breakable.  Quite frankly, I'd advise you to buy two
> while you're at it.  Hub Hobby may have them, but Lowe's, or a hardware
> store, is a better bet.  You really want "tool steel" for the tap.  A lot
> of the ones you'll find (especially at Lowe's or hardware stores) will 
> tend
> to be "carbon steel."  May be marked that way, or a darker color.  Carbon
> steel cuts well, but its a lot more brittle than tool steel, and will 
> break
> easier.
>
> Oh.  If you're going to tap copper, work VERY slowly, use LOTS of fluid;
> cut maybe 1/4-turn, back off, repeat.  Copper is sticky, and will break
> taps very, VERY easily. (Experience speaking.  AND its a )*&(&() getting
> the broken tap out of the hole !  Mostly, you don't.)
>
> Lastly, make sure you don't flex the tap.  It needs to be perpendicular at
> all times.  You can get away with being sloppy with 10-xx and 8-xx taps;
> maybe w/6-xx, but not so much 4-xx.  Smaller than 4-40, I do tapping in 
> the
> drill press or mill (with out power, of course... just to keep alignment 
> of
> the parts).
>
> 73 Donn
> WA2VOI/0
>
> At 16:26 11-02-07 EST, W0ZQ at aol.com wrote:
>>
>>
>>Anyone know of a good source for a 4-40 drill  and tap ?   I suppose Hub
>>Hobby ?   I looked at DigiKey and  did not see a listing for taps.
>>
>>73, Jon
>>W0ZQ
>>
>>
>>Thanks for  your participation in the 2007 MnQP !
>>
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>>
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