Mailing List flyrotary@lancaironline.net Message #39120
From: Ernest Christley <echristley@nc.rr.com>
Subject: Re: [FlyRotary] Re: Tap 'em holes was [FlyRotary] Throttle Body Nut Ideas
Date: Wed, 22 Aug 2007 16:02:35 -0400
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Dale Rogers wrote:
This machinist says:  "Why would you want to *do* that?
Because I had no idea until now that such a tool existed?

For the rest of the story:

http://www.google.com/url?sa=t&ct=res&cd=6&url=http%3A%2F%2Fwww.osgthrane.dk%2Fshared%2Fguide-to-taps%2Ftech-nuroll.pdf&ei=8ZPMRvXuDaCUeNPg4M0L&usg=AFQjCNG25dNKzuyYJfY8HAqa0gjuHo1rIg&sig2=W3mhPq5blrAFQsdDpzHm5Q

Strictly speaking, cut threads - what you get from conventional taps -
are weaker than swaged threads, such as the rolled threads one usually
finds on AN class fastener. So ... if one wants threads in alumin(i)um, one needs a tool that
displaces the metal, rather than cutting it.  Eureka! Such a tool does
exist - the "fluteless thread forming tap"   E.g.:

http://www.shoprutlandtool.com/webapp/wcs/stores/servlet/ProductDisplay;jsessionid=0000aUcDvp-FmIJrmRkZmUaWieP:-1?productId=27670&langId=-1&storeId=10001&catalogId=10001&parent_category_rn= <http://www.shoprutlandtool.com/webapp/wcs/stores/servlet/ProductDisplay;jsessionid=0000aUcDvp-FmIJrmRkZmUaWieP:-1?productId=27670&langId=-1&storeId=10001&catalogId=10001&parent_category_rn=>

Rutland Tool # 21238428

Good hunting,
Dale R.
COZY MkIV #1254



Ernest Christley wrote:
Ed Anderson wrote:
Scott,  I think the best answer is to simply tap those bolt holes for the thread size of your bolts.  This does a number of things.

I've been told by a machinist that tapped holes in aluminum are weak.  Any truth to that?

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