I need a "0" or "very little" clearance M6 tap - confused by 2B, 4H, D3 etc.

Finegrain

Diamond

Joined

Sep 6, 2007

Location

Seattle, Washington

• Sep 13, 2017

• #1

I need a "0" or "very little" clearance M6 tap - confused by 2B, 4H, D3 etc.

Hi guys,

I know I should know this, but, I seem to have forgotten :-(.

Spec says "M6X1.0 THRU ALL TIGHT FIT FOR M6x1 STUD". 303 1/2" thick. So I want an M6 tap with the smallest "class of fit," right? But, I see three different types of "class of fit" when I go searching in the MSC website -- "B" something, "D" something, and "H" something (I know, MSC sucks, but they are there and McMaster-Carr doesn't seem to have any class-of-fit differentiation at all) . Or are those actually not all referring to "class of fit?" Or am I barking up the wrong tree completely with "class of fit" and I want some other spec?

Help me .

Thanks, and regards.

Mike

 

E

ewlsey

Diamond

Joined

Jul 14, 2009

Location

Peoria, IL

• Sep 13, 2017

• #2

In the inch system, we use "H" numbers for tap size over nominal pitch diameter.

In metric they use "D" numbers.

Who knows why they can't be the same

http://www.taylortool.com/wp-content/uploads/Comparison-of-UNC-UNF-and-Metric-pitch-diameter-limits-for-classes-of-fit.pdf

 

L

Limy Sami

Diamond

Joined

Jan 7, 2007

Location

Norfolk, UK

• Sep 13, 2017

• #3

be warned Mike - I did some D3 class a while back - in alu, with taps and gauges supplied, and they were a swine to get right, ........IMO the amount over std pitch diameter was so small - everything had to be ''just right'' ..........my auto reverse tapper - which is neither a Tapmatic or Procunier was not good enough, .......I ended up hand tapping them in a tapping stand - like this but (hopefully) better Hand Tapping Machine | Grizzly Industrial

 

Finegrain

Diamond

Joined

Sep 6, 2007

Location

Seattle, Washington

• Sep 13, 2017

• #4

Thanks for the heads-up LS! It's only 2 holes in one part, so will hand-tap them.

Regards.

Mike

 

E

ewlsey

Diamond

Joined

Jul 14, 2009

Location

Peoria, IL

• Sep 13, 2017

• #5

You might consider a form tap. My experience is that they do not go oversize like cut taps can.

 

M

Modelman

Titanium

Joined

Sep 12, 2007

Location

Northern Illinois

• Sep 13, 2017

• #6

I'm going to stick my neck out here, because it's been a while since I looked, but I recall McMaster not having a selection of fit classes in inch taps, either. McMaster is nice, but they're not really a cutting tool supply house, and odd fit classes are just a little bit too esoteric for them. Call a local cutting tool supplier. I happen to like Walter R. Hammond Co. in Minneapolis, but I'm sure there is someone closer to you.

Dennis

 

D

dave powelson

Cast Iron

Joined

Aug 28, 2007

Location

Yuba City, CA

• Sep 13, 2017

• #7

Finegrain said:

Hi guys,

I know I should know this, but, I seem to have forgotten :-(.

Spec says "M6X1.0 THRU ALL TIGHT FIT FOR M6x1 STUD". 303 1/2" thick.
So I want an M6 tap with the smallest "class of fit," right?

Help me .

Thanks, and regards.

Mike

Click to expand...

The drawing needs to specify dimensional limits for this 'TIGHT FIT'

and query the customer as to exactly how this 'TIGHT FIT' is to be gauged by them and you.

Otherwise, everybody's just sucking wind.

 

D

DMF_TomB

Diamond

Joined

Dec 13, 2008

Location

Rochester, NY, USA

• Sep 14, 2017

• #8

loctite or vibra-tite will fix loose threads

 

L

Larry Dickman

Titanium

Joined

Jan 30, 2014

Location

Temecula, Ca

• Sep 14, 2017

• #9

my favorite has always been the "Tight Slip fit"

Just thread mill them. You can make them whatever size you like.