Date: Mon, 11 Nov 2013 09:30:52 -0500
Reply-To: Derek Drew <derekdrew@DEREKMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Derek Drew <derekdrew@DEREKMAIL.COM>
Subject: My MM to Inches Diameters POSTER w Drills and Taps
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I have uploaded this POSTER for you to print out and put on your garage wall.
The need for this document is 1) for a quick reference as to what
drill sizes to use for a given tap, or 2) to check the nearest MM and
Inch options, and 3) to make sense of your drill bits, and 4) because
the USA sizes are insane. Not only are they typically arranged in
confusing fractions like 3/8 and 5/16, but there are parallel size
nomenclatures being used like Number size Drill Bits (1 to 70 size),
Letter Size Drill Bits (A to Z sizes), Machine Screw Sizes (Size 0 to
16) and 64th sizes and 1,000s of an inch sizes.
I have made the file available in three locations:
============================
FILE ON GOOGLE
DRIVE:
https://drive.google.com/file/d/0B8sxgRMrur9XaWcyaXVacUx5eVE/edit?usp=sharing
then hit CONTROL S or FILE DOWNLOAD to your device. (You might have
to have a google account to get this but I am not sure. While it is
possible that there would be no problem, I would discourage you from
trying to use the file using the Google Docs software. Instead, try
to look at the file in Excel.
FILE ON SUBARU GROUP: I put the file for you all here:
<http://groups.yahoo.com/neo/groups/subaruvanagon/files>http://groups.yahoo.com/neo/groups/subaruvanagon/files
>
<http://f1.grp.yahoofs.com/v1/LON_UhwrI9ccjzuEugT-jDubNPcaOD-oyoRf6ppkDP0H0DkGe12kPDkXJCJIDtlt2LZhIbHaWitjsaRKCtDDKxRyWMYi/Dereks%20MM%20Inches%20Diameters%20and%20Tap%20Chart.xls>Dereks
MM Inches Diameters and Tap Chart.xls I think the (crazy) direct
link to it is this:
http://f1.grp.yahoofs.com/v1/LON_UhwrI9ccjzuEugT-jDubNPcaOD-oyoRf6ppkDP0H0DkGe12kPDkXJCJIDtlt2LZhIbHaWitjsaRKCtDDKxRyWMYi/Dereks%20MM%20Inches%20Diameters%20and%20Tap%20Chart.xls
FILE ON SYNCRO GROUP: You should also be able to get it from the
SOFTWARE AND TOOLS area of the FILES section
of
<http://autos.groups.yahoo.com/group/Syncro/>http://autos.groups.yahoo.com/group/Syncro/
> FILES > SOFTWARE AND
TOOLS >
<http://f1.grp.yahoofs.com/v1/LON_UhwrI9ccjzuEugT-jDubNPcaOD-oyoRf6ppkDP0H0DkGe12kPDkXJCJIDtlt2LZhIbHaWitjsaRKCtDDKxRyWMYi/Dereks%20MM%20Inches%20Diameters%20and%20Tap%20Chart.xls>Dereks
MM Inches Diameters and Tap Chart.xls
============================
I made this for my own convenience, but it has been so extremely
helpful to me that I figure that I better distribute it so everybody
can use it.
I suggest you download the file to your own computer and then print
it out, tape it together, and affix to your garage door or whatever
(NOT the refrigerator in your kitchen if you are married).
=======================================================================
You DO NOT have to read the material below because these notes are
also inside the document.
Important Notes
============
1. This document was prepared in Excel and is meant to be viewd and
printed form Excel. If you are viewing this in Google Docs it
probably won't be displaying correctly and will probably be a mess.
[By default, Google sometimes sets itself to destroy some Microsoft
documents and convert them to Google Docs, but the conversion tends
to introduce errors. For anybody reading this, unless you know you
want to set it otherwise, I suggest that you navigate to your Google
Drive page (if you have one) and then SETTINGS and then UPLOAD
SETTINGS and then uncheck the box that says "convert uploaded files
to Google Docs format".]
2. An "R" designation after a number indicates that the number is
rounded. The first number 0.014 r " is rounded. Many numbers are not
rounded.
3. In the unlikely event that you need to see the unrounded number,
you can often select the cell and then look in the formula field
above to see the detail on that number.
4. To quickly see the main USA fractional sizes, scan down column D
for the mustard colored cells.
5. To quickly see the major metric sizes, scan down column E for the
light blue cells
6. To view any size in 64ths of an inch, see column J, but keep in
mind that these numbers are sometimes rounded.
7. When metric sizes are rounded, they are identified as "r mm" but
if they are not rounded then column F merely says "mm"
8. Many drill bits you find in your shop or garage will be off-size,
meaning that their actual measurement difffers from the measurement
printed on the drill bit
9. To see the actual size of a drill bit, use a micrometer with a
1,000's of an inch readout, not a calipher, which is less accurate
10. To tap a new hole, look up the thread pitch in one of the thread
pitch columns (P, S, V, or Y) and then drill the hole out initially
using a drill bit identified in the associated "Tap Drill "" columns.
11. EXAMPLE a. You want to make a 6mm hole and you want it to have a
1.0 metric thread pitch
b. Find the 6mm row in the chart below and then look across
to the column that says "1" in the thread pitch column (to indicate
1.0 metric thread pitch)
c. Look in the adjacent cell and you will see the number 0.197
d. This number 0.197 is thousandths of an inch, so look down
row B to find 0.197
e. You will see that that corresponds to a 5mm drill bit
f. If you don't have metric drill bits, then look for the
nearest drill bit that you have in an American size
g. The nearest American size will be a #9 or a #8 drill bit
so use one of those if you have number bits
h. If you don't have number bits, then you can look for the
nearest 64ths drill bit, which in this case will be 13/64ths, which
is close enough.
Document Preparation
=================
1. This document was prepared for the purpose of printing and being
posted to the shop or garage wall
2. Do not "unhide" rows or columns or it will probably get very confusing
3. It is suggested to print on a color printer rather than black and white
4. It is suggested that you cut the chart up with sizzors and then
tape all the pages of the chart together in one giant chart that you
can staple to the wall
5. Staple the chart high on the wall so that the most common sizes
(e.g., 10mm are at eye level; otherwise you will have to squat too
much to see what you want)
The Insanely Confusing World of Nuts and Bolts, Drill Bits and Diameters
1. This document uses 1,000s of an inch along the left side as the
primary unit of organization
2. The metric size column is simple and needs no explaination except
to remark that only the blue colored cells are official metric sizes
3. The USA sizes are insane. Not only are they typically arranged in
confusing fractions like 3/8 and 5/16, but there are parallel
size nomenclatures integrated with the chart. These parallel size
nomenclatures are:
-- Number size Drill Bits (1 to 70 size)
-- Letter Size Drill Bits (A to Z sizes)
-- Machine Screw Sizes (Size 0 to 16)
-- 64th sizes are shown in their own column or it would have got
too confusing but keep in mind that the 64th figures are *rounded*
-- 1,000s of an inch sizes are also shown in their own column and
it says "r" where these are rounded
About Tap and Die Sizes
==================
1. The guidelines for what size hole to drill to use with any drill
bit are approximate, and you will see variations from one published
chart to the other
2. Accordingly, there will be differences between what is published
here and what you may see elsewhere.
3. For example, some publishers will state that to make a hole for a
6mm x 1.0 bolt you should drill a hole which is 5.2mm whereas this
chart gives that measurement as 5.0mm
4. Most of the discrepancies are not so large as the example given above.
5. The matter of the hole diameter is actually a mater of personal
preference of whether one prefers to drill the hole, for example, to
60% of thread depth, or 75% of thread depth, and so on.
6. Drilling a hole to 75% of thread depth makes the hole harder to
thread (without breaking your tap), but will provide a slightly
stronger bond with the bolt you will subsequently install.
7. So, if you find it is too hard to tap a hole using the guide given
here, you can try using a slightly larger drill bit and try again
8. Where a tap provides the drill bit diameter printed on the side of
the tap or in the box for the tap set, it will normally be better to
use that number than the number given in this chart
9. The main point here is that there is a variation in the number of
acceptable drill hole sizes that can be used with any given tap.
10. The drill hole size for a given tap may also depend on the type
of metal (e.g., aluminum, bronze, stainless steel, steel, etc.) but
this chart does not go into that detail.
Distribution
=========
1. This document may be reposted freely on the usual enthusiast
websites where it might end up and may be posted to vendor websites
without permission of the author provided that the address for
corrections (next row) is retained.
2. Corrections to derekdrew@derekmail.com, or you can post them in
public to the syncro list (for the purposes of discussion and to
embarrass me).
3. Publication date of this version: Septeber 12, 2013
_______________________________________________
Derek Drew
Washington DC / New York
derekdrew@derekmail.com
Email is best normally but...
PHONE: 202-966-7907 (Call the number at left normally)
(alt/cell for diligent calling only): 703-408-1532