Nice! Thanks. There are some great conversion apps for smartphones, but
nothing else out there that makes sense of the various sizes.

As a quick reference when you can't refer to a chart, remember that for
metric taps, you can just subtract the pitch from the diameter to get the
drill size. For instance, an 8mm x 1.25 tap will use a 6.75mm drill.

Jim

On Mon, Nov 11, 2013 at 8:30 AM, Derek Drew <derekdrew@derekmail.com> wrote:

> 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>htt
> p://groups.yahoo.com/neo/groups/subaruvanagon/files
>  >
> <http://f1.grp.yahoofs.com/v1/LON_UhwrI9ccjzuEugT-jDubNPcaOD-
> oyoRf6ppkDP0H0DkGe12kPDkXJCJIDtlt2LZhIbHaWitjsaRKCtDDKxRyWMY
> i/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-
> oyoRf6ppkDP0H0DkGe12kPDkXJCJIDtlt2LZhIbHaWitjsaRKCtDDKxRyWMY
> i/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-
> oyoRf6ppkDP0H0DkGe12kPDkXJCJIDtlt2LZhIbHaWitjsaRKCtDDKxRyWMY
> i/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
>