Hole vs. tap size

[SpeedCoach]

This is a dumb question I'm sure....but I don't know the answer so I turn to your expertise...

Is there some sort of simple chart that indicates what size hole to drill in order to tap for X size fastener?

I'm certain there is, and I've looked - but I must just not be using the right terminology.

I appreciate the help gang - thanks in advance.

 

[ZTFab]

Search for "Tap chart"

 

[magnetnerd]

Or tap clearance, etc. yes there are definitely standards for these things. If you need to know these type of things frequently, I'd recommend investing in the Machinery's Handbook.

Sent from my SAMSUNG-SGH-I727 using Tapatalk

 

[bobadame]

There are "tap drill charts" that list the information you're looking for. A simple rule of thumb if you are not close a google machine: The size difference between the major diameter of the bolt and the tap drill is equal to the pitch of the thread you want to make. In other words, take a 1/4-20 bolt. The major diameter is .250". The tap drill size is .201". The difference between those diameters is .049". The bolt has a pitch of 20 threads per inch. If you divide an inch by 20 you get .050, really close to the .049" number. This method works for any size or pitch machine screw.

 

[larry_g]

http://www.physics.ncsu.edu/pearl/Tap_Drill_Chart.html

here's one

lg
no neat sig line

 

[mike13u]

Print laminate and hang in your shop or find an old hardware store sign that has this info and hang it. You will use it all the time. A must have.

Here is an old sign/tap chart I found on eBay and have hanging on my wall behind my lathe:

 

[purplezr2]

They make a free Iphone app for it even. I just google drill chart. I found on I like and just leave it as a browser window on my phone/

 

[Mario428]

They make a free Iphone app for it even. I just google drill chart. I found on I like and just leave it as a browser window on my phone/

I have the same thing on my Blackberry

 

[bad_idea]

I love that vintage sign! I need that!

 

[Outlander]

All our tool vendors used to leave us little plastic cards with tap drill sizes, metric equivalents or whatever back in the day. Of course, we didn't have that fancy internet thing and Machineries Handbook was hardcover book

 

[Regnar]

I have this Chart Hanging on one of my Toolboxes. I used Magnetic Paper from
Avery to print it out on. This allows me to move it around to different areas and always return it to a know position for quick reference. If you plan on handling a lot you can alway laminate the top with clear shelf paper from Walmart.

http://www.shender4.com/thread_chart.htm

http://www.amazon.com/dp/B00006HN5Q/?tag=atomicindus08-20

 

[gatewaysysop]

thats nice

I'm cheap, and did the print laminate thing

I have a vintage sign just like this one, only from the Cleveland Twist Drill co., absolutely love it. Have it hanging beside my 1946 floor model Craftsman drill press.

Great to have and really cool.

 

[rockchucker]

Print laminate and hang in your shop or find an old hardware store sign that has this info and hang it. You will use it all the time. A must have.

Here is an old sign/tap chart I found on eBay and have hanging on my wall behind my lathe:

Very nice! I just bought a set of new Twist Drill Bits! They work very well.

 

[NUTTSGT]

I nedd to print one off for the garage. You don't see many of the charts around much any more, atleast newer ones.

 

[zmotorsports]

If you have a local Grainger or Motion Industries dealer/distributor in your area they have some nice laminated ones. Motion Industries has a nice one that is on the backside of the cover of their desk calendars each year. We have several of them hanging around in our shops at work and I have one over my lathe/mill at my home shop.

Mike.

P.S., I have also seen nice ones from Fastenal and Lawson products if you have any of those distributors around.

 

[jeffmoss26]

I have one from Applied Industrial Technologies (came with the desk calendar) and one from Starrett.

 

[Rich1028]

on my craftsman drill bits it is writen as to what size the tap should be.

 

[bczygan]

http://www.bghooke.com/brucehooke/Documents/Tap_Drill_Chart_2.pdf

 

[billp603]

These are my favorite charts, one page for SAE one for metric, has tap sizes for different materials and clearance holes as well.

http://littlemachineshop.com/Reference/TapDrillSizes.pdf

 

[Regnar]

First metric chart that I have seen. I was always taught minus 1 for steel and minus 1.5 for Aluminum. So if you had 10 fastener you need a 9mm hole for steel and a 8.5 for aluminum. Size chart confirms.