Drill charts

[Hukshawn]

where the heck do you find drill/tap charts? I've seen on many occasions in the various shops and factories I've worked in, the old mechanics have shop walls littered with promotional charts and various other posters. Where does one find these nice charts? I could just print something out.... but that's boring...

Also, who has a good reference for thread depth per pitch? What's the math involved with figuring out the depths of various threads? Is that available in easy reference charts as well?

 

[RJSakowski]

As a rule of thumb, the tap drill diameter is equal to the major diameter minus the thread pitch (or 1/tpi for Imperial). This gives approximately a 75% thread. For example, a 3/8-16 thread requires a 5/16" tap drill (3/8 - 1/16tpi = 5/16). It works for both Imperial and metric.

 

[RJSakowski]

I have a number of smaller charts which came with tap and die sets but I also just print one of the many that inhabit the internet and keep in my tooling reference file. Of you're looking for one of the nice metal wall charts that you can read at 10' without squinting, good luck. You might keep your eye out for shop auctions or try e-Bay.

 

[Ken from ontario]

I know,I have been looking for one of those for a long time , I'm talking about the Starrett 4"x6" cards that every machine shop used have pinned on every wall. my employer used to have 10 or so on his desk for us in case we needed one to take home.I now download the same chart and have 2-3 copies in my office and my shop and one with my tap & die set but I still would love to have that small wallet size card ,it was so handy , would fit in your shirt pocket.

 

[Hukshawn]

I'm not sure 10 feet away is necessary, lol. But one of those poster charts would be nice.

 

[Groundhog]

I emailed Starrett's customer service and asked for the 3x5" cards (the Tap Drill Sizes & Decimal Equivalents card and the Decimal / Metric conversion card). They sent then for free.

 

[Firestopper]

Starrett will also send you a wall chart if you request one (free).

 

[Terrywerm]

Many of the local tooling suppliers in your area will provide them for their customers if you order through them. Here in the Minneapolis area some common providers of tap drill wall charts were Discount Steel, WP & RS Mars, F.E. Satterlee and some others. Satterlee is no longer in business, but Mars is. You now have to purchase tap drill charts from them for $6.95 I don't know if Discount Steel still has wall charts or not. On a national level, MSC has a number of wall charts available, but you have to buy them, and the prices vary with what you get. McMaster and Grainger have them too, but they are not wall charts. They are only 8 1/2 x 11 sheets.

So, I wonder just how long it will be before Starrett stops giving them away?

 

[Chip Hacket]

I found this on EBay for about $50. I get a little nostalgic sometimes. Maybe frivolous but I enjoy it on my wall.

 

[BGHansen]

Here's one that may work for you. I recall scabbing it together from a scan of a drill chart in the CDCO catalog and a couple of scans from an old machinist text book. Gives you the decimal equivalents of fractional, letter, number and metric drills, plus the tap drills for standard metric and English threads.

Bruce