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steamer

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Hi all,

I have been reading along on the thread about theading :)
Those of you with some experience came to the rescue and our intrepid member was sucessful!

I enjoy helping out too. I was wondering if an area for resources could be set up with referance files and perhaps threads of some basic topics. Like the basics.
Sometimes the beginner needs information just to form the right question. Not knowing what book to buy or person to ask can be a real hurdle to overcome. To say nothing of trying to cut a thread...that scared me silly the first time I did it....I learned but the curve was steep!

I enjoy teaching what I have learned. I find it very gratifying and I think other members like to do that too.

How about a section or thread here for newbie resources? I think those of us who have twiddled the knobs for a while could all provide something.

Attached is a simple one, a tap drill chart for threaded holes from 0-80 up to the rediculus size. I use it everyday in the shop. Very useful.

Dave




View attachment Decimal equivalents and tap drill sizes.pptx
 
Here's another,

The Hercus lathe manual.

This is a great reference for tool geometry, threading techniques and thread types, chucks and their use, faceplates and their use, steadies, drilling, among other things.

All of these techiniques or discussions transcend the make or model of the lathe. It teaches the "WHY" not the what so much.

View attachment Hercus TextBook of Turning.pdf
 
Dave

Thanks for the references. I'm always looking for info to add to my library.

Andy
 
It's in PDF form on my second post as well.....as an attachment.

Good stuff!

Dave
 
Where can I get a card with the proper drill sizes for metric taps and sizes to turn to for metric dies?
I have broken several taps using the guesstimation method.


Phelonius
 
Phelonius, I have found your best friend for those tables is Google. It seems that everyone that makes or sells taps and dies publishes one on their web site. Just use key words like tap, die, drill, metric
 
The proper formula for tap drill size is:

TD = MD - 0.013*DOT*P

where:

TD = tap drill size
MD = major (i.e., nominal) diameter of thread
DOT = depth-of-thread expressed as a percentage
P = pitch of thread

This is often abbreviated to:

TD = MD - P

which implies that:

0.013*DOT = 1

or:

DOT = 77%

This simpler form is particularly easy to apply for metric threads. If the metric thread designation is (a x b), then the 77% DOT tap drill is given by a-b. (Example: A 6 x 1 mm thread would require a 6 - 1 = 5 mm tap drill.)

If you're tapping difficult materials (e.g., bronzes), use the first formula and a smaller DOT, say 55 or 60%.

Note that both formulae are equally valid for Imperial threads. Simply calculate pitch as the inverse of the tpi (e.g. 32 tpi => P = 1/32 = 0.03125).
 
Hey Marv

How about this? Please open the attachment below

Feel free to add to it. I don't remember M5 off the top of my head...and I haven't seen an M7 and my chart doesn't show it

70% DOT seems to jive with my chart data

Dave




View attachment Metric threading chart.xlsx
 
I have a chart I printed up off this web site long ago-- http://www3.telus.net/public/aschoepp/tapdrill.html

The cool part about it (in addition to the lack-o-math required on-the-spot in general), is it shows 75% drills for Al & brass as well as 50% for steel and the like, drill #'s and decimal sizes plus 'close' and 'free' fit drill sizes. That's handy when the tapping chart says to use a letter F or whatever and you don't have one-- you can poke around the decimals to find the next closest you do have, or if you want a looser or tighter threaded hole. The first printed page covers 0-80 to 3/8" or so and that's most of what I need. Page 2 goes to sizes larger than I have drills. I refer to it constantly when tapping holes.

Print it yourself is where it's at for these kinds of things. I have a big metal Cleveland wall-chart I got at a garage sale that's OK, but I use it far more for the decimal equivalents to the various letter/number/fractional drills than tapping sizes.
 
Thanks Shred!

That one has the metric and the english!

Dave
 
OK

Who's got a good chart with speeds and feeds in the public domain they can put here?

;D
Dave
 
I think that'll do! thanks Bob!


.....and how's your bilge...er ah back...today? ;D


Dave
 
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