|06-11-2007 02:18 PM|
|06-11-2007 02:14 PM|
|hemi43||Metric is the easiest to figure out. just take away the pitch and you have your tap drill. ie, m10X1.25 = 8.75. Dan|
|06-08-2007 07:28 AM|
This little tip is particularly handy when tapping for metric, where the pitch is given as part of the thread specification.
Here's another little tip an old timer gave me when I was starting at Chrysler back in the fifties:
The nominal diameter of a "numbered" screw thread, in thousandths, is equal to the number times 13 plus 60. For instance, for a number 10 screw, the nominal diameter is 10 time 13 plus 60 or 190 thousandths.
I wish there was a similar relationship for numbered drill bits.
|06-07-2007 10:57 PM|
|Blazin72||A Machinerys Handbook is worth it's weight in gold for stuff like that. I have the 26th edition and it's more than 2600 pages. It has everything you ever wanted to know about threads, drills, heat treating, welding, machining, gears. You name it, it's got it.|
|06-07-2007 06:11 PM|
|leldai73||on the subject for low quality taps, i wanted to return a broken craftsman tap the other day because all craftsman hand tools are guaranteed for life, and i would consider a tap a hand tool. but the friendly folks at the local sears disagree. a tap is classified as "a bit" and is there for not covered under the guarantee.|
|06-07-2007 05:41 PM|
|06-07-2007 04:46 PM|
|61bone||Generally,When I plan to tap something, I take the tap over to the window where the light is better and look carefully at the tap. Most say on the side what size bit to use.|
|06-06-2007 08:00 PM|
Yeah ... that over-simplification of thread is one of my pet peeves.
I was at a truck repair shop the other day, and a couple of young guys had just finished constructing a 1" hydraulic hose for a track hoe (where the length HAS to be exact).
They've got a 1" Male NPT on one end and a 1" 37° JIC female on the other. The shop foreman is livid ... and their excuse is "I thought it was just all 'bolt-thread'!"
Needless to say they ended up with about 20 ft of wasted hose that will never fit anything. Sure, some will say that they can "hack it up" and re-use it ... but that seldom happens in the real world, right?
|06-06-2007 07:40 PM|
|leldai73||no ones over doing themselves, the sheer amount of things there is to know about threads would blow any ones mind. pitch diameter, basic P.D., measurement over wires, best wire size, u.n.f, u.n.c, u.n.s, metric, acme, whit worth,class 1A,2A,3A, or 1B,2B,3B, helix angle formulas, lead, imaginary cylinders passing through the thread for the purpose of measurement, the list goes on and on and on.|
|06-06-2007 06:51 PM|
|budthespud||Thanks guys you do overdo yourselves but that's great and I thank-you!!|
|06-05-2007 04:26 PM|
here is one more (like you need another)
3/4-10 21/32 - -
3/4-16 11/16 -
these are off the web as well.
|06-04-2007 06:53 AM|
Another way to find the tap drill size is to minus the pitch from the diameter.
i.e, 3/8-16 thread, .375 - .0625 = .3125 or 5/16
1/4-20 thread, .250-.050 = .200 or 13/64
to find the pitch divide 1 by the number of teeth per inch. Dan
|06-04-2007 04:39 AM|
|budthespud||Yea 11/16" I found it on an internet search. Thanks cucumber.|
|06-03-2007 07:34 PM|
Looks like 11/16"
|06-03-2007 07:15 PM|
What Size Drill Bit???
I'm fabricating my own 4-link and I don't have a drill chart for the size I want to drill. I got to drill out the ends of the rods for a 3/4" 16 fine thread tap, what size drill bit do I need? Any help would be greatly appreciated!!