John, just out of curiosity, are you planning on tapping holes for shear pins?
For carbon or fiberglass, I just use a 5/64" bit and then a different kind of tap (aka, a hammer) to insert them. If the holes are carefully aligned, they'll just tap right in. They can be difficult to remove, however, so tapping the holes might be an advantage if you often have to remove your shear pins.
Jim
Confused ... don't you have to remove them after every launch?
This. Screwing them in is pointless.Just my personal preference... I drill so they push in firmly, not thread in. They won't fall out...
This. Screwing them in is pointless.
Anyone know, off the top of his head, what size drill bit I need for a 2-56 tap? I have the tap, but I don't know what size hole to drill.
Also, any tips or tricks for tapping FG tubes?
Thanks....
Yeah I tried that when I was a newbie. Screwdriver kept coming out of the tiny plastic head, scratching my paint-jobs.After second time, I enlisted a large screwdriver "handle" to just tap 'em in.
Cool beans. Strange how some propellants age more gracefully than others. Probably not strange at all, I just don't know the reason...Yeah I tried that when I was a newbie. Screwdriver kept coming out of the tiny plastic head, scratching my paint-jobs.After second time, I enlisted a large screwdriver "handle" to just tap 'em in.
By the way Chad, flew some of those F-39's at the last launch & they worked just like new... surprising , considering they were made in '99. Thanks again.
Years late, I know, but just did this through paper tube and styrene nose cone, and this bit works great for 2-56 nylon screws used as shear pins, without tapping these materials.I just used the 5/64ths bit (I think that's it, just 1/64 above 1/16) the other day for that same purpose.
-Ken
Oh I’ve never thought about calculating minor diameter like that but it makes so much sense!It. depends on how engineeringyyyy you want to get. The Machinery Handbook has all the details. Buy a copy. Engineering data doesn't really go out of date.....Mine's the 24th edition....
If you want a really good rule of thumb....... Take the screw pitch off the outside diameter of the screw. In metric this is really easy M4 x 0.7 pitch tap is 3.3mm So a 1/8" drill is close enough. 3.175mm
1/4-24 take 1/24 th of an inch off 1/4 and you've got your tapping size.
For your 2-56 measure the outside diameter of your bolt or tap with verniers and remove 1/56th of an inch.
You could just ask google, but there's no real easy explanation like mine..... which is correct enough.....
For my method, it gives a tap drill size of 0.068" Google gives 0.069" 1 thou difference. close enough.....
Google answer. https://www.machiningdoctor.com/threadinfo/?tid=4
And you can thank the metric system for making it that easy to figure out. Only took me 20 years....Oh I’ve never thought about calculating minor diameter like that but it makes so much sense!
For my method, it gives a tap drill size of 0.068" Google gives 0.069" 1 thou difference. close enough.....
I buy the Dubro kit. It contains both.Anyone know, off the top of his head, what size drill bit I need for a 2-56 tap? I have the tap, but I don't know what size hole to drill.
Also, any tips or tricks for tapping FG tubes?
Thanks....
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