prawnabie
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| posted on 3/5/10 at 07:07 PM |
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Tapping a hole....
Hi Guys
I need to tap a 1/2 BSP hole in an alloy rocker covet I have. I have seen some taps on ebay but am confused as to what i need - bottom, tapered etc.
What exactly do i need? The part i want to screw in isnt tapered if it helps.
Also, what size hole will I need to drill to tap 1/2" BSP?
Thanks
Shaun
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2cv
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| posted on 3/5/10 at 07:21 PM |
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Taps are available in carbon or high speed steel (HSS) and in sets of 3. Taper or first tap, second and finally plug or bottoming tap. You will need a
fairly hefty tap holder for that size.
A carbon steel tap should be fine except if you are tapping stainless and then you will need HSS which cost a bit more. Normally one would drill a
hole of the correct size given here:
http://homepages.tesco.net/~a10bsa/bspgo.htm
Use the taper tap first which might be sufficient if you are not tapping a blind hole or don't need the thread to reach the bottom of the
hole.
Hope this helps
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dhutch
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| posted on 3/5/10 at 11:06 PM |
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Yeah, basically you start with a tapor, then do a intermediate, then a bottoming for a full job on a blind hole.
However if your not taping a blind hole you dont need a bottoming tap, and if its fairly thin with plenty of space the other side you can do it all
with a tapor.
I have also used a intermedate only on alumium with care. Not advised with smaller taps!
Daniel
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prawnabie
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| posted on 4/5/10 at 04:05 PM |
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Thanks guys - I the alloy is make 10mm think so I have ordered a 19mm drill bit nd a pair of taps - hopefully I will be ok!
Shaun
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