Hi All.
I just had one of those days where everything goes
wrong.
Im cut, burned and i got a splinter in my eye despite
wearing my safety glasses.
Anyway, i have a problem which maybe someone can help me
with.
I was trying to get my viewports complete and welded
into the tower today. But, one fo the holes went really wrong.
I am drilling and tapping the holes in the
viewports. I have done 29 holes and everything seemed straight
forward.
But, on one of the holes, the pilot drill broke right at
the start. It took me over an hour to get the broken piece
out. After that, i tried to drill it with a new bit but it just wont
drill. When i say it wont drill, i mean it really wont
drill. I went to the shop and bought some special bits designed for
stainless steel and even that wont get though it. Its like trying to
drill a diamond. I dont know what has happened here. It seems such
a simple job, but i'm really stumped.
I have gone through about 6 brand new bits of different
sizes and types but all ive done is make a mess.
The hole is now about only 5mm deep and larger than
needed. I think i may have to drill and tap it to the next size up if i
can even get through it.
Does anyone know what has happaned? The
steel is A516 GR70. I was using a drill press on slow
speed. All the others holes were good with a long trail of swarf
indicating a clean cut.
Perhaps its a "hard bit" on the steel? Does this
happen?
Or, maybe it has work hardened and i now cant get
through it?
I thought of a couple of options.
1. Heat it to red hot and try drilling
it.
2. Drill another hole next to it and fill the
mistake with something, maybe epoxy?
3. Scrap it and make it again. (very
bad)
I had enough ports done to weld into the tower, but i
thought i better stop today. I was so misserable i would probably make
things even worse.
I may take the port to a professional shop to try and
rescue it, but im not sure what they can do that i cant.
Any ideas anyone?
Many thanks as always
James.