Dan wrote in :

Fortunat1 wrote:
Another stupid question!

Been reaming holes in a few 4130 plates. The reamer worked fine for
about 20 holes and then the holes started getting a bit smaller to
the point the bolts got a bit snug.
In my ignorance I thought this one hand reamer would pretty much last
me the whole project, but it's obvious I'm going to need a half a
dozen of them at least just to do the wing hardware.
I did a bit of searching on the net and found some info on reamers.
All hand reamers seem to be HSS which would put me back in the same
boat I'm already in so I was tempted by the carbide reamers I saw for
sale. So, my question is; can you use a carbide tipped reamer
designed for use in a lath in a simple drill press effectively? Or,
for that matter, can you use a reamer designed for use in a lathe as
a hand reamer? Or am I just barking up the wrong tree altogether?

By the way, just for info, the holes I've beenreaming are 5/16 and
1/4. The material is .090 4130 and the holes were all laser cut about
1/64 undersize. I would ream the first hole in each plate and then
clamp together the plates in pairs to ensure accurate alignment of
the holes in each pair of plates.
Just in case it's not the reamer's fault at all!


As has already been mentioned laser cutting has hardened the metal
around the hole. if your drill press runs true go with the carbide
tipped. Avoid solid carbide since the average drill press doesn't run
true enough to prevent breakage. If you need a very smooth bore go
with a spiral reamer, if not go with straight. Depending on size and
from whom you purchase the difference in price can run from about a
dollar to slightly phenomenal. As has also been stated use cutting oil
and debur the reamer as needed.

Things that can reduce reamer life: rotating them backwards,
wobbling
when used, spun too fast, not using cutting oil, poor storage
practice, using the wrong type for the material, not cleaning the
reamer after use, drilling too small a hole before reaming and
throwing across the room when you discover you were supposed to use an
under size reamer vice the over size one you just used (the most
entertaining time for this to happen is after you have spent hours
getting to the point you need to ream and you are almost finished). In
short use common sense.

Having said all this I will add having an extra reamer in sizes you
will use a lot is handy.

I have also noticed plans for various projects I have worked on
have
one thing in common: the more complicated the project the more likely
they will call for a size I don't have. This is why I have about 80
different sizes ranging from 0.0135 ( I don't even remember what I
used it on) to 1.5" which I have used for steam engine cylinders.

Good luck with your project.


Thanks. Of the above, I did keep it clean, didn't turn it backwards
storage was good, oil might not have been perfect (3in1) but I did have
trouble keeping it dead straight.. I tried to keep it as steady as
possible, but I did chatter t from time to time. The reamer i used was a
spiral one.
You have me wondering now about the wisdom of using my drill press,
since it's only a cheapie. I did go out and try it using my now piece
of junk (pointless since it goes the wrong way round) but I did see that
it's not turning 100% true at the tip. I'll just have to get a good
quality reamer and prepare each hole carefully. I'll see if I can get a
drill bit that brings he holes a little closer to the final size.