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I had a boring weekend in the shop. Boring bars,
that is.
I
really like the 3/4" stainless steel boring bars that came with my
Monster hollowing rig. However, I wanted to be able to go though
smaller openings. Over a year ago, I bought a set of Don Pencil
"Stinger" 7/16" boring bars. They were a nice size, but I never did
like the round bar cutting tips that came with them. Plus, the set
screws to hold the cutters were tiny, and they stripped out way too
easily (or my hex wrenches twisted because they were so thin).
After
reading about several guys recently making their own boring bars and
Oland tools, I figured I should give it a shot myself. I wanted 1/2"
bars that were capable of holding the 1/4" cutters that I already had
for the Monster rig.
Saturday, I picked up a 3' piece of 1/2"
cold rolled steel bar and a few set screws at the local hardware store.
The first three bars went so well, I went out Sunday and bought another
3' piece of steel and made a few more. Here are a few progress pics...
First,
I had to figure out how to drill a hole in the end of a 1/2" steel bar.
I took a wooden screw clamp, and drilled a 7/16" hole between the two
halves of the clamp.
That allowed me to hold the bar vertically and drill a pilot hole...
And
then the final hole. (I don't know what size it is...I just
experimented around until I found a hole size the 1/4" square HSS bits
would fit in.)
Then,
to hold the cutting tip in place, I needed a tapped hole for the
setscrew. I ended up using a 10-24 screw, so the pilot hole was a #25
bit...
I
also wanted to make a bar with an angled cutter, so I ground an angled
flat spot on the end of a bar and drilled a hole to fit the cutting
tip...
The angled bar also got a setscrew, but I didn't get any pics of that
operation.
I
also made three different bent bars (with a little help from my propane
torch), but didn't take any pics of the bending process.
And here are the results...
Here are the three bent bars. I'll probably make more after I see how
these perform...
And
here are the three straight bars. One is truly straight, one has an
angled bit, and I ground one of them down to accept a scraper bit from
the Monster gear.
Here's a detail shot of the angled bit...
And the scraper bit...
And as an added bonus, all of them (except the scraper bar) will accept
my Hunter carbide insert...
All
told, including steel bar material and setscrews, I spent under $20 to
make these. I need to stop by the hardware store and pick up some
shorter setscrews, and I'll probably grab a bit more steel just to have
on hand in the event I get a bright idea for another one.
Given
my choice, I would have preferred to buy them from Randy at Monster
Tools (assuming I could talk him into making 1/2" bars for me). Randy
uses much better steel, and his tools are machined instead of hacked
and ground. Unfortunately, being laid off, my tool fund ain't what it
used to be, so these will have to do until I can afford to buy some
better ones.
Discussion
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