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"Gerry" wrote in message news:kpk3hj9jfrq2m2q0l5u5k984ut158a7t2b@4ax.com...I tried to make a tiny hole saw to cut out rusted and broken steel screws galvanicaly bonded into aluminum sheet last year... maybe the year before. It was a work of art, until all the teeth sheared off instantly on the first screw. Then I did what I should have done in the first place and picked up the plasma cutter.
I totally broke Junior's FiL when he sent in a basket of bits for me
to sharpen - among them was a 1/2" concrete bit with the insert
missing. I sent it back nicely sharpened with a hole drilled through
the web and a tag wired to it saying "Drill shaped object - Use only
to make holes in room temperature butter"!
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The most recent drill-shaped object I made was a small hole saw from 3/16" gas welding rod, to free the broken tip of a #1 center drill so I could finish the #8-32 tap hole through the otherwise tediously completed aluminum part. The filed teeth needed several resharpenings to keep the chips flowing but it did the job.
The holes are for setscrews and pins that can push out pressed-in bearings. The parts are bandsaw blade guide rollers similar to this, but minus the sawdust grooves because a scraper of aluminum flashing cleans the blade ahead of them, and the blade back support is a separate bearing on edge instead of the flange.
https://cookssaw.com/parts/roller-guides/
The prototype aluminum rollers wore enough that I made a steel pair. The blade runs at 50-60MPH which is hard on the guides and their bearings, not far from the PV limit of a good bearing and beyond it for some cheap ones from Amazon, or the smaller skate bearings I used before. The ball cages break, pop the seals off and sawdust jams them or the balls fly out. The saw keeps cutting but not as straight.
A safety pin (on my key chain) can remove the rubber seals or metal shields from ball bearings to clean and grease them. Shields are retained by a spring clip at the outer edge that the pin tip can catch the inward beveled end of and pop it out of the groove. Both reinstall without tools after some practice.
When I changed phone carriers the clerk couldn't find his tool to unlatch the SIM card and asked me if I had one (yeah, right). To his surprise I handed him the safety pin which worked fine.
jsw
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