Good morning to all,
My messages weren't intended to be negative. I think Peter was pretty creative to make a 90 deg. drill from a 4-1/2" angle grinder. Like many of you, I've got many tools I've made or modified thru the years. That's part of being a gearhead on a budget.
My first message was to let you guys know about the miniature 90 deg. threaded-bit air drills. Unless you're in aviation maintenance, you may never have seen these.
My second message questioned another member's statement that 4-1/2" grinders don't run at 10,000 rpm. I have a Makita and a cheapy from Harbor Freight (which has been a surprisingly good tool). I looked this morning, and the Makita is labeled at 10,000 rpm no-load spindle speed, the Chicago Electric (Harbor Freight) at 11,000 rpm. My cutting and grinding discs, and flap wheels are labeled for 13,200 or 13,300 rpm.
No doubt others of you may have something different....and that's OK.
As Peter said, the speed, whatever it is, is not an issue for his use on thin aluminum or mild steel. Trying to drill thick steel or stainless steel would probably melt the bit, but he's not doing that. Again, hats off to his ingenuity.
Now, peace to all of you.
Rodger
Threaded Mode
