Drilling a large hole without a drill.

[airmodel]

Hi everyone

I recently needed two 35mm holes in perspex. As large drills are expensive I made a boring bar to be held in a chuck. A pilot hole is drilled to stop the boring bar from wandering off center. The boring bar needs to be a neat fit in the pilot hole. I have used this method  on aluminium and steel. If used on metals a very slow speed is used and also plenty of coolant/cutting oil are needed to help the cutting action.

The photos and video show how it works.   http://youtu.be/Mr6hTa7z_AI

[Thor]

Nice job, I have always drilled such holes with a holesaw.

Thor

[smfr]

Interesting video! I didn't realize that it was so easy to repurpose a microwave oven controller board. 

Simon

[Johnmcc69]

I'm with Simon, that's slick!

 What are you going to use this on?

 John

[b.lindsey]

Very slick...and a nicely done video too!!

Bill

[PStechPaul]

Pretty good! The power control could be used for something like a heater where there is a lot of thermal inertia and a slow PWM works fine. The PCB in a broken CFL is quite useful as well, as it will drive a 10-15 watt fluorescent tube more efficiently than old style ballasts:
 
<a href="https://www.youtube.com/watch?v=e7QJQBSBRCw" target="_blank">http://www.youtube.com/watch?v=e7QJQBSBRCw</a>

[airmodel]

I plan to use it on my vacuum cleaner as a blower for my melting furnace. Before I made this housing it was in the open slapped together with live wires exposed. Now I can use it safely without getting zapped!