| The Breakroom > The Water Cooler |
| So muchfor pilot holes |
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| vintageandclassicrepairs:
Hi All, Going back to Will's original link, In the video, the speaker says the the 3/4 drill has a split point This would certainly help the drill to start without wobble, Although when used in a decent milling machine the need for spotting or centre drilling is reduced An interesting variation on drill sharpening is shown on one of Brian Block's videos where he demonstrates a "spiral point" drill grinder John |
| sparky961:
--- Quote from: AdeV on September 13, 2017, 07:00:09 AM ---Presumably the SFM is measured at the edges of the spade? I'm trying to convert that into RPM in my head, without a lot of luck :D Edit: OK, think that's between 28 and just under 38 RPM? --- End quote --- I get 130 to 172 RPM, which sounds about right to me. |
| AdeV:
Bugger, I forgot to convert feet into inches when I divided the SFM into the circumference. Blast these complicated mathematical thingmajigs! :smart: |
| sparky961:
--- Quote from: AdeV on September 13, 2017, 05:56:27 PM ---Bugger, I forgot to convert feet into inches when I divided the SFM into the circumference. Blast these complicated mathematical thingmajigs! :smart: --- End quote --- LOL... I cheated. I used an app. ;) |
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