Gallery, Projects and General > How to's
Drilling large holes in thin metal using a twist bit!
Lew_Merrick_PE:
Back in the 1960's (when I was an apprentice) some of the Industrial Supply shops sold sheetmetal drills. They were similar in fluting to today's step drill bits for 3-5X the diameter of the bit. Above that there was a section (full round) about .005 (inch)larger than the step drill area that "burnished" the final diameter. I only have a couple left today as they "sprouted feet" with great regularity.
mattinker:
Just pointing out the the method I'm demonstrating requires no modifications to anything, if you have the right sized drill bit, all you need is a bit of rag! Andrew, if it judders about as you describe, you haven't got enough rag in there! I posted this as I thought it might be useful!!
All the best, Matthew
SwarfnStuff:
This topic got my grey matter searching the dusty file section somewhere in me dandruff. I recall needing to enlarge a hole in sheet metal and no drill big enough. Cross the road to the neighbour (a man of many interests including silversmithing, wood work, gem stone faceting and polishing to name a few) to see what he might have.
No, drill that size but he handed me a very large round metal file, told me to set it in the hole and wind it Backwards with the timber boring brace. Worked like a charm although it was no where near 29mm dia, now that would be a big file.
Marvelous what is lurking back there in the memory-bank just needing something to prompt recall.
All the best,
John B
RobWilson:
Good tip Matthew :thumbup:
Rob :dremel:
mattinker:
Thanks Rob!
John B it's a good idea to get thes ideas out of the depths of our memories, they won't be there much longer!!
All the best, Matthew
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