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- Andrew
Very informative Tim. Something else to add to my to buy list.Hi Chris. As I promised, here are some shots of my 5 sided broaches....
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These are the ones I have, from really small (0.4 ish) to larger. As you can see, they are nothing like files. You can hold them in a pin Chuck, or between your fingers.
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Here is a (hopefully) clearer shot of the biggest one. It shows that they are tapered with five equal flat sides. There are no teeth, the edges do the cutting. This enables you to gently increase the size of a hole, and the odd number of sides means it won’t drift off centre. Broaches are particularly useful if you want to make a hole big enough to take a wire of unknown size. You just drill smaller than the wire and broach the hole out to the size you want. For sheet work it can save you a lot on drills because these are more robust and you don’t need to keep every single size in stock. These are obviously no good for blind or deep holes though.
I find them an invaluable tool to have when dealing with etch, especially when building something with a lot of holes that need opening up. Well designed etch should always have undersized holes, because you can always open the holes to size, but if the sheet is over etched you can’t put anything back.....
Hope this helps
ATB.
Andrew