I've used small carbide end mills as my small boring bars. Superior chip extraction to any normal boring bar and you get 4 edges (if it doesn't break first) and they're cheaper. I have tilted the holder like 0,5° for clearance. Only good for bores as long as the flute length of the end mill though and you don't get a flat bottom but that's rarely an issue if ever.
They're boring bars not drill bits. You don't need to make something to hold them. There are holders that are VERY cheap readily available in standard sizes.
What was the material that you first tested the cutter on? It looked like it didn't want to form a decent chip most of the time and I am wondering if the results may be better with a different stock. Thanks
I'm not any good with metric, but the 5mm looks smaller than the 4mm one, guess it's going to be different between standards because 1/8" for us is smaller than 1/4"
![Making of: Small precize lathe tool out of broken drill bits [M4 internal thread cutting]](/img/n.gif)
Hello Alan,
Thanks for the video... The boring tools look quite useful...
Take care.
Paul,,
I've used small carbide end mills as my small boring bars. Superior chip extraction to any normal boring bar and you get 4 edges (if it doesn't break first) and they're cheaper. I have tilted the holder like 0,5° for clearance. Only good for bores as long as the flute length of the end mill though and you don't get a flat bottom but that's rarely an issue if ever.
Looks like your drill bits are ready for the bin or a good sharpening mate.
Thank you for the video.
Very good job sir thanks for you
They're boring bars not drill bits. You don't need to make something to hold them. There are holders that are VERY cheap readily available in standard sizes.
good video
What was the material that you first tested the cutter on? It looked like it didn't want to form a decent chip most of the time and I am wondering if the results may be better with a different stock.
Thanks
not too useful on the mill. That is what reamers are for. On the lathe you can do the usual thing with boring bars to make exact sized holes.
is there a link
Interesting, thanks for sharing!
I'm not any good with metric, but the 5mm looks smaller than the 4mm one, guess it's going to be different between standards because 1/8" for us is smaller than 1/4"