Long boring D bit

Here is another use case of my hand chuck, it is for holding a long boring D bit

http://www.labellenote.fr/file/homem...ong_Dbit_0.JPG

Here is how the D bit is made : it's a piece of HSS round stock, ground to shape, that is silver brazed to a rod of standard steel. The tip has a D shape section, that is to say it is ground just above the diameter line. The tip is also ground at a maybe 30° angle, if you look at it from the top :

http://www.labellenote.fr/file/homem...ong_Dbit_1.JPG

Here it is in use on the lathe, through the tail stock, hold by hand with my hand chuck.

You need a steady rest and you need to drill first a guiding hole in order to drive the D bit at the begining.
The progress is quite slow, you need to be patient. You push for maybe 5 to 10mm, sometimes less, and you remove the bit to clean up the chips that strick together on the flat section of the bit.
I frequently soak the bit in a bottle of lin seed oil in order to lubricate.

http://www.labellenote.fr/file/homem...ong_Dbit_3.JPG

And here is the result, through a 40cm long piece of cherry. This is the output end, you can see that I am only maybe 5 mm off center, which is a quite good result.
No need to say that with a twist bit, this result is nearly impossible, you woold be way more off center.

http://www.labellenote.fr/file/homem...ong_Dbit_4.JPG

The piece is then trued up between centers on the lathe.

Thanks Christophe! I've added your Boring Bit to our Wood Lathes category, as well as to your builder page: Christophe Mineau's Homemade Tools. Your receipt:

<div id="blocks"> <div class="block b1 pngfix"> <div class="bimg"> <div> <a href="/homemade-boring-bit"><img src="https://www.homemadetools.net/uploads/236207/homemade-boring-bit.jpeg" alt="Boring Bit" /></a> </div> </div> <div class="head pngfix"></div> <div class="left pngfix"></div> <div class="right pngfix"></div> <div class="blockover b1 pngfix"> <div class="title"> <a href="/homemade-boring-bit">Boring Bit</a> <span> by <a href="/builder/Christophe+Mineau">Christophe Mineau</a></span> </div> <div class="tags"> tags: <a href="/tag/lathe">lathe</a>, <a href="/tag/grinding">grinding</a>, <a href="/tag/boring">boring</a>, <a href="/tag/turning">turning</a>, <a href="/tag/brazing">brazing</a> </div> </div> </div> </div>

interesting tool.:thumbsup:

Very useful tool :hattip:

Doc

Haven't seen an application like this before. Needless to say, I found it quite interesting.