Thread: making small boring bars

Cant say if the heat put into your HSS from welding will effect it,I have never had a problem when it has either been stick or mig welded.

Thx, Pipeclay. I'm going to try that.

Regards.

Originally Posted by Tiger

Thanks Ben and Russ , The picture explains everything clearly. I've got some discarded drill bits that I can use.

I dunno how others have gone but I have never had much luck using drill bits in a lathe situation. I have found that the shafts from worn taps are very good. I have a round bar with perpendicular fitted tap at work that does a great job - needs a 25mm hole to fit it in though, used to cut a 38mm hole in 2" 316 solid bushes. Have a insert boring bar for that job now fortunately.

Hi Tiger
Just reading all of the input to your question and thought I would add a little just to create more confusion.
When boring small holes not too deep, I would just grind up a suitable shape using solid HSS. I have bored holes and tapered holes in tool steel probably down to 6mm in Dia. Solid High speed is a very rigid material. See photos of some old stuff found in the bottom of the box as most of my really small ones must have been borrowed.
For other awkward jobs I have brazed HSS tips on to various shanks using silver brazing alloy 45% silver currently around $5 to $8 a stick. just keep the heat low. I found the brazing only reduced the hardness to around 60 Rockwell C. Good luck and have fun
Ray

Thanks, Ray, that was helpful particularly the photos. Am interested in how you did the brazing, how did you hold the small cutting tip on the steel shank so that it doesn't move when you brazed?