View Full Version : A boring project

02-26-2005, 10:11 AM
Thought I'd post a few pics of a castle style boring bar holder I made quite a while ago. As for making it, the post and the knurled locking nut are pretty self-explanatory. The sleeve I made by cutting a groove around the cylinder and using the gear on the headstock, use every fourth tooth to mark eight equidistant lines around the cylinder. Each one of the intersection points weas centre drilled and drilled through to the centre of the cylinder. The diameter of the holes drilled matched the diameter of the boring bars you want to use. EG. centre drill and then drill up to a 1/2" hole through to the centre of the cylinder. Turn the cylinder 180 degrees and do the same thing. Now you have a 1/2" hole through the centreline of the cylinder. Repeat for the other sizes. After I had 1/4", 3/8", 7/16" and 1/2" drilled, I chucked the critter and used a parting tool to cut the cylinder in two right through the initial groove. Et voila! Two halves that clamp over the boring bar. I purposely made the cylinder a little too high so I could turn it down until the centreline lined up with the centreline of the headstock. Now any boring bar I use is always on centre. I put a little index mark on the two halves so the right half-holes line up. (is there such a thing as a half-hole? if there is, then is there a whole-hole?) Anyway, you guys said that you like pics, so I thought I'd post these.


Paul Gauthier
02-26-2005, 10:23 AM
Very good, looks like a very rigid unit. Don't you just enjoy making what you need???

Paul G.

02-26-2005, 10:24 AM
Those of us who watch this BBS to soak up knowledge and gather ideas for projects love this sort of post. Thanks for sharing your project with us.

02-26-2005, 12:04 PM
Nicely done!

Two of my BB holders are Armstrong, very similar to your design. They use index pins located 180* apart to keep the halves aligned. Small springs fit over the pins to keep tension on the upper & lower part when changing bars.

Armstrong sells these new for about $800.

Barry Milton

02-26-2005, 05:30 PM
Looks great but do you have any ideas for a turret type holder. I curse the Warner & Swasey everytime it comes to a boring job. Shim, shim, shim. Now yours is a great tool if only I could adapt it. http://bbs.homeshopmachinist.net//biggrin.gif

02-26-2005, 09:19 PM
Most excellent!

02-26-2005, 09:40 PM
Very nice - I think it is a copy of the South Bend unit - a good design for small bars.