Cutter holder at the end of a 6' boring bar

[Eric Gourieux]

I decided to construct a deeper hollowing system similar to the McEvoy system and purchased a 1.5" dia 6' boring bar. Now, I'm trying to decide the best way to attach a cutter to the end of this beast. I have a wood shop and virtually no metal-working tools other than a drill press, grinder and welder. On the smaller hollowing tools I've made, I simply ground a flat spot at the end and tapped for a screw. On this 1.5" diameter bar, that would be difficult. I've considered drilling a hole in the end of the bar to insert various yet-to-be-made cutter holders, but how do I drill a hole in a 6' long bar? I could cut an inch or so off of the end of the bar, drill or grind the smaller piece to shape and weld it back onto the end. That seems fairly doable. Any other suggestions on constructing a cutter attachment? I have completed the rear support for the bar.

[Thom Sturgill]

If you are going to use this on the lathe, build the support system. mount a drill bit in a jacobs chuck in the headstock and feed the bar into it. Might want to clamp some guides to make sure the end comes in square and center punch the center of the bar to start the bit. Drill to accept a commercial bit holder purchased from Monster or Jamison.

[Dennis Nagle]

That would work Thom. You could also lay your drill press down and drill horizontally.

[Brian Finney]

Taper the working end down to ¾” dia, using an angle grinder over 6” length.
Drill 3/8” hole in end ½” deep.
Cut 1” length of HHS ¼”square section.
Grind one end of HHS as the cutting edge and the other to fit the hole.
Use CA glue to fix cutter.
To remove cutter – use heat .

[Eric Gourieux]

Thanks for the suggestions. I'll experiment with it and see what happens.

[Dale Miner]

Since you have a welder;

Obtain a short length (2.5"?) of 1" round bar, Chuck it up in your wood lathe, and drill a suitable size hole in the end for cutter holders, drill and tap the piece for a set screw to hold the cutter holders. Once the piece is prepped, weld it to the end of the 1.5" bar. This helps reduce the diameter near the cutter providing clearance around the cutter, and eliminates the need to drill a hole in the end of the larger bar. I have a 1.25" bar, and use 3/4" cutter holders in the end of the bar. This provides flexibility in swapping out different holders for various uses.

[Dennis Nagle]

Im sure a small machine shop in your area would drill it for you for a couple bucks.