Small Hole Boring Bar

[kingmt01]

If you're not doing a deep bore, I use an endmill slightly smaller than the bore size offset in my boring bar holder. Cheap and effective.

I used a piece of 5/8 drill rod, turned 3/4 length to .500, with a 1/8 shoulder. drilled and reamed it to 3/16, and made a hack saw cut length wise. I put a 2 flute 3/16 end mill in it and put the whole thing in an adjustable boring bar holder for my lathe. I bored a number of holes to .250 with it, only .200 deep, but after all, that's what I wanted to do.

I'd love to see pictures of these. I never thought about using a end mill for a boring bar. It sounds like a great idea for short depths.

 

[savarin]

If you're not doing a deep bore, I use an endmill slightly smaller than the bore size offset in my boring bar holder. Cheap and effective.

Damn, I wish I had seen this before I bored out my little index pin lifter. The steel in that was a ***** to bore.
I shall remember this, thanks.

 

[T Bredehoft]

I'd love to see pictures of these. I never thought about using a end mill for a boring bar.

Here's mine, I still have to put a flat on the adaptor for the set screw, just a matter of a few seconds on the mill.



That's a 2 flute 3/16 end mill. Note that the cutting edge is parallel the axis of adjustment.

Looks like my hack saw slot is off center. Tisk Tisk.

 

[kingmt01]

My boring bar holder I made for the large got slotted off center also. It turned out to look intentionally off set so I'm happy with it.

Yours looks great & is going high in my to do list.

 

[pineyfolks]

This is my tool post setup

 

[pineyfolks]

This is my tool post setup

 

[T Bredehoft]

Nice job on the Y axis indicator, too. I've got a .0001 Starrett hooked up on mine. sometimes I can hit it right on, others, well I recently missed by .002.