Boring Bar Holder

I recently harvested a nice new Kennametal 1.5" dia. Coolant Through Boring Bar off of eBay for about 10% of it's retail cost. I needed the bar for an upcoming job of turning bushings from 5" 4140 pre hard tubing. I'm not a fan of wimpy boring bars!

First a piece of 3 1/5" 1018 square bar is trimmed to size using the Band Saw. This is a vertical Band Saw with a traveling table so it can be used for cut off operations. It has a 12" capacity.

The block is then Face Milled to both clean it up and square it up. Love those face Mills!

A 5/8" hole is then drilled through the block for the mounting stud that holds it to the compound slide of the Lathe. The hole is then chamfered.

Two 9/16" vertical holes are drilled half way through the block and then tapped 5/8 18 to a depth of 5/8" to accomodate large set screws that will push against bronze wedges to lock the bar in place.

The taper being cut on the bronze wedge at a 30° angle using the mill. Two Wedges will be dropped in the vertical holes with large Set Screws installed after them. When the Set Screws are tightened, they will push the Wedges against the side of the Boring Bar forcing the Boring Bar against the bore in the holder and locking it in position.

The Wedges being parted off. One on each end of the bar.

The block installed on the compound and being squared up to the spindle axis prior to boring.

Using an edge finder to find the edge so I can move in a specific distance for drilling and boring.

Center drilling in preperation for pilot drilling.

A 3/8 pilot drill being pushed through in preparation for boring the hole for the bar.

A 1" drill being pushed through. Note the coolant now entering from the back side.

The rough boring is done on the Lathe after the 1" drill was used.

I moved it to the Jig Borer as I needed to be working on another job, and it runs a lot beter and safer with less supervision than the Lathe does.

The last few thousandths are honed from the bore for final sizing. Not really necessary, but I like the finish and had the machine, so I did!

The Wedges ready to drop in and install the set screws to lock the bar in place.

The finished Tool Holder and Boring Bar with the coolant hose connected to it ready to go to work. That's the piece of tubing standing behind it.

Thanks!!

Glenn