Making tooling for boring head

[.RC.]

What is the best way to go about making boring tooling for boring heads..

I seem to have a hell of a lot of trouble with chatter with boring with a boring head...

What is the secret??? I use a bridgeport clone with ISO30 spindle and a 75mm boring head..

[JoeFin]

What material are you cutting ?

I get good results even with Chicom insert boring bars in my boring head. As usuall speed and feed make a big difference, not to mention the angle of the insert to the work

[mikey553]

I used to run an old neglected Bridgeport, which would mill ok but would chatter while boring steel no matter how fast or deep you go. The similar, but new mill would bore the same part with no problem.
I would make an educated guess that spindle bearings were either worn or loose.

[dewat]

After adjusting be sure to tighten the middle screw on the dovetail.

[Boucher]

Boring bars are not all created equal.

I got my Boring head used with half a dozen Criterion Carbide Tip Boring Bars. I bought some Imports the same size and there is no comparison. I have not tried an insert type bar. I was surprised to find that I got a better cut with a little larger DOC. The sharpness and polish of the cutting edge becomes more important with very light cuts. It takes me several trips with no tool advance to nail a dimension. I really do like a Premium cutting oil for boring. The Criterion Carbide Boring Bars have the insert installed with some Positive back rake. I have wanted to try some of the Criterion Cobalt Steel bars. I have also been thinking about cutting down one of the Everede 3/4" bars. This also would be a good application of a Carbide Bar. Most of the holes that I bore are only a couple of inches deep that is a lot easier than a significantly deeper hole.

[Carld]

Have you tried turning the bar in the boring head so it is cutting either negative or positive rake? It don't take much and sometimes that is all you need to do to get rid of chatter.

You have to experiment for which works best each time. Speed and feed and DOC makes a difference too.

[luthor]

Ringer, can you post a picture of your setup?

[loose nut]

Take an old HSS end mill that is dull, grind off all the flutes except one and sharpen the remaining lip as you would a single tooth boring bar tool.

[Glenn Wegman]

Too much overhang. The bar should only be long enough to reach the end of the bore.

If using a boring head, factor the boring head length in the equation as it hangs South of the spindle bearing. That's why the same bar will work fine in a lathe, but chatter in a boring head.

[.RC.]

Here is a pic...I think my tooling which is home made needs more thought..

I also do not like the fact that the arbor has a skinny bit in it below the ISO30 taper..

[BobWarfield]

Saw a clever trick on another board. A fellow took a big fat boring bar from a lathe that wouldn't fit the boring head. He stuck it in his lathe and voila, "Silver and Deming" boring bar. He just turned a little shank down to fit. So now he had a meaty bar for deeper holes.

A solid carbide bar will go deeper than an HSS steel bar just like on the lathe.

Cheers,

BW