Adjustable boring head

[Ed T]

I have used an adjustable boring head several times with good results although my approach seems a bit clumsy. Basically I usually rough the hole undersize with a drill or other means. Then I adjust the boring head to clean up the hole (hopefully still undersize). I measure the hole and from that measurement determine how much larger to adjust the head in one or several steps to get to the diameter that I'm after. I use a similar approach with a boring bar in the lathe as well. Seems like there should be a more "scientific" way to get the setting, but I'm not able to think of one that isn't a lot more trouble than what I described above. Any comments/recommendations?

 

[Jadecy]

I take a very similar approach when cutting an outside daimeter (no hole of course ;D). I adjust the tool to touch, move in another .002" to .005" and adjust the hand wheel dial to zero and take a nice, clean cut. I then measure with a micrometer to determine how much more I have to cut to get to the finished size and take multiple reasonable depth cuts to reach my goal. I check after several cuts and check more frequently as I approach the finished size. I like that first cut to give me a true relationship between the cutting tool and the part.

If I am cutting both the inside and outside part I always do the bore first. I find it much easier to make the peg fit the hole than to make the hole fit the peg.

Boring is a funny thing with me. Sometimes things go beautifully and other times I get these fantastic vibration patters. Some days I just need to back away and come back to it later.

 

[ghart3]

A method of presetting the boring head to a predetermined size.
Find zero in the X axis, on something like the left side of the fixed jaw on your vise.

Find and set your zero on X axis. If no DRO, keep track of backlash by always going in the same direction to take the slack out.

Move away from the fix jaw you zeroed on equal to the radius of the setting you want. You might want to go something like 10 or 20 thou under, measure and then take final cut(s).

Insert boring head and adjust to the fixed jaw you zeroed off of using a piece of paper between cutter and vise jaw to help judge the distance.

 

[kcmillin]

A method of presetting the boring head to a predetermined size.
Find zero in the X axis, on something like the left side of the fixed jaw on your vise.

Find and set your zero on X axis. If no DRO, keep track of backlash by always going in the same direction to take the slack out.

Move away from the fix jaw you zeroed on equal to the radius of the setting you want. You might want to go something like 10 or 20 thou under, measure and then take final cut(s).

Insert boring head and adjust to the fixed jaw you zeroed off of using a piece of paper between cutter and vise jaw to help judge the distance.

Awesome,

I always wanted to know how to do that.

thanks.

kel

 

[Mosey]

Funny, but I used the boring head today and set it up essentially like you just described. The spindle is first set to coaxial with the center of my workpiece, while the boring head is set to zero. And the cutter is set to be parallel with the x axis of the boring head. (nobody ever told me to do that)
Mine (Criterion) has a graduated dial in thousandths, so after a cleanup cut, I measure the hole just bored and that gives me a point to go forward. The present setting gives the number, say .021 that corresponds to the size just bored. If I need to go .020 more to finish the bore, then I know that I need to turn the head out another 20. I go in small steps to make sure it cuts cleanly and I don't overshoot and ruin my work. (never did anything that dumb!)