Help Me Understand my Boring Head Arbor

[SteveHGraham]

You made me nervous. I went out and looked at it. I'm going to replace "absolutely" with "I do not know."

I saw stainless arbors for these things, and the arbor and head I have are absolutely free of even the slightest trace of rust, even though they were clearly not stored carefully. They also have that funny color stainless has. But a magnet will stick to them.

[BadDog]

Austenitic (300 series) stainless is only slightly magnetic. But martensitic and ferritic (400 series) is magnetic. I think I got that right...

[spro]

A shorter drawbar is no problem. I thought there was enough metal at the head, to turn the R-8 taper. The close fitting sleeve really does orient the pressure directly centered to the taper but there would be little torque on the sleeve itself. If the head is apart and clamped by accurate chucking with the center tail register in line, it would be the same as it was. The sleeve and taper turned in place. I must have missed something.

[spro]

I missed some things and now there is possibility the old arbor isn't true. I back out of this ..

[SteveHGraham]

I don't know what to make of this crazy thing.

Today I tried again to indicate it in the 4-jaw. I used aluminum shims in order to avoid giving Harold the satisfaction of boring out soft jaws. I was able to get the far end of the arbor (upper end when in the mill) dialed in, and I was able to get the flange on the arbor (up against the boring head) dialed in, but not both at once.

I put the boring head in a collet and put it in the mill. I checked it with a dial indicator. The flange on the arbor isn't even nearly true. It runs out several thousandths. The tapered bit at the bottom of the arbor isn't all that great, either.

I just assumed that a respected company like Flynn would fix it so the body of the boring head, the flange on the arbor, and the taper would all be within tenths of concentric. Doesn't look that way! I was trying to do better work than they did, and I didn't know it.

I think the best thing to do is to chuck the body of the boring head as well as I can and turn the arbor concentric with it. I know it doesn't matter if a boring head is concentric with its arbor, but it seems sloppy to let them remain out of sync.

At least now I know I'm not the problem. Not all of it!

[GlennW]

Why are you so sure that it is a Flynn arbor and not something made by some home shop dude?

Even if it is a Flynn arbor, there is no guarantee that whoever turned it down even bothered to indicate it in prior to doing so.

[SteveHGraham]

I didn't say I was sure who made it. It looks like the arbors on other Flynn boring heads I've seen.

It's probably not from a home shop, because the seller specializes in industrial merchandise. Whether people who work in professional shops take the time to make their own arbors is a question I can't answer. It seems like a dumb idea, but then Flynn arbors do cost a lot. The flange looks like the flanges on other Flynn arbors I've seen. Same big chamfer.

[Harold_V]

I don't know what to make of this crazy thing.

Today I tried again to indicate it in the 4-jaw. I used aluminum shims in order to avoid giving Harold the satisfaction of boring out soft jaws. I was able to get the far end of the arbor (upper end when in the mill) dialed in, and I was able to get the flange on the arbor (up against the boring head) dialed in, but not both at once.

That's your reward for ignoring my advice!

H

[SteveHGraham]

Wow, that is harsh and judgmental. I need a safe space.

[BadDog]

[ctwo]

Steve, you should be able to dial in the near and far ends of a banana. I think you're doing it wrong.

Dial in the close end by adjusting the jaws, then dial in the far end by knocking it into submission. Then repeat that a couple more times. Unless it's not round I can't see why you can't dial in two diameters on the arbor.

Maybe you should rather dial in the diameter of the boring head, and then dial in the "face" of it by knocking the high side toward the chuck. Abom79 has shown this many times, and there is another guy (poulololio something...) that has a good technique too, which I will not try to explain...

You need to get your youtube channel rolling. I bet your live commentary would be a hoot!

[SteveHGraham]

I like the way you used both blue and pink, to avoid imposing a gender role on me.