2" or 3" Boring Head?

[BCRider]

On doing deeper in suitable size bores with a 2" head....

I can't recall where I've seen it some years back but it was a bigger diameter and size boring bar with two 1/2 or 12mm stubs that fit into both of the holes in the end of the head for greater stiffness. This could be the "in between" solution for those of us with 2" boring heads to reach out further. With some extra care of course. The support from the double stub idea would help but only go so far.

[The Metal Butcher]

On doing deeper in suitable size bores with a 2" head....

I can't recall where I've seen it some years back but it was a bigger diameter and size boring bar with two 1/2 or 12mm stubs that fit into both of the holes in the end of the head for greater stiffness. This could be the "in between" solution for those of us with 2" boring heads to reach out further. With some extra care of course. The support from the double stub idea would help but only go so far.

I remembered that post too. I searched and found it.

One by mattthegamer463 and one by wbc .

2" boring head attachment for those tough bores.



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Another HD boring bar insert holder

Similar boring bar idea as #3581, but these two are NOT adjustable for different boring bar spacings...alas.
Fixed tig'ed posts, and TCMT inserted in some scrap metal.

I will once again reiterate my point of searching for boring bars which stick out past the edge of the boring head for larger bores. This would allow one to use a 2" bar on a 5" bore instead of a 5" bar. Tremendous difference on a 1/2" head.

I would have used a 1" or 1.5" length bar and let the boring head and the spindle nose go down into the bore, but I needed a bar which stuck out past the edge or the boring head. Most don't. I found a HSS bar which did by like 20 thou and took it slow. Make sure you get bars which extend past the edge of the boring head. There is a fella in the shop made tools thread that made a workaround for this.

[Tundra Twin Track]

Well we have a 3" now. I'll let you know which one I use most, but I'd be willing to wager the 2" won't see the light of day much any more.

I looked for a Narex or Waulihopter in my price range to replace my 2" boring head,but there very pricey.I found this US made 4" Flynn which is similar to the common boring heads,it's well built and this one was handled pretty rough but all important parts are good condition.

[BCRider]

Thanks TMB, that's the ones.

Now imagine the one with the short central post but with that post longer and made from 3/4 to 1" bar with an insert on the end.... I'm thinking we could get away with maybe a 5 or 6" long bar? Some care would be needed to avoid chatter on the lighter 2" head.

But for that once in a decade job it might save the day where we'd need to actually buy a 3" head otherwise.

[The Metal Butcher]

TTT, that looks like a super nice head for larger work. I quite like the square bar. I'm sure we'd all love to have Wohlhaupter or D'Andrea head but the vast majority of this forum probably doesn't need that level of precision. 2" Asian boring heads should work fine for most little work, and something like your Flynn would be excellent for the bigger stuff. Even if one of the aforementioned fell into my lap I'd probably sell it and buy other tooling. Hard to say.

When I tried a 6"x1/2" bar it wasn't having it. I'm not sure our spindle bearings are the tightest though, our mill has a ton of hours. Maybe? is my best guess on those lengths.

[BCRider]

I was wondering about the large overhang with a longer boring bar. Sounds like you found the limit for that machine.

[Tundra Twin Track]

TTT, that looks like a super nice head for larger work. I quite like the square bar. I'm sure we'd all love to have Wohlhaupter or D'Andrea head but the vast majority of this forum probably doesn't need that level of precision. 2" Asian boring heads should work fine for most little work, and something like your Flynn would be excellent for the bigger stuff. Even if one of the aforementioned fell into my lap I'd probably sell it and buy other tooling. Hard to say.

When I tried a 6"x1/2" bar it wasn't having it. I'm not sure our spindle bearings are the tightest though, our mill has a ton of hours. Maybe? is my best guess on those lengths.

I'm pretty happy with it,was boring 10-3/4" holes in 3/8" plate with bar in pic,I have 3/4" round Endmill with Carbide insert for smaller holes.

[754]

How many of us have boring heads that feed? I got one but it's a 4 inch I think and I did not make a shank for R8, and its a bit big for that. I had a good 3 inch, but I have not seen it for some time. When I get my mill running soon, I may have to get the feeder 4 inch working if I can't find the other.

[JCByrd24]

The adapters pictured above by metal butcher are similar to what I linked earlier from mesatools. Very reasonable prices even for us hobbiests and made here in the US I believe.

[Mike Burch]

Tungsten Dipper, https://www.aliexpress.com/item/32767540280.html?spm=a2g0s.9042311.0.0.662b4c4dYRc C6V is the link to the VFD. If you buy from this seller, the instruction manual comes only in Chinese, but another seller has it on his website in English. If you strike a problem, let me know and I will scan and email you the English version. I have fitted a three-phase motor to the mill, largely because it is several tens of dB quieter and vastly smoother than the crap single-phase that came with it (which was itself a replacement, I think). My shop has only a single-phase supply, hence the 1-to-3-phase VFD.

CCW Ken, yes, the Rong Fu can be run backwards (just press the button on the VFD), but I would not want to risk the head's unscrewing itself from the arbor.

Later: OK, I've now had a play, and I'm very happy with the head and arbor. I set myself the task of boring out a 10mm hole through a 20mm scrap of mild steel to 15.94mm to fit a bit of nominal 16mm stainless rod. It came out dead nuts on.

My doubts about the longevity of the Chinese brazed carbide bars were justified—the damn thing chipped after barely five minutes.

The inevitable imbalance in such a tool did cause the light little Rong Fu to shake about a bit, but not enough to cause problems.

Oh, and I was slightly wrong about the centre screw on the gib. It actually bears on a steel ball which in turn bears on the dovetail on the slide.

Later still: The good news about the chipped cheap carbide is that it sharpened up again in seconds, using the white wheel intended for HSS. So I guess it's both fragile and soft!

[thaiguzzi]

2 or 3"?
Howzabout in the middle.
A 2 and a 1/2" Jones and Shipman, used for decades on my Beaver (bigger than a B/Port) and the last decade on my 6x28" Tom Senior M1.

[Doozer]

The contraption on the right, the bare steel colored one...
What is the advantage with this thing, over a regular boring bar???

[BCRider]

Doozer, in this particular case there is none that I can see. I assume it was done for a specific reason we don't know about. Or perhaps as a proof of concept.

It does show one possible way of making up a dual pin larger and heavier duty boring bar though.