Is there an appreciable difference in quality between the 2" import boring head typically available on eBay $60 "Buy It Now" auctions and the 2" import boring head set available from MSC for $160?
I'm guessing it depends where the head is imported from. The "buy it now" is Chinese the MSC import is unknown.
My applications are home hobby general purpose infrequent use.
Also what are the considerations in choosing between M-35 cobalt and C-6 carbide boring bar sets?
Thanks for the reply, I was beginning to think nobody here would have anything to do with one who espoused the use of "import" machine tools/accesories, I know it can be a hot button issue sometimes.
I'm a rookie machinist with an older Burke Millrite machine. I've had occassion to use a 2" import (taiwan manufacture) boring head on this machine and, as you say, it worked just fine. The only problem I encountered occured when I took too big of a bite on the material perhaps combined with feeding the spindle down to aggresively, resulting in a bent boring bar like it was just so much taffee. That the bar got bent was mostly my mistake but I'm not discounting the fact that an import boring bar set may be softer (a lot softer?) than higher quality domestic boring bars.
I no longer have access to this particular import head, but the action and accuracy on it seemed just fine to me, certainly for my purposes. In the meantime the need to replace this head has come to the fore front and I can't help but notice the considerable range in selection of boring head brands, sizes and types, both import and domestic. Attendant to the range of selection is a pretty considerable range in price. I can score a 2" import boring head set compete with boring bars and R8 mandrel on eBay for as little as $50 -$60 or I can go in to the catalogues and go as much as $600 for essentially the same set up.
Too many choices on the menu and I go hungry for lack of knowing what to order. (-8
So looking in the MSC catalogue I see APT, Accupro, and Criterion as domestic brands and then the import options. (Not 100% that Accupro isn't an import.)
One option is to get an import head then spend some extra money on domestic boring bars, but even with boring bars types/prices it's a multiple choice dilema. At least on this I can buy the boring bars one at a time as I need them and, by the time I buy them all, not really spend anymore than a complete set costs.
And as long as I'm wasting all this time on detail considerations, I'm wondering if the two inch head will do me or if I might not be better off with a 3 inch head for heavier jobs that might come up. APT has a 2-1/2 inch head for either 1/2" bars or 5/8" bars that looks like it might split the difference in capacity and price nicely.
Concurrent to researching the catalogue I'm tracking a dozen or so eBay auctions on various boring heads.
Long story short (too late for that) I was getting tired of trying to figure all the variables and when I came across a "Buy It Now" for a 3 inch Criterion complete with boring bar set and other accessories I decided the higher price was worth it to be done with this quest.
I hit the button.
Looking forward to the boring head arriving today.
Look on ebay for a used Criterion brand. $60.00 is
More like $100 for just the head. But as you say probably worth it.
I've used an import head and was satisfied with it. I guess what I was after finding out is while there are import heads that will work well enough for infrequent hobby use, are there also import heads that are total crap? I'm guessing there is, the problem is the import heads don't come with brand names so how does one tell one import brand from another in advance of the purchase? Probably the best you can do Is go by country of manufacture but that would hardly be an absolute indicator and again is not a published fact in advance of the purchase out of a catalogue or off of eBay.
As I indicated in my last post I got tired of trying to figure it out and dropped the bucks on an eBay auction for a 3" Criterion complete with boring bars and accesories. (Where IS that UPS truck!)
I bought a 2 inch criterion and I use it a fair amount and I really like it. Its very smooth and pretty easy to hit the target diameter. Based on that I decided that I HAD to have a 3 inch one. I don't think I have ever used it.
Remember that 2 inch heads use 1/2 inch bars and that 3 inch heads use
3/4 inch bars. I think that fact alone prevents you from using a 3 inch head for small holes because the 3/4 inch boring bar have big heads that will not fit inside a small hole.
Good job. I have an Enco and a Criterion. They look identical but they sure don't work indentically. The Enco is OK if accuracy doesn't matter. It is easy to adjust the Criterion to make a hole .001" larger. Not so with the Enco! After loosening just enough to adjust, it can move as much as .001 or .002 when tightening to make the cut. No problem with the Criterion.
Good point. It occured to me there could be a compromise in that a 3 inch head can do larger/heavier than a 2 inch trading the ability to do as small as a 2 inch. However, the particular Criterion I picked up on eBay came with all kinds of extra goodies including an adapter sleeve that steps the 3/4" tool holder bores down to 1/2" so that I can mount the smaller 1/2" boring bars (also included).
That and several other extras got the better of my impulse purchase inclinations so I went for this 3 inch head as much because this particular deal came up just when it did as for the added heavy duty capacity that I may or may not have a true need for.
It arrived this morning and looks like it will work out for me. That said I'm sure I would have done just fine with a 2 inch head. In the long run I can always put this 3 inch back up on eBay if it works out a 2 inch would better serve my needs.
I just went through a process of boring out 7 pulleys for a line shaft. The original diameter of the bores was 1 7/16" and they had to be bored out to 1 11/16". The depth of the holes varied from about 2 1/2" to 4 1/4". I found that 1/2" diameter boring bars just aren't stiff enough when sticking out much over 2 1/2". The tools seem to vibrate and cause a rough finish (using Bridgeports at a night school). I have an old vertical mill that has a B&S #9 spindle, so I can't easily get a
3/4" head, but I sure would if I could! On the subject of imported boring BARS: I bought a set of those 9 cheapies from Enco. They must be some sort of soft carbide becuase they dull very quickly. I can even sharpen them on an aluminum oxide wheel.
Note that there are some boring bars (for lathes) which have a solid carbide shank and accept carbide inserts. I use one on my lathe (a little over 1/2" diameter, with flats to make it 1/2" for the toolholder and to hold proper orientation), and those will extend an amazing distance before chatter becomes a problem. I think that I've run mine with a 6" extension. Solid carbide has a lot less flex than steel of equal diameter. (They are also *quite* expensive. I lucked onto mine on eBay a few years ago at a rather more reasonable price.)
Perhaps check whether a solid carbide boring bar (with insert) could be fit to the boring head.
Or -- you could set up your lathe for "line boring" (where the boring bar is supported between centers on a lathe, and the workpiece is mounted to the carriage (a bit tricky with those pulleys, I suspect).
Or -- you could mount the pulleys in a 4-jaw chuck and bore on the lathe, which is what I probably would do.
And the lathe (assuming one of reasonable size) could also use larger diameter boring bars, such as perhaps a 1" diameter one, which would be quite sufficient for the holes which you were starting with.
It sounds as though you wound up with brazed HSS instead.
What I did was take my solid carbide boring bar and stiffen the bar a bit. I had a T bar in long bar format just from the mill - 4-5 inches long. I was boring out a deep cylinder of iron and the scale within gave me to much chatter. I used super glue on the bar and T bar. It was placed just behind the head and on the back side (the side of the hole not cut). This stopped the vibration.
I got the idea from my hand. I could hold the bar and dampen the vibration. I knew not much was needed.
The depth was very long (deep) - more than it should have been with that size of bar.
I have longer bars and larger bars but they are HHS type so experimentation of a one of a kind wasn't for me.
PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.