Borite Carbide boring bars, are they any good?

[Ken from ontario]

I only have a single 1/2" boring bar from Mesa tool that has a flat edge on the shank ,I may occasionally need to bore smaller diameter than 1/2" so I found this set on ebay (1/2" shank on all 3):



the bars in this Borite set do not have that flat edge, I'm thinking if I mill the flat myself I could use them with my boring head.
I'm not sure about the quality though, are these any better than the cheap imports? will the round shank cause problems when tightening the setscrew in the boring head?
The price is $40 plus shipping, or I could make a lower offer, you comments and opinions are appreciated.

 

[mikey]

The cobalt bars will cut finer and finish better than the brazed carbide bars will. Remember that carbide needs speed to finish well and speed with a boring head leads to higher centripetal forces and greater vibration. You are better off with cobalt bars, in my opinion.

 

[Ken from ontario]

Thanks Mike.
The Boring bars sold by Mesa tool don't go any smaller than 1/2" unfortunately otherwise they would be my first choice, I totally forgot about the need for speed with cabide , thanks for bring that up, I 'll forget about that deal then.

 

[Chipper5783]

Those brazed carbide bars would work fine - in either a boring head on a mill or on the lathe in some sort of tool holder. You don't need the flat, that is simply a convenience (for repeatability and so the burr doesn't cause problems). Don't worry about that little flat.

You do need to be comfortable grinding the cutting edge, but that is no different than any brazed carbide tooling (I buy the cheapo ones, they require grinding right out of the package).

3 bars for $40. Price out the cheapo ones - you can probably get a set of 9 for that price.

The issue with running carbide at speed is really not a big deal - you do not have to run it fast. Of course it usually works better at the designed cutting speed, but that does not mean it won't work at lower speeds. I try to run carbide at about 3x the speed of high speed steel - but if the job won't allow it, don't sweat it.

 

[mikey]

Just like on a lathe, brazed carbide will work in a boring head but it will not finish nearly as well as HSS or cobalt, and there are times when a fine finish is important. I also find that cobalt bars are more accurate because they deflect less than carbide at the speeds a smaller mill typically runs at. Of course, this is a personal choice; I've run my own tests with inserted carbide, brazed carbide, cobalt and HSS bars in a boring head so my advice is biased by my results.

If I was going to run carbide tooling, I would use a DBL-style head and use a counterbalance so I could run at higher speeds.

 

[Ken from ontario]

The bottom line is ,that Borite brand doesn't seem to be anything special, I thought the name alone would justify the cost but as David says I can get a set of 9 for about the same price but they are of the cheaper quality, as far as Carbide vs HSS/Cobalt goes ,I don't have any extensive personal experience with either one to even have a preference but I do try to void the cheaper cutting tools in general, and have read often that Carbide needs higher speed than HSS /cobalt.

I thank you both for giving me different angles of choosing boring bars,obviously there's no " perfect material for cutting edge" you still sacrifice something to gain something. right now my main objective is to be able to bore holes(with my Criterion S-2" boring head) smaller than 1/2" in Aluminum and sometimes in mild steel, based on both your comment I figured A=the deal with that set I posted wasn't that hot . B=now that my quest continues,why not go for cobalt BBs of the opportunity presents itself although if I find a good quality set that happened to be Carbide, with round shanks, it's not the end of the world, I'll get it and deal with the quality of the cut later.

Edit, I just found out Borite sells both HSS and Carbide boring bars:
http://www.boritemanufacturing.com/hi-speed_tools
http://www.boritemanufacturing.com/our_products

 

[mcostello]

+1 for what Chipper said, My experience is the same.

 

[Ken from ontario]

I just ordered a new BORITE Cobalt boring bar, 1/2" (ROUND) shank 3.25" long, 3/8" minimum bore diameter, That's exactly what I was looking for, and we'll see how it performs.
Thank you all for your comments.
BTW, The Carbide of the same tool was only $10 cheaper, for my peace of mind and hobby use the one I bought seemed the most logical choice, and I got the round shank knowing now that it won't matter if it didn't have a flat edge, I'll take care of that if I need to.

 

[mikey]

Borite makes the best solid cobalt bars, in my opinion. It takes just a few seconds to sharpen them and they hold an edge well. However, there are cheaper sets - here is an M42 8% cobalt set for less than $30.00 but I can't attest to the quality: http://www.carbideanddiamondtooling.com/BoringHeadBoringBarsCobaltCarbideTipped

The best solid carbide boring bars I've used come from Micro 100. Many of them have a flat on the shank, which makes orienting them properly a snap. They sharpen easily with a diamond stone and, unlike cheap bars, don't break or distort when I drop them on the floor of my shop. They are expensive and I only use them for boring high carbon steels or stainless but they cut like a cobalt bar at speeds I can achieve, and they can go deeper than a steel bar can.

Ken, whichever bar you choose to use, be sure the bar is oriented correctly in the head. The flat on top of the tip of the cutter must align with the axis of the boring head's lead screw so that the depth of cut you dial in is accurate. The flat sides of an S-type head makes this easy to do.
http://www.carbideanddiamondtooling.com/BoringHeadBoringBarsCobaltCarbideTipped

 

[Doubleeboy]

I have used my Borite brand carbide insert type boring bars at very slow speed, get excellent results, every bit as good as the work I can do with finely honed HSS. I have a wide variety of boring bars for inserts, the carbide shafted ones from Circle are my best but a set of 5 of em from tiny on up will cost you north of $500. If I needed one small bar to do a variety of jobs within its limits I would do as Mikey and use Micro 100. I have half dozen little ity bity ones that I have made holders for to do < .300" bores. They are the cats pajamas. Like most everything Micro sells they are not cheap but I love them for real tiny work. For larger work I like inserts. Speaking of carbide and Micro, their brazed carbide lathe tools will make you forget the sad experiences you might have had with Chinese brazed carbide tools, very sharp right out of box, sharpened with plenty of relief and can handle interrupted cuts with out fracturing. Like all carbide I have dealt with though you need to decide if you are going to cut dry, use mist or flood, intermittent dribbling of oil or coolant is an invitation to cracking.