Any recommendations for boring bar sets?

ScrapMetal

ScrapMetal

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I'm trying to get tooled up for using my Wells-Index 860 mill and I've already gotten a couple of boring heads. Now I need to purchase some boring bars for them.

Both heads can take 3/4" shank bars so that narrows it down a bit. Where I run in to trouble is the choice between HSS/Cobalt and carbide cutting tips. I've also seen the indexable insert types but I'm not real comfortable going that route as of yet.

The top speed of the W-I is about 4000rpm. I plan on milling a wide variety of metals. I've already done some small aluminum parts, the next project is in brass and after that I have some 4140 steel to mangle.

I know that there is seldom a "perfect" answer that will take care of all it's needs but to start I'm trying to determine which would cover the most ground or be most useful at this point. I'd also like to hear which brands you prefer to work with as the quality, I'm sure, varies as much as the prices.

Thanks guys,

-Ron
 
I use both, The brazed carbide are cheap but I like the HSS/Cobalt. There easier to sharpen or grind special profiles on than the carbide at least for me. In time you will end up with all types.
 
Thanks for trying to help guys even though, as usual :rolleyes:, I don't think I made myself very clear. I'm going to try and blame it on the late nights and lack of sleep as opposed to the lack of grey matter. :eek:

Here are the two boring heads that I need to outfit with bars -

germanbore01.JPG

wohlhaupter02.JPG

Now, what I am trying to figure out is, at the speeds that my mill is capable of is it even feasible to use the carbide tipped boring bars or am I better off staying with the HSS/Cobalt that I understand? The reason for my confusion is that will many of the older lathes that we have it's said that carbide doesn't generally work to well due to the slower speeds of the lathes. Granted, we are talking about mills now but I would think that the same premise may apply. So, at what point/rpm/metals can "carbide" be used with the same results, or better, than HSS/Cobalt?

Once that is "settled" I am curious as to which brands you have had good experiences with and which are the "crap" that should be avoided.

To those that posted "where" to buy, curse you all! :biggrin: You caused me to realize that I now have active accounts at every supplier mentioned as well as some others. It's like a bunch of crack dealers saying, "Here you go, go there to get some more!" Just be happy I'm shielding all of you "enablers" from my wife's wrath.

Thanks guys,

-Ron
 
The carbide vs. HSS decision is not always just about speed. In my case, I decide primarily based on what material I will be cutting. Of course, the fact that I have machines that can use either helps, but in your milling machine tool-up, you don't have to worry about the speed issue either. it's a totally different situation from a benchtop lathe, for instance. If you never plan on boring anything but mild steel and plastic, then HSS will serve nicely. Materials that are harder, and/or more abrasive will require carbide to cut at all in some cases. Even in softer metals, the higher speed allowed by the use of carbide will yield better finishes in some cases, more productivity, more consistency, less frequent sharpening jobs, etc.

All in all, I'd just get the brazed carbide tipped set, and make some that will hold square hss tools that you grind. If I'm not mistaken, that head will also face and groove, so that changes the tooling requirements if you intend to use it to its full. You can cut internal snap ring grooves with it. Not that you can't use a carbide, inserted groove tool, but likely it isn't justifiable for the home shop. For the occasional groove, or facing cut, a hand ground hss tool bit will work just fine.


edit: actually, looking at the pics, you have some bars already for holding square tool steel, so unless they won't do the job for you, skip it. Or not......buy the carbide, you can cut more varied materials.
 
Thanks Tony, that was very useful. I'll get some HSS bars but I'll also get a number of the carbide ones as well. That's an easy one as the carbides seem much less expensive on top of it. You mentioned the bars that came with the Wohlhaupter, the longer ones are in pretty good shape, medium a little beat up, and the shortest has a big chunk cracked off the end - someone did something "bad" with it. That's unfortunate as I can see getting the most use out of the shorter bar but I don't think it will be difficult to replace it.

I do plan to use that head for facing and grooving operations and as you said, I have the stuff to do it with. The reason I'm looking for some bars is I figure I'll need them to make smaller holes than I'm able to do with the included bars. On my present project I'm boring hole that are only 1/2" diameter, the 3/4" bars might just hamper things a bit. :)

I do have to ask a follow-up question though - Why is it that the carbide cutting tools are less of an issue on the mill than they are with the lathe? Is the cutting fps that much different due to the type of cutter or what? I would think that in the case of end mills with both machines having a similar rpm the end mill cutting edge would actually "see" a slower fps than a lathe tool as long as the piece being turned on the lathe had a larger diameter than the end mill. What am I missing here?

Thanks much,

-Ron
 
Well, that's where you get people thinking about differences. It's probably best to think in terms of surface speed. I know it makes you do some calculations at first, but you get used to it and it's no biggie. As far as the difference, a 1" diameter shaft spinning at XX RPM will have the same surface speed as a 1" end mill, or in a boring situation a 1" hole would require the same rpm to achieve the same surface speed. Using the 1" as an example, of course, it is π in circumference, and at (let's keep this simple) 100 RPM is running ~ 314 inches per minute, so you divide by 12 to get FPM, the common unit of measure. That's ~26 FPM, on a shaft in a lathe, running an end mill, or in boring a hole....same thing. If you know what speed you want to run, just calculate all that backwards to get the target RPM you need. It's generally not too fussy. Given the same RPM, the surface speed increases with the diameter.

With milling, you're less likely to have a situation where there is too much overhang of the work, or lack of support for the tool. In most cases that translates to an ability to run a heavier chipload. Chipload is another set of calculations based upon RPM and number of edges (single edge insert, 2, 3, 4 flute end mile, etc.) So you can push it harder, and that is also an advantage, most of the time, to carbide. Higher speed means higher temperature that the carbide can handle, higher temperature at the cutting edge itself makes the material softer and easier to cut. That's one reason carbide can be pushed so much faster than HSS. HSS will soften itself at temperatures that carbide can handle.

More material to confuse the issues..............
 
Ron,
Just a thought from the peanut gallery here. I can't really recoment a good boring set, but I can tell you to avoid the brazed sets like the plague. Once the edge chips, its a throw away after that. Indexable with HSS inserts would be a good idea to start with, and move to carbide later when you have done a few holes and aren't chipping the tools. I know I'm kind of late weighing in on this, but I just couldn't not say this to help keep youre expenses low while you learn. Bill Gruby does a ton of boring on the P&W he is building so you might ask him whats best too.
Bob
 
"I do have to ask a follow-up question though - Why is it that the carbide cutting tools are less of an issue on the mill than they are with the lathe? Is the cutting fps that much different due to the type of cutter or what? I would think that in the case of end mills with both machines having a similar rpm the end mill cutting edge would actually "see" a slower fps than a lathe tool as long as the piece being turned on the lathe had a larger diameter than the end mill. What am I missing here?"



One thing, the bearings in a lathe are generally heavier, than a mill, quill. You have more surface area in contact, with the boring bar, using a lathe. Then again, this may be of zero use to you.

Nowadays, I just eyeball a workpiece, and know what speed, and feed; to use. :lmao:

It'll come to you. Keep your chin up.
 
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