X3 Specific tooling Q's

[Teyber12]

Originally Posted by project5k ok, this is gonna be bad, so go easy on me... i keep hearing the term boring bar, and boring head... can someone please explain to me exactly what this is, and how to use it? I'm guessing that its for "drilling" or boring a hole larger than you have drill bits for. so that would mean that it cuts the entire diameter of the hole or pocket. Ok so then am i to understand that a fly cutter dosent cut in the middle, and only cuts on the set outter perimeter? Pictures if at all possible, makes it much easer for me to understand

when my x3 was up and manual, the only thing i found the boring bar half useful was on plastic (polyethylene) and it scared me to try to use it on metal- i could see the column swaying back and forth maybe 1/4"

Sorry to thread jack- but on this topic... Where can i get a 90 degree boring bar? if you guys get what i mean, so if you want to have a round recessed hole say for a bearing, all my boring bars are angled...

cheers

[Teyber12]

Originally Posted by caleb105 Scott, Thanks for the info! Will this drill bit work then: http://www.use-enco.com/CGI/INSRIT?P...PARTPG=INLMK32 -Caleb105-

i hate to double post, im not sure how small of a radius most boring bars can do but you could theoretically just drill with an ordinary 1/2" then use the boring bar and just turn the screw on it to make it larger after each pass till your at the perfect length.

Hope you don't mind me asking- how much did a tap that big cost?

[caleb105]

Originally Posted by Teyber12 Hope you don't mind me asking- how much did a tap that big cost?

$63

-Caleb105-

[Kalvin]

Matt did yuo ever pick a boring head out? I'm in the market for one now......just curious how it worked out for you?

Kalvin

Originally Posted by Matt McColley Piggy back question.... I'm selecting a boring bar set for use with my X3 mill.... could someone please comment on the merits of a threaded boring head on an R8 shank as shown in this link.. https://www.grizzly.com/products/G9322 opposed to boring head with an integral shank as illustrated here.... https://www.grizzly.com/products/H5679 Obviously, you can switch heads on the first.... but just how large of a boring head can be used given the power and rigidity of the X3 mill. Do you lose anything in the way of precision with the threaded head set up. Also.... the diameter of the boring bars themselves is 1/2" on the first and 3/8" on the second. Is the X3 beefy enough to benefit form the rigidity of the 1/2" bars? Or are they just over kill. Thanks in advance... Matt

[Teyber12]

Originally Posted by Kalvin Matt did yuo ever pick a boring head out? I'm in the market for one now......just curious how it worked out for you? Kalvin

Hey there kalvin!
i got this one:
http://cgi.ebay.com/R8-Shank-3-Borin...QQcmdZViewItem
(i think)
and its too big for the x3. if i run it over very low rpm's i can see my column shaking around... however i needed to cut 2-3" holes. if you are not cutting over 2" holes i would recommend a 2" one for the x3.

Also, my biggest complaint with a boring bar is in the picture attached. it makes sense that all the tooling has that tip, (so it can cut lol), however i wish i had a flat boring bar (see right side), IMO it would make it a lot more useful. if you find this please lmk

cheers

[escott76]

Originally Posted by Teyber12 Hey there kalvin! i got this one: http://cgi.ebay.com/R8-Shank-3-Borin...QQcmdZViewItem (i think) and its too big for the x3. if i run it over very low rpm's i can see my column shaking around... however i needed to cut 2-3" holes. if you are not cutting over 2" holes i would recommend a 2" one for the x3. Also, my biggest complaint with a boring bar is in the picture attached. it makes sense that all the tooling has that tip, (so it can cut lol), however i wish i had a flat boring bar (see right side), IMO it would make it a lot more useful. if you find this please lmk cheers

There exist flat bottom boring bars, but you have to understand that for the intended application a tool that chatters horribly at the bottom of a hole (the one you have drawn with a YES) next to it is not a good idea. It's like a record, the outside spins faster than the inside. The tool you show rubs the whole way across, not a great idea.

[BobWarfield]

Hi Teyber.

You can purchase or grind boring bars like you show, but I'm not sure that's really what you should be using with that boring head. I assume you're trying to surface a flat bottom in your hole that way?

It's going to be really slow to work your way out from a tiny hole to 2 or 3" with a boring head. Interpolate the hole with an endmill and save the boring head only for when you need a lot of accuracy on the hole. Many holes won't need it at all, and in particular they won't need the bottom of hole cut accurately, just the sides.

Another thing is quality of boring bars. The ones that come with the heads usually stink. Boring bars are so finicky, a good one really makes a difference. You can purchase carbide inserted or brazed carbide. Either works, just consider finding a nicer one if you use the boring head a lot. There are plenty on eBay. If you see a Circle Boring Bar or a Micro100, those are two great brands that usually don't cost much.

RE your X3 moving around with that boring head, is that just when cutting? I'd have thought it was plenty rigid enough to take the weight swinging around. Make sure you don't run that boring head too fast in the spindle. For a 3" hole in aluminum--1000 rpm. Steel--half that or less.

Cheers,

BW

[ihavenofish]

Originally Posted by BobWarfield RE your X3 moving around with that boring head, is that just when cutting? I'd have thought it was plenty rigid enough to take the weight swinging around. Make sure you don't run that boring head too fast in the spindle. For a 3" hole in aluminum--1000 rpm. Steel--half that or less. Cheers, BW

if its wobbling just from spinning, i think the think needs to be balanced somehow. boring heads are not normally balancable are they since they arent meant to spin very fast?

[cadmonkey]

I used that same head for my X3 conversion and had no problems. When you calculate the RPM & feed based on generic SFM and chipload recommendations you don't run very fast once you get outside of the 1/2" or whatever diameter hole you start with.

I hardly use mine now that I am CNC'd and when I do it's the final pass on a hole that needs a close tolerance or consistent surface finish which boring heads do wonderfully. They're only meant to take a couple 1/1000ths off each adjustment so taking that final .001 in a bore is hardly any pressure and leaves a nice smooth finish especially when fed at a consistent speed in and out.

Greg

[Teyber12]

sorry not trying to thread jack- i mean just as a final pass use that flat thing. i don't have a lathe and often i find i need to have a flat "ridge" for another part to sit on, and with the boring bar labeled "1" it is not 90 degrees obviously which poses problems in some of my parts. I definately realize you would not want to remove a bulk of material this way

once my cnc is up i bet ill end up selling my boring bar.

cheers

[HimyKabibble]

Originally Posted by Teyber12 sorry not trying to thread jack- i mean just as a final pass use that flat thing. i don't have a lathe and often i find i need to have a flat "ridge" for another part to sit on, and with the boring bar labeled "1" it is not 90 degrees obviously which poses problems in some of my parts. I definately realize you would not want to remove a bulk of material this way once my cnc is up i bet ill end up selling my boring bar. cheers

If you use a boring head as it's intended to be used, you will end up with a flat bottomed bore regardless of the shape of the tool. It's only meant for taking a few thou on each pass, to do final sizing and finishing on holes. So, worst case you'll end up with a "shelf" on the bottom of the hole made up of very small concentric ridges, each no more than a few thou tall, and a few thou wide. If you're making a bearing recess, use CNC or a rotary table with an endmill to get the hole within perhaps 10 thou of final size, then the boring head to do the final sizing. You might end up with a small lip (if you don't go deep enough), or a small recess (if you go too deep) around the perimeter at the very bottom of the hole, but neither will matter since bearings always have bevelled or rounded corners on the outer races. In either case, the shape of the tool used in the boring head will have no significant effect on the shape of the hole you end out with.

If you're using a boring head to turn a 1/2" hole into a 3" hole, you're really not using it for what it was designed for.

Regards,
Ray L.

[escott76]

Originally Posted by Teyber12 sorry not trying to thread jack- i mean just as a final pass use that flat thing. i don't have a lathe and often i find i need to have a flat "ridge" for another part to sit on, and with the boring bar labeled "1" it is not 90 degrees obviously which poses problems in some of my parts. I definately realize you would not want to remove a bulk of material this way once my cnc is up i bet ill end up selling my boring bar. cheers

But the 90 degree bar will wind up chattering like crazy at the bottom and not doing what you want either. If it catches wrong you can wind up chewing up the bore as well.
Selling your boring bar after you finish your CNC conversion isn't a great idea either, as you still can get a more precise bore with the boring head than you will be able to get with CNC. If you want bearing journals to fit right, you'll want a boring head.
I run a Hurco VMC at work, ground screws and good servos. We still have a boring head for it. We don't have a whole lot of use for it, but when you need it, you need it.