Gents,

I'm looking for some feedback. I'm looking for the best boring bar for roughing and finishing aluminum. The minimum bore is @ .875 and goes up to @ 4". I will need to rough as aggressive as possible and then get the best finish possible. Can I do this with the same insert or will I need two seperate bars ideally?

No trick contouring required, just some flat bottoms.

Is there a big difference in performance between the different bar manufactures or are they pretty much the same if I go with a solid carbide bar? What about the hybrid carbon/hss bars?

Any particular insert profile to narrow in on?

DCMT inserts are pretty good as a compromise for roughing and finishing. Use a bar with a 95º entering angle, they break chips good at higher feeds and leave a nice finish too.

DCGX is the aluminium specific insert in that geometry.

Carbide bars are a waste of money unless you need to go deeper than 4xD.

Gregor

I've been running some ccgp21.51 inserts that I got from curtis(exkenna) and I have been very happy with these inserts for finish and longevity. They were also crazy cheap.

I run them in carbide boring bars from frank mari, an excellent value if you don't need through tool coolant.

The serious production guys here talk about pcd inserts and they sound great, but they never made much sense for me as I am primarily a hobbyist and can run one edge all weekend and maintain tolerance and finish with zero stress.

Nat,
Here's a pic of those inserts Wren is using.
It's funny that this came up. I was going to run a boring bar promo in April for a 3/4" bar and 10 inserts for aluminum for $109.

This insert rocks. It's waaaay upsharp and polished and bumpy. All the things you want in an insert for Al.
Sorry for the big images. Photobucket has decided to screw up their image re-sizing feature.

Thanks guys, all great info.

exkenna, I've been wanting to try some of your stuff, maybe this would be a good time to get some end mills too. Do any of your boring bars have coolant through?

When we go coolant-thru the prices go up and my vendor choices narrow but I can get you a 3/4" steel coolant thru for that insert in the picture for about $100.
USA made. A nice tool.

Who makes those inserts?

I can't even find a CCGP. They look a lot like some CCGT inserts I've seen in the Iscar AS and Kennametal HP lines.

Just curious...

BW

Pssst,,,

Arno-Rouse

Quick Vic

Psst, Arno makes little if any of their own product. It's re-branded from Cere-Tizit's private label line. They'll deny it till doomsday.

Those are CCGT 32.51 in my pic. I think Wren bought the CCGT21.51's

I know they used a g for tolerance, but for some reason I thought they had a P for the upsharp edge. They are in Tuscaloosa and I am in Huntsville though so I'm not looking at them.

I also got some ccmt21.51 for steel from exkenna at the same time that have been performing extremely well in 4140(Rc~30). At his prices, go ahead and get a box of those too.

Oh good, I hadn't lost my mind. Exkenna, how does one go about ordering them?

Best,

BW

Indeed, those would look dandy on a couple of the bars in my toolbox.

Whatcha got in a CNGP geometry (43 series)?

Coolhand: Here's the CNGG, virtually the same.
Sorry for the giant pic, Photobucket's resizing feature is busted right now.



You guys are welcome to call anytime. I work with a lot of forum people at night and on weekends so that doesn't bother me. 256-658-7623
Or email works: tooling64@gmail.com
Curtis

I popped for a 1" bar and some of these horny looking inserts for a production run in A356. Which is about all I ever turn.:rolleyes:

The bore has always been a bitch to keep in tolerance.

Tonight I lopped the bar in half and put her in the machine. It always makes me feel funny taking a new boring bar over to the saw and having my way with it.

So far the bore has been very stable and the finish is sweet.

Very nice indeed.

Oh, and it runs much quieter.


Now to get some turning tools for this style insert.

I've been using that type of really sharp insert in plastics too and it does quite well in many of them.

I actually got a lot of stainless work done with a sharp insert like that a few years ago doing bores about .75" diameter. It pulled the chip out of the hole and cut better than normal inserts. I'm not sure if it had a different coating, it had the same deep dish shape and sharp edge, but wasn't quite as shiny. I was surprised it worked in SS, all said it couldn't, maybe I got lucky.

i'll second the cnmp....style works great , 2x the indexes , very little chatter with pos/neg
inserts.