PDA

View Full Version : Boring Bars for a home shop?



dan s
02-14-2007, 08:23 PM
What types of boring bars are people using in home shops solid, brazed, insets? Currently Im using cheapo brazed carbide imports and hate them beyond belief. Im hoping to pick up some quality bars when I get my tax return. Most of the boring I do is to 3 in diameter, and up to 4 or 5 inches deep in aluminum and mild steel, though we all know needs change as soon as you buy tooling. With that in mind, what kind of bars would you recommend?


As an aside I have been looking at Everede bars, because I like the fact that they can use either hss, or carbide, and are re-grindable. The catalog says you can get alloy, carbide or heavy metal shanks. Anyone have an opinion on these bars?

chipmaker4130
02-14-2007, 08:26 PM
Hi Dan,
I really like the indexable carbide tooling. I also use an old Armstrong bar with a 3/16 hss bit on occasion. For the really small bores the indexable bars are harder to find and pretty pricey, as are the smaller inserts.

lane
02-14-2007, 08:38 PM
Everede are real nice bars wish i had some . The carbide or heavy metal would be nice. but for price i would be glad to just have some plane heat treated steel ones. they are good handy bars for general work.

BadDog
02-14-2007, 08:39 PM
I started with classic HSS boring bars. But didn't know what I was doing and had poor results. Best luck was with the cheap brazed on carbide boring bars, so I bought a "kit" of C2 and another of C6 from Enco on sale. Did passable well for quite a while. Problem was, I didn't even know what "good" looked like.

I continued to read more on HSS use, a bit more here, and some more there, and finally read some wonderful posts by Harold over on the Chaski site. FINALLY things started falling into place. Turned out I had known most of the bits for some time, just never put it all together and successfully applied it all together. I’ve since all but abandoned carbide for anything other than CI and cleaning up mill scale or rusty surfaces. Obviously it has other uses where it trumps HSS, but I have almost quite using the carbide I had collected in favor of some very nice HSS tooling I’ve been creating as needed.

This includes boring bars for ID threading, grooving, and of course, finish boring and chamfering. I’ve made several boring bar form tools from simple 3/8 and 1/4” blanks. I’ve also made some boring bars from broken HSS drill bits that are among my favorites. But my main favorites for all but the smallest holes (under 1/2”) have become the old classic broached boring bars that hold HSS bits with a set screw. The very boring bars I started with and set aside. I’ve got an inserted TPG 3/4 diameter solid carbide boring bar, a 1/2 TPG inserted Kennametal boring bar, and the 2 sets of brazed carbide boring bars that are ready to grab for things that really need them, but I find myself reaching for them less and less lately...

JCHannum
02-14-2007, 08:51 PM
I have managed to accumulate a pretty good assortment of Everede boring bars and inserts. They are about the best in my opinion. The size of the inserts makes grinding easy, and it is convenient to have different shapes for roughing, finishing, grooving or threading. Mine are plain alloy shanks, and are more than adequate for most purposes.

The cheap brazed carbide cutters, whether boring bars or plain lathe cutters, often are worse than nothing at all, and are a waste of money and time.

Tin Falcon
02-14-2007, 09:27 PM
"Most of the boring I do is to 3 in diameter, and up to 4 or 5 inches deep "
At home I use old fashioned steel boring bars with HHS cutters.Small boring bars can be made from drill rod. The thing to keep in mind here is how much boring bar is sticking out of the tool holder. IIRC steel should not stick out mor than 4x the diameter of the bar. in other words if you are using a 3/8 BB for a 1/2d hole the depth should not be more than 12/8 or 1-1/4 inch. A carbide bar the stick out is 7x the diameter. so the hole can be 21/8 or 2 -5/8 deep. A 1" steel bar will get you 4" deep. This is the rule of thumb we used in a shop I worked in. tool deflection can be effected by setup, material depth of cut, speed, feed ,etc
So for deep holes carbide bars are the way to go. the downside is they are expensive.
Regards
Tin

PaulT
02-14-2007, 09:56 PM
I like boring bars that use the CCMT inserts, this is the same widely available positive insert I use on my turning/facing tools so that way I don't have to stock a special insert for the boring bars. Its an 80 degree insert so the same tool can be used for turning and facing, which I also like a lot. The only bad rub is you only get 2 usable edges compared to 3 for a triangular insert, but for me its worth it and they are a little tougher than the triangular inserts.

Paul T.

fossil
02-14-2007, 11:43 PM
I agree with everything that Paul said. I recently purchsed 5 bars from a guy in Germany. The bars are fantastic, and I highly reccomend them.
He sells them on epay if anyones interested. I found them to be reasonably priced compared to the bars from Glanze. The quality is identical to Glanze.

http://cgi.ebay.com.au/Bohrstange-S-12-M-SCLC-R-06-Klemmdrehhalter-Drehmeissel_W0QQitemZ160085340589QQihZ006QQcategor yZ129222QQrdZ1QQcmdZViewItem

Mcgyver
02-15-2007, 12:08 AM
I've a bunch of bars that take in the inserts, but have where ever possible gotten away from them in favour in hss, preference being the old style that hold a square hss bit (or piece there of). I find unless they are new the inserts are liable to produce crappy finish and sorry, I'm not willing to spend $50 an evening as the price of admission (if you went around using the lathe and mil and changed carbide tooling every time the finish started to worsen). probably its that i buy i the cheap inserts, but my arm starts to get rigamortise as it reaches for the wallet for the brand name ones. as far as economics go, in the home shop you care about lowest overall cost not hourly rates and overhead so in that environment you can't be hss.

hss has the additional advantage of using less cutting force, a big advantage given the overhang there is with boring. might not matter on a 4" dia bore where there is room for a massive bar, but our diy stuff is usually smaller.

dan s
02-15-2007, 12:25 AM
I have managed to accumulate a pretty good assortment of Everede boring bars and inserts. They are about the best in my opinion.

JCHannum

Can you speak to the difference in cost between inserts and Everede? When I looked it seemed like the small inserts where ridiculously priced (pack of 10 costing as much as the bar; non EBay purchase of course).

dan s
02-15-2007, 12:29 AM
The thing to keep in mind here is how much boring bar is sticking out of the tool holder. IIRC steel should not stick out mor than 4x the diameter of the bar.

This is one of the reasons I hade the brazed carbide bars I have, the shank diameter is different from the neck (for lack of a better term), thus you cant easily adjust the amount bar sticking out.

lazlo
02-15-2007, 01:08 AM
Can you speak to the difference in cost between inserts and Everede?.

Yeah, that's the problem with the Everede bars -- those propriety triangular inserts are very expensive, and I've never seen them come up on Ebay (although the bars themselves are pretty common on Ebay).

matador
02-15-2007, 03:21 AM
I've just finished boring 1 1/2" holes in 2 blocks of cast iron.(model steam loco cylinders)I drilled out to 22mm,the biggest drill i've got.Then bored with 3/8"bar with brazed carbide bit.When the hole was big enough to take it,I used a 3/4 bar with coated carbide insert(160 308),a triangle shape.I tried an uncoated insert without radius ,but it was not suitable for this application,giving a very rough cut.
Finished off with a brake cylinder hone.
http://img.photobucket.com/albums/v401/bramleynz/cyls/cyl1.jpg

http://img.photobucket.com/albums/v401/bramleynz/cyls/cyl2.jpg

dan s
02-15-2007, 04:05 AM
Yeah, that's the problem with the Everede bars -- those propriety triangular inserts are very expensive, and I've never seen them come up on Ebay (although the bars themselves are pretty common on Ebay).

Lazlo,

Are you referring to the carbide Everede inserts? The HSS ones are cheap $3.44 for the largest (MSC). The most expensive carbide bit MSC carries is $28.76, and is designed for 5/8 to 1 bars. Thirty bucks definitely seems high, but then again I dont know how many times the bit can be re-sharpened.

Your Old Dog
02-15-2007, 07:14 AM
I'm using YSS type bars and they work great for my needs. I have about 6. These Yard Sale Specials , while harder to locate, are very inexpensive and work like the ones the big boys use!

Swarf&Sparks
02-15-2007, 08:24 AM
Haven't seen it on this thread, so I'll throw in my 2c worth.
Turn the bar upside down and bore at the back.

bob308
02-15-2007, 10:25 AM
make my own out of old inserts. just hit them with a hammer and silversoder it on a shank i made to fit the job.

SGW
02-15-2007, 10:37 AM
I've got some of these http://everede.net/Lathe_and_Boring_Bars.html (or possibly these http://everede.net/Jig_Boring_Bars.html ) and like them a lot.

JCHannum
02-15-2007, 12:19 PM
The inserts are relatively expensive when you buy them new. I rarely buy anything new. I have two prescription vials full uf inserts I have gleaned from auctions, the bars came from the same sources.

The inserts are usually too long, and will need to be cut down, yielding two or three inserts, each end can be ground, producing 4-6 cutters. Cutter life is comparable to any HSS cutter.

The inserts HSS inserts are $2.00-$3.00 each. Considering the use you can get out of them, that is not excessive.

motomoron
02-15-2007, 01:53 PM
The Arthur Warner Company, purveyors of some very nice indexable turning tool holders that use their HSS inserts also sell a boring bar that uses the same. After being so favorably impressed with the turning tools I bought at Vabin Fever the year prior, I picked up the boring bar this year. It's really nice and I recommend it wholeheartedly.

Forrest Addy
02-15-2007, 06:41 PM
I prefer HHS bars both factory for my Criterion heads and home-made for my lathe. Carbidee is fin if you can get the speed up to suit carbide's characteristics. I have several Kennametal factory bars both steel and solid carbide. There are no words to compare the stiffness and overhang to diameter of carbide Vs steel broing bars. One of these days I will make some HSS inserts for the solid carbide bars then I will be a happy camper.

When carbide is run at HSS speeds you get crumbling edges, poor finishes, shorter (usually) tool life than HSS, and other problems. Most of the time it's not worth messing with for small work unless you can ramp up the spindle speed to make it work right. Generally I push newbies to HSS tooling. Carbide is touchier stuff and the tricks you use to make HSS work right apply to carbide.

Tin Falcon
02-15-2007, 07:34 PM
Forrest :
your dream come true. these guys make HSS inserts in all kinds of sizes and shapes. So you should be able to buy inserts for your carbide bars. carbide bar with HHS insert what a combo. http://www.arwarnerco.com/
great company they sell at Cabin Expo here on the east coast. I have one of there boring bar sets.
Tin

dixdance
03-01-2007, 11:07 AM
For those that make their own boring bars, does it help use tool steel and harden it? Is hardened steel stiffer than unhardened? Clearly carbide is, but I've always wondered if hardness equates to stiffness, seems like they are 2 different qualities.

I have to do some internal threading in 1018, 1 7/8" - 6, 2.5" deep. In the past I've always felt my boring bar (3/4" steel broached bar) was flexing. Since this is a pretty big ID, thought I'd make up a heavier bar with a square shank to hold in an Aloris.

Richard

Your Old Dog
03-01-2007, 11:36 AM
I've got some of these http://everede.net/Lathe_and_Boring_Bars.html (or possibly these http://everede.net/Jig_Boring_Bars.html ) and like them a lot.

Actually, those are the Yard Sale Specials I was talking about. Gave $4.00 for 4 of them with inserts in them. Now that I know what they are I can order up some more inserts. :D

dan s
03-01-2007, 12:22 PM
For those that make their own boring bars, does it help use tool steel and harden it? Is hardened steel stiffer than unhardened? Clearly carbide is, but I've always wondered if hardness equates to stiffness, seems like they are 2 different qualities.


you could try making a homemade carbide bar if you have the tools to grind carbide, and do some brazing.

pcarpenter
03-01-2007, 01:56 PM
The modulus of elasticity is pretty much the same for steel, so hardening will not make it more rigid, which is the concern. Stepped bars are the way to make them more rigid and still use steel. You leave as much of the bar as thick as possible up to the portion that has to go into a smaller bore....something that you can do with a home-made bar. You also should "choke up" on it as far as is possible.

Carbide is not stiffer because it is harder. It just happens to be both.

Paul