boring bar

S

skeetlee

Active member
Fellas
what type of boring bar would be best used to pre bore a chamber before using a reamer? I am looking to buy a new boring bar so i need some suggestions? Should i use a solid carbide tool? I have a little Arther r warner HSS incert borong bar and it seems to work just fine. The only reason i ask about any of this is that i was told that i need a carbide one piece tool for best results. This particular fella claims my steel bar from Arthur r warner isnt strong or stiff enough. Can anyone share some insite on all this please. thanks Lee
 
not all but most boring bars are too big....
i use a small hole carbide boring tool...all one pc....has about 2" depth and less than .2 width if i remember correctly.....circle mfg.....

mike in co
 
Lee:
try the solid Carbide from the firm of OSG tap &Die, Glendale Heights, Ill I don't have a number.
 
I haven't been able to get the Circle Manufacturing "F" series boring bars for quite some time. Their phone number on the packaging is no longer a working number. That said, I've tried the replacement boring bar made by Hertel and by Kinnametal. I've had trouble with the Hertel boring bar breaking inserts. And at $13 per insert, that adds up fast. The Kinnametal bar doesn't seem to have that problem so far. The solid carbide boring bar would be better, but the HSS boring bar will work. The carbide boring bar is 4 times as stiff as the same diameter HSS. But, that also comes at a price. The Kinnametal 1/4" diameter boring bar is $92.81 from MSC. The same thing in carbide is $285.36. I used to buy the Circle Manufacturing boring bars with 10 inserts when they would go on sale at about the same price as buying the bar by itself now.
 
Is there an issue cutting in reverse with a chuck that is threaded on the spindle, or is yours camlock? Also, is the issue of bar stiffness really all that critical when pre-boring a short chamber?
 
Those are almost the exact one's that I have been using Lee. I would like to get one that is a .320x 1.250. It would be a little shorter and stiffer than the one I am using now.

I predrill with a solid carbide stub drill that is slightly smaller than shoulder diameter on a PPC case and then bore at a slight taper to match the case angle with very light cuts. I bore it so the case goes in the hole a bit less than half way.

This leaves enough material to cut out and clean up the hole. I then check the runout of the bored hole before starting with the reamer. If there is an unacceptable amount of runout, you can rebore a small amount and keep the hole very straight. This will let the reamer follow a very straight path and cut a nice chamber. Yes, this takes more time than some of the other ways, but with the equipment I have you can't push things to hard. Besides, I am more worried about results than getting done quicker.

Hope this helps

Joe Hynes
 
liljoe is right on. I would find a right hand unit. To easy to have a brain fart and ouch a barrel when you are going backwards.
 
Maybe I am wrong but by having the tool on the far side of the chamber cutting in reverse spinal direction wouldn't it be easier to see what's going on?
 
Do a search on the micro 100 series in a major tool catalog....they make a smaller longer ..i think....
Small cuts are your friend......
 
skeetlee said:
Maybe I am wrong but by having the tool on the far side of the chamber cutting in reverse spinal direction wouldn't it be easier to see what's going on?
Click to expand...

Greg, you are now an official lathe operator so it is time you grind yourself a HSS or HSSCo tool. You are only going to cut a few thousants anyway and for about 1/2" or so.

Grind one from 1/4 x 1/4 like the one in the foreground.


 
Lee,

I took Mike Bryant's advice and got a Circle C carbide bar and inserts when they were on sale-----and couldn't be happier with the results.

The increased rigidity of the bar has allowed much smoother holes to be bored----as compared to other bars I tried.

Don't know why other solid carbide bars wouldn't work as well.

A. Weldy
 
Skeet, I'm in construction. My rule is NEVER cheap out where needed (Honda, Stihl, DeWalt etc) but also NEVER spend money unnecessarily. I'm completely with Sharrett, make one from a hunka' HSS/HSSCo

That said, I use this setup now. http://www.grizzly.com/products/Boring-Bar-Holder-Series-200/G5701

I've got 5-6 of them set up for different situations and have bored some long chambers with them. I did 5 338 Lapuas last year. I generally bore "inside out" because for me it's wicked easy to run in dead, check my offsets by hand, turn on the lathe and advance the bit until I hear it engage and flip the feed lever feeding OUT of the hole. I can't understand why anyone would bore inward, maybe someone can tell me :)

I've bored outward front-side and rear-side, don't have a preference as far as cutting except that I normally use the front side from habit because it comes in wicked handy for cutting internal threads (say threading a muzzle brake) and in my brain it "should" be smoother just because it's loading instead of unloading the spindle bearings. (This may well be flawed thinking but for heavy cutting with MY lathe loading the bearing seems smoother cutting)

Boring a chamber is of course far from heavy cutting :)

I use a 2.00 inspection mirror made by Chinese slaves to set my cutting angles inside the bore.

I've got a half-dozen bars, three Aloris style holders and prolly 30 bits made up (including three ground from square stock and one large one from rectangular scrap) and my total investment is under 150.00

My bored holes look like mirrors.

One thing, DON"T TOUCH THE BEAUTIFUL WAD OF STEEL WOOL SWARF!!!!!! The stuff that comes out of the hole is fascinating, like a green mamba, it'll WRECK YOU!!! My buddy out here nearly bled out dead from flicking boring swarf, he just idly plucked at it cuz it was kinda' loading up on the boring bar......

God Give Ya Two Eyes and Ten Fingers......

preach OFF

al
 
Jerry should like a close up of the grind. When I click on the picture to enlarge it, it gets smaller?

J.Louis
 
I misdoubt that's his boring grind Louis, I think he's just pointing out the stock to use. At least it shore don't look like any of my boring bits!!

al
 
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