Seeking boring bar recommendation

spencer313 said:
I am looking for a boring bar recommendation. The application is preboring a barrel prior to chambering; in particular for 223 REM, for starters. One I am considering is this one from MariTool:

http://www.maritool.com/Indexable-T...G-BAR-.250-Dia-Coolant-Thru/product_info.html

SOLID CARBIDE BORING BAR .250 Dia Coolant Thru [E04-SCLCR2]

My lathe is a Haas TL-1.

I am eager to hear your recommendations.

Thanks!
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Should work just fine.

Probably even a little over-kill for rough chamber pre-boring, coolant flush, and carbide.

I actually prefer to use an indexable plain steel 3/8x 1/2 inch diameter x 4 inch long, with the 3/8 diameter turned down to .320" for maximum stiffness, still capable of boring a .350" diameter............Don
 
I've been using small, solid carbide bars from Micro 100 & Circle - they both offer them in a range of sizes suitable for a variety of chambers. These are somewhat fragile bars - if you run one of them into the end of the chamber, they'll usually snap into pieces. That's not necessarily a bad thing - I've broken two of them in the last few years, and it didn't knock the setup out of kilter either time.

Depending on the size, they usually run from $22 to $28 in Enco or KBC sale fliers.
 
Holding on to it will be the fun part. Beware using a set screw setup on carbide that small, or any carbide actually. I find those 10-1 overhang claims a bit far fetched, especially any indexable bar that only cost 90 bucks.

Good luck
 
spencer313 said:
I am looking for a boring bar recommendation. The application is preboring a barrel prior to chambering; in particular for 223 REM, for starters. One I am considering is this one from MariTool:

http://www.maritool.com/Indexable-T...G-BAR-.250-Dia-Coolant-Thru/product_info.html

SOLID CARBIDE BORING BAR .250 Dia Coolant Thru [E04-SCLCR2]

My lathe is a Haas TL-1.

I am eager to hear your recommendations.

Thanks!
Click to expand...
Spencer, in the example you give and since you are using CNC I suggest for the 223 Remington chamber drilling with a R (0,339") drill as first choice or an 11/31" (0.3437") as a second choice.

With the diameter to overhang ratio, you are not going to be able to take over about 0.002"/side/cut. As to the boring bar you reference, it is gross overkill, in expense and practicality. Get something like http://www1.mscdirect.com/CGI/NNSRIT?PMPXNO=9158356&PMT4NO=75169310. Note that this bar is for a max depth of 1.10". You will find that in your example, you will not be able to bore all the way to the chamber neck/shoulder intersection. Chip removal will prohibit going the full 1.43" depth.

For a pre drill and pre bore operation on most chambers, about 3/4" to 1" is sufficient to guide the reamer. Do the math on a particular chamber and pre drill and pre bore to where the bored hole will support that starting part of the reamer while allowing the reamer pilot to enter the existing barrel bore. This supports the reamer in two places and still keeps the reamer centerline on the centerline of the chamber neck.
 
Jerry,

A belated thank you for the excellent information.

S
 
flatlander said:
I've been using small, solid carbide bars from Micro 100 & Circle - they both offer them in a range of sizes suitable for a variety of chambers. These are somewhat fragile bars - if you run one of them into the end of the chamber, they'll usually snap into pieces. That's not necessarily a bad thing - I've broken two of them in the last few years, and it didn't knock the setup out of kilter either time.

Depending on the size, they usually run from $22 to $28 in Enco or KBC sale fliers.
Click to expand...


i'll second the small micro-100 stuff.
 
I use a Circle Industries .25" solid carbide bar with triangle inserts. If you buy them when MSC has them on sale, you can often times get the bar with 10 inserts for around $90. Buy them off sale and they are expensive. I use a Dorian BXA holder with a 5 C collet to hold the boring bar. It works well.
 
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Has anyone ever tried a carbide ball nose end mill for boring? Have the tool slightly angled so only the end near nose cuts. I have done it but not on a chamber. Seemed to work OK.
 
J. Pendergraft said:
Has anyone ever tried a carbide ball nose end mill for boring? Have the tool slightly angled so only the end near nose cuts. I have done it but not on a chamber. Seemed to work OK.
Click to expand...

I have used end mills for boring applications, it seems to work just fine for 1 offs or low volume. When you start to get into any quantity it can exhibit erratic wear or chipping of the cutting edges, that's when I prefer a quality indexable boring bar.
 
Carbide boring bars..

You might look at Thin Bit Tooling. Sit down before you look at their prices. I have several of their boring bars. I bought a shoe box sized order is it was well over $1,200.00 But exceptional tooling.

Nat Lambeth
 
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