What boring bar

[WSnyder]

Thanks for the reply.
The boring bars that I have are to big.

Hal

For small chambers people have been using various Micro 100’s for a long time. If you’d like I can look in the morning as to which particular part number I’m using for a PPC. It will most likely work for .223 and if not I guarantee they make one that will.

 

[Scott-ak]

Micro 100

 

[INTJ]

What diameter as depth do you like to bore? Is there a percent of case diameter and length that is a good rule of thumb?

 

[Hal]

For small chambers people have been using various Micro 100’s for a long time. If you’d like I can look in the morning as to which particular part number I’m using for a PPC. It will most likely work for .223 and if not I guarantee they make one that will.

Thanks that would be great.

Hal

 

[sfinn1]

What do you use to hold your small boring bars?

 

[LVLAaron]

What do you use to hold your small boring bars?

Micro 100 makes a holder. But you have a lathe, make your own shank. It's a good little project in precision.

 

[WSnyder]

Thanks that would be great.

Hal

What do you use to hold your small boring bars?

Micro 100 BB-1801500
I hold it in an AXA2 (BXA2 on the larger lathe) toolholder. The 2 has a groove to index and hold round bars. The Micro 100 bar has a flat on top so it indexes the cutting edge at the proper angle. Easy peasy

 

[Bamban]

Bought a couple (L and R) of the carbide boring bars on Practical Machinist forum along with a partial box of inserts. I have yet to wear out a single insert.

 

[tobnpr]

What do you use to hold your small boring bars?

Type 202 holder- which can be used for anything including boring bars. I don't see a reason to complicate it.

Boring Turning and Facing Holder #2 Type 202 BXA

www.shars.com

 

[Dusty Stevens]

@WSnyder
Dont get drawn in

 

[Dusty Stevens]

Doesnt make much sense now that the post was deleted @WSnyder

 

[VA_XTC_Shooter]

That's why I mentioned using "GT" style polished inserts. They are sharp as a cats claw and provide a beautiful finish. They cut easier than HSS.

View attachment 1361098

What are GT inserts?

 

[LVLAaron]

You'd have to look up the nomenclature for carbide inserts... it's quite complex. Short version is, they're for aluminum. They are polished and sharp as a tack with a high rake angle.

So, at low/medium speed and a low feedrate they cut stainless and leave a beautiful finish.... and they're cheap. Even no name Chinese inserts of this style cut well.

 

[Bamban]

You'd have to look up the nomenclature for carbide inserts... it's quite complex. Short version is, they're for aluminum. They are polished and sharp as a tack with a high rake angle.

So, at low/medium speed and a low feedrate they cut stainless and leave a beautiful finish.... and they're cheap. Even no name Chinese inserts of this style cut well.

Except for the boring bar, all inserts I use are for aluminum from WNMG, DCGT, VCGT, CCGT, TNMG and 16ER AG60. I can afford to sacrifice longevity at the price point.

When I acquired my machines in 2015 while @butchlambert was coaching me how to chamber I was also experimenting with different inserts with different coatings, spent a few bucks buying big name brand stuff till I settled on inserts for aluminum and never looked back.

 

[LVLAaron]

Except for the boring bar, all inserts I use are for aluminum from WNMG, DCGT, VCGT, CCGT, TNMG and 16ER AG60. I can afford to sacrifice longevity at the price point.

When I acquired my machines in 2015 while @butchlambert was coaching me how to chamber I was also experimenting with different inserts with different coatings, spent a few bucks buying big name brand stuff till I settled on inserts for aluminum and never looked back.

View attachment 1361749

Smart man. The inserts we "should" be using really need high rpm and a lot of feed pressure. If you can give them that they work great. I have some Kennametal KC5010 inserts that cut like absolute shit unless you're turning a barrel 1000 RPM with at least a 30 thou cut. The finish is like glass... but that's not quite how we want to do this type of work

I too, like Korloy! Or Mitsubishi

 

[DaveTooley]

Smart man. The inserts we "should" be using really need high rpm and a lot of feed pressure. If you can give them that they work great. I have some Kennametal KC5010 inserts that cut like absolute shit unless you're turning a barrel 1000 RPM with at least a 30 thou cut. The finish is like glass... but that's not quite how we want to do this type of work

I too, like Korloy! Or Mitsubishi

Speak for yourself. I run 325 SFM .040" deep and a feed rate .006". Maybe a bit more on the feed rate to get a chip instead of spaghetti.

 

[LVLAaron]

Speak for yourself. I run 325 SFM .040" deep and a feed rate .006". Maybe a bit more on the feed rate to get a chip instead of spaghetti.

What kind of inserts?

 

[DaveTooley]

Korloy VNMG431 PC300
14 years ago I snagged 40 of them off E-bay for $40 delivered. I have one left.
Remember I have 7HP and rigid machine. Spindle load is still under 50%

 

[WSnyder]

Most all of the carbide I use was recommended by a gunsmith that came before me or from my local tooling rep. The Circle was recommended by Mike Bryant. The Kennametal came from Bill Myers who had a friend that worked for Kennametal and they sourced those inserts for Bill's work on his rimfire actions. They cut beautifully. I use them for truing actions and bolt lugs. The larger Circle bar works just as well for truing actions. The Iscar WPEX came from SpeedyG. They also cut beautifully. Note the IC908 grade. Speedy originally used plain carbide but those were discontinued. My rep then recommended the IC908 and I think they cut better than my original bare inserts. The lay-down Iscar threading inserts came from my tooling rep. He specified the IC908 grade for manual machines. All of this tooling has proven out over the years on manual machines. None of it takes high speeds or heavy loads to work.

I also have and use a bit of the Alu specific inserts, they work well.

EDIT: I just rmembered who and where I got these (Alu inserts) from. Curtis Payne Toolsource/latheinserts.com Curtis used to be a tool rep for a major manufacturer and knows his stuff. I believe he can or could provide TMX chucks and Titan taps at competitive pricing. I bought a fair amount of tooling in the past from him. I have several Korloy face mills from him that I run on manual mills. Good stuff!

https://www.latheinserts.com/main.sc

I've posted this elsewhere before but not much has changed:

Circle Industries QCBI-375-6-5R Carbide Boring Bar w/TPCH-2205-CG5 Inserts.

Circle Industries FCBI-250-4-5R Carbide Boring Bar w/TDAB-505-CG5 Inserts. Pre-boring chambers.

Kennametal E08SDUPR2 Carbide Boring Bar w/DPGT2151HP KC5010 Inserts. Sharp high positive insert.

Kennametal SDJCRF082D Turning Holder w/DCGT2151HP KC5010 Inserts. Sharp high positive insert.

Iscar SWAPR-1414-06 Turning Holder w/WPEX060402R08 IC908 Inserts. Honed, sharp.

Iscar SER0625H16 Threading Holder. IC908 grade.

 

[Bamban]

Speak for yourself. I run 325 SFM .040" deep and a feed rate .006". Maybe a bit more on the feed rate to get a chip instead of spaghetti.

Thanks, Dave.

At the right feed running 400 RPM with the WNMG Trigon I can make smoking hot 2 inch spring chips roughing 416. Scared of those of those long razor sharp stuff.