Advice on carbide insert boring bar

[mike-sid]

I need to make a replacement part for a suppressor. (Yes It is registered with the  NFA, and Yes I have an FFL)  From time to time I get asked to do this from a customer, so I finally want to buy a carbide insert boring bar for the task.  I currently have an Ultradex 1/2" x 6" (S08M SCLCR3) that used CCGT type inserts. This tool is too big to make the cut I need.  The part I'm making is .91" in dia  with a .25" hole in the center.  Now I need to boar out a 60 deg taper cut inside making a cone.  I can start by opening up the center hole, but when I get to the inside of the taper my tool is too big.     I'm thinking a 3/8" boring bar might do the trick but there are so many to choose from. Any thoughts?

[EdK]

Grind one from HSS.

But if you want to stick with insert tooling I'd suggest this one.

http://www.maritool.com/p380/SOLID-STEEL..._info.html

Ed

[mike-sid]

(01-15-2015, 06:46 PM)EdK Wrote: Grind one from HSS.  

I suppose I can grind one until I figure out which one to buy

(01-15-2015, 06:46 PM)EdK Wrote: But if you want to stick with insert tooling I'd suggest this one.

http://www.maritool.com/p380/SOLID-STEEL..._info.html

Ed

    Thanks, I really love carbide inserts  ever since PixMan showed me the light  

[EdK]

Maritool makes good stuff at a decent price.

Ed

[Mayhem]

I've had no issues with the toolmex holders that I have picked up in the US. If you already have CC_T inserts, I'd get a boring bar to take them. You will want to use an insert with a small radius to reduce cutting forces and reduce chatter.

The only problem I see here is that the ones I just looked at in my Toolmex catalog and also the one that Ed linked to is that the minimum bore size is more than you have specified. However, given the taper you may get away with it. I know I squeezed my 16mm bar into some tight places.

Could you open the hole up a bit more at the front? that would give you more room and it is metal you are going to have to remove anyway. Drilling is much faster then boring!

[PixMan]

I don't see how a 3/8" bar is going to be able to get all the way down to a 1/4" hole.

Minimum bore diameter for most 3/8" bars will be around .410".

With a 3/8" bar you would have to go to the smaller CCxT21.5x size insert anyhow, so consider going to the CPxT1.81.51 size or smaller CPxT1.51.21. The smaller the insert, the smaller the boring bar can be, the smaller the minimum bore.

If it's not more than an inch & half or so deep, I just use Micro 100 solid carbide boring bars. They rock!

[Highpower]

(01-16-2015, 08:30 AM)PixMan Wrote: If it's not more than an inch & half or so deep, I just use Micro 100 solid carbide boring bars. They rock!

+1

[EdK]

(01-16-2015, 08:30 AM)PixMan Wrote: ...
If it's not more than an inch & half or so deep, I just use Micro 100 solid carbide boring bars. They rock!

+2

You can find them on eBay at reasonable prices.

Ed

[mike-sid]

(01-16-2015, 08:30 AM)PixMan Wrote: I don't see how a 3/8" bar is going to be able to get all the way down to a 1/4" hole.

Minimum bore diameter for most 3/8" bars will be around .410".

With a 3/8" bar you would have to go to the smaller CCxT21.5x size insert anyhow, so consider going to the CPxT1.81.51 size or smaller CPxT1.51.21. The smaller the insert, the smaller the boring bar can be, the smaller the minimum bore.

 You are so right Ken    The scary part for me, is that I understand the insert designations you are referring to.  Before we met I was clueless.  Today.....well I'm still clueless but I have a good understanding of carbide inserts.

(01-16-2015, 08:30 AM)PixMan Wrote: If it's not more than an inch & half or so deep, I just use Micro 100 solid carbide boring bars. They rock!

(01-16-2015, 10:31 AM)Highpower Wrote:

(01-16-2015, 08:30 AM)PixMan Wrote: If it's not more than an inch & half or so deep, I just use Micro 100 solid carbide boring bars. They rock!

+1

(01-16-2015, 12:19 PM)EdK Wrote:

(01-16-2015, 08:30 AM)PixMan Wrote: ...
If it's not more than an inch & half or so deep, I just use Micro 100 solid carbide boring bars. They rock!

+2

You can find them on eBay at reasonable prices.

Ed

 Well then off to Ebay to buy a Micro 100 solid carbide boring bar.  

Here is my clueless part again......Can I sharpen the Micro 100 boring bar? or hone the edge if it becomes necessary?
  I'm using 6160 AL.  I might have to step up my speed, time to do some math

Thanks to all!

[EdK]

Yes, a diamond hone works well on carbide. I have some of these that come in different grits.

http://www.amazon.com/EZE-LAP-PAK-Color-...12ZNEWM7ZH

Ed