Gunsmithing Barrel fluting after barrel is already finished... Like a factory barrel..

B

BenY 2013

Gunny Sergeant
Full Member
Minuteman
Jan 23, 2012
1,294
16
30
SW Arkansas
#1
So I am wanting my CZ 455 Varmint barrel fluted. My work and school both have Haas mills setup with a 4th axis and my boss/professor will not mind me using them. I also already have a Lilja barrel for the 455 if things were to go south. I want the flutes and got to thinking about just keeping the factory barrel and finding what kind of ammo it likes best.

I guess my question is, how many people have barrels fluted AFTER they are already turned down, chambered, fitted, etc.? I understand that IF done wrong accuracy can be thrown out the window. But that's why I'm not starting on the lilja barrel. Also I am almost 100% doing this just for the looks, might as well since it will be free to me. So any comments would be greatly appreciated.

fluting 10/22 barrel - YouTube
This is what I have in mind. I believe this video was done by a member here on the hide.

Ben
 
#2
Do it.

I took my AR barrel from a bull barrel to a .750 profile and fluted it with no change in accuracy. Also fluted another friends 700 factory hunting barrel on his ultra light 280 ackley and it shoots the same as before.
 
#5
Your not inducing stress. So don't even worry about it.

If you use TIALN coated tooling LEAVE THE COOLANT OFF! Failure to do so on steel and/or SS only results in dramatically reduced tooling life. TIALN works at/above 800 Celsius. (around 1400F) running coolant on a tool like this just induces thermal shock. You end up micro fracturing the coating and dramatically killing the usable life of the insert.

Seriously. leave it off. Try a test piece first if you like. Rip that biche at a .003" chip load and 900SFM and just get the hell out of the way. Use earplugs. It'll sound like a router if your doing it with a 3F tool. It's bad ass!

Modern tooling is nothing short of amazing. If your speeds/feeds are correct you have no reason not to expect bright/shiny surface finishes at 900SFM and beyond. I do it every day here on an early 1990's vintage Haas VF1. with a 3 flute tool! DRY!

Study your work holding options hard/heavy. (hint) It's not as simple as a 4th axis and a tail stock. You need a means of supporting the barrel without distorting it and without losing critical support due to an even flute count (180* from side your cutting on)

Good luck. If your setup correctly your barrel will be luke warm when it comes out of the machine. Chips will be a yellow/goldish tone and hot. The inserts put about 90% of the heat into the chips. About 8% goes into the tool itself and the residual is transfered to the part and lost to convection.

FEAR NOT!

Good luck.

C.



Another Tip:

Use of a local sub routine will make programming really simple. If you use a G10 command in conjuction with an L2P2 it'll (check your manual first though) automatically update the A offset you can just incrementally bounce around the barrel and cut as many flutes as you like. (assuming your barrel circumference and tool width will support it)

Don't make the mistake I did early on with entry/exit on tooling. I used to program a conservative entry in the effort to mitigate chatter. You want the opposite actually. Run that bugger in hard/fast so that it loads instantly and stays loaded. This will mitigate chatter in the flute start/end point.

M11 on the 4th if your doing a helix. It'll shut off the brake and allow the rotary to spool up instantly instead of pausing to unclamp the brake.

Good luck!
 
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#6
Wow thank you very much for all that information! It means alot that someone with your knowledge would take the time to help me out! I'm going to have to read it a few more times to say I've got it all! I am still not sure what kind of tooling I am going to be using, but I believe it will be a carbide tool. I'm still not sure about that tho! I will also look into additional way to support the barrel!

Thanks!
Ben
 
#7
BenY 2013 said:
Any advice on doing it? I'm gonna be running flood coolant on it to try and keep the temp down, but still a little curious as to what type of cutter would be best?

Ben
Click to expand...



Chad pretty much summed it up with this:

" Study your work holding options hard/heavy. (hint) It's not as simple as a 4th axis and a tail stock. You need a means of supporting the barrel without distorting it and without losing critical support due to an even flute count (180* from side your cutting on)"


Supporting the barrel through the length of the cut is key as with how you hold when you hit a flute. Other than that you should have er dicked. Have fun!
 
#11
Meh hem. . .

%
O9876(BARREL FLUTING MASTER)
G20
G00G17G40G49G80G90
T1M06
M11
G0 G90 G55 X.073 Y-2.3545 A0. S4200M3
G43H21Z0.
M97P9999L6
G28G91G0Z0.
T9M6
G55G90G0X0.Y-2.
M05
M30


N9999
G0 G90 G55 X.073 Y-2.3545 A0.
G43 H21 Z0.
G1 G41 D21 Y-1.3568 F42.0
G3 X-.5 Y-.7838 I-.573 J0.
G1 X-17.5527 Y-.8632 A200.
G3 X-18.123 Y-1.4362 I.0027 J-.573
G0 G40 Y-2.4385
G10L2P2G91A60.
G0 G90 G55 X.073 Y-2.3545 A0.
M99
%


A program like this should work for a Haas control. Make sure you run it WELL ABOVE the part first! For all my fluting ops I use the T1 pocket position with the H21 height callout. This is so that I don't have to keep touching off tools. (the G43 H21 callup is what I'm referencing)

You can set this however you'd like. Just know that if you don't alter the registry values accordingly something REALLY BAD could happen. Have your buddy who owns the machine look this over if your not familiar.

Also. The G3 values will likely need to be edited heavily. This is the arc move that enters/exits the part. The Y values will also need to change along with the X. This is merely intended as an example to show one possible way to format the program so that you don't have to write each segement individually.

Basically it's like this.

First part of the code just gets the tool to postion and spun up. The M97 is the local subroutine callup. P#### is the portion of the program where it looks for information. The information starts at N9999 (line number followed by the characters)

From here its the actual "meat" of the program that does the work. Then the L# is the number of times the program loops (repeats)

The G10 values update the G55 A axis values. The G91 does it incrementally. If you want six flutes, set the A value to 60. and the L value to 6. The flute index and loops need to reflect one another. (meaning if you wanted 7 flutes you'd be wrong if you went A60. and L7. You'd end up with 6 flutes on a 60* index with one flute cutting twice. It would need to read: A51.428 and L7 for it to work right)

Depending on the age of the machine, you may want to check the parameters of the 4th axis and ensure it's set to run at the diameter your cutting. It's not always straight forward. If I set it 1:1 (1.25 barrel 1.25 setting) the flutes have a tendency to over rotate at the exit. Meaning the X outruns the A a little bit. Going UP in OD SHOULD slow down the rotation and get everything synchronized properly. It's mathematically figured in the machine. How it works I don't know. What it actually ends up doing is slowing down the X axis a bit. This is why I have a G0 in conjunction with the G40. Normally this would be a G1G40. (just gets the tool away from the part quickly while shutting off the cutter compensation)

DSC_0033.jpg


Good luck!
 
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#12
Wow, that right there is like stumbling upon gold! You have no idea what that means! Thank you VERY much! I'll be sure to have my boss/professor look it over and see if he'll let me do it! I'll try and get pictures up once done! Thank you again!

Ben
 
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