Gunsmithing work holding while fluting

[hero's machine]

I guess I need to give the fluting a try. I have a 9x42 vert mill to work with and I currently have a 14" yuasu rotary table. I am a bit nervous on using this table for two reasons:
It weighs about 250# and would sit at the very end of the table.
It's c line is 8" or so above table, making it difficult to add rigid support and I feel it adds potential torque on the table....although I don't anticipate anything but light cuts.

I like that it has a mt4 so I can get a 4 jaw easy. Getting a tailstock up to 8" c line is gonna take some fab work, but that does not bother me.

Or......I could go to an 8" ish rotab and tail from enco/griz/etc.

Or.....I could do the same with a dividing head. I like the simplicity or plates, but the dividing head means I am driving with a dog, or hunting for a bs taper chuck.

The dividing head and small rotab look like a rotating dead center might be out of the question. I have never touched one.

Soooo, those who have been here, what would you do or not do.

Thanks.

 

[colchester]

Re: work holding while fluting

Heres an alternative approach. If you wanted 6 flutes you could take a piece of hex stock bore it so it could be affixed to one end of the barrel and use a vise to hold that end. You can use your dividing head to make multi sided adapters to correspond to the # of flutes desired. Use the center in the end opposite the vise. Depending on how you plan to present the tool for milling would influence how best to stabilize the center of the barrel. I like a stub arbor with a horizontal style milling cutter or a right angle head and a horizontal arbor as opposed to a ball style end mill

 

[swd]

Re: work holding while fluting

We use a spin/index fixture with a center on the other end. You need to support the barrel in the middle to keep chatter down. I normaly do a light cut and then rotate to the next flute to induce as little stress as possible. A radius side cutter seems slightly faster than a ball end mill. Hope you have power feed, it takes forever and is like watching paint dry.

 

[LRI]

Re: work holding while fluting

Go buy a 5C collet holder from Enco that has six sides. Cost you about $15 bucks for an import. Clamp whichever end you want in the collet, set up a stop, fixture the opposite side, and have at it.

If possible, put a backrest or clamping device in the middle of the barrel to reduce the "flyrod" effect while cutting.

IMHO its better to use a key style cutter as it'll develop some surface speed rather than a ball endmill. No matter how fast you spin a ball, the center is going to essentially remain motionless. It won't cut, it'll bubblegum its way through the material. I guess you could rotate your head so that it's dragging the center of the tool behind itself, that'd help, but its easier just to use a side mill with a radius.

For the record: Machining/cutting/removing material from a piece of stock (any stock) does not induce stress.

It relieves it (stress).

Good luck.

C.

 

[hero's machine]

Re: work holding while fluting

I was always gunshy of the spindexers as they look way too light.

I have the cutter issue under cotrol, ab will build what ever I want.

thanks.

 

[apache308]

Re: work holding while fluting

Here are a few pics of my fluting set up. I use a Phase II 6" Super Spacer, a small but beefy adjustable tailstock, a couple of "tower braces", and a centerpiece that keeps the set up rigid and eliminates any chatter. I use PTG and other cutters for .187", .250" and .312" flutes. A Trico Microdrop mist coolant system keeps everything nice and cool. Servo 150 powerfeed, Newall Sapphire DRO.

IMHO, the key is having a reliable and repeatable set up that is quick, easy, and rigid. There are multiple ways of setting up for fluting, this one works for me and produces great looking flutes.


Setting up on the mill table:

Centerpiece:

27" Barrel in process:

Another view:

Making chips:

 

[LRI]

Re: work holding while fluting

Very nice setup /\ /\ /\

Clever fixturing for the middle support!

 

[300sniper]

Re: work holding while fluting

i have the feeling i have said this before in another thread but that's some damn fine machine work apache!

 

[colchester]

Re: work holding while fluting

Apache did the worklight come with the mill it or did you purchase it and add it on. I have one just like it on my lathe and love it just havent been able to find another like it.Props on the very cool center support fixtures. Do you use carbide tipped cutters or HSS

 

[apache308]

Re: work holding while fluting

Thanks guys.....coming from y'all that is a compliment indeed. I long for CNC but still have to pay for another semester of daughter's college, upcoming wedding, and knock the mortgage down a little more. Getting closer. Someday.

I bought the mill used from a small shop that folded up back in 2008 and it came with the light. Not sure of the brand. I use an Electrix on my lathe and it is a good piece. Carbide. PTG and AB cutters.

 

[hero's machine]

Re: work holding while fluting

thanks. I think i am gonna go with the dividing head. I found that I can get a chuck for it for a fair price here in town....and I can use it for some other widgets. I was out slumming today and came across a used inspection outfit that has a few fixtures just like what you have there. I made an offer on it so I will see if it saves me the work...lol. I picked up a stash of plastic to build some additional stuff. now if I could get a half rack of spare time.....I might get somewhere.

thanks!

 

[hero's machine]

Re: work holding while fluting

btw, is that a 38spl flow controller?

 

[apache308]

Re: work holding while fluting

38 spl? Oh...I see it now. No it is the mist nozzle. From that angle it does look like a 38 case. The dividing head should work fine. Multiple roads to arrive at the same place. SR

 

[Keith Johns]

Re: work holding while fluting

Nice setup sir