Milling a spiral?

I need to cut a 7 mm diameter spiral flute for 5" in the center a 10" long piece of 4" round 5086 aluminum. The pitch is 3/inch. I did something similar in delrin last year by grinding a piece of tool stock and turning the piece by hand in the lathe but that is not going to work with aluminum. (A picture of what I did with the delrin is on this page about 1/3 down on the right:)

formatting link
I am thinking that the only way will be with a ball end mill. Mounting the piece in a chuck geared to the table feed. What I need now is to see an example of the gearing mechanism to drive the chuck. I can get the right ratio using some of the lathe change gears but how do I mount them?

Or is there a simpler way?

Reply to
Glenn Ashmore
Loading thread data ...

I would mount in in a mill in a dividing head. Use a 7mm ball endmill. Calculate how much to advance mill table for every 5 degrees of rotation & plunge to a set depth.

Reply to
Wwj2110

This is a piece of cake with my CNC mill with fourth axis. You might just farm it out. I'd be glad to do it if you can wait till harvest is over.

I have seen where someone has taken the whole change gear assembly out of a lathe and mounted it to the X axis screw and to the indexing head drive. There was a really nicely built one on Ebay last winter. You'd need a pile of change gears to do this if you don't find one already done. Do a search for Spiral milling.

Karl

Reply to
Karl Townsend

I've seen setups like this in photos, using a horizontal milling machine like the one I have. There's a drive shaft geared to the spindle, that operates a dividing head.

The part is mounted between centers on the dividing head.

The Hardinge dividing head comes in a flavor with the external drive shaft that pokes out of the housing for this - although mine does not have this.

But the theory you have about how this was done before NC machines is correct. I suspect you could (as another poster suggested) adapt an existing geared dividing head to run via some change gears that drive off the spindle.

If you had that setup, it would probably take about three minutes to make the cut.

Jim

================================================== please reply to: JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com ==================================================

Reply to
jim rozen

I may be confused about what you want to achieve, but could you mount a router on the cross slide of your lathe and turn the lathe by hand.. Obviously you would need to make multiple light cuts and wear a face shield. At least you are not trying to machine stainless steel. Dan

Reply to
Dan Caster

What I need now is to

Glenn,

The "Practical Treatise on Milling and Milling Machines" by B&S has a chapter on this. It involves the use of a helical milling attachment which looks like a dividing head driven by a gear on the X-feed crank. Might be a use for one of the HF minilathes- mount the lathe on the milling table and drive the spindle from the X-feed leadscrew. Atlas made a set of centers to do this kind of thing with their horizontal miller. I can take a picture of mine if it would do you any good.

Kevin Gallimore

Reply to
axolotl

On 21 Sep 2003 12:44:19 -0700, Pete Logghe wrote in Msg.

So what's "almost" about that?

--Daniel

Reply to
Daniel Haude

Glenn Ashmore scribed in :

in the lathe, with a router (or electric drill if you are desperate) mounted on the crossslide to cut the groove using the ball end mill. set up the lathe feed gears for what you need, but since this is a fast pitch, fit a handle to the leadscrew and turn that by hand, since here the leadscrew will turn a fair bit faster than the spindle.

mist kerosene on the cutter if you can.... I dab on with a paint brush but mist might be better.

swarf, steam and wind

-- David Forsyth -:- the email address is real /"\

formatting link
\ / ASCII Ribbon campaign against HTML E-Mail > - - - - - - -> X If you receive email saying "Send this to everyone you know," / \ PLEASE pretend you don't know me.

Reply to
DejaVU

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.