Taper The Neck? - Or Not.

[richard37066]

Burt -

I've done a little lathe work many years ago but absolutely nothing on a miller. Have started to do some reading on millers and am a little intimidated by the volume of information I've run into. Nothing I can't handle but it WILL take a bunch of time.

Jumping wwaaaay ahead, how would you mill the "flare" on the end of the neck where it approaches the nut? Seems like it would be a real chore without some kind of CNC setup. Just curious.

My thanks.

Richard

[Bent]

Richard, you took the words outa my mouth! The straight flare like on a ZumSteel seems somewhat easier than the radii on say a Rains. All I know so far is with a manual mill it is all handwork...get real accurate on those cranks.

Burt, we are anxiously awaiting your reply!

[burt]

First I would draw it out to scale.
I would say that there are two radii on the Emmons type neck flare.
Once it has been drawn out, the centrepoints and the length of the radius will be the datums to work everything out, using Pythagoras, Tangent, and Sine calculations.

I would probably work it out in increments of 10 thou on the x axis, which would tell me how far to move the table in the y axis.

If I knew how to do it, the formula for the calculations could be put into a spreadsheet, thus making a long, tedious mathematics session quite quick and simple.

Then, after roughing the neck out as close as possible, I would finish it off by plunging the end mill on a Bridgeport type vertical miller, in the aforementioned increments.

Incidentally, a horizontal miller has its place, it is invaluable when making the roller nut housing

[burt]

I can write the formulas down for working out each incremental step, as long as you know how to use Tangent, Sine and Pythagoras you should be able to do the tedious mathematical labour

I recently had to produce a perfect bull-nose on the lathe, it took longer to do the calculations than to actually make the thing

[Ross Shafer]

Yo Bent,

I somehow missed your comments about cutting curves without CNC capability....yep, they're not so simple. I've got an 85 year old pal who's manual mill work is just plain amazing....I call him the human CNC...what he can do while tuning the x and y handles at the same time has always boggled my mind.

As I know you've seen on the Fulawka you tube bits...you can do some pretty complex curves using a hand cut pattern and a router table....not necessarily the safest way to cut aluminum, but its not too bad if you're careful and concentrate on what you're doing...the same as with wood. Wood's not a whole lot softer than aluminum when it goes flying into body parts.

[richard37066]

Burt -

I had composed a lengthy response to your concerns about having to do a zillion calculations in order to mill an arc. Somehow, the post did not take so here I am again.

Lucky for me since I had a belated brainstorm and decided to do a bit of searching on the 'net for something which came to mind near the end of my abortive post.

What about a "rotary table" for the miller? Looked them up on the net and they were as I had envisioned them. Clamp the piece to the table, turn the crank and you have a perfect arc! Yeh, I know - they can get a bit pricey for the larger variety but, if one is going to do a bunch of this kind of machining then they might very well be able to justify the price.

Anyone have any experience with such a device? Would they be difficult to use in the application being discussed? Could one cut an "ellipse" without too much hassle?

Inquiring minds with a bunch of questions would love to know.

Richard

[richard37066]

Burt -

Managed to answer my own question regarding one way to cut an ellipse.

See: http://www.rittercnc.com/metalworking/U ... 20514-.htm

The post is by "IGNORAMUS8727" with a link to the "perl script" that he's loaded on his laptop. It's still an incremental approach but, apparently, it works.

Ain't the 'net wunnerful?

Richard