How do I make this cut?

[juliancrouch]

OK, so I have taken one machining class, but before I could complete the second half (second semester) I had to move away, and we never covered making a radius cut on a vertical mill.

This is the basic idea of what I want to cut:

So, this is just a guess, but would I use a non divided rotary table, use some hold downs to keep it in place, and then use that?

or should I just be asking if it can be done manually at all?

last, would my best bet be using round stock that I clean up on a lathe, and then mill the top half square-ish? Or would I be better off doing it all on a mill using square stock?

Thanks for the help!

julian

[RICHARD ZASTROW]

The center of the hole appears appears to have an offset from the external radius. You can use a rotary table to mill the outside radius, then offset the center of the table whatever distance the hole is offset from the outer radius. Then install the hole. There appears to be a thin wall between the arcs, so you may want to do it in reverse order, whichever way is less likely to deform the work piece. Or fill the hole, then cut the outer radius.

Or farm it out. lol

Dick Z

[under-dog]

Looks like a ring blank to me. Am I correct?

[juliancrouch]

Thanks for the help dick, I just wanted to make sure I was on the right track with the rotary table before I went out and bought one...

So then obviously depending on where I mount it to the table it changes the size of my arc. cool cool.

and yes underdog, it is a ring blank.

Oh yeah, and if anyone is still reading this, a end mill rougher is just to hog of material fast and then make it so your final cut has a nice finish? Just saw those, and well, never got a chance to use one of those either. Just trying to put it all together, as my teacher was very old school, not that being old school is bad, I kinda like it intimacy with the work

cheers fellas.

[under-dog]

I have been a jewelry Model maker for over 15 years. So I come from an old school background I would do it on a lathe and then cut the outer form more likely than not but you never know I might throw it on my CNC mill. I have been trying to use it whenever it seems logical or just to watch the thing go. It is still fun to watch for me.

Are you making it in wax, white metal or sterling as a master pattern/model or directly into your desired metal?


I believe thel make a wax blank very similar to that that you can slab off. Check Contenti, Gesswein or Rio


Edit: just looked it up on Contenti: http://www.contenti.com/products/casting/172-720.html

[juliancrouch]

haha, it's not going to be wax, but I definitely did reference my rio catalog in the process of making that template to make sure I had a roughly traditional cross section.

I will be making it out of stainless, don't know what grade yet, and maybe ti down the road once I get the process down etc. Oh yeah, and can cope with the waste.

In any event, I am at the folks house taking time off of school till around august and not having access to any tools is driving me crazy. So I am considering just starting up a jewelry business, using the business to buy a basic shop (lathe/mill) and sell enough stainless/ti rings at shows to (hopefully) pay for it by the time I go back to school and can use their more expansive facilities.

No doubt if I do it I will end up making the plethora of wax pieces I have been wanting to make so that as soon as I have access to a casting setup I can do em up, but for now it will just be stainless and ti.

[juliancrouch]

one more thing

instead of starting another post, do any of you guys have a favorite way of sealing metal from oxidation. I have heard of people using nail polish, but that just seams cheap. Was wondering if their was any sort of lacquer or clear coat anything that could be sprayed on a piece of metal to give it protection from tarnishing. Matt or gloss, just curious whats out there.

cheers

[under-dog]

one more thing

instead of starting another post, do any of you guys have a favorite way of sealing metal from oxidation. I have heard of people using nail polish, but that just seams cheap. Was wondering if their was any sort of lacquer or clear coat anything that could be sprayed on a piece of metal to give it protection from tarnishing. Matt or gloss, just curious whats out there.

cheers

We always used a laquer of some sort in production to seal off sterling and gold platings. Patinas as well will seal the surface but that is a specific look and not applicable to stailnless ....."I think"

Stainless might not need anything. One of the benefits of stainless is well....its stainless. Resists rusts and oxidations. Then again you will have to experiment and be the judge. I have not put this to the test just my assumption.

[juliancrouch]

I won't be using it on stainless, as it is as you said, stainless. I should have clarified, sorry. In any event, it would be for silver (non pure), brass, copper, and gold.

Sounds like you know of something?

[under-dog]

I won't be using it on stainless, as it is as you said, stainless. I should have clarified, sorry. In any event, it would be for silver (non pure), brass, copper, and gold.

Sounds like you know of something?

Is the plans for the master pattern to be stainless?

If so why?

Hard to carve, hard to ploish hard to solder to.

Or ar you planning on one offing these things on the mill?

[Mike Stevenson]

One way to make the part on a CNC:

1.) Make your blanks an oversized square that the part fits in.

2.) Hold the parts in a vise and cut the hole out.

3.) Make a fixture with a spud that the hole in the part fits on.

4.) Using a washer and a bolt hold the part on the fixture.

5.) Cut the outside contour of the part.

[juliancrouch]

Is the plans for the master pattern to be stainless? If so why?

Yes, for now I think the final product will be out of stainless and copper (it has some copper parts, hence the sealant question. Later on if it looks nice I may play with using ti for this shape ring (right now I have about 6 or so designs I am sitting on that deal with this basic ring style). However before I ever even get to the stainless I plan to practice it on a piece of AL, just to get used to cuts and machine, as this is one of the first projects when I get the new mill.

Hard to carve, hard to polish hard to solder to.

Yes it is all of these things, but for some reason I have always been attracted to the rugged/hardware look of stainless jewelry (rings and pendents), so while I have the time I thought I might make a line of it.

Or are you planning on one offing these things on the mill?

For now it may be one offing, if everything goes according to plan over the next few months I may do a "common" (if there was such a thing) run of sizes in it, and the others I mentioned.

So what lacquer did you use?

As for what you said Mike, I will be doing it manually, but, I kinda figured on that procedure for making it, but I like the idea of making a fixture just for bolting it to the table, that will be used.


Also, got one more fancy shmancy question for you guys, I know, when will it end, but is it blasphemy to square stock on a lathe, or more specifically can you part pieces off of square stock with a cut off tool? I have done it on wood lathes, but this is a whole different beast. For that matter, is it even safe/possible to turn any square piece down to a cylinder on a lathe?