[hst]

Gentlemen:

I am have been at this for a while but the wall is not getting any softer.

I am trying to machine the highlited areas in the attached image, but am unable to devise a boundary that will limit the tool path to these areas. The rings are fixtured on posts in the orientation shown. The horizontal surfaces are finished and the part is clamped by a cap that covers the horizontal surface of the ring, so I need a tool path that will only cut the sides, and not top surfaces or the ID.

The parts will be machined down to the equator and then flipped over for the second side.

Any help would be much appreciated.


Glenn

[jrmach]

Looks like you have a very slight spherical radius along the sides?
If that is the case you only can machine 1/2 way down then you will have to flip part and do again.
Have you tried machining without a boundary and using top of job setting to limit to just the sides?
another thing is dont use your solid model to define your stock,,draw your actual stock before it is machined

[hst]

JR:

Thank you for your help. Yes, the hoop is radiused and will have to be machined from each side.

I am using the stock wizard square block as the stock. Mayhaps if I used a solid machined to this point as the stock it will help. I will try it.

I will also try it sans boundaries, path limited by top and bottom as you suggest. That upper surface is at Z .375. Your idea brings to mind that if I set the top to .374" perhaps the tool path would no longer insist on going over the top.

Thanks again for your time. It is much appreciated.

Glenn

[jrmach]

When defining Stock in the stock Wizard,nothing wrong with using a square block,But,try drawing a 2d wire frame above only the area you will be cutting,,,do not draw over the base

If you need a hand you can pm me

[Superman]

Just a quick side question...( I hate to be a spoiler)
.... how is the scope going to be clamped ?
normally the ring is split

[hst]

SM:

Damn, I knew I forgot something...

I work predominately on late 19th century British sporting rifles. Back then the usual technique was to disassemble the scope, solder the tube into the rings, re-black (blue) and reassemble the scope. There were no unsightly ocular or objective bells then. This is for some custom work along those lines and will use an old fixed Lyman Alaskan as the basis of the scope.


Glenn

[Superman]

SM:

Damn, I knew I forgot something...

I work predominately on late 19th century British sporting rifles. Back then the usual technique was to disassemble the scope, solder the tube into the rings, re-black (blue) and reassemble the scope. There were no unsightly ocular or objective bells then. This is for some custom work along those lines and will use an old fixed Lyman Alaskan as the basis of the scope.
Glenn

I'm glad there was a reason....

... now my suggestion... probably an alternative using machines unavailable to you.
-lathe .... turn it like a towball... hold onto excess stock
-mill + 4th axis .... mill flats & m/c bore, dovetail clamp area
-saw .... cutoff excess and mill saw face to size.

[BurrMan]

I'm glad there was a reason....

... now my suggestion... probably an alternative using machines unavailable to you.
-lathe .... turn it like a towball... hold onto excess stock
-mill + 4th axis .... mill flats & m/c bore, dovetail clamp area
-saw .... cutoff excess and mill saw face to size.

Hey superman,
I have a question. Nothing to add to the op, and coming with a caveat that i have never done this nor know anything about it...

My mind says the holes are the most important part. The outside is esthetics and can be variable.

I like the lathe idea. Wouldbt a guy want to do the hole first, possibly in 1 shot through enough for both pieces, to make a set, then do all the exterior as secondary ops.

I guess you would have to have something that holds the piece by the hole?

Anyway, just wondering about thoughts along those lines.

[jrmach]

Hey Burr,absolutely a good plan
Then make a mandrel and the rest is pretty straight forward
the hole also is the best Datum point for all other dimensions to come from

[Superman]

Hey Burr,absolutely a good plan
Then make a mandrel and the rest is pretty straight forward
the hole also is the best Datum point for all other dimensions to come from

In theory probably OK... but looking deeper at his model..
.. turning a ball may not be a feasible method.... wrong shape to suit his ring.... ( oh boy, does that sound so bad )

I'm still leaning to a single setup for milling on a machine that has a 4th (rotary) axis
you would need to remove excess material before finishing any feature, so to avoid any material stresses moving finished features during any rough machining.

1. face all 4 faces
2. rough large hole
3. 3D rough radius form around hole ... then finish those.surfaces
4. finish bore
5. surface finish features for dovetail plates
6. drill & tap holes
7. m/c base face that rests on breech
8. saw off excess
9. manual mill... dress saw excess to be under the faces done at #7