Ball Mill Bit

[svrfsvp]

I need to cut some curves in the z axis that will have a large radius, and have been wondering what bit might best accomplish this. Ultimately I will want to cut spherical section shapes, and I need to find a source for bits that will handle such cuts - I was thinking that a large diameter ball mill bit would do the trick - does anyone have experience with those, and know of a source for them?

[ramdesgn@juno.com]

I have available 3/8" and 1/2" dia spiral flute end mills, ball or fillet radius, with flute lengths in excess of 1.50"( some are up to 3" long flutes) that are "reground" to like new sharpness. They originally were used in the aircraft industry but no longer meet the tight tolerrances of that industry's specification but for the wood workers there is no problem. Either size I sell at $4.oo each with a minimum of 4 per order. For your first order I pay the postage. Subsequent orders is an adder of 20% for postage.

e-mail or call 918-342-4051 (FAX @ 918-342-4391)

[Ron B]

Corebox and roundnose carbide tipped router bits are available from a variety of sources. A better discription of the cut might help. I had some 'custom' profile bits made from dull bits last year at the reasonable price of $35 for the first bit and $12 each thereafter.

Ron

[svrfsvp]

The cuts I am trying to make are a series of cuts that are linear in the x and y axes, with a shallow s shaped curve in z - the radius of the curves is probably 4 or 5 feet - very small changes in value over a relatively long distance in x. A core box may do the trick, but I was wondering if a large diameter ball mill would be better suited to making such cuts - like the curves themselves, perhaps a wide shallow bit would be the best bet. Does anyone have experience making this sort of shape?

[dale]

svrfsvp:
What I would do is to draw the surface I would like to cut in Mastercam. Mastercam has the capability of drawing and programming 3D surfaces. I can then run the G-code converter to get a sbp file. I would need to know what the geometry was like but if you could send me a drawing in dxf I could give it a try. I normally use 1/2" solid carbide end mills. Both flat bottom and ball end. I stay away from HSS end mills. Even if they have been reground a standard router runs at too high a speed. You will burn it up on the first cut. Most hardwoods should be cut at between 900-1200 sfm with HSS. this would give an rpm of 6840-9120 for a 1/2" cutter. most routers cannot be run that slow.
If you like, send me an idea of what you want and I will send you a sbp file.
Dale

[Ron B]

svrfsvp:

Depending on how much of this you are doing, you are going to have to decide how much 'cleanup' you will need and what width cuts you need.

From what I get, you will want a bit with an almost flat, but not quite flat bottom. Hinge mortising bits with a relief cut might do the trick. Also, you never said the depth you were needing to cut.

Like Dale was saying, it is dificult to advise on little information.

Ron

[cmrtom@worldnet.att.net]

I have just had a series of cutter bits fabricated for use with low density materials. They are balls....2in and 3 in in diameter. 1/2 inch shanks. They look like a porcupine made of 3/16 tungsten carbide quills....works fantastic on bead board for quick material removal

tom

[gacox!bc.cc.ca.us]

While cutting letters on my Shopbot the x and y movements are jerky when they change directions. Is this because of the speed? What speed should I use (for smaller letters)?

I'm new at this so pardon the rookie question!!!

[rgengrave@aol.com]

Gary when I cit small letters I set my cut speed to .25 _ .50 , I am not in a race to cut fast, this spped gives me nice clean cuts.

You can set your jog speed to 2.0, mine is set to 1.0, again I am not in a race for speed.

The speed settings above will work with any size material it you are cutting all the way thru.

Ron V