1 degree indexing on a 4th axis (horizontal)

I would like some opinions on whole degree indexing on a horizontal with a 4th axis. Does it cover enough of the work (job shop) to justify it over a regular 3-axis with 90 degree indexing?

meowkat said:

I would like some opinions on whole degree indexing on a horizontal with a 4th axis. Does it cover enough of the work (job shop) to justify it over a regular 3-axis with 90 degree indexing?

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no ideal on cost. curvic gear every 1 degree has stronger clamp ability for roughing. many a rotary table will fault if moves .01 degree or .001 degree so same part needs to run at reduced feeds and speeds on a finer adjust rotary table usually depends how big the cutter. obviously rotary table only takes seconds to rotate. usually 3 sides at least done with same program. sometimes many parts setup on column or tombstone. some doing many dozens of parts at a time. programming can be more difficult. part loading unloading takes more time usually multiple pallets for one cnc so setup loading done while other pallet in cnc running program. pallets cost money too. automated pallet system with over 30 pallets can be very expensive
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some curvic gears have limited electronic adjust, obviously mechanical adjust more difficult for grid shift and center of index calibration.

DMF_TomB said:

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no ideal on cost. curvic gear every 1 degree has stronger clamp ability for roughing. many a rotary table will fault if moves .01 degree or .001 degree so same part needs to run at reduced feeds and speeds on a finer adjust rotary table usually depends how big the cutter. obviously rotary table only takes seconds to rotate. usually 3 sides at least done with same program. sometimes many parts setup on column or tombstone. some doing many dozens of parts at a time. programming can be more difficult. part loading unloading takes more time usually multiple pallets for one cnc so setup loading done while other pallet in cnc running program. pallets cost money too. automated pallet system with over 30 pallets can be very expensive
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some curvic gears have limited electronic adjust, obviously mechanical adjust more difficult for grid shift and center of index calibration.

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Wow, great post. Thanks!

usually pallets go to setup station where overhead hoist or crane is used. once parts get over 20 lbs and especially 40 lbs most not moving heavy parts without a hoist or crane. fixtures, columns and tombstones obviously can be heavy. even a big mill vise can be heavy
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usually crane or hoist in 1 to 10 ton range. some setups take minutes but others can take much more time (over a hour) usually done outside cnc while its doing other parts

There was a thread a short while back asking a similar thing (though it was 1 degree vs .001 degree indexing between horizontals)

Used HMC decisions, full 4th ?

Seems for most people, 1 degree is enough. It would be enough for me too. however, I have 3 horizontals with full 4ths (.001) and I love the fact that I can slap a fixture on there and not worry that it is indicated in within a degree. I can usually just bolt, set B to whatever random angle it is at, and go.

Occasionally there are parts with fractional degree features but they are relatively rare.


Edit: I am dumb and see you were asking 1 degree vs 90 degree indexing on a vertical mill. Apples to oranges.

Horizontals are great for the job shop, although they are more expensive and have more of a learning curve. But I consider them essential for what we do now. We run a lot of things on the horizontal that the company had run 10-20 years ago on verticals, with many improvements in cycle time and accuracy, etc.

For -operators- who may struggle with adjusting offsets on a vertical mill, I find it near impossible for some of them to understand how to adjust an offset on the horizontal. Too many sides? Too many things moving?

dandrummerman21 said:

There was a thread a short while back asking a similar thing (though it was 1 degree vs .001 degree indexing between horizontals)

Used HMC decisions, full 4th ?

Seems for most people, 1 degree is enough. It would be enough for me too. however, I have 3 horizontals with full 4ths (.001) and I love the fact that I can slap a fixture on there and not worry that it is indicated in within a degree. I can usually just bolt, set B to whatever random angle it is at, and go.

Occasionally there are parts with fractional degree features but they are relatively rare.


Edit: I am dumb and see you were asking 1 degree vs 90 degree indexing on a vertical mill. Apples to oranges.

Horizontals are great for the job shop, although they are more expensive and have more of a learning curve. But I consider them essential for what we do now. We run a lot of things on the horizontal that the company had run 10-20 years ago on verticals, with many improvements in cycle time and accuracy, etc.

For -operators- who may struggle with adjusting offsets on a vertical mill, I find it near impossible for some of them to understand how to adjust an offset on the horizontal. Too many sides? Too many things moving?

Click to expand...

I expect I will be adopting a used horizontal in the near future. It seems like you just get more for the money, horsepower and features-wise.

a rougher usually to nearest degree ok obviously depends on part design. many features not at 90 degree increments. but often at 45 degree for example
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a finisher sometimes recuts done at .001 degree increments, for example surface indicates .0005" error per 10". obviously mechanically adjusting part takes more time than editing program for 90.001 degree
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work offsets easier if CAD CAM program does most of it using common G55 on all sides. requires dynamic G55 that is as part table rotates the X, Y, Z offsets move Z can move to X for example and if not at exact 90 degree increments theirs math involves as number values change depending on degree rotation of B axis. old way if part has only 4 sides at 90 degree increments G55 used one side, G56, G57, G58 used other sides
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hard to describe but obviously work offset like G55 not all zeroes depends on part, fixture, etc, P offsets common to use for drilling hole depths of rough cast surfaces using probing, if not probed its more time consuming setting offsets. programming is much more complicated, complex parts can be impossible or very difficult to program manually, 99.9% is programmed using CAD CAM. takes a lot of training to learn programming
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restarts more complicated, obviously if restarting B axis table rotation important. crashing into wrong side of part fixture been known to happen of operator not paying attention.
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grid shift and center of table rotation requires checking or calibration. hard to describe but depending on tolerances depends how often checked. obviously if B axis off more than .002" per 20" it could be a problem. basically usually indicate front of pallet with indicator and see if parallel to X axis. curvic gear to nearest degree table fine rotation electronic adjust is limited, mechanical adjust much more time consuming. Z soft stroke limit used so CNC column does crash into table so electronic Z travel limits used. obviously cutter sticking out of spindle can still cause a crash into table/pallet/part/fixture. hard to describe
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obviously horizontal cnc can be more complicated to operate