Variable pitch rotary (nice video)

[mostagear]

I want to share this video.

http://www.youtube.com/watch?v=Th97I...eature=channel


i wonder what's the easiest way to make such workpiece (with variable pitch).

i tried doing similar work,i used simple hand written program. it was ok. but the pitch was fixed.

in general, 'm using edgecam for rotary works. but for screw like, i make it manually.

[jabezkin]

Video? I don't see no stinkin' video.

[mostagear]

sorry,

link added

[jabezkin]

Originally Posted by mostagear

sorry,

link added

Yippee!!!!!!!!!

Nice video, thanks.

[HuFlungDung]

That sure is a growly old indexer

I wonder if that is a variable pitch helix, or is it two constant lead helices, one with a longer lead than the other one? The fact that the land between the two grows uniformly wider along the length is what makes me think this might be the case.

[John Welden]

The trick is to hold a 2x4 against the part.

[Ghost]

Anyone know what the deal is with that piece of wood?

[HuFlungDung]

Originally Posted by Ghost

Anyone know what the deal is with that piece of wood?

What wood? Oh, you mean the backlash elimination device?

[mostagear]

Originally Posted by Ghost

Anyone know what the deal is with that piece of wood?

i think that piece of wood is for damping, to avoid workpiece vibration while cutting

[spork2367]

We cut pieces like that all the time. They are typically used in the bread making industry to feed dough. (although I'm sure there are a million other uses) We run ours the same way (minus the 2x4). I think he is wedging the 2x4 underneath to keep it from flexing. We have the same problem only worse since the screws we run are 6-8 ft. long. We made special trays that go underneath with screw jack adjusters. I'm going to suggest for time savings though that we switch to the 2x4 method. Maybe a 2x6 for our larger items.

[scudzuki]

Looks like a screw for an extruder.
The wood is to dampen harmonics probably.
Joe

[mostagear]

Originally Posted by spork2367

We cut pieces like that all the time. They are typically used in the bread making industry to feed dough. (although I'm sure there are a million other uses) We run ours the same way (minus the 2x4). I think he is wedging the 2x4 underneath to keep it from flexing. We have the same problem only worse since the screws we run are 6-8 ft. long. We made special trays that go underneath with screw jack adjusters. I'm going to suggest for time savings though that we switch to the 2x4 method. Maybe a 2x6 for our larger items.

thanks spork2367

but what the 2x4 method refers to , as well as 2x6??

what software do you use?

[spork2367]

Originally Posted by mostagear

thanks spork2367

but what the 2x4 method refers to , as well as 2x6??

what software do you use?

I was joking about the 2x4 and 2x6. He was likely using the wood to stop the piece from flexing down. We use a custom made tray with adjustable screw jacks to support the bottom of the part. Ours were programmed in mastercam and run on an old Fadal.

[curtrnev]

Maybe the wood burnishes the edge?

[bryan_machine]

mostagear - 2x4 and 2x6 are standard (in inches) dimensions for lumber in the US. Our houses, for example, are framed with 2x4's and 2x6's...

I imagine in Egypt you buy wood sized in metric units....

[gatz]

Agree about the combined different pitches as opposed to "variable" pitch.

That's certainly not a 2x4...more like a 1 x 4 (3/4 x 3 1/2) or thinner, could be a slat from a pallet.

Don't know what other countries use for "standard" finished dimensions of wood products.....
U.S. system may seem very strange to others.......along with most everything else we've standardized.

My guess is that the wood is used to eliminate or reduce chatter. Can't see that large a diameter for given length material flexing enough to cause problems; although spork2367 has a somewhat different scenario and, as he said, would serve to avoid flexing.