[fc911c]

Is it possible to remove all or most of the backlash on a 8" Grizzley Rotary Table?

I plan on converting it to be a 4th axis on my CNC mill.

Thanks for the help

[rustyolddo]

Yes & no.

Backlash occurs or results at two places. The most common point is in the meshing of the gears. This is adjustable, the problem that you'l probably encounter is that the gears are not concentric. When you get the least backlash, you may find that the gears bind at another point of rotation.

Secondly, the worm backlash will have to be adjusted a little loose to allow it to turn freely. With 0 backlash on the worm and no thrust bearings, it will bind and you'll have difficulty driving it. Backlash in the worm adds to the backlash in the table.

All that said, you can make a rotary table into a 4 axis, it just takes a little modification to make it work.

[fc911c]

Thank you for the great explenation. I guess I will open it up and take a look.

Is it possible to install a thurst on the worm?

Thanks
Frank

[Clementvs]

Hello fc911c,

I beleive that you found a solution already. But I do answer for people that may have the same question kind.

There are way to adjust backlash to zero or very close if you rather have a bit loose. Therefore you may need to change your worm gear. I would recommend either a duplex system or a 2 half worms and worm wheel.

http://www.allytech.eu/index_fichier...dwormwheel.htm

Rustyoldo is perfectly right regarding "a little loose to allow it to turn freely" but there is 2 other options, that will only work on the 2 half worm concept :
-OTT- MATIC which allow this "loose" to be dynamically adjusted, so you allow a high gap for fast moves and a low gap for precise moves.

-the 2 half worm concept may have multiple starts worms, this allow high fast moves because the lead is bigger. therefore you don't have to adjust backlash dynamically anymore.

I know a company that can define, provide this concept and even adapt it onto your own existing rotary table. They may have other solutions too. their webpage isn't really but at least you can have contact info.

http://www.allytech.eu/index_fichiers/services.htm

Hope this help

[motorcon]

It is possible to eliminate backlash completely by using direct drive rotary tables. Visit http://www.intellidrives.com/direct-...y-c-28_34.html
to see many available models